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Tag: NASA OSIRIS-REx
From NASA OSIRIS-Rex : “NASA Asteroid Sampling Mission Renamed ‘OSIRIS-APEX’ for New Journey”
The former OSIRIS-REx spacecraft sets off on a journey to study asteroid Apophis and take advantage of the asteroid’s 2029 flyby of Earth, the likes of which hasn’t happened since the dawn of recorded history.
At the end of a long-haul road trip, it might be time to kick up your feet and rest awhile – especially if it was a seven-year, 4 billion-mile journey to bring Earth a sample of asteroid Bennu. But OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification and Security – Regolith Explorer), the NASA mission that accomplished this feat in September, is already well on its way (with a new name) to explore a new destination.
When OSIRIS-REx left Bennu in May 2021 with a sample aboard, its instruments were in great condition, and it still had a quarter of its fuel left. So instead of shutting down the spacecraft after it delivered the sample, the team proposed to dispatch it on a bonus mission to asteroid Apophis, with an expected arrival in April 2029. NASA agreed, and OSIRIS-APEX (Origins, Spectral Interpretation, Resource Identification, and Security – Apophis Explorer) was born.
A Rare Opportunity at Apophis
After considering several destinations (including Venus and various comets), NASA chose to send the spacecraft to Apophis, an “S-type” asteroid made of silicate materials and nickel-iron – a fair bit different than the carbon-rich, “C-type” Bennu.
The intrigue of Apophis is its exceptionally close approach of our planet on April 13, 2029. Although Apophis will not hit Earth during this encounter or in the foreseeable future, the pass in 2029 will bring the asteroid within 20,000 miles (32,000 kilometers) of the surface – closer than some satellites, and close enough that it could be visible to the naked eye in the Eastern Hemisphere.
Scientists estimate that asteroids of Apophis’ size, about 367 yards across (about 340 meters), come this close to Earth only once every 7,500 years.
These images of asteroid Apophis were recorded in March 2021 by radio antennas at the Deep Space Network’s Goldstone complex in California and the Green Bank Telescope in West Virginia. The asteroid was 10.6 million miles (17 million kilometers) away, and each pixel has a resolution of 127 feet (38.75 meters). Credit: NASA/JPL-Caltech and NSF/AUI/GBO
“OSIRIS-APEX will study Apophis immediately after such a pass, allowing us to see how its surface changes by interacting with Earth’s gravity,” said Amy Simon, the mission’s project scientist based at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
Apophis’ close encounter with Earth will change the asteroid’s orbit and the length of its 30.6-hour day. The encounter also may cause quakes and landslides on the asteroid’s surface that could churn up material and uncover what lies beneath.
“The close approach is a great natural experiment,” said Dani Mendoza DellaGiustina, principal investigator for OSIRIS-APEX at the University of Arizona in Tucson. “We know that tidal forces and the accumulation of rubble pile material are foundational processes that could play a role in planet formation. They could inform how we got from debris in the early solar system to full-blown planets.”
Apophis represents more than just the opportunity to learn more about how solar systems and planets form: As it happens, most of the known potentially hazardous asteroids (those whose orbits come within 4.6 million miles of Earth) are also S-types. What the team learns about Apophis can inform planetary defense research, a top priority for NASA.
OSIRIS-APEX: Travel Itinerary
By April 2, 2029 – around two weeks before Apophis’ close encounter with Earth – OSIRIS-APEX’s cameras will begin taking images of the asteroid as the spacecraft catches up to it. Apophis will also be closely observed by Earth-based telescopes during this time. But in the hours after the close encounter, Apophis will appear too near the Sun in the sky to be observed by ground-based optical telescopes. This means any changes triggered by the close encounter will be best detected by the spacecraft.
Animation of Asteroid Apophis’ 2029 Close Approach with Earth.
This animation depicts the orbital trajectory of asteroid 99942 Apophis as it zooms safely past Earth on April 13, 2029. Earth’s gravity will slightly deflect the trajectory as the 1,100-foot-wide (340-meter-wide) near-Earth object comes within 20,000 miles (32,000 kilometers) of our planet’s surface. The motion has been sped up 2,000 times. Credit: NASA/JPL-Caltech.
OSIRIS-APEX will arrive at the asteroid on April 13, 2029, and operate in its proximity for about the next 18 months. In addition to studying changes to Apophis caused by its Earth encounter, the spacecraft will conduct many of the same investigations OSIRIS-REx did at Bennu, including using its instrument suite of imagers, spectrometers, and a laser altimeter to closely map the surface and analyze its chemical makeup.
As an encore, OSIRIS-APEX will reprise one of OSIRIS-REx’s most impressive acts (minus sample collection), dipping within 16 feet of the asteroid’s surface and firing its thrusters downward. This maneuver will stir up surface rocks and dust to give scientists a peek at the material that lies below.
Although the rendezvous with Apophis is more than five years away, the next milestone on its journey is the first of six close Sun passes. Those near approaches, along with three gravity assists from Earth, will put OSIRIS-APEX on course to reach Apophis in April 2029.
What OSIRIS-APEX will discover about Apophis remains to be seen, but if the mission’s previous incarnation is any indication, surprising science lies ahead. “We learned a lot at Bennu, but now we’re armed with even more questions for our next target,” Simon said.
The OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is a NASA asteroid study and sample-return mission. The mission’s main goal is to obtain a sample of at least 60 grams (2.1 oz) from 101955 Bennu, a carbonaceous near-Earth asteroid, and return the sample to Earth for a detailed analysis. The material returned is expected to enable scientists to learn more about the formation and evolution of the Solar System, its initial stages of planet formation, and the source of organic compounds that led to the formation of life on Earth. If successful, OSIRIS-REx will be the first U.S. spacecraft to return samples from an asteroid. The Lidar instrument used aboard the OSIRIS-REx was built by Lockheed Martin, in conjunction with the Canadian Space Agency.
OSIRIS-REx was launched on 8 September 2016, flew past Earth on 22 September 2017, and reached the proximity of Bennu on 3 December 2018, where it began analyzing its surface for a target sample area over the next several months. It is expected to return with its sample to Earth on 24 September 2023.
The cost of the mission is approximately US$800 million not including the Atlas V launch vehicle, which is about US$183.5 million. It is the third planetary science mission selected in the New Frontiers program, after Juno and New Horizons. The principal investigator is Dante Lauretta from the University of Arizona.
President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.
Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.
The Hayabusa2 mission cements Japan’s role in exploring the solar system, but finding its asteroid cargo presents one last challenge.
JAXA/Hayabusa 2 Credit: JAXA/Akihiro Ikeshita.
Members of JAXA, Japan’s space agency, installed an antenna in Woomera, southern Australia, in preparation for the Hayabusa2’s return to Earth. Credit: JAXA, via Associated Press.
Japan’s space agency is nearing the end of a journey of discovery that aims to shed light on the earliest eons of the solar system and possibly provide clues about the origins of life on Earth.
But first, it is going to have to go on a scavenger hunt in the Australian outback.
This weekend, bits of an asteroid will land in a barren region near Woomera, South Australia. These are being ferried to Earth by Hayabusa2, a robotic space probe launched by JAXA, Japan’s space agency, in 2014 to explore an asteroid named Ryugu, a dark, carbon-rich rock a bit more than half a mile wide.
The success of the mission and the science it produces will raise Japan’s status as a central player in deep space exploration, together with NASA, the European Space Agency and Russia. JAXA currently has a spacecraft in orbit around Venus studying that planet’s hellish climate and is collaborating with the Europeans on a mission that is on its way to Mercury.
In the coming years, Japan plans to bring back rocks from Phobos, a moon of Mars, and contribute to NASA’s Artemis program to send astronauts to Earth’s moon.
NASA ARTEMIS spacecraft depiction.
But the immediate challenge will be searching in darkness for a 16-inch-wide capsule containing the asteroid samples somewhere amid hundreds of square miles in a region 280 miles north of Adelaide, the nearest large city.
“It’s really in the middle of nowhere,” said Shogo Tachibana, the principal investigator in charge of the analysis of the Hayabusa2 samples. He is part of a team of more than 70 people from Japan who have arrived in Woomera for recovery of the capsule. The area, used by the Australian military for testing, provides a wide open space that is ideal for the return of an interplanetary probe.
The small return capsule separated from the main spacecraft at 12:30 a.m. Eastern time, about 12 hours before the scheduled landing, when it was about 125,000 miles from Earth. The mission’s managers confirmed the capsule’s ejection using data beamed back from the spacecraft, as well as with visual assistance from telescopes, like one at Kyoto University in Japan.
Kyoto University’s Seimei telescope (JP).
JAXA will broadcast live coverage of the capsule’s landing beginning at 11:30 a.m. Eastern time on Saturday. (It will be pre-dawn hours on Sunday in Australia.)
The capsule is expected to hit the ground a few minutes before noon.
The asteroid Ryugu, viewed by Hayabusa2 after leaving its orbit in November 2019. Credit:JAXA/JiJi Press, via Agence France-Presse — Getty Images.
Ryugu’s surface, taken on Oct. 26, 2018, by one of the two rovers deployed on the asteroid.Credit: JAXA, via Associated Press.
Hyabusa2’s probe successfully landed on Ryugu’s surface on July 11, 2019, collecting the samples to be returned to Earth. Credit: Agence France-Presse — Getty Images.
Hyabusa2 casting a shadow on Ryugu’s surface in February 2019. Credit: JAXA/EPA, via Shutterstock.
In an interview, Makoto Yoshikawa, the mission manager, said there is an uncertainty of about 10 kilometers, or about six miles, in pinpointing where the capsule will re-enter the atmosphere. At an altitude of six miles, the capsule will release a parachute, and where it will drift as it descends will add to the uncertainty.
“The landing place depends on the wind on that day,” Dr. Yoshikawa said. The area that searchers might have to cover could stretch some 60 miles, he said.
The trail of the fireball of superheated air created by the re-entering capsule will help guide the recovery team, as will the capsule’s radio beacon. The task will become much more difficult if the beacon fails or if the parachute fails to deploy.
There is a bit of a rush, too. The team hopes to recover the capsule, perform initial analysis and whisk it back to Japan within 100 hours. Even though the capsule is sealed, the worry is that Earth air will slowly leak in. “There is no perfect sealing,” Dr. Tachibana said.
Once the capsule is found, a helicopter will take it to a laboratory that has been set up at the Australian air force base at Woomera. There an instrument will extract any gases within the capsule that may have been released by the asteroid rocks as they were shaken and broken during re-entry. Dr. Yoshikawa said the scientists would also like to see if they can detect any solar wind particles of helium that slammed into the asteroid and became embedded in the rocks.
