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  • richardmitnick 3:55 pm on June 15, 2017 Permalink | Reply
    Tags: A call for proposals for regular Cycle 1 observations will be issued later this year, , , , , Guaranteed Time Observations, Guaranteed Time Observers were awarded 10 percent of the total JWST observing time in the prime mission, , NASA/ESA/CSA Webb   

    From Hubble: “Icy Moons, Galaxy Clusters, and Distant Worlds Among Selected Targets for James Webb Space Telescope” 

    NASA Hubble Banner

    NASA/ESA Hubble Telescope

    NASA/ESA Hubble Telescope

    Jun 15, 2017

    Christine Pulliam
    Space Telescope Science Institute, Baltimore, Maryland

    Ray Villard
    Space Telescope Science Institute, Baltimore, Maryland

    Felicia Chou
    NASA Headquarters, Washington, D.C.

    Natasha Pinol
    NASA Headquarters, Washington, D.C.

    NASA/ESA/CSA Webb Telescope annotated

    Mission officials for NASA’s James Webb Space Telescope announced some of the science targets the telescope will observe following its launch and commissioning. These specific observations are part of a program of Guaranteed Time Observations (GTO), which provides dedicated time to the scientists that helped design and build the telescope’s four instruments.

    “From the very first galaxies after the Big Bang, to searching for chemical fingerprints of life on Enceladus, Europa, and exoplanets like TRAPPIST-1e, Webb will be looking at some incredible things in our universe,” said Eric Smith, James Webb Space Telescope Director at NASA Headquarters in Washington. “With over 2,100 initial observations planned, there is no limit to what we might discover with this incredible telescope.”

    The broad spectrum of initial GTO observations will address all of the science areas Webb is designed to explore, from first light and the assembly of galaxies to the birth of stars and planets. Targets will range from the solar system’s outer planets (Jupiter, Saturn, Uranus, and Neptune) and icy Kuiper Belt to exoplanets to distant galaxies in the young universe.

    “The definition of observations to be conducted by the Webb Guaranteed Time Observers is a major milestone along the timeline for producing revolutionary science with this incredibly powerful observatory. These observations by the teams of people who designed and built the Webb instruments will yield not only amazing science, but will be crucial in putting the observatory through its paces and understanding its many capabilities,” said Dr. Ken Sembach, director of the Space Telescope Science Institute in Baltimore, which will lead science and mission operations for Webb.

    “I am very pleased that we’re at this point since it is now possible for the broader science community to begin selecting targets and designing observations for the Early Release Science program and the Cycle 1 call for proposals, which will be issued this fall,” he added.

    Observing time on Webb is scheduled in a series of cycles. Cycle 1 will encompass about 8,700 hours, or nearly a year. For their dedicated work on the project, the Guaranteed Time Observers were awarded 10 percent of the total JWST observing time in the prime mission. To maximize the overall Webb scientific return, the GTO projects will be scheduled earlier in the mission, and are expected to be completed within the first two years of telescope operations.

    The observations announced today will help the broader scientific community plan their proposals for observations to be made during Cycle 1. A call for proposals for regular Cycle 1 observations will be issued later this year.

    Webb is designed to complement and extend the scientific capabilities of other NASA missions such as the Hubble Space Telescope. It will be the most powerful space telescope ever built. Webb is an international project led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency). The Space Telescope Science Institute (STScI) in Baltimore, Maryland will conduct Webb science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

    See the full article here .

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    The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA’s Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI), is a free-standing science center, located on the campus of The Johns Hopkins University and operated by the Association of Universities for Research in Astronomy (AURA) for NASA, conducts Hubble science operations.

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  • richardmitnick 7:23 am on April 22, 2017 Permalink | Reply
    Tags: , , , , JWST lights out inspection, NASA/ESA/CSA Webb   

    From ESA: “JWST lights out inspection” 

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    European Space Agency



    After completion of its vibration and acoustic testing in March, the James Webb Space Telescope – JWST – is shown here undergoing a detailed ‘lights out’ inspection in one of NASA’s cleanrooms at the Goddard Space Flight Center.

    This is a special type of visual inspection to check for any forms of contamination. Both bright white LEDs and UV lights are used in order to better search for possible contamination, with the lights inside the cleanroom switched off to improve the contrast.

    The low lighting means the image had to be taken with a longer than normal exposure time. This makes the technicians appear somewhat ghostly as they moved about the cleanroom during the exposure.

    The image shows the segmented and gold-coated primary mirror of the telescope, which has a diameter of about 6.5 m when unfolded. It consists of 18 hexagonal segments, which will work together as one gigantic state-of-the-art mirror.

    In order to fit inside the Ariane 5 rocket that will boost it into space, some segments will be folded, which will then open in orbit.

    By the end of April, the telescope and the instruments will be shipped from NASA Goddard Space Flight Center in Maryland to Johnson’s Space Center in Texas where, over the course of the summer, it will go through final cryogenic-temperature testing.

    JWST is joint project of NASA, ESA and the Canadian Space Agency, and is scheduled for launch in October 2018 from Europe’s Spaceport in Kourou, French Guiana. This image was first published on 15 March via the NASA JWST pages.
    Credits: NASA–C. Gunn

    See the full article here .

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    The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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  • richardmitnick 10:47 am on March 20, 2017 Permalink | Reply
    Tags: , , , , , , NASA Plans To Turn The Largest Object in Our Solar System into a Telescope, NASA/ESA/CSA Webb   

    From Futurism: “NASA Plans To Turn The Largest Object in Our Solar System into a Telescope” 



    Chelsea Gohd

    A Solar Scope

    Each day we get closer to exploring farther reaches of our solar system and universe. We have come incredibly far and seem to make progress with each day. However, our ability to survey the outer corners of the cosmos is limited by our current telescopic technology. Now, modern telescopes are nothing to scoff at. As the iconic Hubble Telescope is phased out, the James Webb Space Telescope will continue to capture the beauty of outer space. But scientists have figured out a way to push the boundaries of telescopic technology even further: by turning the Sun (yes, that sun) into a telescope.

    Gravitational Lensing NASA/ESA

    Gravitational microlensing, S. Liebes, Physical Review B, 133 (1964): 835

    To use the sun as some sort of massive magnifying glass, scientists have deferred to Einstein’s Theory of Relativity. According to the theory, large objects (like the Sun) bend the space around them, and so anything traveling in that space (even light) bends as well. In a phenomenon known as gravitational lensing, if light is bent around an object in a particular way, it can magnify the space (quite literally, space) behind it.

    Scientists have previously used gravitational lensing to help telescopes to be more effective, but now, researchers aim to use this distribution of matter as a “telescope.” This new approach certainly has its pros and cons. In order to harness this lensing, the necessary instruments would need to approach pretty close to the sun, in order to reach a target 550 AU away. While humans and probes have traveled much closer to the sun than this, and plan to do so in the future, this difficult journey would take a long time and the equipment would have to be somehow “placed” into the middle of space.

    However, if this is pulled off, it would be a massive leap forward in imaging technology. We could finally get a closer, clearer look at Trappist-1, and would be that much closer to discovering life outside of Earth.

    A target pixel file representing light levels captured by the Kepler space telescope. Image Credit: NASA Ames/G. Barentsen

    James Webb

    As mentioned previously, this “sun scope” is not the only highly advanced space-imaging technology that’s surfacing. The James Webb Space Telescope, set to launch in October of 2018, will hopefully continue and advance the incredible work of the Hubble Telescope.

    NASA/ESA/CSA Webb Telescope annotated

    In fact, this telescope is so powerful that Lee Feinberg, an engineer and James Webb Space Telescope Optical Telescope Element Manager at Goddard, was quoted as saying. “The Webb telescope is the most dynamically complicated article of space hardware that we’ve ever tested.”

