## Science Magazine: NASA weighs trimming WFIRST to hold down costs

The proposed Wide Field Infrared Survey Telescope. NASA

Oct. 23, 2017
Daniel Clery

NASA will have to scale back its next big orbiting observatory to avoid busting its budget and affecting other missions, an independent panel says. The Wide Field Infrared Survey Telescope (WFIRST) is due for launch in the mid-2020s. But 1 year after NASA gave the greenlight its projected cost is $3.6 billion, roughly 12% overbudget. “I believe reductions in scope and complexity are needed,” Thomas Zurbuchen, head of NASA’s Science Mission Directorate in Washington, D.C., wrote in a memo that NASA released last Thursday. Designed to investigate the nature of dark energy and study exoplanets, WFIRST was chosen by the astronomy community as its top space-based mission priority in the 2010 decadal survey entitled New Worlds, New Horizons in Astronomy and Astrophysics. But the start of the project was initially delayed by the huge overspend on its predecessor, the James Webb Space Telescope, which will be launched in 2019. NASA/ESA/CSA Webb Telescope annotated Then last year, a midterm review of the 2010 decadal survey warned that WFIRST could go the same way and advised NASA to form a panel of independent experts to review the project. NASA assembled that panel in April this year and it recently submitted its conclusions. The agency has not released its report, as it is due to be discussed by the Committee for Astronomy and Astrophysics of the National Academies of Sciences, Engineering, and Medicine this week, but it did release a memo from Zurbuchen to Christopher Scolese, director of the Goddard Space Flight Center in Greenbelt, Maryland, which is leading the project. In it, Zurbuchen directs the lab “to study modifying the current WFIRST design … to reduce cost and complexity sufficient to have a cost estimate consistent with the$3.2 billion cost target [set last year].” Though the panel heaped praise on the WFIRST team for the work done so far, according to Zurbuchen’s memo, it faulted NASA managers for creating several challenges that have made the project “more complicated than originally anticipated.”

Paul Hertz, head of NASA’s astrophysics division, told ScienceInsider that one major demand was enlarging the spacecraft to accommodate a 2.4-meter mirror that the National Reconnaissance Office donated in 2012. Another was adding an instrument called a coronagraph.

WFIRST, which will have the sensitivity of the Hubble Space Telescope but with 100 times its field of view, was originally designed to survey the sky for signs of cosmic acceleration caused by dark energy. But when exoplanet researchers realized it would also benefit their field they lobbied for the inclusion of a coronagraph. This device acts as a mask inside the telescope to block out the glaring brightness of a star and reveal any dim planets around it.

NASA also decided to split the ground segment for the mission between the Space Telescope Science Institute in Baltimore, Maryland, and the California Institute of Technology in Pasadena.

And in an act of future-proofing, NASA wanted WFIRST to carry equipment making it compatible with a starshade, a proposed spacecraft that can be stationed at a distance to block out starlight and reveal exoplanets (more effectively than a coronagraph). “All these things added complexity,” Hertz says.

Zurbuchen’s memo to Scolese directs the lab to retain the basic elements of the mission—the 2.4-meter mirror, widefield camera, and coronagraph—but to seek cost-saving “reductions.” Hertz says this will require reducing the capabilities of instruments but ensuring they remain “above the science floor laid down by the decadal survey.” The coronagraph will be recategorized as a “technology demonstration instrument,” removing the burden of achieving a scientific target. The change will also save money, Hertz explains.

Hertz says exoplanet researchers shouldn’t worry about the proposed changes. “We know we’ll get good science out of the coronagraph. We’ll be able to see debris disks, zodiacal dust, and exoplanets in wide orbits,” he says. Astronomers wanting to see Earth twins in the habitable zone may be disappointed, however.

Zurbuchen also asked project managers to save money in the ground segment and by letting industry build some components or subsystems. The WFIRST team will need to submit a revised design by February 2018, before vendors are chosen, to begin building the hardware.

If costs continue to escalate, Zurbuchen says in his memo, NASA may need to abandon the 2.4-meter mirror and revert to the original, cheaper design using a 1.5-meter one. “That is plan B,” says Hertz, “but we very much like the 2.4-meter mirror.”

Stem Education Coalition

## From NASA on tumblr: “A Wider Set of Eyes on the Universe”

After years of preparatory studies, we are formally starting an astrophysics mission designed to help unlock the secrets of the universe.
Introducing…
the Wide Field Infrared Survey Telescope, aka WFIRST.

With a view 100 times bigger than that of our Hubble Space Telescope, WFIRST will help unravel the secrets of dark energy and dark matter, and explore the evolution of the cosmos. It will also help us discover new worlds and advance the search for planets suitable for life.

WFIRST is slated to launch in the mid-2020s. The observatory will begin operations after traveling about one million miles from Earth, in a direction directly opposite the sun.

Telescopes usually come in two different “flavors” – you have really big, powerful telescopes, but those telescopes only see a tiny part of the sky. Or, telescopes are smaller and so they lack that power, but they can see big parts of the sky. WFIRST is the best of worlds.

No matter how good a telescope you build, it’s always going to have some residual errors. WFIRST will be the first time that we’re going to fly an instrument that contains special mirrors that will allow us to correct for errors in the telescope. This has never been done in space before!

Employing multiple techniques, astronomers will also use WFIRST to track how dark energy and dark matter have affected the evolution of our universe. Dark energy is a mysterious, negative pressure that has been speeding up the expansion of the universe. Dark matter is invisible material that makes up most of the matter in our universe.

Single WFIRST images will contain over a million galaxies! We can’t categorize and catalogue those galaxies on our own, which is where citizen science comes in. This allows interested people in the general public to solve scientific problems.

Stem Education Coalition

The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

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.

NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

## From astrobites: “Bubbles from reionization at the cosmic dawn”

Astrobites

Title: Dark-ages reionization & galaxy formation simulation XII: Bubbles at dawn
Authors: Paul Geil, Simon Mutch, Gregory Poole, Alan Duffy, Andrei Mesinger, and Stuart Wyithe
First Author’s Institution: University of Melbourne, Parkville, Victoria, Australia

Status: Submitted to MNRAS, open access

The early universe encompasses many scarcely understood phenomena both cosmological and astrophysical that we hope to begin exploring. This can be made possible by looking at the highly redshifted 21cm emission (see here for why this emission happens) from neutral hydrogen which puts these observations from the cosmic dawn relevant to today’s astrobite into the radio frequency range of 100-140 MHz. But this signal is notoriously faint, and requires some of the most sensitive instruments ever designed to observe it. Currently this is an emerging field where most of the instruments with the necessary sensitivity are only now entering the development stage. This certainly won’t stop us from understanding the potential pitfalls we may encounter along the way in measuring the early universe. We can of course anticipate how well we can detect this signal through simulations of the 21cm emission and our next generation radio telescopes.

Cosmic Dawn and Galactic Reionization Bubbles

When the first galaxies began to form they also began to emit UV radiation. This UV radiation reionized the surrounding neutral hydrogen, which means that it can no longer emit the 21cm emission. From our perspective when observing this we see large spherical holes (bubbles) begin to form over time, making a ‘Swiss cheese’-like effect at the largest scales. To make up for a lack of bubble observations, simulations of bubble formation from the Dark ages Reionization & Galaxy Formation Simulation (DRAGONS) (for an example see Fig. 1) were created.

Fig 1: Example of two galaxies with similar luminosities and solar mass from the DRAGON simulation. The progression of reionization of the galaxies is seen in the form of growing bubble size over redshift.