The gases would also reassure the scientists that Hayabusa2 did indeed successfully collect samples from Ryugu. A minimum of 0.1 grams, or less than 1/280th of an ounce, is needed to declare success. The hope is the spacecraft brought back several grams.
In Japan, the Hayabusa2 team will begin analysis of the Ryugu samples. In about a year, some of the samples will be shared with other scientists for additional study.
To gather these samples, Hayabusa2 arrived at the asteroid in June 2018. It executed a series of investigations, each of escalating technical complexity. It dropped probes to the surface of Ryugu, blasted a hole in the asteroid to peer at what lies beneath and twice descended to the surface to grab small pieces of the asteroid, an operation that proved much more challenging than expected because of the many boulders on the surface.
Displays in the Royal Australian Air Force’s Woomera range complex, where Hayabusa2’s landing will be monitored. Credit: Morgan Sette/Agence France-Presse — Getty Images.
Small worlds like Ryugu used to be of little interest to planetary scientists who focused on studying planets, said Masaki Fujimoto, deputy director general of the Institute of Space and Astronautical Science, part of JAXA. “Minor bodies, who cares?” he said. “But if you are serious about the formation of planetary systems, small bodies actually matter.”
Studying water trapped in minerals from Ryugu could give hints if the water in Earth’s oceans came from asteroids, and if carbon-based molecules could have seeded the building blocks for life.
Part of the Ryugu samples will go to NASA, which is bringing back some rocks and soil from another asteroid with its OSIRIS-REX mission.
NASA OSIRIS-REx Spacecraft.
The OSIRIS-REx space probe has been studying a smaller carbon-rich asteroid named Bennu and it will start back to Earth next spring, dropping off its rock samples in September 2023.
The successful sampling of the asteroid Bennu’s surface by the OSIRIS-REX spacecraft, which preliminary data showed touched the surface for six seconds before maneuvering away.Credit: NASA
The asteroid Bennu, observed on Dec. 2 by the OSIRIS-REx spacecraft from a range of 15 miles.Credit: NASA/Goddard/University of Arizona.
The OSIRIS-REx spacecraft making an attempt to retrieve a sample from Bennu’s surface in October.Credit: NASA/Goddard/University of Arizona, via Associated Press.
This canister and its contents are headed Earth’s way in 2023. Video credit: NASA/Goddard/University of Arizona/Lockheed Martin.
Dr. Connolly hopes to go to Japan next summer to take part in analyzing the Ryugu samples.
Hayabusa2 is not Japan’s first planetary mission. Indeed, its name points to the existence of Hayabusa, an earlier mission that brought back samples from another asteroid, Itokawa. But that mission, which launched in 2003 and returned in 2010, faced major technical problems. So did JAXA’s Akatsuki spacecraft, currently in orbit around Venus, which the Japanese agency managed to restore to a scientific mission after years of difficulty.
JAXA/AKATSUKI
A Japanese mission to Mars also failed in 2003.
By contrast, operations of Hayabusa2 have gone almost flawlessly, even though it retains the same general design as its predecessor. “Actually, there are no big issues,” Dr. Yoshikawa, the mission manager, said. “Of course, small ones.”
He said the team studied in detail the failures on Hayabusa and made changes as needed, and also conducted numerous rehearsals to try to anticipate any contingencies it might encounter.
The Japanese missions generally operate on smaller budgets than NASA’s and thus often carry fewer instruments. Hayabusa2’s cost is less than $300 million while OSIRIS-REx’s price will run about $1 billion.
Dropping off the Ryugu samples is not the end of the Hayabusa2 mission. After releasing the return capsule, the main spacecraft shifted course to avoid a collision with Earth, missing by 125 miles. It will now travel to another asteroid, a tiny one designated 1998 KY26 that is only 100 feet in diameter but spinning rapidly, completing one rotation in less than 11 minutes.
Hayabusa2 will use two flybys of Earth to fling itself toward KY26, finally arriving in 2031. It will conduct some astronomical experiments during its extended deep space journey, and the spacecraft still carries one last projectile that it may use to test that space rock’s surface.
Video for the extended mission. Credit: JAXA.
Hayabusa2, viewed from Ryugu’s surface after separation from the two rovers it brought from Earth in 2018. Credit: Agence France-Presse — Getty Images.
President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.
Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.
The Japan Aerospace Exploration Agency (JAXA) (JP) was born through the merger of three institutions, namely the Institute of Space and Astronautical Science (ISAS), the National Aerospace Laboratory of Japan (NAL) and the National Space Development Agency of Japan (NASDA). It was designated as a core performance agency to support the Japanese government’s overall aerospace development and utilization. JAXA, therefore, can conduct integrated operations from basic research and development, to utilization.
In 2013, to commemorate the 10th anniversary of its founding, JAXA created the corporate slogan, “Explore to Realize,” which reflects its management philosophy of utilizing space and the sky to achieve a safe and affluent society.
JAXA became a National Research and Development Agency in April 2015, and took a new step forward to achieve optimal R&D achievements for Japan, according to the government’s purpose of establishing a national R&D agency.
Eric Warren
Director, Public Relations
Space Dynamics Laboratory
435-881-8439
eric.warren@sdl.usu.edu
On a clear fall evening in September 2016, NASA launched a spacecraft to a distant asteroid to help answer questions central to the human experience: Where did we come from, and what is our destiny?
USU and Bennu: How USU’s Space Dynamics Laboratory Helped NASA’s OSIRIS-REx Mission.
SDL built the camera electronics for a three-camera suite onboard OSIRIS-REx named OCAMS. The onboard cameras SDL helped to build are known as PolyCam, MapCam and SamCam. PolyCam enabled NASA to acquire images of Bennu from approximately 1.2 million miles away and assisted with the spacecraft’s navigation to the asteroid during approach.
Credit: NASA/Goddard/University of Arizona.
Under the leadership of the University of Arizona’s Lunar and Planetary Laboratory, NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer spacecraft (OSIRIS-REx) extended its articulated robotic arm yesterday at approximately 6:12 pm EDT to collect debris, called regolith, from the surface of asteroid Bennu.
NASA OSIRIS-REx Spacecraft.Asteroids Bennu and Ryugu ESA.
SDL built the camera electronics for a three-camera suite onboard OSIRIS-REx named OCAMS.
The onboard cameras SDL helped to build are known as PolyCam, MapCam and SamCam. PolyCam enabled NASA to acquire images of Bennu from approximately 1.2 million miles away and assisted with the spacecraft’s navigation to the asteroid during approach. MapCam was responsible for searching the asteroid for a suitable place to collect the sample. MapCam also mapped Bennu and searched for outgassing plumes and other debris ejected from the asteroid. SamCam is a close-range camera that verified the sample acquisition and will image the sampling mechanism.
“The successful collection of regolith from Bennu perfectly illustrates the ingenuity of the dedicated men and women from America’s storied space program, who routinely collaborate in order to provide valuable science,” said Jed Hancock, SDL’s executive director of programs and operations. “SDL is honored to be a part of this historic mission that builds upon our decades-long partnership with NASA and helps the agency achieve its vision to ‘reach for new heights and reveal the unknown for the benefit of humankind.’”
The Touch-And-Go Sample Acquisition Mechanism, TAGSAM, is the arm on the spacecraft responsible for collecting Bennu’s regolith sample and includes a round sampler head at the end. During the touch-and-go maneuver, the sampler head was extended toward Bennu. The momentum of the spacecraft’s slow, downward trajectory pushed the sampler head against the asteroid’s surface for about ten seconds—just long enough to obtain a sample. At contact, the spacecraft fired nitrogen gas onto the surface to roil up dust and small pebbles, which were then captured.
OSIRIS-REx fired its thruster to back away from Bennu’s surface, and now the mission team will measure the sample amount by spinning the spacecraft with the collection arm extended. The team will compare the change in the spacecraft’s inertia with a previous, empty TAGSAM spin to ensure that enough sample was collected. The TAGSAM head will then be placed in the Sample Return Capsule for return to Earth. After successful stowage, the spacecraft will slowly drift away from Bennu to a safe distance, where it will stay until its departure in 2021 for the Return Cruise Phase back to Earth.
Why Bennu?
Currently about 207 million miles away from Earth, asteroid Bennu is a carbon-based asteroid whose regolith may contain evidence of our solar system’s primeval history. Contained within its regolith could be clues that Bennu may also have molecular precursors to the origin of life and Earth’s oceans, scientists believe.
With a polar diameter of approximately 510 meters—the Empire State Building is 443 meters tall—Bennu is also one of the most potentially hazardous asteroids and has a relatively high probability of impacting Earth late in the 22nd century. OSIRIS-REx will determine Bennu’s physical and chemical properties, which will be critical knowledge in the event of an impact mitigation mission.
According to NASA, asteroids like Bennu contain natural resources such as water, organics and precious metals. In the future, these asteroids may fuel solar system exploration by robotic and crewed spacecraft.
“It is incredibly exciting to be involved with missions like OSIRIS-REx,” said Alan Thurgood, SDL’s Civil and Commercial Space division director. “Being a part of exciting science with historically significant missions and pushing human knowledge forward motivates our team at SDL to do great work.”
The OSIRIS-REx Sample Return Capsule will land in Utah’s West Desert in 2023.
SDL has been solving the technical challenges faced by the military, science community, and industry for six decades and supports NASA’s mission to drive advances in science, technology, aeronautics, and space exploration to enhance knowledge, education, innovation, economic vitality and stewardship of Earth. As one of 14 University Affiliated Research Centers, SDL serves as a subject matter expert in its core research areas to the U.S. Government, ensuring that essential engineering and technology capabilities are maintained. SDL is a research laboratory headquartered in North Logan, UT, and has offices in Albuquerque, NM; Bedford, MA; Colorado Springs, CO; Dayton, OH; Huntsville, AL; Houston, TX; Los Angeles, CA; Stafford, VA; and Washington, DC. For more information, visit http://www.sdl.usu.edu.
Since its founding in 1888, Utah State University has evolved from a small-town college tucked away in the Northern Utah mountains to a thriving research university respected around the world. Students can choose from an array of academic and social opportunities at a university known throughout the world for its intellectual and technological leadership.
The setting. USU is just minutes from two mountain ranges and within a half-day’s drive of six national parks, including Yellowstone and Arches. It provides big-school opportunities with a small-school feel, and all for a great value.
In fact, USU is the #5 public university in the nation in “National Universities Rankings 2017” by Washington Monthly (2017).