    The technology that we use to capture the incredible images of space is improving every day. Modern telescopes will continue to advance, becoming more powerful, more precise, and more detailed. So, while the idea of a sun-based telescope is incredible and could yield unprecedented images and information, even if it doesn’t pan out, we will most certainly continue to find improved ways to look at the Universe.

    See the full article here .

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    Futurism covers the breakthrough technologies and scientific discoveries that will shape humanity’s future. Our mission is to empower our readers and drive the development of these transformative technologies towards maximizing human potential.

  • richardmitnick 5:50 pm on March 8, 2017 Permalink | Reply
    Tags: , , , , NASA/ESA/CSA Webb,   

    From Universe Today: “The James Webb Space Telescope” 


    Universe Today

    8 Mar , 2017
    Evan Gough

    A full-scale model of the JWST went on a bit of a World Tour. Here it is in Munich, Germany. Image Credit: EADS Astrium

    NASA/ESA/CSA Webb Telescope annotated

    The James Webb Space Telescope (JWST, or the Webb) may be the most eagerly anticipated of the Super Telescopes. Maybe because it has endured a tortured path on its way to being built. Or maybe because it’s different than the other Super Telescopes, what with it being 1.5 million km (1 million miles) away from Earth once it’s operating.

    The JWST will do its observing while in what’s called a halo orbit at L2, a sort of gravitationally neutral point 1.5 million km from Earth. Image: NASA/JWST

    LaGrange Points map. NASA

    If you’ve been following the drama behind the Webb, you’ll know that cost overruns almost caused it to be cancelled. That would’ve been a real shame.

    The JWST has been brewing since 1996, but has suffered some bumps along the road. That road and its bumps have been discussed elsewhere, so what follows is a brief rundown.

    Initial estimates for the JWST were a $1.6 billion price tag and a launch date of 2011. But the costs ballooned, and there were other problems. This caused the House of Representatives in the US to move to cancel the project in 2011. However, later that same year, US Congress reversed the cancellation. Eventually, the final cost of the Webb came to $8.8 billion, with a launch date set for October, 2018. That means the JWST’s first light will be much sooner than the other Super Telescopes.

    The Webb was envisioned as a successor to the Hubble Space Telescope, which has been in operation since 1990. But the Hubble is in Low Earth Orbit, and has a primary mirror of 2.4 meters. The JWST will be located in orbit at the LaGrange 2 point, and its primary mirror will be 6.5 meters. The Hubble observes in the near ultraviolet, visible, and near infrared spectra, while the Webb will observe in long-wavelength (orange-red) visible light, through near-infrared to the mid-infrared. This has some important implications for the science yielded by the Webb.

    The Webb’s Instruments

    The James Webb is built around four instruments:

    The Near-Infrared Camera (NIRCam)
    The Near-Infrared Spectrograph (NIRSpec)
    The Mid-Infrared Instrument(MIRI)
    The Fine Guidance Sensor/ Near InfraRed Imager and Slitless Spectrograph (FGS/NIRISS)

    This image shows the wavelengths of the infrared spectrum that Webb’s instruments can observe. Image: NASA/JWST

    The NIRCam is Webb’s primary imager. It will observe the formation of the earliest stars and galaxies, the population of stars in nearby galaxies, Kuiper Belt Objects, and young stars in the Milky Way. NIRCam is equipped with coronagraphs, which block out the light from bright objects in order to observe dimmer objects nearby.

    NIRSpec will operate in a range from 0 to 5 microns. Its spectrograph will split the light into a spectrum. The resulting spectrum tells us about an objects, temperature, mass, and chemical composition. NIRSpec will observe 100 objects at once.

    MIRI is a camera and a spectrograph. It will see the redshifted light of distant galaxies, newly forming stars, objects in the Kuiper Belt, and faint comets. MIRI’s camera will provide wide-field, broadband imaging that will rank up there with the astonishing images that Hubble has given us a steady diet of. The spectrograph will provide physical details of the distant objects it will observe.

    The Fine Guidance Sensor part of FGS/NIRISS will give the Webb the precision required to yield high-quality images. NIRISS is a specialized instrument operating in three modes. It will investigate first light detection, exoplanet detection and characterization, and exoplanet transit spectroscopy.

    The Science

    The over-arching goal of the JWST, along with many other telescopes, is to understand the Universe and our origins. The Webb will investigate four broad themes:

    First Light and Re-ionization: In the early stages of the Universe, there was no light. The Universe was opaque. Eventually, as it cooled, photons were able to travel more freely. Then, probably hundreds of millions of years after the Big Bang, the first light sources formed: stars. But we don’t know when, or what types of stars.
    How Galaxies Assemble: We’re accustomed to seeing stunning images of the grand spiral galaxies that exist in the Universe today. But galaxies weren’t always like that. Early galaxies were often small and clumpy. How did they form into the shapes we see today?

    The Birth of Stars and Protoplanetary Systems: The Webb’s keen eye will peer straight through clouds of dust that ‘scopes like the Hubble can’t see through. Those clouds of dust are where stars are forming, and their protoplanetary systems. What we see there will tell us a lot about the formation of our own Solar System, as well as shedding light on many other questions.

    Planets and the Origins of Life: We now know that exoplanets are common. We’ve found thousands of them orbiting all types of stars. But we still know very little about them, like how common atmospheres are, and if the building blocks of life are common.

    These are all obviously fascinating topics. But in our current times, one of them stands out among the others: Planets and the Origins of Life.

    The recent discovery the TRAPPIST 1 system has people excited about possibly discovering life in another solar system. TRAPPIST 1 has 7 terrestrial planets, and 3 of them are in the habitable zone. It was huge news in February 2017. The buzz is still palpable, and people are eagerly awaiting more news about the system. That’s where the JWST comes in.

    One big question around the TRAPPIST system is “Do the planets have atmospheres?” The Webb can help us answer this.

    The NIRSpec instrument on JWST will be able to detect any atmospheres around the planets. Maybe more importantly, it will be able to investigate the atmospheres, and tell us about their composition. We will know if the atmospheres, if they exist, contain greenhouse gases. The Webb may also detect chemicals like ozone and methane, which are biosignatures and can tell us if life might be present on those planets.

    You could say that if the James Webb were able to detect atmospheres on the TRAPPIST 1 planets, and confirm the existence of biosignature chemicals there, it will have done its job already. Even if it stopped working after that. That’s probably far-fetched. But still, the possibility is there.

    Launch and Deployment

    The science that the JWST will provide is extremely intriguing. But we’re not there yet. There’s still the matter of JWST’s launch, and it’s tricky deployment.

    The JWST’s primary mirror is much larger than the Hubble’s. It’s 6.5 meters in diameter, versus 2.4 meters for the Hubble. The Hubble was no problem launching, despite being as large as a school bus. It was placed inside a space shuttle, and deployed by the Canadarm in low earth orbit. That won’t work for the James Webb.

    The Webb has to be launched aboard a rocket to be sent on its way to L2, it’s eventual home. And in order to be launched aboard its rocket, it has to fit into a cargo space in the rocket’s nose. That means it has to be folded up.

    The mirror, which is made up of 18 segments, is folded into three inside the rocket, and unfolded on its way to L2. The antennae and the solar cells also need to unfold.

    Unlike the Hubble, the Webb needs to be kept extremely cool to do its work. It has a cryo-cooler to help with that, but it also has an enormous sunshade. This sunshade is five layers, and very large.

    We need all of these components to deploy for the Webb to do its thing. And nothing like this has been tried before.

    The Webb’s launch is only 7 months away. That’s really close, considering the project almost got cancelled. There’s a cornucopia of science to be done once it’s working.

    But we’re not there yet, and we’ll have to go through the nerve-wracking launch and deployment before we can really get excited.