Using information about mean bubble size and luminosity from DRAGONS, a relationship between the two can be found. This helps us in sampling appropriate galaxies to survey from the future Wide-Field Infrared Survey Telescope High Latitude Survey (WFIRST-HLS).

NASA/WFIRST

Fig 2. shows that the mean bubble size \bar{R}, increases linearly with luminosity. (Another example of associating bubble size and luminosity can be seen in this astrobite.)

Fig. 2: The authors show through simulation of reionization bubbles around galaxies that they have a linear relationship between the mean bubble size \bar{R} and the UV magnitude M_{UV}

1cm Bubble Observing with the SKA

The Square Kilometer Array (SKA) is an upcoming radio interferometer array located in South Africa and Western Australia.

SKA-Square Kilometer Array

Murchison Widefield Array,SKA Murchison Widefield Array, Boolardy station in outback Western Australia, at the Murchison Radio-astronomy Observatory (MRO)

It will consist of 1 sq. km of collecting area, making it the most sensitive array to ever exist, and a perfect instrument for observing the 21cm signal. Observation of the 21cm signal is dependent on the differential brightness temperature, \delta T_b.

\delta T_b \propto x_{HI}(1+\delta)(1 – \frac{T_{\gamma}}{T_{S}})

The differential brightness temperature depends on the dark matter over-density \delta (small fluctuations in the density), the spin temperature T_S, the CMB temperature T_{\gamma}, and the fraction of neutral hydrogen x_{HI}. It’s important to note that \delta T_b is spatially dependent, as both \delta and x_{HI} depend on position.

For simulating the observation of the 21cm differential brightness temperature from the cosmic dawn, they use the SKA1-Low specifications which determine the sensitivity (see here for some basic interferometry) and observational hours required . But the sensitivity of the SKA isn’t enough, so stacking spectra (averaging observations over frequency) must be used. By focusing on high redshift galaxies (z > 9) predicted from the WFIRST-HLS, and stacking future SKA1-Low observations centered on these galaxies, the bubbles from reionization should be observable. An example of how likely these bubbles can be measured is seen in Fig. 3, which shows that the signal to noise ratio (SNR) grows considerably for stacking 100+ galaxy observations in the case where T_{S} >> T_{\gamma} (right).

Fig. 3: The SNR for observing reionization bubbles increases if more spectra are stacked (100,200,300) and if \delta T_b is saturated (right), which means \delta T_b >> T_{\gamma}.

It appears from the author’s results that imaging individual bubbles from reionization doesn’t seem too likely as there is too much uncertainty in redshift and a high sensitivity required from the radio interferometer. But the technique the authors of today’s astrobite describe of stacking spectra over many galaxies does appear to provide that extra sensitivity for a measurement. There is also the big caveat of this being an ideal case, because our observations of the early universe are troubled by bright galactic and extragalactic foregrounds. The work in this astrobite also demonstrates that making a measurement of reionization and its characteristic bubbles may rely on a synthesized approach e.g. using both 21cm and near infrared observations.

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What do we do?

Astrobites is a daily astrophysical literature journal written by graduate students in astronomy. Our goal is to present one interesting paper per day in a brief format that is accessible to undergraduate students in the physical sciences who are interested in active research.

Reading a technical paper from an unfamiliar subfield is intimidating. It may not be obvious how the techniques used by the researchers really work or what role the new research plays in answering the bigger questions motivating that field, not to mention the obscure jargon! For most people, it takes years for scientific papers to become meaningful.
Our goal is to solve this problem, one paper at a time. In 5 minutes a day reading Astrobites, you should not only learn about one interesting piece of current work, but also get a peek at the broader picture of research in a new area of astronomy.

## From Universe Today: “Rise Of The Super Telescopes: The Wide Field Infrared Survey Telescope – WFIRST”

Universe Today

2 May , 2017
Evan Gough

NASA’s Wide Field Infrared Survey Telescope (WFIRST) will capture Hubble-quality images covering swaths of sky 100 times larger than Hubble does. These enormous images will allow astronomers to study the evolution of the cosmos. Its Coronagraph Instrument will directly image exoplanets and study their atmospheres. Credits: NASA/GSFC/Conceptual Image Lab

We humans have an insatiable hunger to understand the Universe. As Carl Sagan said, “Understanding is Ecstasy.” But to understand the Universe, we need better and better ways to observe it. And that means one thing: big, huge, enormous telescopes.

In this series we’ll look at the world’s upcoming Super Telescopes:

The Giant Magellan Telescope
The Overwhelmingly Large Telescope
The 30 Meter Telescope
The European Extremely Large Telescope
The Large Synoptic Survey Telescope
The James Webb Space Telescope
The Wide Field Infrared Survey Telescope

The Wide Field Infrared Survey Telescope (WFIRST)

It’s easy to forget the impact that the Hubble Space Telescope has had on our state of knowledge about the Universe. In fact, that might be the best measurement of its success: We take the Hubble, and all we’ve learned from it, for granted now. But other space telescopes are being developed, including the WFIRST, which will be much more powerful than the Hubble. How far will these telescopes extend our understanding of the Universe?

“WFIRST has the potential to open our eyes to the wonders of the universe, much the same way Hubble has.” – John Grunsfeld, NASA Science Mission Directorate

The WFIRST might be the true successor to the Hubble, even though the James Webb Space Telescope (JWST) is often touted as such.

NASA/ESA/CSA Webb Telescope annotated

But it may be incorrect to even call WFIRST a telescope; it’s more accurate to call it an astrophysics observatory. That’s because one of its primary science objectives is to study Dark Energy, that rather mysterious force that drives the expansion of the Universe, and Dark Matter, the difficult-to-detect matter that slows that expansion.

WFIRST will have a 2.4 meter mirror, the same size as the Hubble. But, it will have a camera that will expand the power of that mirror. The Wide Field Instrument is a 288-megapixel multi-band near-infrared camera. Once it’s in operation, it will capture images that are every bit as sharp as those from Hubble. But there is one huge difference: The Wide Field Instrument will capture images that cover over 100 times the sky that Hubble does.

Alongside the Wide Field Instrument, WFIRST will have the Coronagraphic Instrument. The Coronagraphic Instrument will advance the study of exoplanets. It’ll use a system of filters and masks to block out the light from other stars, and hone in on planets orbiting those stars. This will allow very detailed study of the atmospheres of exoplanets, one of the main ways of determining habitability.

WFIRST is slated to be launched in 2025, although it’s too soon to have an exact date. But when it launches, the plan is for WFIRST to travel to the Sun-Earth LaGrange Point 2 (L2.)

LaGrange Points map. NASA

L2 is a gravitationally balanced point in space where WFIRST can do its work without interruption. The mission is set to last about 6 years.

Probing Dark Energy

“WFIRST has the potential to open our eyes to the wonders of the universe, much the same way Hubble has,” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate at Headquarters in Washington. “This mission uniquely combines the ability to discover and characterize planets beyond our own solar system with the sensitivity and optics to look wide and deep into the universe in a quest to unravel the mysteries of dark energy and dark matter.”

In a nutshell, there are two proposals for what Dark Energy can be. The first is the cosmological constant, where Dark Energy is uniform throughout the cosmos. The second is what’s known as scalar fields, where the density of Dark Energy can vary in time and space.