Oct. 20, 2020
Grey Hautaluoma
Headquarters, Washington
202-358-0668
grey.hautaluoma-1@nasa.gov
Joshua Handal
Headquarters, Washington
202-358-2307
joshua.a.handal@nasa.gov
Nancy Neal Jones
Goddard Space Flight Center, Greenbelt, Md.
301-286-0039
nancy.n.jones@nasa.gov
Erin Morton
University of Arizona, Tucson
520-269-2493
morton@orex.lpl.arizona.edu
NASA’s OSIRIS-REx mission readies itself to touch the surface of asteroid Bennu. Credits: NASA/Goddard/University of Arizona.
NASA’s Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer (OSIRIS-REx) spacecraft unfurled its robotic arm Tuesday, and in a first for the agency, briefly touched an asteroid to collect dust and pebbles from the surface for delivery to Earth in 2023.
This well-preserved, ancient asteroid, known as Bennu, is currently more than 200 million miles (321 million kilometers) from Earth. Bennu offers scientists a window into the early solar system as it was first taking shape billions of years ago and flinging ingredients that could have helped seed life on Earth.
After traveling for two years and billions of kilometers from Earth, the OSIRIS-REx probe is only a few months away from its destination: the intriguing asteroid Bennu. When it arrives in December, OSIRIS-REx will embark on a nearly two-year investigation of this clump of rock, mapping its terrain and finding a safe and fruitful site from which to collect a sample.
The spacecraft will briefly touch Bennu’s surface around July 2020 to collect at least 60 grams (equal to about 30 sugar packets) of dirt and rocks. It might collect as much as 2,000 grams, which would be the largest sample by far gathered from a space object since the Apollo Moon landings. The spacecraft will then pack the sample into a capsule and travel back to Earth, dropping the capsule into Utah’s west desert in 2023, where scientists will be waiting to collect it.
This years-long quest for knowledge thrusts Bennu into the center of one of the most ambitious space missions ever attempted. But the humble rock is but one of about 780,000 known asteroids in our solar system. So why did scientists pick Bennu for this momentous investigation? Here are 10 reasons.
Artist’s concept of OSIRIS-REx flying past Earth.Credit: NASA’s Goddard Space Flight Center.
1. It’s close to Earth
Unlike most other asteroids that circle the Sun in the asteroid belt between Mars and Jupiter, Bennu’s orbit is close in proximity to Earth’s, even crossing it. The asteroid makes its closest approach to Earth every 6 years. It also circles the Sun nearly in the same plane as Earth, which made it somewhat easier to achieve the high-energy task of launching the spacecraft out of Earth’s plane and into Bennu’s. Still, the launch required considerable power, so OSIRIS-REx used Earth’s gravity to boost itself into Bennu’s orbital plane when it passed our planet in September 2017.
Credit: NASA’s Goddard Space Flight Center.
2. It’s the right size
Asteroids spin on their axes just like Earth does. Small ones, with diameters of 200 meters or less, often spin very fast, up to a few revolutions per minute. This rapid spinning makes it difficult for a spacecraft to match an asteroid’s velocity in order to touch down and collect samples. Even worse, the quick spinning has flung loose rocks and soil, material known as “regolith” — the stuff OSIRIS-REx is looking to collect — off the surfaces of small asteroids. Bennu’s size, in contrast, makes it approachable and rich in regolith. It has a diameter of 492 meters, which is a bit larger than the height of the Empire State Building in New York City, and rotates once every 4.3 hours.
Artist’s concept of asteroids falling on forming planet. Credit: NASA Goddard Space Flight Center.
3. It’s really old
Bennu is a leftover fragment from the tumultuous formation of the solar system. Some of the mineral fragments inside Bennu could be older than the solar system. These microscopic grains of dust could be the same ones that spewed from dying stars and eventually coalesced to make the Sun and its planets nearly 4.6 billion years ago. But pieces of asteroids, called meteorites, have been falling to Earth’s surface since the planet formed. So why don’t scientists just study those old space rocks? Because astronomers can’t tell (with very few exceptions) what kind of objects these meteorites came from, which is important context. Furthermore, these stones, that survive the violent, fiery decent to our planet’s surface, get contaminated when they land in the dirt, sand, or snow. Some even get hammered by the elements, like rain and snow, for hundreds or thousands of years. Such events change the chemistry of meteorites, obscuring their ancient records.
Artist’s concept of asteroid Bennu.
4. It’s well preserved
Bennu, on the other hand, is a time capsule from the early solar system, having been preserved in the vacuum of space. Although scientists think it broke off a larger asteroid in the asteroid belt in a catastrophic collision between about 1 and 2 billion years ago, and hurtled through space until it got locked into an orbit near Earth’s, they don’t expect that these events significantly altered it.
Credit: NASA Goddard Space Flight Center.
5. It might contain clues to the origin of life
Analyzing a sample from Bennu will help planetary scientists better understand the role asteroids may have played in delivering life-forming compounds to Earth. We know from having studied Bennu through Earth- and space-based telescopes that it is a carbonaceous, or carbon-rich, asteroid. Carbon is the hinge upon which organic molecules hang. Bennu is likely rich in organic molecules, which are made of chains of carbon bonded with atoms of oxygen, hydrogen, and other elements in a chemical recipe that makes all known living things. Besides carbon, Bennu also might have another component important to life: water, which is trapped in the minerals that make up the asteroid.
Artist’s concept of OSIRIS-REx collecting samples.
6. It contains valuable materials
Besides teaching us about our cosmic past, exploring Bennu close-up will help humans plan for the future. Asteroids are rich in natural resources, such as iron and aluminum, and precious metals, such as platinum. For this reason, some companies, and even countries, are building technologies that will one day allow us to extract those materials. More importantly, asteroids like Bennu are key to future, deep-space travel. If humans can learn how to extract the abundant hydrogen and oxygen from the water locked up in an asteroid’s minerals, they could make rocket fuel. Thus, asteroids could one day serve as fuel stations for robotic or human missions to Mars and beyond. Learning how to maneuver around an object like Bennu, and about its chemical and physical properties, will help future prospectors.
Artist’s view of a solar system forming.Credit: NASA Goddard Space Flight Center.
7. It will help us better understand other asteroids
Astronomers have studied Bennu from Earth since it was discovered in 1999. As a result, they think they know a lot about the asteroid’s physical and chemical properties. Their knowledge is based not only on looking at the asteroid, but also studying meteorites found on Earth, and filling in gaps in observable knowledge with predictions derived from theoretical models. Thanks to the detailed information that will be gleaned from OSIRIS-REx, scientists now will be able to check whether their predictions about Bennu are correct. This work will help verify or refine telescopic observations and models that attempt to reveal the nature of other asteroids in our solar system.
Credit: NASA Goddard Space Flight Center.
8. It will help us better understand a quirky solar force …
Astronomers have calculated that Bennu’s orbit has drifted about 280 meters (0.18 miles) per year toward the Sun since it was discovered. This could be because of a phenomenon called the Yarkovsky effect, a process whereby sunlight warms one side of a small, dark asteroid and then radiates as heat off the asteroid as it rotates. The heat energy thrusts an asteroid either away from the Sun, if it has a prograde spin like Earth, which means it spins in the same direction as its orbit, or toward the Sun in the case of Bennu, which spins in the opposite direction of its orbit. OSIRIS-REx will measure the Yarkovsky effect from close-up to help scientists predict the movement of Bennu and other asteroids. Already, measurements of how this force impacted Bennu over time have revealed that it likely pushed it to our corner of the solar system from the asteroid belt.
Artist’s concept of an asteroid passing close to Earth.
9. … and to keep asteroids at bay
One reason scientists are eager to predict the directions asteroids are drifting is to know when they’re coming too-close-for-comfort to Earth. By taking the Yarkovsky effect into account, they’ve estimated that Bennu could pass closer to Earth than the Moon is in 2135, and possibly even closer between 2175 and 2195. Although Bennu is unlikely to hit Earth at that time, our descendants can use the data from OSIRIS-REx to determine how best to deflect any threatening asteroids that are found, perhaps even by using the Yarkovsky effect to their advantage.
10. It’s a gift that will keep on giving
Samples of Bennu will return to Earth on September 24, 2023. OSIRIS-REx scientists will study a quarter of the regolith. The rest will be made available to scientists around the globe, and also saved for those not yet born, using techniques not yet invented, to answer questions not yet asked.
If Tuesday’s sample collection event, known as “Touch-And-Go” (TAG), provided enough of a sample, mission teams will command the spacecraft to begin stowing the precious primordial cargo to begin its journey back to Earth in March 2021. Otherwise, they will prepare for another attempt in January.
“This amazing first for NASA demonstrates how an incredible team from across the country came together and persevered through incredible challenges to expand the boundaries of knowledge,” said NASA Administrator Jim Bridenstine. “Our industry, academic, and international partners have made it possible to hold a piece of the most ancient solar system in our hands.”
At 1:50 p.m. EDT, OSIRIS-REx fired its thrusters to nudge itself out of orbit around Bennu. It extended the shoulder, then elbow, then wrist of its 11-foot (3.35-meter) sampling arm, known as the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), and transited across Bennu while descending about a half-mile (805 meters) toward the surface. After a four-hour descent, at an altitude of approximately 410 feet (125 meters), the spacecraft executed the “Checkpoint” burn, the first of two maneuvers to allow it to precisely target the sample collection site, known as “Nightingale.”
Ten minutes later, the spacecraft fired its thrusters for the second “Matchpoint” burn to slow its descent and match the asteroid’s rotation at the time of contact. It then continued a treacherous, 11-minute coast past a boulder the size of a two-story building, nicknamed “Mount Doom,” to touch down in a clear spot in a crater on Bennu’s northern hemisphere. The size of a small parking lot, the site Nightingale site is one of the few relatively clear spots on this unexpectedly boulder-covered space rock.
“This was an incredible feat – and today we’ve advanced both science and engineering and our prospects for future missions to study these mysterious ancient storytellers of the solar system,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate at the agency’s headquarters in Washington. “A piece of primordial rock that has witnessed our solar system’s entire history may now be ready to come home for generations of scientific discovery, and we can’t wait to see what comes next.”
“After over a decade of planning, the team is overjoyed at the success of today’s sampling attempt,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona in Tucson. “Even though we have some work ahead of us to determine the outcome of the event – the successful contact, the TAGSAM gas firing, and back-away from Bennu are major accomplishments for the team. I look forward to analyzing the data to determine the mass of sample collected.”