    See the full article here .

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  • richardmitnick 12:09 pm on January 11, 2017 Permalink | Reply
    Tags: , , , , , , NASA/ESA/CSA Webb   

    From Ethan Siegel: “The James Webb Space Telescope Will Truly Do What Hubble Only Dreamed Of” 

    Ethan Siegel
    Jan 10, 2017

    NASA/ESA/CSA Webb Telescope annotated
    NASA/ESA/CSA Webb Telescope annotated

    In 1990, NASA launched the Hubble Space Telescope. This observatory would come to revolutionize not only our scientific understanding of the Universe, but would reveal to humanity, for the first time, what our Universe actually looked like. We could peer inside the densest, most gas-and-dust-rich star forming nebulae, and see exactly how and were stars were beginning to form.

    NASA/ESA Hubble Telescope
    NASA/ESA Hubble Telescope

    The pillars of creation, as taken for Hubble’s 25th anniversary. Image credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA).

    We could look out at dying stars, reaching the end of their lives, and see exactly what their final moments in the Universe looked like.

    Four individual planetary nebulae — He 2-47, NGC 5315, IC 4593, and NGC 5307 — were imaged by Hubble in February of 2007. Image credit: NASA, ESA, and The Hubble Heritage Team (STScI/AURA).

    We could look out at distant galaxies, and reveal their shapes, ages, stellar populations and histories with simply a glimpse.

    The irregular, interacting galaxy pair Arp 230. Image credit: ESA/Hubble & NASA. Acknowledgement: Flickr user Det58.

    We could look out at the largest gravitationally bound structures in the Universe, and see how mass bent starlight, giving us a firsthand, visual look at the stunning phenomenon of gravitational lensing.

    Gravitational lensing in galaxy cluster Abell S1063, showcasing the bending of starlight by the presence of matter and energy. Image credit: NASA, ESA, and J. Lotz (STScI).

    And perhaps most importantly of all, we were able to look into the vast abyss of nothingness, photographing what lies beyond our visual reach for hours, days or even weeks at a time. What we wound up seeing changed our view of everything.

    The full UV-visible-IR composite of the Hubble eXtreme Deep Field; the greatest image ever released of the distant Universe. Image credit: NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI).

    Thanks to Hubble, we now know how stars are born, live and die. We know how galaxies form and grow in the Universe. We know what the ultimate fate of our Universe will be, and where we’re headed in the future. But even without any of this scientific knowledge, Hubble taught us something absolutely incredible: it showed us that this is what our Universe looks like.

    The James Webb Space Telescope vs. Hubble in size (main) and vs. an array of other telescopes (inset) in terms of wavelength and sensitivity. Image credit: NASA / JWST team.

    By the same token, the James Webb Space Telescope will teach us an incredible amount about the Universe, including further details about how stars form, what the earliest stellar populations look like, will show us gas giants and rogue planets in unprecedented detail and will tell us what made up the Universe at any given time in the past. It will show us a whole slew of things that Hubble cannot, by virtue of it reaching to much longer wavelengths of light than Hubble could ever hope to see. And with its huge, large-aperture primary mirror, it will be able to collect more light in a single day than Hubble could in a week. The most exciting things, of course, will be the unexpected: the things we’ll discover that we don’t even know to look for yet.

    An artist’s conception of what the Universe might look like as it forms stars for the first time. Image credit: NASA/JPL-Caltech/R. Hurt (SSC).

    But even if you don’t learn about any of the science that James Webb will bring to us, there’s one thing it will deliver that everyone can enjoy: the James Webb Space Telescope will show us how the Universe grew up.

    An illustration of CR7, the first galaxy detected that’s thought to house Population III stars: the first stars ever formed in the Universe. JWST will reveal actual images of this galaxy and others like it. Image credit: ESO/M. Kornmesser.

    It will show us how the Universe went from the hot Big Bang and a state with no stars, no planets and no galaxies into the Universe we have today. It will reveal the very first populations of stars, which were created out of the pristine elements — hydrogen and helium alone — which provided the first light in the Universe.

    On the left, the infrared light from the end of the Universe’s dark ages is shown, with the (foreground) stars subtracted out. JWST will be able to probe all the way back to the very first stars of all. Image credit: NASA/JPL-Caltech/A. Kashlinsky (GSFC).

    It will reveal how these first stars grew into star clusters, dwarf galaxies and eventually massive behemoths like our own. It will show us how the neutral atoms became ionized, and transparent to visible light. It will show us when and where the Universe became filled with oxygen, carbon and nitrogen: the elements essential to life. In short, it will tell us how the Universe went from being an inhospitable, smooth complex of pristine gas to the rich, diverse set of planets, stars, galaxies, clusters and great cosmic voids we enjoy today.

    The biggest ‘big idea’ that JWST has is to reveal to us the very first luminous objects in the Universe, including stars, supernovae, star clusters, galaxies, and luminous black holes. Image credit: Karen Teramura, UHIfA / NASA.

    Hubble showed us what the Universe looks like; James Webb will show us how the Universe came to be the way it is today. Don’t ever say that James Webb is the “next Hubble,” it isn’t and it should never be. Instead, it’s the first James Webb, and when it starts returning images of the Universe, you may never look at your place in the Cosmos the same way again.

    See the full article here .

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    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

  • richardmitnick 3:57 pm on November 22, 2016 Permalink | Reply
    Tags: , , , NASA/ESA/CSA Webb,   

    From NYT: “Telescope That ‘Ate Astronomy’ Is on Track to Surpass Hubble” 

    New York Times

    The New York Times

    NOV. 21, 2016
    Dennis Overbye

    The 18 mirrors that make up the heart of NASA’s James Webb Space Telescope, at the Goddard Space Flight Center. Credit Kevin Lamarque/Reuters

    The next great space telescope spread its golden wings this month.

    Like the petals of a 20-foot sunflower seeking the light, the 18 hexagonal mirrors that make up the heart of NASA’s James Webb Space Telescope were faced toward a glassed-in balcony overlooking a cavernous clean room at the Goddard Space Flight Center here.

    Inside the room, reporters and a gaggle of space agency officials, including the ebullient administrator Charles Bolden, were getting their pictures taken in front of the giant mirror.

    Now, after 20 years with a budget of $8.7 billion, the Webb telescope is on track and on budget to be launched in October 2018 and sent a million miles from Earth, NASA says.

    The telescope, named after NASA Administrator James Webb, who led the space agency in the 1960s, is the long-awaited successor of the Hubble Space Telescope.

    NASA/ESA Hubble Telescope
    NASA/ESA Hubble Telescope

    Seven times larger than the Hubble in light-gathering ability, the Webb was designed to see farther out in space and deeper into the past of the universe. It may solve mysteries about how and when the first stars and galaxies emerged some 13 billion years ago in the smoky aftermath of the Big Bang.

    Equipped with the sort of infrared goggles that give troops and police officers night vision, the Webb would peer into the dust clouds and gas storms of the Milky Way in which stars and planets are presently being birthed. It would be able to study planets around other stars.

    That has been NASA’s dream since 1996 when the idea for the telescope was conceived with a projected price tag then of $500 million But as recently as six years ago, the James Webb Space Telescope was, in the words of Nature magazine, the telescope that ate astronomy, mismanaged, over budget and behind schedule so that it had crushed everything else out of NASA’s science budget.

    A House subcommittee once voted to cancel it. Instead, the program was rebooted with a strict spending cap.

    The scientific capabilities of the telescope emerged unscathed from that period, astronomers on the project say. The major change, said Jonathan P. Gardner, the deputy senior project scientist, was to simplify the testing of the telescope.

    Most of the pain was dealt to other NASA projects like a proposed space telescope to study dark energy, which the National Academy of Sciences had hoped to put on a fast track to be launched this decade. It’s now delayed until 2025 or so.