We used to think that the Universe expanded at a steady rate. Then in the 1990s we discovered that the expansion had accelerated. Dark Energy is the name given to the force driving that expansion. Image: NASA/STSci/Ann Feild

Since the 1990s, observations have shown us that the expansion of the Universe is accelerating. That acceleration started about 5 billion years ago. We think that Dark Energy is responsible for that accelerated expansion. By providing such large, detailed images of the cosmos, WFIRST will let astronomers map expansion over time and over large areas. WFIRST will also precisely measure the shapes, positions and distances of millions of galaxies to track the distribution and growth of cosmic structures, including galaxy clusters and the Dark Matter accompanying them. The hope is that this will give us a next level of understanding when it comes to Dark Energy.

If that all sounds too complicated, look at it this way: We know the Universe is expanding, and we know that the expansion is accelerating. We want to know why it’s expanding, and how. We’ve given the name ‘Dark Energy’ to the force that’s driving that expansion, and now we want to know more about it.

Probing Exoplanets

Dark Energy and the expansion of the Universe is a huge mystery, and a question that drives cosmologists. (They really want to know how the Universe will end!) But for many of the rest of us, another question is even more compelling: Are we alone in the Universe?

There’ll be no quick answer to that one, but any answer we find begins with studying exoplanets, and that’s something that WFIRST will also excel at.

Artist’s concept of the TRAPPIST-1 star system, an ultra-cool dwarf that has seven Earth-size planets orbiting it. We’re going to keep finding more and more solar systems like this, but we need observatories like WFIRST to understand the planets better. Credits: NASA/JPL-Caltech

“WFIRST is designed to address science areas identified as top priorities by the astronomical community,” said Paul Hertz, director of NASA’s Astrophysics Division in Washington. “The Wide-Field Instrument will give the telescope the ability to capture a single image with the depth and quality of Hubble, but covering 100 times the area. The coronagraph will provide revolutionary science, capturing the faint, but direct images of distant gaseous worlds and super-Earths.”

“The coronagraph will provide revolutionary science, capturing the faint, but direct images of distant gaseous worlds and super-Earths.” – Paul Hertz, NASA Astrophysics Division

The difficulty in studying exoplanets is that they are all orbiting stars. Stars are so bright they make it impossible to see their planets in any detail. It’s like staring into a lighthouse miles away and trying to study an insect near the lighthouse.

The Coronagraphic Instrument on board WFIRST will excel at blocking out the light of distant stars. It does that with a system of mirrors and masks. This is what makes studying exoplanets possible. Only when the light from the star is dealt with, can the properties of exoplanets be examined.

This will allow detailed measurements of the chemical composition of an exoplanet’s atmosphere. By doing this over thousands of planets, we can begin to understand the formation of planets around different types of stars. There are some limitations to the Coronagraphic Instrument, though.

The Coronagraphic Instrument was kind of a late addition to WFIRST. Some of the other instrumentation on WFIRST isn’t optimized to work with it, so there are some restrictions to its operation. It will only be able to study gas giants, and so-called Super-Earths. These larger planets don’t require as much finesse to study, simply because of their size. Earth-like worlds will likely be beyond the power of the Coronagraphic Instrument.

These limitations are no big deal in the long run. The Coronagraph is actually more of a technology demonstration, and it doesn’t represent the end-game for exoplanet study. Whatever is learned from this instrument will help us in the future. There will be an eventual successor to WFIRST some day, perhaps decades from now, and by that time Coronagraph technology will have advanced a great deal. At that future time, direct snapshots of Earth-like exoplanets may well be possible.

But maybe we won’t have to wait that long.

There is a plan to boost the effectiveness of the Coronagraph on WFIRST that would allow it to image Earth-like planets. It’s called the EXO-S Starshade.

The EXO-S Starshade is a 34m diameter deployable shading system that will block starlight from impairing the function of WFIRST. It would actually be a separate craft, launched separately and sent on its way to rendezvous with WFIRST at L2. It would not be tethered, but would orient itself with WFIRST through a system of cameras and guide lights. In fact, part of the power of the Starshade is that it would be about 40,000 to 50,000 km away from WFIRST.

Dark Energy and Exoplanets are priorities for WFIRST, but there are always other discoveries awaiting better telescopes. It’s not possible to predict everything that we’ll learn from WFIRST. With images as detailed as Hubble’s, but 100 times larger, we’re in for some surprises.

“This mission will survey the universe to find the most interesting objects out there.” – Neil Gehrels, WFIRST Project Scientist

“In addition to its exciting capabilities for dark energy and exoplanets, WFIRST will provide a treasure trove of exquisite data for all astronomers,” said Neil Gehrels, WFIRST project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This mission will survey the universe to find the most interesting objects out there.”

With all of the Super Telescopes coming on line in the next few years, we can expect some amazing discoveries. In 10 to 20 years time, our knowledge will have advanced considerably. What will we learn about Dark Matter and Dark Energy? What will we know about exoplanet populations?

Right now it seems like we’re just groping towards a better understanding of these things, but with WFIRST and the other Super Telescopes, we’re poised for more purposeful study.

Stem Education Coalition

## From Cornell: Women in STEM – “The Space between Stars and Galaxies” Rachel E. Bean

Cornell University

10.5.16
Jackie Swift

Rachel E. Bean

Mystery shrouds the birth of our universe. In a fraction of a second, the universe transformed from a size smaller than a subatomic proton through expanding exponentially faster than the speed of light, according to the Big Bang theory. At the heart of this event lies the explanation for all the constituents of the cosmos today. If the moment of the Big Bang can be understood, we may finally have the theory of everything that can reconcile the quantum Standard Model of particle physics with Einstein’s general theory of relativity, which holds that gravity is a result of the curvature of space and time.

Even the most powerful particle physics experiments on Earth don’t have enough clout to recreate the conditions in the early universe. We can find evidence of them, however, in the cosmic microwave background (CMB), which functions like a fossil remnant of that very early universe, says Rachel E. Bean, Astronomy.

CMB per ESA/Planck

“The CMB was made about 400 thousand years after the start of the universe,” she says. “It’s a pristine glimpse of what the universe was like at that instant, and buried inside that signal is a signature of what happened a trillionth of a second after the Big Bang.”

The Early Universe and the Cosmic Microwave Background

The CMB is a faint glow in the microwave wavelength that can be seen with telescopes that detect microwave radiation in the space between stars and galaxies. It has been traveling toward us for 13 billion years carrying information about those early moments. “At that time the universe was governed by quantum physics at a level that we don’t think we fully understand,” Bean says. “As we go back in time, the universe gets smaller, hotter and denser. At its very earliest instances, it was at temperatures and densities that we can never recreate on earth.”

In an effort to understand physics at those extreme properties, Bean looks for tiny temperature fluctuations in the CMB. These were generated a trillionth of a second after the Big Bang during a process called primordial inflation when the universe is thought to have expanded faster than the speed of light for a brief time. “We have to describe how quantum properties behave with gravity and space and time,” says Bean. “We don’t know how to do that. The only way we can try to figure this out is to look at these very early moments.” Bean hopes to connect these temperature fluctuations in the CMB to one of the potential theories—especially string theory—that are candidates to reconcile quantum mechanics and the general theory of relativity.

The CMB can also tell scientists about the effects of gravity on objects through time.

“The CMB has essentially seen everything that has been created since it was formed,” says Bean. “It traveled through the universe as it evolved, and as it did that it had the signatures of that history imbued upon it.”