All spacecraft telemetry data indicates the TAG event executed as expected. However, it will take about a week for the OSIRIS-REx team to confirm how much sample the spacecraft collected.
Real-time data indicates the TAGSAM successfully contacted the surface and fired a burst of nitrogen gas. The gas should have stirred up dust and pebbles on Bennu’s surface, some of which should have been captured in the TAGSAM sample collection head. OSIRIS-REx engineers also confirmed that shortly after the spacecraft made contact with the surface, it fired its thrusters and safely backed away from Bennu.
“Today’s TAG maneuver was historic,” said Lori Glaze, Planetary Science Division director at NASA Headquarters in Washington. “The fact that we safely and successfully touched the surface of Bennu, in addition to all the other milestones this mission has already achieved, is a testament to the living spirit of exploration that continues to uncover the secrets of the solar system.”
____________________________________________________________________ The Full Story
August 12, 2020
Erin Morton
OSIRIS-REx Communications
520-269-2493
morton@orex.lpl.arizona.edu
A Successful Second Rehearsal Puts NASA’s OSIRIS-REx on a Path to Sample Collection
NASA’s first asteroid-sampling spacecraft just completed its second successful sample collection rehearsal and is now ready for the main event – touching down on asteroid Bennu’s surface in October. Yesterday, the OSIRIS-REx spacecraft performed its final practice run of the sampling sequence, reaching an approximate altitude of 131 feet (40 meters) over sample site Nightingale before executing a back-away burn. Nightingale, OSIRIS-REx’s primary sample collection site, is located within a crater in Bennu’s northern hemisphere.
Captured on Aug. 11 during the second rehearsal of the OSIRIS-REx mission’s sample collection event, this series of images shows the SamCam imager’s field of view as the NASA spacecraft approaches asteroid Bennu’s surface. The rehearsal brought the spacecraft through the first three maneuvers of the sampling sequence to a point approximately 131 feet (40 meters) above the surface, after which the spacecraft performed a back-away burn. Credit: NASA/Goddard/University of Arizona.
The approximately four-hour “Matchpoint” rehearsal took the spacecraft through the first three of the sampling sequence’s four maneuvers: the orbit departure burn, the “Checkpoint” burn and the Matchpoint burn. Checkpoint is the point where the spacecraft autonomously checks its position and velocity before adjusting its trajectory down toward the event’s third maneuver. Matchpoint is the moment when the spacecraft matches Bennu’s rotation in order to fly in tandem with the asteroid surface, directly above the sample site, before touching down on the targeted spot.
Four hours after departing its 0.6-mile (1-km) safe-home orbit, OSIRIS-REx performed the Checkpoint maneuver at an approximate altitude of 410 feet (125 meters) above Bennu’s surface. From there, the spacecraft continued to descend for another eight minutes to perform the Matchpoint burn. After descending on this new trajectory for another three minutes, the spacecraft reached an altitude of approximately 131 ft (40 m) – the closest the spacecraft has ever been to Bennu – and then performed a back-away burn to complete the rehearsal.
During the rehearsal, the spacecraft successfully deployed its sampling arm, the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), from its folded, parked position out to the sample collection configuration. Additionally, some of the spacecraft’s instruments collected science and navigation images and made spectrometry observations of the sample site, as will occur during the sample collection event. These images and science data were downlinked to Earth after the event’s conclusion.
Because the spacecraft and Bennu are currently about 179 million miles (288 million km) from Earth, it takes approximately 16 minutes for the spacecraft to receive the radio signals used to command it. This time lag prevented live commanding of flight activities from the ground during the rehearsal. As a result, the spacecraft performed the entire rehearsal sequence autonomously. Prior to the rehearsal’s start, the OSIRIS-REx team uplinked all of the event’s commands to the spacecraft and then provided the “Go” command to begin the event. The actual sample collection event in October will be conducted the same way.
This second rehearsal provided the mission team with practice navigating the spacecraft through the first three maneuvers of the sampling event and with an opportunity to verify that the spacecraft’s imaging, navigation and ranging systems operated as expected during the first part of the descent sequence.
Matchpoint rehearsal also confirmed that OSIRIS-REx’s Natural Feature Tracking (NFT) guidance system accurately estimated the spacecraft’s trajectory after the Matchpoint burn, which is the final maneuver before the sample collection head contacts Bennu’s surface. This rehearsal was also the first time that the spacecraft’s on-board hazard map was employed. The hazard map delineates areas that could potentially harm the spacecraft. If the spacecraft detects that it is on course to touch a hazardous area, it will autonomously back-away once it reaches an altitude of 16 ft (5 m). While OSIRIS-REx did not fly that low during the rehearsal, it did employ the hazard map to assess whether its predicted touchdown trajectory would have avoided surface hazards, and found that the spacecraft’s path during the rehearsal would have allowed for a safe touchdown on sample site Nightingale.
During the last minutes of the spacecraft’s descent, OSIRIS-REx also collected new, high-resolution navigation images for the NFT guidance system. These detailed images of Bennu’s landmarks will be used for the sampling event, and will allow the spacecraft to accurately target a very small area.
“Many important systems were exercised during this rehearsal – from communications, spacecraft thrusters, and most importantly, the onboard Natural Feature Tracking guidance system and hazard map,” said OSIRIS-REx principal investigator Dante Lauretta of the University of Arizona, Tucson. “Now that we’ve completed this milestone, we are confident in finalizing the procedures for the TAG event. This rehearsal confirmed that the team and all of the spacecraft’s systems are ready to collect a sample in October.”
The mission team has spent the last several months preparing for Matchpoint rehearsal while maximizing remote work as part of the COVID-19 response. On the day of rehearsal, a limited number of personnel monitored the spacecraft’s telemetry from Lockheed Martin Space’s facility, NASA’s Goddard Space Flight Center and the University of Arizona, taking appropriate safety precautions, while the rest of the team performed their roles remotely.
The spacecraft will travel all the way to the asteroid’s surface during its first sample collection attempt, scheduled for Oct. 20. During this event, OSIRIS-REx’s sampling mechanism will touch Bennu’s surface for several seconds, fire a charge of pressurized nitrogen to disturb the surface and collect a sample before the spacecraft backs away. The spacecraft is scheduled to return the sample to Earth on Sept. 24, 2023.
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“It’s hard to put into words how exciting it was to receive confirmation that the spacecraft successfully touched the surface and fired one of the gas bottles,” said Michael Moreau, OSIRIS-REx deputy project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The team can’t wait to receive the imagery from the TAG event late tonight and see how the surface of Bennu responded to the TAG event.”
The spacecraft carried out TAG autonomously, with pre-programmed instructions from engineers on Earth. Now, the OSIRIS-REx team will begin to assess whether the spacecraft grabbed any material, and, if so, how much; the goal is at least 60 grams, which is roughly equivalent to a full-size candy bar.
OSIRIS-REx engineers and scientists will use several techniques to identify and measure the sample remotely. First, they’ll compare images of the Nightingale site before and after TAG to see how much surface material moved around in response to the burst of gas.
“Our first indication of whether we were successful in collecting a sample will come on October 21 when we downlink the back-away movie from the spacecraft,” Moreau said. “If TAG made a significant disturbance of the surface, we likely collected a lot of material.”
Next, the team will try to determine the amount of sample collected. One method involves taking pictures of the TAGSAM head with a camera known as SamCam, which is devoted to documenting the sample-collection process and determining whether dust and rocks made it into the collector head. One indirect indication will be the amount of dust found around the sample collector head. OSIRIS-REx engineers also will attempt to snap photos that could, given the right lighting conditions, show the inside of the head so engineers can look for evidence of sample inside of it.
These images show the OSIRIS-REx Touch-and-Go Sample Acquisition Mechanism (TAGSAM) sampling head extended from the spacecraft at the end of the TAGSAM arm. The spacecraft’s SamCam camera captured the images on Nov. 14, 2018 as part of a visual checkout of the TAGSAM system, which was developed by Lockheed Martin Space to acquire a sample of asteroid material in a low-gravity environment. The imaging was a rehearsal for a series of observations that will be taken at Bennu directly after sample collection. Credits: NASA/Goddard/University of Arizona.
A couple of days after the SamCam images are analyzed, the spacecraft will attempt yet another method to measure the mass of the sample collected by determining the change in the spacecraft’s “moment of inertia,” a phrase that describes how mass is distributed and how it affects the rotation of the body around a central axis. This maneuver entails extending the TAGSAM arm out to the side of the spacecraft and slowly spinning the spacecraft about an axis perpendicular to the arm. This technique is analogous to a person spinning with one arm extended while holding a string with a ball attached to the end. The person can sense the mass of the ball by the tension in the string. Having performed this maneuver before TAG, and now after, engineers can measure the change in the mass of the collection head as a result of the sample inside.
“We will use the combination of data from TAG and the post-TAG images and mass measurement to assess our confidence that we have collected at least 60 grams of sample,” said Rich Burns, OSIRIS-REx project manager at Goddard. “If our confidence is high, we’ll make the decision to stow the sample on October 30.”
To store the sample, engineers will command the robotic arm to place the sample collector head into the Sample Return Capsule (SRC), located in the body of the spacecraft. The sample arm will then retract to the side of the spacecraft for the final time, the SRC will close, and the spacecraft will prepare for its departure from Bennu in March 2021 — this is the next time Bennu will be properly aligned with Earth for the most fuel-efficient return flight.
This (silent) animation shows the OSIRIS-REx spacecraft deploying its Touch-and-Go Sample Acquisition Mechanism (TAGSAM) to collect a sample of regolith (loose rocks and dirt) from the surface of the asteroid Bennu. The sampler head, with the regolith safely inside, is then sealed up in the spacecraft’s Sample Return Capsule, which will be returned to Earth in late 2023. Scientists will study the sample for clues about the early solar system and the origins of life. Credits: NASA/Goddard.
If, however, it turns out that the spacecraft did not collect enough sample at Nightingale, it will attempt another TAG maneuver on Jan. 12, 2021. If that occurs, it will touch down at the backup site called “Osprey,” which is another relatively boulder-free area inside a crater near Bennu’s equator.
OSIRIS-REx launched from Cape Canaveral Air Force Station in Florida Sept. 8, 2016. It arrived at Bennu Dec. 3, 2018, and began orbiting the asteroid for the first time on Dec. 31, 2018.
____________________________________________________________________ NASA’s OSIRIS-REx Spacecraft Enters Close Orbit Around Bennu, Breaking Record
By Lonnie Shekhtman
Media Contact
Erin Morton
OSIRIS-REx Communications
520-269-2493
morton@orex.lpl.arizona.edu
On Dec. 31, 2018, NASA’s OSIRIS-REx spacecraft went into orbit around asteroid Bennu for the first time.