    Charles Bolden, left, and John Mather of NASA at the unveiling of the James Webb Space Telescope’s mirror at NASA’s Goddard Space Flight Center earlier this month. Credit Kevin Lamarque/Reuters

    Typically for NASA, the Webb telescope was a technologically ambitious project, requiring 10 new technologies to make it work. Bill Ochs, a veteran Goddard engineer who became project manager in 2010 during what he calls the “replan,” said the key to its success so far, was having enough money in the budget to provide a cushion for nasty surprises.

    The telescope smiling up at us like a giant Tiffany shaving mirror is 6.5 meters in diameter, or just over 21 feet, compared with 2.4 meters for the Hubble. The aim is to explore a realm of cosmic history about 150 million to one billion years after time began — known as the reionization epoch, when bright and violent new stars and the searing radiation from quasars were burning away a gloomy fog of hydrogen gas that prevailed at the end of the Big Bang.

    In fact, astronomers don’t know how the spectacle that greets our eyes every night when the sun goes down or the lights go out wrenched itself into luminous existence. They theorize that an initial generation of stars made purely of hydrogen and helium — the elements created during the Big Bang — burned ferociously and exploded apocalyptically, jump-starting the seeding of the cosmos with progressively more diverse materials. But nobody has ever seen any so-called Population 3 stars, as those first stars are known. They don’t exist in the modern universe. Astronomers have to hunt them in the dim past.

    That ambition requires the Webb to be tuned to a different kind of light than our eyes or the Hubble can see. Because the expansion of the cosmos is rushing those earliest stars and galaxies away from us so fast, their light is “red-shifted” to longer wavelengths the way the siren from an ambulance shifts to a lower register as it passes by.

    So blue light from an infant galaxy bursting with bright spanking new stars way back then has been stretched to invisible infrared wavelengths, or heat radiation, by the time it reaches us 13 billion years later.

    As a result, the Webb telescope will produce cosmic postcards in colors no eye has ever seen. It also turns out that infrared emanations are the best way to study exoplanets, the worlds beyond our own solar system that have been discovered in the thousands since the Webb telescope was first conceived.

    In order to see those infrared colors, however, the telescope has to be very cold — less than 45 degrees Fahrenheit above absolute zero — so that its own heat does not swamp the heat from outer space. Once in space, the telescope will unfold a giant umbrella the size of a tennis court to keep the sun off it. The telescope, marooned in permanent shade a million miles beyond the moon, will experience an infinite cold soak.

    The sunshield consists of five thin, kite-shaped layers of a material called Kapton. Way too big to fit into a rocket, the shield, as well as the telescope mirror, will have be launched folded up. It will then be unfolded in space in a series of some 180 maneuvers that look in computer animations like a cross between a parachute opening and a swimming pool cover going into place.

    Or at least that is the $8 billion plan.

    Engineers have done it on the ground, and it worked. The same people who refolded the shield after each test will fold it again, in a process Mr. Ochs compares to packing up your parachute before a jump. The test will come in space, where no one will be able to help if things go wrong.

    That whole process will amount to what Mr. Ochs called “six months of high anxiety.”

    “For the most part, it all has to work,” Mr. Ochs said.

    The last time NASA did something this big astronomically, in 1990, things didn’t quite work. Once in orbit, the Hubble couldn’t be focused; it had a misshapen mirror that had never been properly tested. Astronauts eventually fitted it with corrective lenses, and it went on to become the crown jewel of astronomy.

    Making sure that doesn’t happen this time is the agenda for the next two years. “Our telescope is finished,” John C. Mather, the senior project scientist, said. “Now we are about to prove it works.”

    The Integrated Science Instrument Module planned for the James Webb Space Telescope. Credit Chris Gunn/NASA

    In the coming weeks, the mirror and the box of scientific instruments on its back will be put on a rig and shaken to simulate the vibrations of a launch, and then sealed in an acoustic chamber and bombarded with the noise of a launch.

    If the parts survive unscathed, the telescope assembly will be shipped to a giant vacuum chamber at the Johnson Space Center in Houston. There it will be chilled to the deep-space temperatures at which it will have to work, and engineers will actually focus the telescope, twiddling the controls for seven actuators on each of the 18 mirror segments. No Hubble surprises here.

    Then the telescope will go to Los Angeles to be mounted on its gigantic sunshield. That whole contraption, now too big for even the giant C-5A military transport plane, will travel by ship through the Panama Canal to French Guiana.

    It will be launched on an Ariane 5 rocket supplied by the European Space Agency as part of Europe’s contribution to the observatory, and go into orbit around the sun at a point called L2 about a million miles from Earth. Canada, NASA’s other partner, supplied some of the instruments.

    LaGrange Points map. NASA
    LaGrange Points map. NASA

    Then come the six months of anxiety. Sometime in the spring of 2019, if all goes well, the telescope will record its first real image — of what, the assembled astronomers were not ready to guess. In a bonus undreamed of when the Webb telescope was first conceived, it looks as if the Hubble will still be going strong when the Webb is launched. They will share the sky and the potential for joint observing projects. A million miles apart, they can view objects in the solar system from different angles, providing a kind of stereoscopic perspective.

    Besides the expected baby galaxies and the exoplanets, there are, as astronomers like to remind us, always new surprises (like colliding black holes when the LIGO observatory was turned on last year) when humanity devises a new way to look at the sky.

    LSC LIGO Scientific Collaboration

    Asked what the telescope’s greatest discovery would be, Dr. Mather said, “If I knew, I would tell you.”

    Nor would the project members talk about contingency plans to rescue the telescope if anything goes wrong a million miles from Earth. There are no plans to fix it or bring it back. They know how to attach a probe or robot to the telescope, Dr. Mather said, but “we are planning to not need it, thank you.”

    See the full article here .

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  • richardmitnick 4:39 pm on August 30, 2016 Permalink | Reply
    Tags: , , , NASA/ESA/CSA Webb,   

    From GIZMODO: “How We’ll Get Our First Big Clue About Life on Proxima b” 

    GIZMODO bloc


    Artist’s concept of Proxima b orbiting Proxima Centauri. (Image: ESO./L. Calçada/Nick Resigner)

    Last week, astronomers announced that our nearest neighboring star hosts an Earth-sized planet in the habitable zone—an exciting prospect for alien life, and a possible second home for humanity. But before we assemble the interstellar welcoming party to greet our cosmic neighbors, we need to figure out whether Proxima b is capable of supporting life at all. Thanks to the James Webb Space Telescope, that question could be answered in less than three years.

    NASA/ESA/CSA Webb Telescope annotated
    NASA/ESA/CSA Webb Telescope annotated

    “It is controversial whether or not life can exist in low mass star systems like Proxima Centauri,” Harvard astronomer Avi Loeb told Gizmodo. “Some people have argued that such planets cannot have an atmosphere.”

    That’s why Loeb, along with Harvard astronomer Laura Kreidberg, has just submitted a paper to Astrophysical Journal Letters describing how we can use the JWST—the highly-anticipated successor to Hubble that launches in 2018—to answer this critical question within just a few days of observation.

    The concern that Proxima b may be a dead, airless world stems from the fact that it orbits its dim red dwarf star, Proxima Centauri, at a distance of just 4.6 million miles. (Earth, for comparison, is 93 million miles from the Sun.) This tight orbit affords Proxima b enough sunlight for Earth-like temperatures and liquid water, but it also subjects the planet to powerful, atmosphere-stripping solar winds. What’s more, it virtually ensures that Proxima b is tidally locked, with a permanent dayside and a permanent nightside. Unfortunately, models suggest that the atmospheres of tidally locked planets may be prone to sudden collapse, as volatile gases freeze out on the nightside.