Massive Galaxy Clusters, Dark Matter, and Dark Energy

Bean is interested in the information the CMB carries about its travels through the most massive objects in the universe: galaxy clusters. These are about a thousand times larger than our galaxy. As the CMB passes through a cluster, the heat of the cluster and its movement leaves a sort of Doppler shift on the frequency of the light from the CMB. “We can use the CMB as a motion detector for these clusters,” Bean explains. “We can see how fast they were moving when the CMB passed through them. This is useful because those clusters were moving because of the properties of gravity at that time.”

Bean will also be looking for evidence of the effects of dark matter and dark energy—two components of the universe that we cannot see. They do not emit light or absorb it, and none of our instruments can detect them. Scientists think that 95 percent of the matter in the universe is dark matter and dark energy, which change the properties of how gravity behaves. The only way to learn about the properties of these components is to look at their impact on astrophysical bodies such as galaxy clusters, Bean says. “By looking at how fast the galaxy clusters were moving in the past, we can test the properties of gravity and dark matter.”

Big Bold Telescopes, Up Soon

Astronomers will be able to do that in unparalleled detail over the next decade when four new telescopic surveys come online. These large-scale structure surveys will look at millions to billions of galaxies. They will either take multicolor images of them, revealing through color different physical properties, or they will record the galaxies’ spectra, the emission or absorption lines of light of particular wavelengths, which pinpoint the galaxies’ positions in space. “We’re going to be able to survey out billions of light years to be able to understand the structure of our universe with unprecedented precision,” Bean says.

Two of the telescopes will be ground-based and two will be space-based. Bean is the leader of an international collaboration of approximately 500 scientists—the LSST Dark Energy Science Collaboration—that will be using the data from one of the ground-based photometric imaging telescopes, the Large Synoptic Survey Telescope (LSST), which is an international venture led by two United States agencies, the National Science Foundation and the United States Department of Energy.

LSST/Camera, built at SLAC

LSST telescope, currently under construction at Cerro Pachón Chile

The LSST will be commissioned in 2019 with the first surveys coming online in 2021. Bean is scrambling to prepare for the challenge of analyzing all the anticipated data. “It’s going to be like a massive gush,” Bean says. “If we’re able to analyze it properly, we will get orders of magnitude improvement in our understanding of the properties of the cosmos.”

The LSST will share the ground-based spotlight with another state-of-the-art telescope, the Dark Energy Spectroscopic Instrument (DESI), a United States Department of Energy initiative, which will come online in 2019.

“LBL/DESI spectroscopic instrument on the Mayall 4-meter telescope at Kitt Peak National Observatory starting in 2018

The final two telescopes, both space-based, will be launched in the next decade: the European Space Agency’s Euclid in 2021 and the National Aeronautics and Space Administration’s Wide Field Infrared Survey Telescope (WFIRST) in the mid-twenties.

ESA/Euclid spacecraft

NASA/WFIRST

Bean plans to take the new information on the nature of galaxies provided by the four surveys and combine it with data on the motions of galaxy clusters gleaned from the CMB. Altogether they should help her and other cosmologists uncover the true properties of dark matter and dark energy, “We’ll be able to test whether general relativity holds on a cosmic scale,” Bean says. “That’s really exciting!”

Stem Education Coalition
Once called “the first American university” by educational historian Frederick Rudolph, Cornell University represents a distinctive mix of eminent scholarship and democratic ideals. Adding practical subjects to the classics and admitting qualified students regardless of nationality, race, social circumstance, gender, or religion was quite a departure when Cornell was founded in 1865.

Today’s Cornell reflects this heritage of egalitarian excellence. It is home to the nation’s first colleges devoted to hotel administration, industrial and labor relations, and veterinary medicine. Both a private university and the land-grant institution of New York State, Cornell University is the most educationally diverse member of the Ivy League.

On the Ithaca campus alone nearly 20,000 students representing every state and 120 countries choose from among 4,000 courses in 11 undergraduate, graduate, and professional schools. Many undergraduates participate in a wide range of interdisciplinary programs, play meaningful roles in original research, and study in Cornell programs in Washington, New York City, and the world over.

## From Astro Watch: “NASA’s WFIRST Spacecraft Expected to Be a Huge Step Forward in Our Understanding of Dark Matter”

Astro Watch

NASA/WFIRST telescope

NASA’s Wide Field Infrared Survey Telescope (WFIRST) could be a space observatory of the future, destined for great discoveries in the field of astrophysics. With a view about 100 times bigger than that of the iconic Hubble Space Telescope, WFIRST is expected to yield crucial results about the still-elusive dark matter and dark energy.

NASA/ESA Hubble Telescope

Perplexing astronomers for years, dark matter and dark energy could soon reveal their real nature. WFIRST is currently being designed to address the most baffling questions about these mysterious substances, together accounting for about 95 percent of the mass-energy of the universe. The spacecraft could provide a major improvement in our understanding of this subject.

“WFIRST will survey large areas of the sky measuring the effects of dark matter on the distribution of galaxies in the universe. It will also observe distant Type Ia supernovae to use them as tracers of dark matter and dark energy. It will provide a huge step forward in our understanding of dark matter and dark energy,” Brooke Hsu of NASA’s Goddard Space Flight Center in Greenbelt, Md. told Astrowatch.net.

WFIRST is managed at Goddard, with participation by the Jet Propulsion Laboratory (JPL) in Pasadena, California, the Space Telescope Science Institute in Baltimore, the Infrared Processing and Analysis Center, also in Pasadena, and a science team comprised of members from U.S. research institutions across the country.

The spacecraft is currently in Phase A of preparations. The purpose of this phase is to develop the mission requirements and architecture necessary to meet the programmatic requirements and constraints on the project and to develop the plans for the Preliminary Design phase. The preparations are on track for a mid-2020 launch. After liftoff, the telescope will travel to a gravitational balance point known as Earth-Sun L2, located about one million miles from Earth in a direction directly opposite the Sun.

LaGrange Points map

Operating at L2, WFIRST will study dark matter and dark energy with several techniques. The High Latitude Spectroscopic Survey will measure accurate distances and positions of a very large number of galaxies. It will measure the growth of large structure of the universe, testing theory of Einstein’s General Relativity.

“It will perform large surveys of galaxies and galaxy clusters to see the effects of dark matter and energy on their shapes and distributions in the universe. All told, more than a billion galaxies will be observed by WFIRST,” Hsu revealed.

The spacecraft will conduct the Type Ia Supernovae (SNe) Survey which will use type Ia SNe as “standard candles” to measure absolute distances. Calculating the distance to and redshift of the SNe provides another means of measuring the evolution of dark energy over time, providing a cross-check with the high latitude surveys.

“It will observe Type Ia supernovae to determine their distance and properties. More than 2,000 supernovae will be observed,” Hsu said.

WFIRST will also carry out the High Latitude Imaging Survey that will measure the shapes and distances of a very large number of galaxies and galaxy clusters. This survey is expected to determine both the evolution of dark energy over time as well as provide another independent measurement of the growth of large structure of the universe.

But WFIRST is not only about astrophysics. The infrared telescope will also have a chance to prove its usefulness as an exoplanet hunter. It will use microlensing techniques to expand our catalog of known extrasolar planets and will directly characterize these alien worlds using coronagraphy.

“WFIRST will study exoplanets with two very different techniques: microlensing and coronagraph. The mission will stare at the a dense star region toward the direction of the center of our Milky Way galaxy to observe microlensing events. These brightenings caused when two stars exactly align and also provide a tally of the exoplanets around the stars. Over 2,000 exoplanets will be detected this way,” Hsu noted.