At 2:43 p.m. EST on December 31, while many on Earth prepared to welcome the New Year, NASA’s OSIRIS-REx spacecraft, 70 million miles (110 million kilometers) away, carried out a single, eight-second burn of its thrusters – and broke a space exploration record. The spacecraft entered into orbit around the asteroid Bennu, and made Bennu The smallest object ever to be orbited by a spacecraft.
“The team continued our long string of successes by executing the orbit-insertion maneuver perfectly,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson. “With the navigation campaign coming to an end, we are looking forward to the scientific mapping and sample site selection phase of the mission.”
Lauretta, along with his team, spent the last day of 2018 with his feet planted on Earth, but his mind focused on space. “Entering orbit around Bennu is an amazing accomplishment that our team has been planning for years,” Lauretta said.
Inching around the asteroid at a snail’s pace, OSIRIS-REx’s first orbit marks a leap for humankind. Never before has a spacecraft from Earth circled so close to such a small space object – one with barely enough gravity to keep a vehicle in a stable orbit.
Now, the spacecraft will circle Bennu about a mile (1.75 kilometers) from its center, closer than any other spacecraft has come to its celestial object of study. (Previously the closest orbit of a planetary body was in May 2016, when the Rosetta spacecraft orbited about four miles (seven kilometers) from the center of the comet 67P/Churyumov-Gerasimenko.) The comfortable distance is necessary to keep the spacecraft locked to Bennu, which has a gravity force only 5-millionths as strong as Earth’s. The spacecraft is scheduled to orbit Bennu through mid-February at a leisurely 62 hours per orbit.
Now that the OSIRIS-REx spacecraft is closer to Bennu, physical details about the asteroid will leap into sharper focus, and the spacecraft’s tour of this rubble pile of primordial debris will become increasingly detailed and focused.
“Our orbit design is highly dependent on Bennu’s physical properties, such as its mass and gravity field, which we didn’t know before we arrived,” said OSIRIS-REx’s flight dynamics system manager Mike Moreau, who is based at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
“Up until now, we had to account for a wide variety of possible scenarios in our computer simulations to make sure we could safely navigate the spacecraft so close to Bennu. As the team learned more about the asteroid, we incorporated new information to hone in on the final orbit design,” he said.
The simulations have played a critical role. The OSIRIS-REx mission, after all, was designed based on complex computer programs that predicted — quite accurately, as it turns out — the properties of Bennu and how the spacecraft’s trajectory would behave. This diligent preparation allowed the team to navigate the vehicle safely to Bennu in December and put some questions to rest (there are, indeed, signs of ancient water preserved in Bennu’s rocks) and to fly over its poles and equator in a preliminary survey that led to some surprises (Bennu has many large boulders).
Having completed the preliminary survey of Bennu with a flyby of its south pole on December 16, the spacecraft moved to a safe 31 miles (50 kilometers) away from the asteroid to give the navigation team a chance to regroup and prepare for orbit insertion. Next, Lockheed Martin engineers programmed the spacecraft to begin moving back to a position about nine miles (15 kilometers) over Bennu’s north pole to prepare for three burns of its thrusters over the course of 10 days that would place the spacecraft into orbit.
OSIRIS-REx Begins Orbiting Asteroid Bennu
Even though OSIRIS-REx is in the most stable orbit possible, Bennu’s gravitational pull is so tenuous that keeping the spacecraft safe will require occasional adjustments, said Dan Wibben, OSIRIS-REx maneuver and trajectory design lead at KinetX Aerospace in Simi Valley, California.
“The gravity of Bennu is so small, forces like solar radiation and thermal pressure from Bennu’s surface become much more relevant and can push the spacecraft around in its orbit much more than if it were orbiting around Earth or Mars, where gravity is by far the most dominant force,” he said.
The OSIRIS-REx navigation team will use “trim” maneuvers to slightly thrust the spacecraft in one direction or another to correct its orbit and counter these small forces. If the spacecraft drifts away from Bennu, or some other problem forces it into safe mode, it has been programmed to fly away from the asteroid to stay safe from impact.
“It’s simple logic: always burn toward the Sun if something goes wrong,” said Coralie Adam, OSIRIS-REx lead optical navigation engineer at KinetX. Engineers can navigate the spacecraft back into orbit if it drifts away, Adam said, though that’s unlikely to happen.
The navigation and spacecraft operations teams are focused on the first orbital phase. Their primary goal is to transition away from star-based navigation, which allowed the team to locate the spacecraft based on pictures of the star formations around it taken by the cameras onboard. Navigators use methods like this since there is no GPS in deep space and we can’t see the spacecraft from Earth-based telescopes. From this point forward, though, the OSIRIS-REx team will rely on landmarks on Bennu’s surface to track OSIRIS-REx, a more precise technique that will ultimately guide them to a sample-collection site clear of boulders and large rocks, said Adam.
“After conducting a global imaging and mapping campaign during our recent preliminary survey phase, the science team has created 3-D models of Bennu’s terrain that we’re going to begin using for navigation around the asteroid,” she said.
Another critical objective of this orbital phase, Adam said, is to get a better handle on Bennu’s mass and gravity, features that will influence the planning of the rest of the mission, notably the short touchdown on the surface for sample collection in 2020. In the case of Bennu, scientists can only measure these features by getting OSIRIS-REx very close to the surface to see how its trajectory bends from Bennu’s gravitational pull.
“The Orbital A phase will help improve our detailed models for Bennu’s gravity field, thermal properties, orientation, and spin rate,” said Wibben. “This, in turn, will allow us to refine our trajectory designs for the even more challenging flight activities we will perform in 2019.”
The December 31 maneuver to place the spacecraft into orbit about Bennu is the first of many exciting navigation activities planned for the mission. The OSIRIS-REx team will resume science operations in late February. At that point, the spacecraft will perform a series of close flybys of Bennu for several months to take high-resolution images of every square inch of the asteroid to help select a sampling site. During the summer of 2020, the spacecraft will briefly touch the surface of Bennu to retrieve a sample. The OSIRIS-REx mission is scheduled to deliver the sample to Earth in September 2023.
The spacecraft is scheduled to return to Earth Sept. 24, 2023, when it will parachute the SRC into Utah’s west desert where scientists will be waiting to collect it.
Goddard provides overall mission management, systems engineering and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and is providing flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.
The OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is a NASA asteroid study and sample-return mission. The mission’s main goal is to obtain a sample of at least 60 grams (2.1 oz) from 101955 Bennu, a carbonaceous near-Earth asteroid, and return the sample to Earth for a detailed analysis. The material returned is expected to enable scientists to learn more about the formation and evolution of the Solar System, its initial stages of planet formation, and the source of organic compounds that led to the formation of life on Earth. If successful, OSIRIS-REx will be the first U.S. spacecraft to return samples from an asteroid. The Lidar instrument used aboard the OSIRIS-REx was built by Lockheed Martin, in conjunction with the Canadian Space Agency.
OSIRIS-REx was launched on 8 September 2016, flew past Earth on 22 September 2017, and reached the proximity of Bennu on 3 December 2018, where it began analyzing its surface for a target sample area over the next several months. It is expected to return with its sample to Earth on 24 September 2023.
The cost of the mission is approximately US$800 million not including the Atlas V launch vehicle, which is about US$183.5 million. It is the third planetary science mission selected in the New Frontiers program, after Juno and New Horizons. The principal investigator is Dante Lauretta from the University of Arizona.
President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.
Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.
Mikayla Mace
University Communications
520-621-1878
mikaylamace@arizona.edu
NASA’s OSIRIS-REx mission created these images using false-color Red-Green-Blue composites of asteroid Bennu. A 2D map and spacecraft imagery were overlaid on a shape model of the asteroid to create these false-color composites. In these composites, spectrally average and bluer-than-average terrain looks blue, and surfaces that are redder than average appear red. Bright green areas correspond to the instances of a mineral pyroxene, which likely came from a different asteroid, Vesta. Black areas near the poles indicate no data. Credit: NASA/Goddard/University of Arizona.
NASA OSIRIS-REx Spacecraft.
Scientists now know much more about the material NASA’s first asteroid sample return mission will be collecting in just a few weeks.
In a special collection of six papers published today in the journals Science and Science Advances, scientists with the University of Arizona-led OSIRIS-REx mission present new findings on asteroid Bennu’s surface material, geological characteristics and dynamic history. They also say that the sample delivered from Bennu may be unlike anything we have in the meteorite collection on Earth.
These discoveries complete the OSIRIS-REx mission’s pre-sample collection science requirements and offer insight into an asteroid sample that scientists will study for generations to come.
Rocks in Rouge
One of the papers – published in Science and led by Dani DellaGiustina, lead scientist on the mission’s image processing team and senior staff scientist at the UArizona Lunar and Planetary Laboratory – details a striking discovery at the mission’s primary sample site, Nightingale, where OSIRIS-REx will make its first sample collection attempt on Oct. 20. The rocky debris covering the site has only recently been exposed to the harsh space environment. That means the mission will be collecting and returning some of the most pristine material on the asteroid.
Using spectroscopy – a technique that reveals a material’s composition based on the pattern of reflected wavelengths of light – the scientists found that Nightingale is part of a population of young craters whose composition reflects mostly red light. Bennu’s colors, as revealed through spectroscopy, are much more diverse than originally anticipated. This diversity results from a combination of different materials inherited from Bennu’s parent body and different durations of exposure to the space environment.
While Bennu appears quite black to the naked eye, the authors illustrate the diversity of Bennu’s surface by using false-color renderings of spectral data collected by the mission’s MapCam camera. The freshest material on Bennu, such as that found at the Nightingale site, is spectrally redder than average and thus appears red in the images. Surface material turns vivid blue when it has been exposed to space weathering for an intermediate period of time. As the surface material continues to weather over long periods of time, it ultimately brightens across all wavelengths, becoming a less intense blue – the average spectral color of Bennu.
“When a material is exposed to the space environment, its surface weathers, but in a very different way than things do on Earth,” DellaGiustina said. “In space, weathering is caused by exposure to solar wind and the rain of tiny micrometeorites. On the moon’s surface and many asteroids, we have observed that space weathering darkens and reddens surfaces. On Bennu, however, the opposite is true. We see that over time Bennu has become brighter and bluer in response to space weathering. This is an exciting finding because it tells us that something about Bennu is quite different than other planetary surfaces we’ve observed.”