    But atmospheres can also be replenished through volcanic activity, and on planets with strong magnetic fields, they’re less likely to escape. Since we know nothing of Proxima b’s volcanic activity or magnetic field strength, we can’t even make an educated guess about its prospects of having an atmosphere. But we’re dying to know, because an atmosphere means oceans are possible, and the two together mean life is.

    That’s where the JWST comes in. As Loeb and Kreidberg discuss in their paper, the key to sniffing out Proxima b’s atmosphere lies in the planet’s infrared heat signature. And it just so happens that Hubble’s successor is highly attuned to the infrared part of the spectrum.

    “As Proxima b moves about its star, there is no day-night variation,” Loeb explained. “The day side is hot and the night side is cold. But the temperature difference between day and night depends on whether the planet is bare rock, or if it has an atmosphere or ocean, because these redistribute heat.”

    In other words, the temperature difference between Proxima b’s day side and its night side will be larger if there is no atmosphere. In fact, the day side will re-emit all of the energy it absorbs from Proxima Centauri as a blackbody, and we can calculate exactly how much blackbody radiation there should be. The night side, on the other hand, will be hell frozen over.

    If the temperature difference between day and night is less extreme, we can infer the presence of an atmosphere. Conveniently, it won’t take long for the JWST to measure IR emissions from both faces of Proxima b as it orbits its star—an entire year only takes 11.2 Earth days.

    If Proxima b does have an atmosphere, the next step will be figuring out what it’s made of. We’ll specifically want to look for things like oxygen, water vapor, and methane, which could indicate habitable conditions if not active biological processes. This, however, requires us to catch starlight as it bounces off or filters through the planet’s atmosphere—an extraordinarily difficult thing to do. While the JWST might be able to detect a few compounds including ozone, full atmospheric analysis will have to wait for future ground-based observatories like the Extremely Large Telescope, which is expected to see first light in the mid-2020s.

    “The important thing is that in a couple of years, we should be able to start learning about the atmosphere [of Proxima b],” Loeb said. “If there is one, it’s quite likely there’d be a call for a special mission to study just this planet.”

    As we continue building the tools to study Proxima b from Earth, Loeb is already thinking about how we might pay the planet a visit. He’s chairing the advisory committee for Breakthrough Starshot, a billionaire-backed effort to develop tiny, laser-propelled spacecraft that can travel at up to 20 percent the speed of light. While Breakthrough Starshot was initially packaged as a voyage to the nearby binary star system Alpha Centauri, the discovery of Proxima b changes everything.

    “I think it’s extremely important, psychologically, to have a target,” Loeb said. “If you ask a person to build a ship without knowing where it will sail, it’s quite different than if you have a destination in mind. The fact that we now have a target, in the habitable zone, is very exciting.”

    See the full article here .

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    “We come from the future.”

    GIZMOGO pictorial

  • richardmitnick 7:32 am on April 29, 2016 Permalink | Reply
    Tags: , , NASA/ESA/CSA Webb, Webb's mirror unveiled   

    From Goddard: “James Webb Space Telescope’s Golden Mirror Unveiled” 

    NASA Goddard Banner
    NASA Goddard Space Flight Center

    April 27, 2016
    Laura Betz
    NASA Goddard Space Flight Center

    NASA engineers recently unveiled the giant golden mirror of NASA’s James Webb Space Telescope as part of the integration and testing of the infrared telescope.

    Standing tall and glimmering gold inside NASA’s Goddard Space Flight Center’s clean room in Greenbelt, Maryland is the James Webb Space Telescope primary mirror. It will be the largest yet sent into space. Credits: NASA/Chris Gunn

    The 18 mirrors that make up the primary mirror were individually protected with a black covers when they were assembled on the telescope structure. Now, for the first time since the primary mirror was completed, the covers have been lifted.

    Standing tall and glimmering gold inside NASA’s Goddard Space Flight Center’s clean room in Greenbelt, Maryland, this mirror will be the largest yet sent into space. Currently, engineers are busy assembling and testing the other pieces of the telescope.

    Scientists from around the world will use this unique observatory to capture images and spectra of not only the first galaxies to appear in the early universe over 13.5 billion years ago, but also the full range of astronomical sources such as star forming nebulae, exoplanets, and even moons and planets within our own Solar System. To ensure the mirror is both strong and light, the team made the mirrors out of beryllium. Each mirror segment is about the size of a coffee table and weighs approximately 20 kilograms (46 pounds). A very fine film of vaporized gold coats each segment to improve the mirror’s reflection of infrared light. The fully assembled mirror is larger than any rocket so the two sides of it fold up. Behind each mirror are several motors so that the team can focus the telescope out in space.

    This widely anticipated telescope will soon go through many rigorous tests to ensure it survives its launch into space. In the next few months, engineers will install other key elements, and take additional measurements to ensure the telescope is ready for space.

    The James Webb Space Telescope is the scientific successor to NASA’s Hubble Space Telescope.

    NASA/ESA/CSA Webb Telescope annotated
    NASA/ESA/CSA Webb Telescope annotated

    NASA/ESA Hubble Telescope
    NASA/ESA Hubble Telescope

    It will be the most powerful space telescope ever built. Webb will study many phases in the history of our universe, including the formation of solar systems capable of supporting life on planets similar to Earth, as well as the evolution of our own solar system. It’s targeted to launch from French Guiana aboard an Ariane 5 rocket in 2018. Webb is an international project led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.

    See the full article here.

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    NASA’s Goddard Space Flight Center is home to the nation’s largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

    Named for American rocketry pioneer Dr. Robert H. Goddard, the center was established in 1959 as NASA’s first space flight complex. Goddard and its several facilities are critical in carrying out NASA’s missions of space exploration and scientific discovery.

    NASA Goddard Campus
    NASA/Goddard Campus

  • richardmitnick 8:58 am on February 19, 2016 Permalink | Reply
    Tags: , , , NASA/ESA/CSA Webb   

    From AAAS: “Building James Webb: the biggest, boldest, riskiest space telescope” 



    Feb. 18, 2016
    Daniel Clery

    Download mp4 video here .

    For months, inside the towering Building 29 here at Goddard Space Flight Center, the four scientific instruments at the heart of the James Webb Space Telescope (JWST, or Webb) have been sealed in what looks like a house-sized pressure cooker.

    NASA Webb telescope annotated

    A rhythmic chirp-chirp-chirp sounds as vacuum pumps keep the interior at a spacelike ten-billionth of an atmosphere while helium cools it to –250°C. Inside, the instruments, bolted to the framework that will hold them in space, are bathed in infrared light—focused and diffuse, in laserlike needles and uniform beams—to test their response.

    The pressure cooker is an apt metaphor for the whole project. Webb is the biggest, most complex, and most expensive science mission that NASA has ever attempted, and expectations among astronomers and the public are huge. Webb will have 100 times the sensitivity of the Hubble Space Telescope.

    NASA Hubble Telescope
    NASA/ESA Hubble

    It will be able to look into the universe’s infancy, when the very first galaxies were forming; study the birth of stars and their planetary systems; and analyze the atmospheres of exoplanets, perhaps even detecting signs of life. “If you put something this powerful into space, who knows what we can find? It’s going to be revolutionary because it’s so powerful,” says Matt Mountain, director of the Association of Universities for Research in Astronomy in Washington, D.C., and former JWST telescope scientist. Like that of Hubble, however, Webb’s construction has been plagued by redesigns, schedule slips, and cost overruns that have strained relationships with contractors, partners in Canada and Europe, and—most crucially—supporters in the U.S. Congress. Other missions had to be slowed or put on ice as Webb consumed available resources. A crisis in 2010 and 2011 almost saw it canceled, although lately the project has largely kept within its schedule and budget, now about $8 billion.