To fulfill its scientific goals, WFIRST will be equipped in a 2.4-meter telescope hosting two instruments: the Wide-Field Instrument (WFI) and a high contrast coronagraph. WFI will provide the wide-field imaging and slitless spectroscopic capabilities required to perform the Dark Energy, Exoplanet Microlensing, and near-infrared (NIR) surveys while the coronagraph instrument is being designed for the exoplanet high contrast imaging and spectroscopic science.

“The Wide Field Instrument provides wide-field imaging and spectroscopy in support of the dark energy and microlensing surveys and integral field spectroscopy in support of the supernova survey,” Hsu said.

The coronagraph will be able to detect more than 50 exoplanets and observe their properties.

“It will be a huge leap forward compared to current instruments. Most exciting will be spectral observations of the light from the planets to see what the properties are of the atmospheres and possibly surfaces. Searches will be made for signatures of life on the planets,” Hsu said.

By operating WFIRST, NASA hopes to make major discoveries in the areas of dark matter and energy, exoplanets and general astrophysics. The agency expects to learn the nature of dark matter and energy to determine what they are.

“We will survey the sky to find the most exotic and interesting galaxies, black holes, and stars. We will take a census of exoplonets that are beyond on astronomical unit from their stars, a region that Kepler is not able to survey. We will make the first sensitive direct observation of nearby exoplanets and find what their nature is and if there are signatures of life,” Hsu concluded.

Stem Education Coalition

## From LBL: “Berkeley Lab, UC Berkeley Scientists to Participate in New NASA Space Telescope Project”

Berkeley Lab

February 18, 2016
Glenn Roberts Jr. 510-486-5582
geroberts@lbl.gov

Scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley will play a role in an upcoming space telescope project, formally set in motion this week by NASA, that will explore the mysteries of the expanding universe and observe alien worlds circling distant suns, among other science aims.

The Wide Field Infrared Survey Telescope (WFIRST) will launch into its six-year mission from Cape Canaveral, Fla., in the mid-2020s. NASA’s Agency Program Management Council made the decision to move forward with the WFIRST mission.

WFIRST

Saul Perlmutter, a Berkeley Lab astrophysicist and UC Berkeley astrophysics professor who shared the 2011 Nobel Prize in Physics for his research team’s discovery that our universe is expanding at an accelerating rate, will lead a 29-member scientific team, from 15 institutions, that will plan for the use of WFIRST supernovae observations to explore “dark energy,” the presumed cause of this mysterious acceleration.

Saul Perlmutter

Tracing the history of the universe to its so-called cosmic dawn, gaining new insight about star and galaxy formation and evolution, finding faint dwarf galaxies, studying distant objects through a light-bending phenomenon known as gravitational lensing, and surfacing new details from objects near the center of the Milky Way are also among WFIRST’s goals. The telescope will be NASA’s next major astrophysics observatory following the launch of the James Webb Space Telescope [JWST] in 2018.

JWST

“The question that was raised with the 2011 Nobel Prize is, ‘Why is the universe’s expansion accelerating?’” Perlmutter said. “With this new mission we get the chance to begin exploring the nature of dark energy.”

He added, “We think that this detailed expansion history is our current best shot as to getting a hint at which explanations for the accelerating expansion of the universe are true: If it’s dark energy, is it constant in time or changing over time? And if it’s not dark energy, are there revisions needed in [Albert] Einstein’s theory of general relativity”—a sort of rule book for spacetime and other fundamental physics—to best explain this acceleration?

Perlmutter and other Berkeley Lab scientists co-led earlier proposals, dating back to 1999, for a space telescope designed to study dark energy. The core dark energy mission of the earlier proposals, and more, can now be accomplished with WFIRST, Perlmutter noted.

WFIRST is a 2.4-meter telescope with a primary mirror the same size as that of the Hubble Space Telescope.

NASA/ESA Hubble

It has a field of view that is 100 times larger than Hubble’s infrared instrument and will measure light from an estimated billion galaxies.

WFIRST is expected to discover thousands of exoplanets—planets outside our solar system. It will be equipped with a device called a coronagraph that will record information about the chemistry of atmospheres for dozens of nearby exoplanets by blocking out light from their central stars, creating an artificial eclipse.

“In addition to its exciting capabilities for dark energy and exoplanets, WFIRST will provide a treasure trove of exquisite data for all astronomers,” said Neil Gehrels, WFIRST project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md. “This mission will survey the universe to find the most interesting objects out there.”

In measuring the shapes, positions and distances of millions of galaxies, WFIRST will provide fresh data on dark matter—the mysterious, unseen stuff that can be measured through its gravitational effects and makes up most of the universe’s matter.

Perlmutter noted that while his research team has used the Hubble telescope to study tens of Type Ia supernovae, WFIRST will gather more detailed information for thousands of supernovae. This precision should allow scientists to categorize Type Ia supernovae into different subclasses, he said.

The telescope’s dark energy mission will include three separate surveys:

A Type Ia Supernovae Survey will focus on the subclass of exploding stars that emit light in a narrow range of peak brightness. Type Ia supernovae are often referred to as standard candles because their common brightness provides researchers with a standard gauge of their distance from us. This survey, which will be the focus of Perlmutter’s team, will calculate the distance and redshift of Type Ia supernovae. Redshift is a measure of how light is stretched to redder wavelengths as the universe stretches during light’s multi-billion-year trip from the supernovae to us.
A High Latitude Spectroscopic Survey will determine changes in the concentration of galaxies throughout the history of the universe by precisely measuring the distance and position of galaxies.
A High Latitude Imaging Survey will study galaxies and galaxy clusters and calculate the mass distribution of the universe in 3-D. This can be useful in understanding the effects of dark energy over time and the evolution of the universe’s large-scale structure.

Perlmutter’s team, which has received approval for a five-year NASA grant, will work over the next few years to identify scientific requirements for the telescope’s instruments and to help guide the capabilities of the instrumentation. A dozen of these Science Investigation Teams were formalized in early January to explore different areas of WFIRST science, including two teams focusing on the supernova measurements of dark energy.

“We have to understand the exact properties of the instruments and figure out how to get the most precise measurements,” said David Rubin of the Space Telescope Science Institute in Maryland, a member of the WFIRST science team led by Perlmutter. “We also will conduct overall survey planning, including studies of possible ties with other observatories’ observations.”

Wendy Freedman, a fellow team member at University of Chicago, said it’s gratifying to see the space telescope project moving forward.

“With WFIRST, we should be able to graph a beautiful history of the expansion of the universe in unprecedented detail,” Freedman said. “This will be one for the textbooks, for years to come.”

The Berkeley Lab-led WFIRST Science Investigation Team will include scientists from the Carnegie Institution of Washington; California Institute of Technology; Florida State University; Harvard University; Las Cumbres Observatory Global Telescope Network Inc.; NASA Goddard Space Flight Center; Space Telescope Science Institute; Texas A&M University; University of Chicago; University of Pennsylvania; University of Pittsburgh; University of Texas, Austin; University of Washington; and Yale University.

As a principal investigator of the team, Perlmutter will serve on a Formulation Science Working Group that will include lead investigators from all of the WFIRST science teams.

WFIRST is managed at NASA’s Goddard Space Flight Center in Greenbelt, Md., with participation by the Jet Propulsion Laboratory in Pasadena, Calif.; the Space Telescope Science Institute in Baltimore; the Infrared Processing and Analysis Center in Pasadena; and a science team comprised of members from U.S. research institutions across the country.