The paper led by DellaGiustina also distinguishes two main types of boulders on Bennu’s surface: dark and rough, and, less commonly, bright and smooth. The different types may have formed at different depths in the parent asteroid of Bennu.
A ‘Scientific Triumph’
Another paper published in Science, led by Amy Simon from NASA’s Goddard Space Flight Center in Greenbelt, Maryland, shows that carbon-bearing, organic material is widespread on the asteroid’s surface, including at the Nightingale site. These findings indicate that hydrated minerals and organic material will likely be present in the collected sample.
This organic matter may contain carbon in a form often found in biology or in compounds associated with biology. Scientists are planning detailed experiments on these organic molecules and expect that the returned sample will help answer complex questions about the origins of water and life on Earth.
“The abundance of carbon-bearing material is a major scientific triumph for the mission. We are now optimistic that we will collect and return a sample with organic material – a central goal of the OSIRIS-REx mission,” said Dante Lauretta, OSIRIS-REx principal investigator and UArizona planetary science professor, who co-authored all six papers in the collection.
History Hidden in Rocks
During fall 2019, NASA’s OSIRIS-REx spacecraft captured this image, which shows one of asteroid Bennu’s boulders with a bright vein that appears to be made of carbonate. The image within the circle (lower right) shows a focused view of the vein. Credit: NASA/Goddard/University of Arizona.
Another study in the collection, published in Science and led by Hannah Kaplan from Goddard, found that carbonate minerals – which are compounds containing special combinations of carbon, oxygen and metals – make up some of the asteroid’s geological features and might be present in the returned sample. Because these carbonate minerals form under certain conditions, scientists theorize that Bennu’s parent asteroid likely hosted an environment where water interacted with and altered the rock on Bennu’s parent body.
A Science Advances paper led by Ben Rozitis from The Open University in the U.K. shows that the dark boulders are weaker and more porous, whereas the bright boulders are stronger and less porous. However, both boulder types are weaker than scientists expected. Rozitis and colleagues suspect that Bennu’s dark boulders – the weaker, more porous and more common type – would not survive the journey through Earth’s atmosphere. It’s therefore likely that the returned samples of asteroid Bennu will provide a missing link for scientists, as this type of material is not currently represented in meteorite collections.
A Surprising Shape
Bennu is a diamond-shaped pile of rubble floating in space, but there’s more to it than meets the eye. Data obtained by the OSIRIS-REx Laser Altimeter, or OLA, has allowed the mission team to develop a 3D digital terrain model of the asteroid that, at nearly 8-inch resolution, is unprecedented in detail and accuracy.
In a Science Advances paper led by Michael Daly of York University (CA), scientists explain how detailed analysis of the asteroid’s shape revealed ridge-like mounds on Bennu that extend from pole-to-pole but are subtle enough that they could be easily missed by the human eye. Their presence has been hinted at before but only became clear when the northern and southern hemispheres were split apart in the OLA data for comparison.
The digital terrain model also shows that Bennu’s northern and southern hemispheres have different shapes. The southern hemisphere appears to be smoother and rounder, which the scientists believe is a result of loose material getting trapped by the region’s numerous large boulders.
What’s at the Center of Bennu?
Another Science Advances paper in the special collection, led by Daniel Scheeres of University of Colorado Boulder, examines the gravity field of Bennu, which has been determined by tracking the trajectories of the OSIRIS-REx spacecraft and the particles that are naturally ejected from Bennu’s surface.
The reconstructed gravity field shows that the interior of Bennu is not uniform. Instead, there are pockets of higher and lower density material inside the asteroid. It’s as if there is a void at its center, within which you could fit a couple of football fields.
All six publications in the special collection use global and local datasets collected by the OSIRIS-REx spacecraft from February through October 2019. The special collection underscores that sample return missions like OSIRIS-REx are essential to fully understanding the history and evolution of the solar system.
The mission is less than two weeks away from fulfilling its biggest goal – collecting a piece of a pristine, hydrated, carbon-rich asteroid. OSIRIS-REx will depart Bennu in 2021 and deliver the sample to Earth on Sept. 24, 2023.
The University of Arizona (UA) is a place without limits-where teaching, research, service and innovation merge to improve lives in Arizona and beyond. We aren’t afraid to ask big questions, and find even better answers.
In 1885, establishing Arizona’s first university in the middle of the Sonoran Desert was a bold move. But our founders were fearless, and we have never lost that spirit. To this day, we’re revolutionizing the fields of space sciences, optics, biosciences, medicine, arts and humanities, business, technology transfer and many others. Since it was founded, the UA has grown to cover more than 380 acres in central Tucson, a rich breeding ground for discovery.
U Arizona mirror lab-Where else in the world can you find an astronomical observatory mirror lab under a football stadium?University of Arizona’s Biosphere 2, located in the Sonoran desert. An entire ecosystem under a glass dome? Visit our campus, just once, and you’ll quickly understand why the UA is a university unlike any other.
OSIRIS-REx has scouted out a boulder-free target area in sampling dress rehearsals.
NASA/Goddard/University of Arizona
NASA OSIRIS-REx Spacecraft.
OSIRIS-REx is ready to get the goods. On 20 October, after several years of patient study of its enigmatic target, NASA’s $800 million spacecraft will finally stretch out its robotic arm, swoop to the surface of the near-Earth asteroid Bennu, and sweep up some dust and pebbles. The encounter, 334 million kilometers from Earth, will last about 10 seconds. If it is successful, OSIRIS-REx could steal away with up to 1 kilogram of carbon-rich material from the dawn of the Solar System for return to Earth in 2023.
Bennu. Credit: NASA/Goddard/University of Arizona.
Since OSIRIS-REx (short for Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) arrived in 2018, Bennu has yielded surprises, not all of them welcome. The 500-meter-wide asteroid was not smooth, as expected, but studded with more than 200 large boulders that could upset the sampling maneuver. And every so often, the asteroid ejected coin-size pebbles, probably propelled by meteoroid impacts or solar heating. The boulder hazard, in particular, forced the team to target an area just 16 meters across for sampling, 10 times smaller than planned. “Bennu has not made things easy for us,” says Mike Moreau, the mission’s deputy project manager at NASA’s Goddard Space Flight Center.
Despite the logistical challenge, the boulders contain a prize: veins of carbonate minerals thicker than your hands, the team reports in one of six studies published today in Science and Science Advances. The minerals, which precipitate out of hot water, popped out of data gathered during a close flyby of light-colored boulders near the target site, called Nightingale. Researchers believe the veins grew in channels of fluid circulating within Bennu’s parent body, a larger planetesimal thought to have formed beyond Jupiter’s orbit soon after the dawn of the Solar System 4.56 billion years ago, before being smashed apart in the asteroid belt within the last billion years. Heat from the decay of radioactive elements in its interior presumably drove the churning, and the presence of so much carbonate “suggests large-scale fluid flow, possibly over the entire parent body,” says Hannah Kaplan, a planetary scientist at Goddard who led the work.
(GRAPHIC) G. GRULLÓN/SCIENCE; (IMAGES, LEFT TO RIGHT) NASA; NASA/GODDARD/UNIVERSITY OF ARIZONA.
This ancient water world is consistent with the idea that objects like Bennu delivered much of Earth’s water when they struck the planet billions of years ago, says Dante Lauretta, the mission’s principal investigator and a planetary scientist at the University of Arizona. The veins also suggest watery bodies like Bennu were a cauldron for the organic chemistry that generated the amino acids and other unusual prebiotic compounds found in carbon-rich meteorites.
OSIRIS-REx won’t be sampling the carbonate veins directly: The chamber at the end of its robotic arm is designed to suck up grit smaller than a penny. That’s all right, however, because the small pebbles strewn across Nightingale also contain signs of carbonates and other organic molecules, the team reports today. “This gives me a hint that my dream is going to come true,” Lauretta says. “I want to bring back something we’ve never seen before.”
The team picked Nightingale for its abundant pebbles and because the site appears young, probably because an impact exposed it in recent geological time, leaving it largely unaltered by bombarding cosmic rays. But navigating the van-size spacecraft to a safe touchdown still won’t be easy; the site is ringed with building-size rocks, including one nicknamed Mount Doom, along with smaller boulders throughout. Observations suggest many of these boulders are porous, almost fluffy, and would crumble if touched. But the team doesn’t want to take that chance: Using its cameras to navigate, the spacecraft will automatically abort its approach at an altitude of 5 meters if the site appears hazardous.
The entire sampling attempt, lasting 4.5 hours, needs to be autonomous; Bennu is currently five times farther from Earth than Mars, and radio signals take 18 minutes to reach it. After thruster maneuvers bring it to the touch point with Bennu, blasts of nitrogen should push dust and pebbles into the doughnut-shaped collector at the end of the robotic arm. It will be several days before NASA can judge how much was gathered, based on images of the target site and sampling head, and changes in how the spacecraft spins. By the end of the month, managers will decide whether to make a second attempt at a backup site in January 2021. Either way, the spacecraft will leave Bennu next year and head back to Earth. It will arrive in September 2023 and eject the sample capsule, which will parachute to a landing in the Utah desert.
Aug. 12, 2020
Brittany Enos, University of Arizona
Yesterday, the OSIRIS-REx spacecraft performed its final practice run of the sampling sequence, reaching an approximate altitude of 131 feet (40 meters) over sample site Nightingale before executing a back-away burn. Nightingale, OSIRIS-REx’s primary sample collection site, is located within a crater in Bennu’s northern hemisphere.
The approximately four-hour “Matchpoint” rehearsal took the spacecraft through the first three of the sampling sequence’s four maneuvers: the orbit departure burn, the “Checkpoint” burn and the Matchpoint burn. Checkpoint is the point where the spacecraft autonomously checks its position and velocity before adjusting its trajectory down toward the event’s third maneuver. Matchpoint is the moment when the spacecraft matches Bennu’s rotation in order to fly in tandem with the asteroid surface, directly above the sample site, before touching down on the targeted spot.
Four hours after departing its 0.6-mile (1-km) safe-home orbit, OSIRIS-REx performed the Checkpoint maneuver at an approximate altitude of 410 feet (125 meters) above Bennu’s surface. From there, the spacecraft continued to descend for another eight minutes to perform the Matchpoint burn. After descending on this new trajectory for another three minutes, the spacecraft reached an altitude of approximately 131 ft (40 m) – the closest the spacecraft has ever been to Bennu – and then performed a back-away burn to complete the rehearsal.