    NASA Webb primary mirror assembled
    Primary mirror assembled

    But plenty could go wrong between now and the moment in late 2018 when the telescope begins sending back data from its vantage point 1.5 million kilometers from Earth. It faces the stresses of launch, the intricate unfurling of its mirror and sunshield after it emerges from its chrysalis-like launch fairing, and the possibility of failure in its many cutting-edge technologies. Unlike Hubble, saved by a space shuttle mission that repaired its faulty optics, it is too far from Earth to fix. And not just the future of space-based astronomy, but also NASA’s ability to build complex science missions, depends on its success.

    That’s why those instruments sat in Goddard’s pressure cooker for what is known as cryo-vacuum test 3 (CV3). And it is why Webb’s other components—including the mirror and telescope structure, the “bus” that will supply power and control the telescope, and the tennis court–sized, multilayer parasol that will help keep it cool—must undergo a gauntlet of testing, alone and in combinations, until the whole spacecraft is ready. For those on the inside, the strain will only increase as assembly continues, the tests get bigger and more comprehensive, and the spacecraft is launched into space. Only when Webb opens its eye and successfully focuses on its first star will the strain be released.

    In the mid-1990s, after Hubble had had its optics corrected and was busy revolutionizing astronomy, researchers began planning its successor. The catch phrase in NASA at the time, championed by agency chief Daniel Goldin, was “faster, better, cheaper.” Goldin challenged NASA engineers and the astronomical community to come up with a follow-on that was cheaper than Hubble but bigger, with a mirror 8 meters across.

    NASA Hubble mirror vs Webb mirror
    Mirrors: Hubble on left, Webb on right

    He received a standing ovation when he described the plans to the American Astronomical Society in 1996. Whereas Hubble covered the whole range of visible light, plus a smidgen of ultraviolet and infrared, the Next Generation Space Telescope (as it was then known) would be a dedicated infrared observatory.

    For astronomers, the infrared spectrum was a beckoning frontier. Visible light from the most distant objects in the universe, the very first stars and galaxies that formed after the big bang, gets stretched so much by the expansion of the universe that it ends up in the infrared range by the time it reaches us. Many chemical signatures in exoplanet atmospheres also show themselves in the infrared region. Yet Earth’s atmosphere blocks most infrared. Webb will give us “the first high-definition view of the midinfrared universe,” says Matt Greenhouse, JWST project scientist for the instrument payload at Goddard.

    To capture that light, however, NASA engineers had to overcome huge challenges. The first was heat: To keep the infrared glow of the telescope itself from swamping faint astronomical signals, Webb would need to operate at about –233°C, 40° above absolute zero (40 K). That would require entirely new instrument designs. Size and weight constraints posed additional hurdles: An 8-meter mirror would never fit inside a rocket fairing, so it would have to fold up for launch. The sunshield, too, would have to be collapsible and made of a superthin, lightweight membrane. And the telescope structure would have to be absolutely rigid but lightweight enough to limit the weight of the whole orbiting observatory to no more than 6 tonnes, just a few percent of the weight of a similar-size ground-based telescope. “We knew we would have to invent 10 new technologies” to make the telescope work, says NASA’s JWST Program Director Eric Smith, in Washington, D.C.

    Take the mirror. Hubble’s was made from a single slab of glass, but Webb’s folding mirror would need to be segmented, made up of separate hexagonal pieces—a design used in many top ground-based instruments, including the Keck telescopes in Hawaii.

    Keck Observatory
    Keck Observatory Interior
    Keck Observatory

    Keck mirror
    One of the Keck mirrors

    The segments would have to be minutely controlled to meld them into a single optical surface, with their reflected light completely in step—a process known as phasing. In Webb, each hexagonal segment will sit on six actuators that control its orientation, plus one in the center to adjust its curvature.

    Choosing the mirror material itself was a challenge, because it would have to stand up to a grueling ordeal. Because any material will change shape as it cools, each segment would have to be ground to a shape that is optically wrong at room temperature but warps into one that is correct—to within nanometers—at 40 K. To do that, the mirrormakers planned to combine sophisticated computer modeling with a laborious, iterative process of grinding, cooling, measuring, warming, regrinding, cooling again, and so on. After testing both glass and the metal beryllium, Webb planners chose beryllium because it is strong and light, and it behaves more predictably during repeated cooling and warming cycles.

    The final design for Webb fell short of NASA’s original ambitions. Beginning in 2001, concerns about the swelling cost of the telescope forced NASA to shrink the mirror from 8 meters to 6.5 meters, reducing the number of mirror segments from 36 to 18 and its light-collecting area from 50 square meters to 25. But review panels decided that Webb could still achieve its scientific goals. To cut costs further, NASA decided to use less precise mirrors that could be manufactured with many fewer cooling-warming-grinding steps. The change would make Webb less sharp at near-infrared wavelengths between 1 and 2 micrometers—no great loss, as ground-based telescopes already cover that part of the spectrum.

    By 2006, all of Webb’s key technologies had been tested and proven viable. The final design was drawn up, and construction of components got underway. Meanwhile, NASA engineers began dreaming up the byzantine series of tests each separate component would have to pass—and the additional tests to be done as components were combined to form larger elements of the spacecraft. “As soon as we put two or three parts together, we test them,” says Scott Willoughby, who is in charge of the Webb effort at Northrop Grumman in Redondo Beach, California.

    To put Webb’s enormous mirror through its paces, engineers at the Johnson Space Center in Houston, Texas, completely refitted Chamber A, a huge cryo-vacuum chamber built to test the crew-carrying spacecraft of the Apollo program. For the instruments, they devised the peculiar tortures at Goddard.

    The flight models of the instruments began arriving in 2012: four infrared imagers and spectrographs built by collaborators including the European Space Agency, a NASA/European consortium, the University of Arizona, and the Canadian Space Agency. Once the instruments were secured on their rigid framework, they were vigorously shaken to simulate the stresses of launch, as well as blasted with 150 decibels by loudspeaker horns as tall as a person. Next came the first cryo-vacuum test to simulate space conditions.

    Problems emerged almost immediately. The heating and cooling caused the delicate multilayer semiconductor sandwiches that make up the infrared detectors to swell and crack. Another critical technology, the microshutter array in the near-infrared spectrograph, also succumbed. This is a device the size of four postage stamps with a grid of 250,000 tiny flaps that can be opened selectively so that the instrument can take separate spectra from, say, 100 galaxies in a single field of view—the first such multiobject spectrograph to fly in space. But the deafening noise of the acoustic chamber caused many of the flaps to jam.

    Instrument teams and manufacturers scrambled to identify the problems and produce new parts. Meanwhile, testing went on. All the replacements came together in time for the recent CV3 test, and as the test ended in late January the signs were encouraging that the fixes had worked. “We’re quite pleased with the performance,” says astronomer Marcia Rieke of the University of Arizona’s Steward Observatory in Tucson, principal investigator for the near-infrared camera. “We’re very close to ready for launch.”

    While the instruments underwent their ordeal, white-clad engineers in a nearby clean room were painstakingly fitting the mirror segments onto their support, known as the backplane. Hollowed out on the back to reduce weight, each 1.3-meter-wide segment can be carried by a single person, and each has a particular destination on the backplane, depending on its precise optical qualities.

    Now that the instruments have been tested and the mirror assembled, these two elements will be mated in March. Then the combined telescope and instrument package, collectively known as OTIS, will endure the shaker tables and acoustic chamber before being inserted into a specially built shipping container. In the dead of night, a truck will carry the container at just 8 kilometers per hour from Goddard to Joint Base Andrews, where it will be placed into a huge C-5 Galaxy transport plane, with just centimeters of clearance, for its flight to Houston.