Stem Education Coalition

A U.S. Department of Energy National Laboratory Operated by the University of California

## From UCSC: “Astronomers plan science projects for powerful new space telescope”

UC Santa Cruz

February 18, 2016
Tim Stephens

NASA begins formal development of the Wide Field Infrared Survey Telescope (WFIRST), planned to launch in the mid-2020s

WFIRST

The Wide Field Infrared Survey Telescope (WFIRST) will image large regions of the sky in near-infrared light to answer fundamental questions about the structure and evolution of the universe and greatly expand our knowledge of planetary systems around other stars. (Credit: NASA’s Goddard Space Flight Center)

A team of astronomers is beginning to plan projects and strategies for making the best use of a powerful new space telescope now under development by NASA.

NASA announced the formal start of the Wide Field Infrared Survey Telescope (WFIRST) mission on February 18. Planned as the agency’s next major astrophysics observatory following the launch of the James Webb Space Telescope [JWST], WFIRST will survey large regions of the sky in near-infrared light to answer fundamental questions about the structure and evolution of the universe and to expand our knowledge of planetary systems around other stars.

JWST

Brant Robertson, associate professor of astronomy and astrophysics at UC Santa Cruz, leads the WFIRST Extragalactic Potential Observations (EXPO) Science Investigation Team, which will identify the most pressing and scientifically compelling projects for WFIRST beyond the primary survey projects already planned for the telescope.

“There will be a huge amount of data from the surveys, and part of our job is to think about how we can make that data most useful for general astronomers in order to optimize the science payoffs,” Robertson said. “We are also helping to evaluate the design of the telescope, running simulations of how it will work and analyzing simulated images.”

Wide Field Instrument

WFIRST incorporates components from an existing telescope NASA acquired from another agency in 2012, including a 2.4-meter mirror of identical size and quality to the one used by the Hubble Space Telescope. The telescope’s Wide Field Instrument will give it the ability to capture a single image with the depth and quality of Hubble but covering 100 times Hubble’s field of view. WFIRST will also carry a Coronagraph Instrument designed to block the glare of individual stars and reveal the faint light of planets orbiting around them.

“The design work is already well advanced, and it is a really impressive telescope,” Robertson said. “Its camera is about 200 times larger than Hubble’s, and this capability will enable astronomers around the world to use WFIRST to explore the deepest reaches of space over an area thousands of times larger than the size of the moon on the sky.”

Guest investigators will be able to conduct their own investigations using data from the surveys, while guest observers can propose additional survey projects for the telescope. The WFIRST-EXPO team will evaluate guest investigator and guest observer projects to help maximize the scientific return of the WFIRST cosmological surveys and realize the full power of the telescope for extragalactic astronomy. The team, one of a dozen WFIRST science investigation teams, will receive \$2.3 million to perform these studies over the next five years.

Robertson leads the team of 11 astronomers, including world-wide experts in designing and executing space-based extragalactic survey programs, multi-object spectroscopic campaigns in optical and infrared wavelengths, and theoretical modeling of galaxy formation, exotic supernovae, and cosmic reionization. They include Piero Madau and Stan Woosley at UC Santa Cruz; Dan Marrone and Daniel Stark at the University of Arizona; Risa Wechsler at Stanford University; Jenny Greene at Princeton University; Steven Furlanetto and Alice Shapley at UCLA; Henry Ferguson at the Space Science Telescope Institute; and Mark Dickinson at the Association of Universities for Research in Astronomy.

In addition to surveys of deep space beyond our galaxy, WFIRST’s sensitivity and wide field of view will enable a large-scale search for exoplanets by monitoring the brightness of millions of stars in the crowded central region of our galaxy. The survey will net thousands of new exoplanets, complementing the work started by NASA’s Kepler mission and the upcoming work of the Transiting Exoplanet Survey Satellite.

Other wide-field surveys will enable astronomers to track how dark energy and dark matter have affected the expansion of the universe over the past 10 billion years or more. By measuring the distances to thousands of supernovae, astronomers can map in detail how cosmic expansion has increased with time. WFIRST can also precisely measure the shapes, positions and distances of millions of galaxies to track the distribution and growth of cosmic structures.

﻿Coronagraph

The Coronagraph Instrument will enable detailed measurements of the chemical makeup of planetary atmospheres. Comparing this data across many worlds will allow scientists to better understand the origin and physics of their atmospheres and to search for chemical signs of environments suitable for life.

“In addition to its exciting capabilities for dark energy and exoplanets, WFIRST will provide a treasure trove of exquisite data for all astronomers,” said Neil Gehrels, the WFIRST Project Scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This mission will survey the universe to find the most interesting objects out there.”

The James Webb Space Telescope (JWST), planned to launch in 2018, will see deeper into space and further back in time than WFIRST. With its larger mirror, JWST will be able to observe much fainter galaxies, but its field of view is much smaller.

On the left, Hubble’s mirror; on the right JWST’s mirror

“JWST will conduct very deep observations of a small area, while WFIRST will cover large areas at the same depth as Hubble,” Robertson said. “If they overlap and JWST is still operational when WFIRST launches, it will be a very powerful combination.”

WFIRST is slated to launch in the mid-2020s. The project is managed at Goddard, with participation by the Jet Propulsion Laboratory in Pasadena, California, the Space Telescope Science Institute (STScI) in Baltimore, the Infrared Processing and Analysis Center (IPAC) in Pasadena, and a science team with members from U.S. research institutions across the country.

Stem Education Coalition
The University of California, Santa Cruz, opened in 1965 and grew, one college at a time, to its current (2008-09) enrollment of more than 16,000 students. Undergraduates pursue more than 60 majors supervised by divisional deans of humanities, physical & biological sciences, social sciences, and arts. Graduate students work toward graduate certificates, master’s degrees, or doctoral degrees in more than 30 academic fields under the supervision of the divisional and graduate deans. The dean of the Jack Baskin School of Engineering oversees the campus’s undergraduate and graduate engineering programs.

## From Princeton: “Princeton professors to lead NASA science team probing universe and planets”

February 18, 2016
John Sullivan

Princeton University faculty members have been selected to lead [?]* the team of scientists responsible for a major NASA space observatory that will gauge the expansion of the cosmos and plumb the light of distant worlds.

WFIRST

NASA announced the establishment of the mission, the Wide-Field Infrared Space Telescope (WFIRST) project, on Feb. 18. Scheduled to launch in about 10 years, the telescope will be located at a point in space roughly 1 million miles from Earth [Lagrange Point 2] and positioned to observe a wide swath of interstellar space.

Lagrange Point map

The mission will have two broad objectives: to study the nature of dark energy, a substance that scientists believe holds the key to understanding the expansion and, perhaps, the ultimate fate of the universe; and to directly observe and analyze light from planets orbiting distant stars as a way to understand their composition and atmosphere.

“WFIRST is designed to address science areas identified as top priorities by the astronomical community,” said Paul Hertz, director of NASA’s Astrophysics Division in Washington, D.C. “The Wide-Field Instrument will give the telescope the ability to capture a single image with the depth and quality of Hubble, but covering 100 times the area. The coronagraph will provide revolutionary science, capturing the faint, but direct images of distant gaseous worlds and super-Earths.”