These images were captured over a 13.5-minute period. The imaging sequence begins at approximately 420 feet (128 meters) above the surface – before the spacecraft executes the “Checkpoint” maneuver – and runs through to the “Matchpoint” maneuver, with the last image taken approximately 144 feet (44 meters) above the surface of Bennu. The spacecraft’s sampling arm – called the Touch-And-Go Sample Acquisition Mechanism (TAGSAM) – is visible in the lower part of the frame.Credits: NASA/Goddard/University of Arizona.
During the rehearsal, the spacecraft successfully deployed its sampling arm, the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), from its folded, parked position out to the sample collection configuration. Additionally, some of the spacecraft’s instruments collected science and navigation images and made spectrometry observations of the sample site, as will occur during the sample collection event. These images and science data were downlinked to Earth after the event’s conclusion.
Because the spacecraft and Bennu are currently about 179 million miles (288 million km) from Earth, it takes approximately 16 minutes for the spacecraft to receive the radio signals used to command it. This time lag prevented live commanding of flight activities from the ground during the rehearsal. As a result, the spacecraft performed the entire rehearsal sequence autonomously. Prior to the rehearsal’s start, the OSIRIS-REx team uplinked all of the event’s commands to the spacecraft and then provided the “Go” command to begin the event. The actual sample collection event in October will be conducted the same way.
This second rehearsal provided the mission team with practice navigating the spacecraft through the first three maneuvers of the sampling event and with an opportunity to verify that the spacecraft’s imaging, navigation and ranging systems operated as expected during the first part of the descent sequence.
Matchpoint rehearsal also confirmed that OSIRIS-REx’s Natural Feature Tracking (NFT) guidance system accurately estimated the spacecraft’s trajectory after the Matchpoint burn, which is the final maneuver before the sample collection head contacts Bennu’s surface. This rehearsal was also the first time that the spacecraft’s on-board hazard map was employed. The hazard map delineates areas that could potentially harm the spacecraft. If the spacecraft detects that it is on course to touch a hazardous area, it will autonomously back-away once it reaches an altitude of 16 ft (5 m). While OSIRIS-REx did not fly that low during the rehearsal, it did employ the hazard map to assess whether its predicted touchdown trajectory would have avoided surface hazards, and found that the spacecraft’s path during the rehearsal would have allowed for a safe touchdown on sample site Nightingale.
During the last minutes of the spacecraft’s descent, OSIRIS-REx also collected new, high-resolution navigation images for the NFT guidance system. These detailed images of Bennu’s landmarks will be used for the sampling event, and will allow the spacecraft to accurately target a very small area.
“Many important systems were exercised during this rehearsal – from communications, spacecraft thrusters, and most importantly, the onboard Natural Feature Tracking guidance system and hazard map,” said OSIRIS-REx principal investigator Dante Lauretta of the University of Arizona, Tucson. “Now that we’ve completed this milestone, we are confident in finalizing the procedures for the TAG event. This rehearsal confirmed that the team and all of the spacecraft’s systems are ready to collect a sample in October.”
The mission team has spent the last several months preparing for Matchpoint rehearsal while maximizing remote work as part of the COVID-19 response. On the day of rehearsal, a limited number of personnel monitored the spacecraft’s telemetry from Lockheed Martin Space’s facility, NASA’s Goddard Space Flight Center and the University of Arizona, taking appropriate safety precautions, while the rest of the team performed their roles remotely.
The spacecraft will travel all the way to the asteroid’s surface during its first sample collection attempt, scheduled for Oct. 20. During this event, OSIRIS-REx’s sampling mechanism will touch Bennu’s surface for several seconds, fire a charge of pressurized nitrogen to disturb the surface and collect a sample before the spacecraft backs away. The spacecraft is scheduled to return the sample to Earth on Sept. 24, 2023.
NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.
The OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is a NASA asteroid study and sample-return mission. The mission’s main goal is to obtain a sample of at least 60 grams (2.1 oz) from 101955 Bennu, a carbonaceous near-Earth asteroid, and return the sample to Earth for a detailed analysis. The material returned is expected to enable scientists to learn more about the formation and evolution of the Solar System, its initial stages of planet formation, and the source of organic compounds that led to the formation of life on Earth. If successful, OSIRIS-REx will be the first U.S. spacecraft to return samples from an asteroid. The Lidar instrument used aboard the OSIRIS-REx was built by Lockheed Martin, in conjunction with the Canadian Space Agency.
OSIRIS-REx was launched on 8 September 2016, flew past Earth on 22 September 2017, and reached the proximity of Bennu on 3 December 2018, where it began analyzing its surface for a target sample area over the next several months. It is expected to return with its sample to Earth on 24 September 2023.
The cost of the mission is approximately US$800 million not including the Atlas V launch vehicle, which is about US$183.5 million. It is the third planetary science mission selected in the New Frontiers program, after Juno and New Horizons. The principal investigator is Dante Lauretta from the University of Arizona.
President Dwight D. Eisenhower established the National Aeronautics and Space Administration (NASA) in 1958 with a distinctly civilian (rather than military) orientation encouraging peaceful applications in space science. The National Aeronautics and Space Act was passed on July 29, 1958, disestablishing NASA’s predecessor, the National Advisory Committee for Aeronautics (NACA). The new agency became operational on October 1, 1958.
Since that time, most U.S. space exploration efforts have been led by NASA, including the Apollo moon-landing missions, the Skylab space station, and later the Space Shuttle. Currently, NASA is supporting the International Space Station and is overseeing the development of the Orion Multi-Purpose Crew Vehicle and Commercial Crew vehicles. The agency is also responsible for the Launch Services Program (LSP) which provides oversight of launch operations and countdown management for unmanned NASA launches. Most recently, NASA announced a new Space Launch System that it said would take the agency’s astronauts farther into space than ever before and lay the cornerstone for future human space exploration efforts by the U.S.
July 17, 2020
Lindsey Valich
lvalich@ur.rochester.edu
Artist’s rendition of the OSIRIS-REx robotic explorer collecting samples on the Bennu asteroid’s surface. (NASA’s Goddard Space Flight Center image)
Recent NASA missions to asteroids have gathered important data about the early evolution of our Solar System, planet formation, and how life may have originated on Earth. These missions also provide crucial information about how to deflect asteroids that could hit Earth.
Missions like the OSIRIS-REx mission to asteroid Bennu and Japan’s Hayabusa 2 mission to asteroid Ryugu are often conducted by robotic explorers that send images back to Earth showing complex asteroid surfaces with cracked, perched boulders and rubble fields.
NASA OSIRIS-REx SpacecraftJAXA Hayabusa2
In order to better understand the behavior of asteroid material and design successful robotic explorers, researchers must first understand exactly how these explorers impact the surface of asteroids during their touchdown.
Researchers from the University of Rochester’s Department of Physics and Astronomy, including Alice Quillen, a professor of physics and astronomy, and Esteban Wright, a graduate student in Quillen’s lab, conducted lab experiments before the quarantine lockdown in March to determine what happens when explorers and other objects touch down on complex, granular surfaces in low-gravity environments. Their research, published in the journal Icarus, provides important information in improving the accuracy of data collection on asteroids.
“Controlling the robotic explorer is paramount to mission success,” Wright says. “We want to avoid a situation where the lander is stuck in its own landing site or potentially bounces off the surface and goes in an unintended direction. It may also be desirable for the explorer to skip across the surface to travel long distances.”
The researchers used sand to represent an asteroid’s surface in the lab. They then used marbles to measure how objects impact the sandy surfaces at different angles, and filmed the marbles with high-speed video in order to track the marbles’ trajectories and spin during impact with the sand.
“Granular materials like sand are usually quite absorbent upon impact,” Quillen says. “Similar to a cannonball ricocheting off of water, pushed sand can act like a snow in front of a snowplow, lifting the projectile, causing it to skip off the surface.”
Collaborating with members of Rochester’s Departments of Mechanical Engineering, Earth and Environmental Sciences, and Computer Science, the researchers constructed a mathematical model that includes the Froude number, a dimensionless ratio that depends on gravity, speed, and size. By scaling the model with the Froude number, the researchers were able to apply the knowledge gained from their experiments with the marbles to low-gravity environments, such as those found on asteroid surfaces.
“We found that at velocities near the escape velocity—the velocity at which an object will escape gravitational attraction—many if not most rocks and boulders are likely to ricochet on asteroids,” Wright says.
The results provide an explanation for why asteroids have strewn boulders and rocks that are perched on their surfaces, and they also influence the angle at which robotic missions will need to successfully touch down on the surface of an asteroid.
“Robotic missions that touch down on the surface of an asteroid will need to control the moment of touch down so that they don’t bounce,” Quillen says. “The robots can accomplish this by making their angle of impact nearly vertical, by reducing the velocity of impact to a very small value, or by making the velocity of impact large enough to form a deep crater that the robotic explorer won’t bounce out of.”
Grants from NASA and the National Science Foundation supported this research.
The University of Rochester is one of the country’s top-tier research universities. Our 158 buildings house more than 200 academic majors, more than 2,000 faculty and instructional staff, and some 10,500 students—approximately half of whom are women.
Learning at the University of Rochester is also on a very personal scale. Rochester remains one of the smallest and most collegiate among top research universities, with smaller classes, a low 10:1 student to teacher ratio, and increased interactions with faculty.
University students and researchers working on a NASA mission orbiting a near-Earth asteroid have made an unexpected detection of a phenomenon 30 thousand light years away. Last fall, the student-built Regolith X-Ray Imaging Spectrometer (REXIS) onboard NASA’s OSIRIS-REx spacecraft detected a newly flaring black hole in the constellation Columba while making observations off the limb of asteroid Bennu.
Regolith X-Ray Imaging Spectrometer (REXIS)
MIT graduate students Pronoy Biswas (left) and Mark Chodas prepare the Regolith X-Ray Imaging Spectrometer (REXIS) instrument for flight. REXIS can image X-ray emission from Bennu in order to provide an elemental abundance map of the asteroid’s surface. Credits: William Litant/MIT.
This image shows the X-ray outburst from the black hole MAXI J0637-043, detected by the REXIS instrument on NASA’s OSIRIS-REx spacecraft. The image was constructed using data collected by the X-ray spectrometer while REXIS was making observations of the space around asteroid Bennu on Nov. 11, 2019. The outburst is visible in the center of the image, and the image is overlaid with the limb of Bennu (lower right) to illustrate REXIS’s field of view. Credits: NASA/Goddard/University of Arizona/MIT/Harvard.