    The few months OTIS spends in Chamber A early next year will be the most critical it will face. Light sources on the ceiling will create an artificial universe, allowing NASA engineers to run light all the way through the system from main mirror to detectors for the first and only time in spacelike conditions. They will practice phasing up the mirror and will check out all observing modes of the four instruments. “Hubble didn’t do an end-to-end optical test. We’re not skipping that on this program,” Greenhouse says.

    Then it’s back into the shipping container and another C-5 flight to Redondo Beach, where Northrop Grumman has been building the bus and sunshield. There the full observatory will take shape as the telescope and instruments are mated to these last two elements.

    Now too large to fit inside a plane, Webb will make its final prelaunch journey by ship, down the California coast and through the Panama Canal to French Guiana—home of Europe’s spaceport, and a waiting Ariane 5 launcher, part of Europe’s contribution to the project. In October 2018, the Ariane will fling Webb towardL2 [Lagrange Point 2], a gravitational balance point 1.5 million kilometers from Earth, directly away from the sun.

    LaGrange Points map
    Lagrange Point map

    The journey will take 29 days.

    Webb will begin unfolding and deploying components almost as soon as it hits space. Deployment will be “3 weeks of terror,” Mountain says. “No one has done this before, ever.” First to deploy will be solar arrays and antennas to provide power and communications with Earth; then the sunshield will unfurl to begin cooling the telescope and instruments; finally, the secondary mirror will swing into position and the main mirror wings will snap into place. Once the mechanical gymnastics routine is finished, there will come the heart-stopping moment when the mirror first looks at the sky. Then the mirror has to be phased up, and the instruments cooled and all their modes tested. Commissioning is expected to take a full 6 months after launch.

    “A whole chain of things have to be done to get that really good-looking star,” says Lee Feinberg, JWST telescope manager at Goddard. “But then we can really rest.”

    Until then, the pressure will be unrelenting. But the builders of Webb say they do find time to reflect on what they are doing. Pierre Ferruit, JWST project scientist at the European Space Agency in Noordwijk, the Netherlands, recalls watching from the control room at Goddard during CV3 as technicians carried mirror segments into the clean room and fitted them to the backplane. “Even for someone working on the mission, it’s quite incredible,” he says. Rieke had the same sensation: “It’s just enchanting to be witnessing history.”

    See the full article here .

    The American Association for the Advancement of Science is an international non-profit organization dedicated to advancing science for the benefit of all people.

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  • richardmitnick 4:38 pm on February 4, 2016 Permalink | Reply
    Tags: , , NASA/ESA/CSA Webb,   

    From Ethan Siegel: “The Future Of Astronomy: NASA’s James Webb Space Telescope” 

    Starts with a bang
    Starts with a Bang

    Ethan Siegel

    NASA Webb telescope annotated
    NASA/ESA/CSA James Webb Telescope

    How the biggest NASA mission of the decade will solve some of the Universe’s greatest mysteries.

    “Now the world has gone to bed,
    Darkness won’t engulf my head,
    I can see by infrared,
    How I hate the night.” -Douglas Adams

    With every extra inch of aperture, every extra second of observing time, and every extra atom of atmospheric interference you remove from your telescope’s field-of-view, the better, deeper and more clearly you’re able to see the Universe. When the Hubble Space Telescope began operation in 1990, it ushered in a new era in astronomy: that of space-based astronomy.

    NASA Hubble Telescope
    NASA/ESA Hubble

    No longer did we have to fight with the atmosphere; no longer did we have to worry about clouds; no longer was electromagnetic scintillation a problem. All we needed to do was point our telescope at the target, stabilize it, and collect photons. In the 25 years since, we’ve began to cover the entire electromagnetic spectrum with our space-based observatories, getting our first true glimpse of what the Universe really looks like in every wavelength of light.

    Table of Space Based telescopes
    Image credit: NASA / JPL, via Wikimedia Commons user Bricktop.

    But as our knowledge has increased, so has our sophisticated understanding of what the unknowns are. The farther we look away in the Universe, the farther back in time we look as well: the finite amount of time since the Big Bang coupled with the finite speed of light ensures that there’s a limit to what we can see. Moreover, the expansion of space itself works against us, by stretching the wavelength of the emitted starlight as it travels through the Universe towards our eyes. Even the Hubble Space Telescope, which gives us the deepest, most spectacular view of the Universe we’ve ever uncovered, is limited in that regard.

    Hubble is an amazing piece of equipment, but it’s fundamentally limited in a number of ways:

    It’s only 2.4 meters in diameter, limiting its resolving power the farther away we look in space.
    Despite being coated in reflective materials, it still spends all of its time in direct sunlight, which heats it. This heat means that it can’t observe wavelengths of light longer than about 1.6 microns, due to thermal effects.
    And the combination of light-gathering limitations and the wavelengths to which it’s sensitive means that it can “only” see back to galaxies that are about 500 million years old.

    Now, these galaxies are beautiful, distant and from when the Universe was just around 4% of its current age. But we know that stars and galaxies exist from even earlier times.

    NASA Hubble mirror vs Webb mirror
    Hubble vs Webb. Image credit: NASA / JWST / HST team.

    James Webb Space Telescope (JWST) is designed to overcome exactly these limitations: with a 6.5 meter diameter light-gathering area (grabbing more than seven times the light that Hubble can), the capability to do ultra-high resolution spectroscopy from about 600 nanometers to 6 microns (some four times the wavelength Hubble can grab), the ability to do mid-infrared observing to higher sensitivity than ever before, and to both passively cool everything down below the temperature of Pluto and to actively cool the mid-infrared instruments down to just 7 K, JWST should be able to do the science that no one else has been able to do.

    Telescope wavelengths

    In particular, this means:

    observing the earliest galaxies ever to form,
    seeing through the neutral gas and probing the first stars and the reionization of the Universe,
    doing spectroscopic analysis of the very first stars (Population III stars) to form after the Big Bang,
    and possibly some amazing surprises, like uncovering how the earliest supermassive black holes and quasars formed in the Universe.

    The science we’re bound to learn from JWST is unlike anything else we’ve ever learned, and that’s why it was selected as the flagship NASA mission of this decade: the 2010s.

    [Following is a stunning video of James Webb getting ready to go to work. You won’t want to miss it. It is worth downloading.]

    JWST deployment sequence
    Download mp4 video here .

    From a technical standpoint, JWST is an incredible piece of work, and it’s all coming together beautifully. Those of you who’ve been following it for a long, long time might have, in the back of your mind, a distant memory of how the program went over budget and fell behind schedule, and was in danger of being cancelled. When new management stepped in, though, everything changed. The project was suddenly very tightly managed, allowances were made and budgeted for as far as mistakes, errors, setbacks and challenges, and thus far the JWST team has hit every single deadline and made every single deliverable on schedule and within budget. They’re slated for launch in 2018, and they’re not only on schedule, they’ve got a nine month cushion for when they planned to have everything assembled and launch-ready. There are four main pieces to JWST, and here’s the status on each one.

    1.) The Optical Assembly. This includes all the mirrors; most spectacularly the eighteen primary, segmented gold mirrors that will be used to gather the distant starlight and focus it for the instruments to analyze. These mirrors are currently all complete and flawless, and are right on schedule as far as installation goes. When it’s all complete, these mirrors will be folded up into a packaged array, launched more than a million kilometers from Earth to the L2 Lagrange point, and then robotically unfolded to create that honeycomb-like structure that will gather that ultra-distant light for years to come. It’s truly a thing of beauty and the successful result of a herculean effort by many.