Princeton University professors David Spergel, left, and N. Jeremy Kasdin, right, will head [?] a team of scientists designing a major NASA space observatory. The mission, WFIRST (Wide-Field Infrared Survey Telescope), will investigate the nature of dark energy and observe the light from planets orbiting distant stars. Spergel, the Charles A. Young Professor of Astronomy on the Class of 1897 Foundation and chair of the Department of Astrophysical Sciences, is an expert on dark energy. Kasdin, a professor of mechanical and aerospace engineering and vice dean of the School of Engineering and Applied Science, is a leader in exoplanet research. (Photo illustration by David Kelly Crow for the Office of Engineering Communications)

Two Princeton professors, N. Jeremy Kasdin and David Spergel, will lead the teams of outside scientists [that’s better, Princeton] and experts who are developing the mission. Although both hold responsibility for the scientific success of the project, Kasdin is an expert in the observation of exoplanets, and Spergel is a leader in the study of dark energy. Kasdin is a professor of mechanical and aerospace engineering and vice dean of the School of Engineering and Applied Science. Spergel is the Charles A. Young Professor of Astronomy on the Class of 1897 Foundation and chair of the Department of Astrophysical Sciences.

NASA created a new title for the pair — adjutant scientists. They will ensure the project meets the needs of the scientific community and shepherd the research supporting its development.

The WFIRST project was named the top priority large space mission by the astronomy community in the nation’s last 10-year assessment in 2010, but the project could not start promptly due to budget constraints. Despite this, Spergel and Kasdin continued to work on the science proposal, leading outside study teams and coordinating meetings of interested scientists.

The project was given a boost after the U.S. intelligence agency responsible for satellite surveillance, the National Reconnaissance Office, told NASA that it had several surplus telescopes that could be repurposed for civilian use. Scientists believed that one of the scopes — a large, powerful instrument that could survey a broad area of the sky — could be adapted to fulfill the mission to explore dark energy. The telescope holds a mirror 2.4 meters in diameter, the same size as the Hubble Space Telescope, and could be refit to explore questions about dark energy and to examine light from distant planets. The mission was reborn.

Dominic Benford, NASA’s Program Scientist for WFIRST, said the science mission has several major components.

“The first component is that WFIRST will be the most advanced measurement of cosmology — of dark energy and the growth of cosmic structures in the universe — that has been undertaken,” he said. “The second is that is that WFIRST will complete the census of exoplanets begun by NASA’s Kepler mission and will conduct detailed studies by directly imaging a select number of exoplanetary systems.”

Kepler

The WFIRST spacecraft will hold packages of instruments to support its two primary missions.

As with most NASA observatory missions, WFIRST will make the telescope available for projects proposed by the international astronomy community. Benford said the mission design and construction will proceed over the next several years and the launch is slated for the mid-2020s.

Dark energy

For nearly a century, astronomers believed that the universe had been expanding since the Big Bang and would eventually slow and contract under the force of gravity. But in 1998, teams of scientists discovered that the universe’s expansion was not slowing down; in fact, it was accelerating.

There were two possible explanations for the acceleration: either scientists’ understanding of the universe, and gravity, was flawed, or there was some mysterious energy propelling the universe apart. Physicists dubbed this mysterious force dark energy and estimated that it could make up roughly 70 percent of the universe. Together with Lyman Page, chair of the Department of Physics, Spergel was one of the lead scientists for a previous NASA mission that looked for clues to explain the expansion of the universe. That mission, the Wilkinson Microwave Anisotropy Probe [WMAP] (named for the late Princeton physics professor David Wilkinson), examined microwave radiation to measure residual heat from the Big Bang.

WMAP

The mission concluded in 2010, and Spergel has used the mission data to produce a series of studies weighing dark energy and the observed behavior of the cosmos.

“Physicists are struggling to understand why the expansion rate of the universe is accelerating,” Spergel said. “We expect that gravity should be slowing the expansion just as gravity slows the motion of a rocket launched into space. We have two possible explanations for cosmic acceleration: the most popular notion suggests that most of the universe is in the form of dark energy associated with empty space. The other possibility is that general relativity is failing on cosmological scales. We are hoping that WFIRST will yield new insights into this mystery.”

The WFIRST mission will use three techniques to measure the universe’s expansion with far greater detail than anything that has come before. The telescope will peer so far out that mission scientists will be able to examine light that has been traveling over 11 billion years — most of the 13.7 billion years of the universe’s existence.

The time is important, Benford said, “because it covers the entire period of time in which the universe went from a decelerating to an accelerating mode.”

The instruments will use exploding stars called supernovae as a benchmark to measure the universe’s expansion. Because the color and brightness of supernovae is governed by well-understood physics, scientists can use the varying levels of brightness from these explosions to measure their distance. Another technique will take measurements of hundreds of millions of galaxies and use tiny distortions to attempt to map the distribution of dark matter. A third technique will take spectroscopic measurements of billions of galaxies to develop a three-dimensional distribution of the universe’s expansion. Taken together, readings from the instruments should give scientists a better understanding of the mechanisms driving the universe’s expansion and provide insight into how it fits into current theories of physics.

“These are all tests of the underlying nature of the universe,” Benford said.

Distant planets

Spergel and Kasdin were thrilled to learn of the new telescope but there was an immediate problem: the scope’s supporting structure was completely wrong to fit the device Kasdin’s team would use to observe distant planets. Most telescopes use thin supports, called spiders, to attach mirrors to the scope’s exterior barrel. Besides holding the mirror in place, the spiders slightly change the direction of light entering the telescope — they are responsible for the rays that emerge from stars in astronomy photographs.

For most astronomy projects, this slight diffraction does not matter, but because Kasdin’s project relies on channeling light to an incredibly precise degree, many people did not think it would be possible to use the repurposed telescope.

“The telescope was not designed for it, but Jeremy and Bob Vanderbei figured out a way,” Spergel said, referring to Robert Vanderbei, a professor of operations research and financial engineering at Princeton.

The team designed a special instrument, called a coronagraph, to tailor the light passing through the telescope. The science behind the device is complex, but in very simple terms, the coronagraph divides the light of a distant star from the light reflecting off a planet orbiting that star. It is a difficult task. For an Earth-sized planet, the difference in contrast between the star and the planet in orbit is about 10 billion times. It is like spotting a tiny fleck of tinsel floating in front of a spotlight.

“There is a mathematical function for how light behaves as it moves through an aperture,” said Vanderbei. “We put the light from the planet into a spot at which we cancel out the light from the star.”

Currently, most planets have been detected around distant stars by recording slight variations in the stars’ light caused by transiting planets that obscure part of the star. The coronagraph, on the other hand, would allow for direct observation of the light from the planets. This would allow astronomers to learn much more about the composition of the planets and their atmospheres — both by observation and spectral analysis.

“It is a quantum leap in capability,” said Adam Burrows, a professor of astrophysical sciences at Princeton and a member of the WFIRST exoplanet team.

Burrows said the project will allow scientists to discover “what these planets are made of, how they develop, what is their character.” This information will allow scientists to develop theories about how variations in stars impact the evolution of planetary systems, he said.

The WFIRST coronagraph will be capable of observing planets several times the size of Earth, around the size of Neptune and beyond, although it is possible that it might be able to spot slightly smaller worlds.

“This is a real stepping stone,” Kasdin said.

Kasdin said the long-term goal for projects like WFIRST is to achieve direct observation of Earth-like planets.

“It will get us nearer to answering the question of whether we are alone in the universe,” he said. “It is one of the most important questions, scientifically and philosophically, that we have ever asked.”

*I think it is far fetched to think that NASA wiould let any outsider actually lead a science mission. Maybe this was just poor editing.