REXIS, a shoebox-sized student instrument, was designed to measure the X-rays that Bennu emits in response to incoming solar radiation. X-rays are a form of electromagnetic radiation, like visible light, but with much higher energy. REXIS is a collaborative experiment led by students and researchers at MIT and Harvard, who proposed, built, and operate the instrument.
This visualization simulates an X-ray outburst from the black hole MAXI J0637-043, detected by the REXIS instrument on NASA’s OSIRIS-REx spacecraft, as it moves through REXIS’s line of sight. At first, the outburst is visibly intense, but it gradually fades as it subsides. The animation was constructed using data collected by the X-ray spectrometer while REXIS was making observations of the space around asteroid Bennu on Nov. 11, 2019. Credits: NASA/Goddard/University of Arizona/MIT/Harvard.
On Nov. 11, 2019, while the REXIS instrument was performing detailed science observations of Bennu, it captured X-rays radiating from a point off the asteroid’s edge. “Our initial checks showed no previously cataloged object in that position in space,” said Branden Allen, a Harvard research scientist and student supervisor who first spotted the source in the REXIS data.
The glowing object turned out to be a newly flaring black hole X-ray binary – discovered just a week earlier by Japan’s MAXI telescope – designated MAXI J0637-430.
NASA’s Neutron Star Interior Composition Explorer (NICER) telescope also identified the X-ray blast a few days later. Both MAXI and NICER operate aboard NASA’s International Space Station and detected the X-ray event from low Earth orbit. REXIS, on the other hand, detected the same activity millions of miles from Earth while orbiting Bennu, the first such outburst ever detected from interplanetary space.
“Detecting this X-ray burst is a proud moment for the REXIS team. It means our instrument is performing as expected and to the level required of NASA science instruments,” said Madeline Lambert, an MIT graduate student who designed the instrument’s command sequences that serendipitously revealed the black hole.
X-ray blasts, like the one emitted from the newly discovered black hole, can only be observed from space since Earth’s protective atmosphere shields our planet from X-rays. These X-ray emissions occur when a black hole pulls in matter from a normal star that is in orbit around it. As the matter spirals onto a spinning disk surrounding the black hole, an enormous amount of energy (primarily in the form of X-rays) is released in the process.
“We set out to train students how to build and operate space instruments,” said MIT professor Richard Binzel, instrument scientist for the REXIS student experiment. “It turns out, the greatest lesson is to always be open to discovering the unexpected.”
The main purpose of the REXIS instrument is to prepare the next generation of scientists, engineers, and project managers in the development and operations of spaceflight hardware. Nearly 100 undergraduate and graduate students have worked on the REXIS team since the mission’s inception.
NASA’s Goddard Space Flight Center in Greenbelt, Maryland, provides overall mission management, systems engineering, and the safety and mission assurance for OSIRIS-REx. Dante Lauretta of the University of Arizona, Tucson, is the principal investigator, and the University of Arizona also leads the science team and the mission’s science observation planning and data processing. Lockheed Martin Space in Denver built the spacecraft and provides flight operations. Goddard and KinetX Aerospace are responsible for navigating the OSIRIS-REx spacecraft. OSIRIS-REx is the third mission in NASA’s New Frontiers Program, which is managed by NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington.
For more information on NASA’s OSIRIS-REx mission, visit:
The OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is a NASA asteroid study and sample-return mission. The mission’s main goal is to obtain a sample of at least 60 grams (2.1 oz) from 101955 Bennu, a carbonaceous near-Earth asteroid, and return the sample to Earth for a detailed analysis. The material returned is expected to enable scientists to learn more about the formation and evolution of the Solar System, its initial stages of planet formation, and the source of organic compounds that led to the formation of life on Earth. If successful, OSIRIS-REx will be the first U.S. spacecraft to return samples from an asteroid. The Lidar instrument used aboard the OSIRIS-REx was built by Lockheed Martin, in conjunction with the Canadian Space Agency.
OSIRIS-REx was launched on 8 September 2016, flew past Earth on 22 September 2017, and reached the proximity of Bennu on 3 December 2018, where it began analyzing its surface for a target sample area over the next several months. It is expected to return with its sample to Earth on 24 September 2023.
The cost of the mission is approximately US$800 million not including the Atlas V launch vehicle, which is about US$183.5 million. It is the third planetary science mission selected in the New Frontiers program, after Juno and New Horizons. The principal investigator is Dante Lauretta from the University of Arizona.
The University of Arizona (UA) is a place without limits-where teaching, research, service and innovation merge to improve lives in Arizona and beyond. We aren’t afraid to ask big questions, and find even better answers.
In 1885, establishing Arizona’s first university in the middle of the Sonoran Desert was a bold move. But our founders were fearless, and we have never lost that spirit. To this day, we’re revolutionizing the fields of space sciences, optics, biosciences, medicine, arts and humanities, business, technology transfer and many others. Since it was founded, the UA has grown to cover more than 380 acres in central Tucson, a rich breeding ground for discovery.
U Arizona mirror lab-Where else in the world can you find an astronomical observatory mirror lab under a football stadium?University of Arizona’s Biosphere 2, located in the Sonoran desert. An entire ecosystem under a glass dome? Visit our campus, just once, and you’ll quickly understand why the UA is a university unlike any other.
Planets, asteroids and Arrokoth were the focus of new discoveries.
Japan’s Hayabusa2 spacecraft, whose shadow is visible in this image, took this photo of the asteroid Ryugu in February after briefly touching down on the asteroid’s surface to collect a sample. The spacecraft is now heading back to Earth.
JAXA, Univ. of Tokyo, Kochi Univ., Rikkyo Univ., Nagoya Univ., Chiba Inst. Of Technology, Meiji Univ., Univ. of Aizu, AIST JAXA/Hayabusa 2 Credit: JAXA/Akihiro Ikeshita
From asteroids to exoplanets, spacecraft are leaving no space rock unturned. While agencies in China, India and Israel made headlines with missions to the moon, here are some other places that space probes scouted in 2019.
Zoom and enhance
Touring Pluto in 2015 may have been New Horizons’ main event (SN: 12/26/15, p. 16), but flying by what used to be called Ultima Thule was an awesome encore.
WORLD LIKE NO OTHER Long out of reach, Pluto came into focus in 2015 with the NASA/Mew Horizons mission.
JHU-APL, NASA, SwRI
Arrokoth appears as a ruddy deformed snowman in this composite image acquired by NASA’s New Horizons spacecraft as it sped past on January 1, 2019. NASA gave Ultima Thule a new official name, Arrokoth.
NASA, Johns Hopkins University Applied Physics Laboratory, Southwest Research Institute, Roman Tkachenko
I spy exoplanets
NASA’s Transiting Exoplanet Survey Satellite, or TESS, racked up eight exoplanet finds in its first few months of observation (SN: 2/2/19, p. 12).
NASA/MIT TESS replaced Kepler in search for exoplanets
That initial cache included some weirdos, such as a planet that is about as dense as pure water and a “lava world” known as LHS 3844b that sizzles at about 540° Celsius. TESS has since discovered a new type of exoplanet called an ultrahot Neptune, which appears to be a fluffy gas giant in the process of stripping down to its rocky core (SN: 8/31/19, p. 11).
Among the exoplanets discovered by NASA’s Transiting Exoplanet Survey Satellite, TESS, is LHS 3844b (illustrated), a “lava world” slightly bigger than Earth.TESS/NASA and MIT
Asteroids to go
The Japan Aerospace Exploration Agency’s Hayabusa2 is expected to become the second spacecraft ever to bring a bit of asteroid back to Earth, after the original Hayabusa probe returned with a souvenir from the asteroid Itokawa in 2010.
JAXA’s original Hayabusa spacecraft
Hayabusa2 touched down on the asteroid Ryugu in February to fetch a sample from the asteroid’s surface (SN Online: 2/22/19). Then, to get a deeper sample, Hayabusa2 fired a copper projectile at Ryugu to punch a crater into the asteroid (SN Online: 4/5/19). The probe then ducked down to snag some rubble excavated from the interior (SN: 8/17/19, p. 14). Scientists won’t know exactly how much of Ryugu was collected until Hayabusa2, which started its journey home on November 13, arrives at Earth in late 2020.
Another sample-return mission, NASA’s OSIRIS-REx, is still orbiting its asteroid. NASA OSIRIS-REx Spacecraft
When the spacecraft first arrived at Bennu in December 2018, observations unveiled a rugged surface littered with boulders — bad news for a probe designed to navigate more beachlike terrain (SN: 4/13/19, p. 10).
This mosaic image of asteroid Bennu is composed of 12 PolyCam images collected on Dec. 2 by the OSIRIS-REx spacecraft from a range of 15 miles (24 km). The image was obtained at a 50° phase angle between the spacecraft, asteroid and the Sun, and in it, Bennu spans approximately 1,500 pixels in the camera’s field of view.
Using OSIRIS-REx’s detailed mapping of Bennu from orbit, NASA selected a site for sample collection in the asteroid’s northern hemisphere (SN Online: 12/12/19). Bits of Bennu, to be returned in 2023, may reveal whether a similar asteroid could have delivered to early Earth a molecular starter pack for life (SN: 1/19/19, p. 20).
The space probe zipped by this Kuiper Belt object, now called Arrokoth, on New Year’s Day (SN Online: 12/30/18).
Kuiper Belt. Minor Planet Center
Scientists were on the edge of their seats as the probe snapped pictures and sent higher- and higher-resolution images over several weeks, revealing the visage of Arrokoth to look like an elongated blob, then a snowman and finally a pair of lumpy pancakes (SN: 3/16/19, p. 15). Uncovering the origins of Arrokoth’s awkward shape may lend insight into the early stages of planet formation (SN: 4/13/19, p. 11).
Meanwhile, on Mars
NASA’s Mars InSight mission may have made the first recording of a Marsquake. InSight’s seismometer is covered by the domed shield shown here.JPL-Caltech/NASA
NASA/Mars InSight Lander
InSight arrived on the Red Planet in November 2018, and the rookie lander may have already captured the first recording of a Marsquake (SN Online: 4/23/19). Unlike tremors on Earth, underground rumblings on Mars are thought to result from the planet contracting as it cools. Studying such seismic signals could help scientists better understand the structure of Mars’ deep interior.
While InSight had its ear to the ground, the veteran Curiosity rover was measuring the consistency of a Martian mountain (SN Online: 1/31/19).
NASA/Mars Curiosity Rover
As Curiosity scaled Mount Sharp, accelerometer readings indicated surprisingly loose rock beneath the rover’s wheels — suggesting that winds formed the mountain by sweeping sediment into a giant pile.
sciencesprings 