    2.) The science instruments. There are four of these, and they are all 100% complete! They are:

    The Near Infrared Camera, James Webb’s primary imaging camera. Extending over an order of magnitude of wavelengths, from visible, orange light deep into the infrared, it should be able to give us unprecedented views of the earliest stars, the youngest galaxies in the process of formation, young stars in the Milky Way and nearby galaxies, hundreds of new objects in the Kuiper Belt, as well as being optimized for directly imaging planets around other stars.

    Kuiper Belt
    Known objects in the Kuiper belt beyond the orbit of Neptune. (Scale in AU; epoch as of January 2015.)

    This will be the main camera used by most observers on JWST.

    The Near Infrared Spectrograph, which not only breaks the light from individual objects apart into its individual wavelengths, it’s designed to do this for more than 100 separate objects at once, in a single image! This workhorse will be Webb’s all-purpose spectrograph, capable of three distinct modes of spectroscopy. It was built by the European Space Agency, but with many components, including the detectors and multi-shutter array, provided by Goddard Space Flight Center/NASA. This instrument has been robustly tested and is complete.

    The Mid-Infrared Instrument will be the one most useful for wide-field broadband imaging, meaning that it will return the most visually striking pictures of all of Webb’s instruments. Scientifically, it will be most useful for the measurement of proto-planetary disks around incredibly young stars, measuring/imaging Kuiper Belt objects to unprecedented accuracy, and dust that has been warmed by starlight. This will be the only instrument that’s cryogenically (i.e., with extra on-board coolant) cooled: down to 7 K. This will improve on what, for example, the Spitzer Space Telescope saw by about a factor of 100.

    NASA Spitzer Telescope

    And the last of the four instruments, the Near-InfraRed Imager and Slitless Spectrograph (NIRISS), will allow Webb to perform wide-field spectroscopy at near infrared wavelengths (1.0–2.5 microns); single-object grism spectroscopy over visible and infrared wavelengths (0.6–3.0 microns); aperture-masking interferometry between 3.8–4.8 µm (where we expect to see the first stars and galaxies); and broad-band imaging across its entire field of view. This is the lone instrument that was built by the Canadian Space Agency, and after passing cryogenic testing, it, too, is complete and integrated within the entire instrument module.

    3.) The Sunshield. This is new! This is one of the scariest parts of any mission: the brand new stuff. Rather than cooling the entire spacecraft actively, with some type of disposable/consumable coolant, JWST uses a brand new technology: a 5-layer sunshield, which will deploy and block the heat from the Sun from the entire spacecraft. These five 25-meter-long sheets will be held taut, in place, by titanium rods that will deploy when the entire spacecraft unfolds. The Sunshield was tested extensively in 2008 and 2009, and full-scale models for laboratory testing have passed everything they’ve been subjected to here on Earth. It’s truly an innovative thing of beauty.

    This is also an incredible concept: you don’t just block the light from the Sun and place the telescope in shadow, you make sure that all the heat is radiated away in the direction opposite to the telescope! The five-layered structure in the vacuum of space means that each progressive layer gets cooler and cooler as it approaches equilibrium. While the outermost layer is going to be quite a bit warmer than the Earth’s surface temperature — somewhere around 350–360 K — by time you get to the end of the fifth layer, the temperature should be down to right around 37–40 K, or cooler than the surface of Pluto during the night.

    In addition, there are some tremendous precautions in place to protect against the catastrophic environment of deep space. You see, one of the things everyone needs to worry about are tiny rocks — pebble-sized, grain-of-sand-sized, dust-mote-sized and even smaller — that are flying about through interplanetary space at tens or even hundreds of thousands of miles per hour. These micrometeroids can rip and punch tiny, microscopic holes in everything they encounter: spacecraft hulls, astronaut suits, telescope mirrors and more. While the mirrors would only be dented or dinged, slightly reducing the amount of “good light” available, the sunshield could develop a tear that runs from end-to-end, rendering an entire layer useless. So they did something brilliant to fight this.

    They compartmentalized every bit of the sunshield, so that if a small tear emerges in one, or two, or even three pieces, it won’t necessarily render the entire layer useless by spreading, the way a crack in your car’s windshield might spread. Instead, the sectioning should keep the general structure intact, an important precaution against degradation. And finally…

    4.) The spacecraft bus, assembly and control systems. This is actually the most routine component, as all space telescopes and science missions need these. JWST’s will be unique, but this is also completely ready. All we need to do is finish the sunshield, finish installing the mirrors, put the whole thing together with the appropriate testing, and we’ll be ready for launch in two years.

    If things go right, we’re in for the next great scientific leap forward. The curtain of neutral gas — currently obscuring our view of the earliest stars and galaxies — will be pulled back by this telescope’s infrared capabilities and huge light-gathering power from space. It will be the greatest, most sensitive telescope over a huge wavelength range, from 0.6 microns to about 28 microns (where the human eye can see from about 0.4 to 0.7 microns), ever constructed. If it launches, deploys and operates properly, as it’s expected to, we could get a full decade of observations out of it. According to NASA:

    Webb’s mission lifetime after launch will be between 5–1/2 years and 10 years. The lifetime is limited by the amount of fuel used for maintaining the orbit, and by the lifetime of the electronics and hardware in the harsh environment of space. Webb will carry fuel for a 10-year lifetime; the project will do mission assurance testing to guarantee 5 years of scientific operations starting at the end of the commissioning period 6 months after launch.

    The primary limiting factor is the amount of on-board fuel, required to keep the telescope operating, in orbit, and pointing accurately at its targets. When that fuel runs out, it will drift away from the L2 Lagrange point, entering a chaotic orbit in the vicinity of Earth.

    LaGrange Points map
    Lagrange Points
    [In celestial mechanics, the Lagrangian points (/ləˈɡrɑːndʒiən/; also Lagrange points, L-points, or libration points) are positions in an orbital configuration of two large bodies where a small object affected only by gravity can maintain a stable position relative to the two large bodies. The Lagrange points mark positions where the combined gravitational pull of the two large masses provides precisely the centripetal force required to orbit with them. There are five such points, labeled L1 to L5, all in the orbital plane of the two large bodies. The first three are on the line connecting the two large bodies and the last two, L4 and L5, each form an equilateral triangle with the two large bodies. The two latter points are stable, which implies that objects can orbit around them in a rotating coordinate system tied to the two large bodies.]

    Other things that could fail are:

    degradations of the mirrors, which will impact the amount of light gathered and will create image artifacts, but which will still allow the telescope to be usable,
    failure of part or all of the sunshield, which will increase the telescope’s temperature and narrow the usable wavelength bands to the very near infrared (out to only 2–3 microns),
    and the coolant on the mid-IR instrument, which is consumable; this would render the mid-IR instrument unusable but wouldn’t affect the other instruments (from 0.6 to 6 microns).

    The nightmare scenario is that the telescope doesn’t launch or deploy properly, and that’s exactly what the tests being done (and passed, by the way) ensure against.

    If JWST works as expected, it’s carrying enough fuel on-board that it should operate from 2018 through 2028, and although it’s never been done, the potential exists for a robotic (or crewed, if the technology gets developed by then) re-fueling mission to L2, which could increase the telescope’s lifetime by another decade. Just as Hubble’s been in operation for 25 years and counting, JWST could give us a generation of revolutionary science if things work out as well as they could. It’s the future of astronomy, and after more than a decade of hard work, it’s almost time to come to fruition. The future of space telescopes is almost here!

    See the full article here .

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    “Starts With A Bang! is a blog/video blog about cosmology, physics, astronomy, and anything else I find interesting enough to write about. I am a firm believer that the highest good in life is learning, and the greatest evil is willful ignorance. The goal of everything on this site is to help inform you about our world, how we came to be here, and to understand how it all works. As I write these pages for you, I hope to not only explain to you what we know, think, and believe, but how we know it, and why we draw the conclusions we do. It is my hope that you find this interesting, informative, and accessible,” says Ethan

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