Princeton University is a vibrant community of scholarship and learning that stands in the nation’s service and in the service of all nations. Chartered in 1746, Princeton is the fourth-oldest college in the United States. Princeton is an independent, coeducational, nondenominational institution that provides undergraduate and graduate instruction in the humanities, social sciences, natural sciences and engineering.

As a world-renowned research university, Princeton seeks to achieve the highest levels of distinction in the discovery and transmission of knowledge and understanding. At the same time, Princeton is distinctive among research universities in its commitment to undergraduate teaching.

Today, more than 1,100 faculty members instruct approximately 5,200 undergraduate students and 2,600 graduate students. The University’s generous financial aid program ensures that talented students from all economic backgrounds can afford a Princeton education.

## From NASA/HubbleSite- “NASA Introduces New, Wider Set of Eyes on the Universe: Baltimore’s Space Telescope Science Institute to Partner on New NASA ‘Wide-View’ Space Telescope”

NASA

February 18, 2016

Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4514
villard@stsci.edu

Roeland van der Marel
Space Telescope Science Institute, Baltimore, Maryland
410-338-4931
marel@stsci.edu

After years of preparatory studies, NASA is formally starting an astrophysics mission designed to help unlock the secrets of the universe — the Wide-Field Infrared Survey Telescope (WFIRST).

Illustration Credit: NASA’s Goddard Space Flight Center/Conceptual Image Lab

With a view 100 times bigger than that of NASA’s Hubble Space Telescope, WFIRST will aid researchers in their efforts to unravel the secrets of dark energy and dark matter, and explore the evolution of the cosmos.

NASA/ESA Hubble

It will also discover new worlds outside our solar system and advance the search for worlds that could be suitable for life.

NASA’s Agency Program Management Council, which evaluates the agency’s programs and projects on content, risk management, and performance, made the decision to move forward with the mission on Wednesday.

“WFIRST has the potential to open our eyes to the wonders of the universe, much the same way Hubble has,” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate at NASA Headquarters in Washington, D.C. “This mission uniquely combines the ability to discover and characterize planets beyond our own solar system with the sensitivity and optics to look wide and deep into the universe in a quest to unravel the mysteries of dark energy and dark matter.”

WFIRST is the agency’s next major astrophysics observatory, following the launch of the James Webb Space Telescope in 2018.

NASA/ESA/CSA Webb

The observatory will survey large regions of the sky in near-infrared light to answer fundamental questions about the structure and evolution of the universe, and expand our knowledge of planets beyond our solar system — known as exoplanets.

“As a general-purpose observatory, astronomers will use WFIRST to create panoramic views of the universe,” said Jason Kalirai of the Space Telescope Science Institute (STScI) in Baltimore, Maryland, who is one of the members of the WFIRST Formulation Science Working Group (FSWG). “These new windows on our solar system, the Milky Way galaxy, and the distant universe will yield fundamental progress in many astrophysical topics.”

WFIRST will carry a wide-field instrument for surveys, and a coronagraph instrument designed to block the glare of individual stars and reveal the faint light of planets orbiting around them. By blocking the light of the host star, the coronagraph instrument will enable detailed measurements of the chemical makeup of planetary atmospheres. Comparing these data across many worlds will allow scientists to better understand the origin and physics of these atmospheres, and search for chemical signs of environments suitable for life.

“The coronagraph will provide us an entirely new window for the detection of planets around other stars, and for the study of their atmospheres,” said STScI’s Nikole Lewis, another member of the FSWG. “It will also develop technology that will pave the way for finding and characterizing Earth-like planets in the future.”

“WFIRST is designed to address science areas identified as top priorities by the astronomical community,” said Paul Hertz, director of NASA’s Astrophysics Division in Washington, D.C. “The wide-field instrument will give the telescope the ability to capture a single image with the depth and quality of Hubble, but covering 100 times the area. The coronagraph will provide revolutionary science, capturing the faint, but direct images of distant gaseous worlds and super-Earths.”

The telescope’s sensitivity and wide view will enable a large-scale search for exoplanets by monitoring the brightness of millions of stars in the crowded central region of our galaxy. The survey will net thousands of new exoplanets similar in size and distance from their star as those in our own solar system, complementing the work started by NASA’s Kepler mission and the upcoming work of the Transiting Exoplanet Survey Satellite [TESS].

Kepler

TESS

Employing multiple techniques, astronomers also will use WFIRST to track how dark energy and dark matter have affected the evolution of our universe. Dark energy is a mysterious, negative pressure that has been speeding up the expansion of the universe. Dark matter is invisible material that makes up most of the matter in our universe.

By measuring the distances of thousands of supernovae, astronomers can map in detail how cosmic expansion has increased with time. WFIRST also can precisely measure the shapes, positions, and distances of millions of galaxies to track the distribution and growth of cosmic structures, including galaxy clusters and the dark matter accompanying them.

“In addition to its exciting capabilities for dark energy and exoplanets, WFIRST will provide a treasure trove of exquisite data for all astronomers,” said Neil Gehrels, WFIRST project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This mission will survey the universe to find the most interesting objects out there.”

WFIRST is slated to launch in the mid-2020s. The observatory will begin operations after traveling to a gravitational balance point known as Earth-sun L2, which is located about one million miles from Earth in a direction directly opposite the sun.

WFIRST is managed at Goddard, with participation by the Jet Propulsion Laboratory (JPL) in Pasadena, California; the Space Telescope Science Institute (STScI) in Baltimore, Maryland; the Infrared Processing and Analysis Center (IPAC), also in Pasadena; and a science team comprised of members from U.S. research institutions across the country. The leading members of the science team, together with NASA and science center representatives, make up the FSWG.

“The WFIRST mission will provide tremendous synergy with Hubble and Webb,” STScI director Ken Sembach said. “It will extend the legacy of Hubble-quality imaging to much wider fields, and will likely find many unique objects suitable for detailed follow-up study by Webb.”

STScI is the science operations center for both the Hubble and Webb telescopes. It will also be a partner in the WFIRST science center, sharing science operations responsibilities with Goddard and IPAC. STScI astronomers are also represented on the WFIRST science team and the FSWG.

During the mission formulation phase, STScI’s work will focus on the mission’s observation scheduling system, wide-field imaging data processing system, and the data archive. The Barbara A. Mikulski Archive for Space Telescopes (MAST) at STScI already holds the astronomical data from some 20 astronomy missions, and the addition of the WFIRST data will add considerably to its scientific discovery potential.

“We are proud that NASA has made us a partner in this revolutionary new mission,” said Roeland van der Marel, the WFIRST mission lead at STScI. “Our expertise with the Hubble and Webb space telescopes puts us in a unique position to support the science teams and the astronomical community, and to make this mission a success. The new observations and discoveries are guaranteed to be spectacular.”

http://wfirst.gsfc.nasa.gov/

For additional images and video associated with this story, visit:

Stem Education Coalition

The National Aeronautics and Space Administration (NASA) is the agency of the United States government that is responsible for the nation’s civilian space program and for aeronautics and aerospace research.

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.

NASA science is focused on better understanding Earth through the Earth Observing System, advancing heliophysics through the efforts of the Science Mission Directorate’s Heliophysics Research Program, exploring bodies throughout the Solar System with advanced robotic missions such as New Horizons, and researching astrophysics topics, such as the Big Bang, through the Great Observatories [Hubble, Chandra, Spitzer, and associated programs. NASA shares data with various national and international organizations such as from the [JAXA]Greenhouse Gases Observing Satellite.

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