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Nancy Grace Roman Telescope

Flyaway

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Report lays out potential changes to WFIRST to reduce its cost

WASHINGTON — An independent review board for NASA’s next flagship astronomy mission concluded in its final report that the project is “not executable” without additional funding or adjustments to the spacecraft.

NASA released the report, a 65-page document in the form of a PowerPoint presentation, Nov. 22, a month after the agency published its response calling for a reduction in the proposed cost of the Wide-Field Infrared Survey Telescope (WFIRST) and changes to its management.

The report, prepared by an outside committee established by NASA called the WFIRST Independent External Technical/Management/Cost Review (WIETR), found that various changes made to WFIRST since it was proposed as the top-ranking large, or flagship, mission in the 2010 astrophysics decadal survey created cost and technical difficulties.

“After multiple discussions that set the boundary conditions, NASA HQ made a series of decisions that set the stage for an approach and mission system concept that is more complex than probably anticipated from the point of view of scope, complexity, and the concomitant risks of implementation,” the report stated.

 
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Flyaway

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WFIRST Will See the Big Picture of the Universe


NASA Goddard
Published on Dec 22, 2017


Scheduled to launch in the mid-2020s, the Wide Field Infrared Survey Telescope (WFIRST) will function as Hubble’s wide-eyed cousin. While just as sensitive as Hubble's cameras, WFIRST's 300-megapixel Wide Field Instrument will image a sky area 100 times larger. This means a single WFIRST image will hold the equivalent detail of 100 pictures from Hubble.

The mission’s wide field of view will allow it to generate a never-before-seen big picture of the universe, which will help astronomers explore some of the greatest mysteries of the cosmos, like why the expansion of the universe seems to be accelerating. Some scientists attribute the speed-up to dark energy, an unexplained pressure that makes up 68 percent of the total content of the cosmos.

The Wide Field Instrument will also allow WFIRST to measure the matter in hundreds of millions of distant galaxies through a phenomenon dictated by Einstein’s relativity theory. Massive objects like galaxies curve space-time in a way that bends light passing near them, creating a distorted, magnified view of far-off galaxies behind them. WFIRST will paint a broad picture of how matter is structured throughout the universe, allowing scientists to put the governing physics of its assembly to the ultimate test.

WFIRST can use this same light-bending phenomenon to study planets beyond our solar system, known as exoplanets. In a process called microlensing, a foreground star in our galaxy acts as the lens. When its motion randomly aligns with a distant background star, the lens magnifies, brightens and distorts the background star. WFIRST's microlensing survey will monitor 100 million stars for hundreds of days and is expected to find about 2,500 planets, well targeted at rocky planets in and beyond the region where liquid water may exist.

These results will make WFIRST an ideal companion to missions like NASA's Kepler and the upcoming Transiting Exoplanet Survey Satellite (TESS), which are designed to study larger planets orbiting closer to their host stars. Together, discoveries from these three missions will help complete the census of planets beyond our solar system. The combined data will also overlap in a critical area known as the habitable zone, the orbiting distance from a host star that would permit a planet's surface to harbor liquid water — and potentially life.

By pioneering an array of innovative technologies, WFIRST will serve as a multipurpose mission, formulating a big picture of the universe and helping us answer some of the most profound questions in astrophysics, such as how the universe evolved into what we see today, its ultimate fate and whether we are alone.

This video is public domain and along with other supporting visualizations can be downloaded from the Scientific Visualization Studio at: http://svs.gsfc.nasa.gov/2238

Credit: NASA's Goddard Space Flight Center/Scott Wiessinger

https://www.youtube.com/watch?v=Nu4DsKlKKMQ?t=001

https://www.youtube.com/watch?v=Nu4DsKlKKMQ
 

Flyaway

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NASA plans to have WFIRST reviews complete by April

NATIONAL HARBOR, Md. — NASA hopes to have a major astronomy mission back on track by April after completing efforts to reduce its cost, an agency official said Jan. 8.

Speaking at a meeting of astronomers prior to the start of the 231st Meeting of the American Astronomical Society here, Paul Hertz, director of NASA’s astrophysics division, said the agency plans to hold a key review for the Wide-Field Infrared Survey Telescope (WFIRST), known as Key Decision Point B, by April.

The biggest changes to WFIRST to lower its cost involve one of its instruments, a coronagraph. That instrument is designed to precisely block light from individual stars, allowing observations of planets or dust disks orbiting them.

That instrument, he said, will now be considered a technology demonstration, and its cost will be shared with the agency’s Space Technology Mission Directorate. “Their contribution, and international contributions, do not count against the $3.2 billion,” he said.

The mission is also planning reductions for WFIRST’s other main instrument, a wide-field instrument. Hertz said the instrument will have fewer operating modes and relaxed detector requirements, and some capabilities will be provided by unannounced international partners.

Another change has been revisions to the overall project schedule, which allows for a launch about six months sooner than previously planned, saving money. However, he said the project will spend more money on “mission assurance” activities in response to a finding by last fall’s independent review that argued the mission was taking on a higher risk profile than warranted for one of this size.

http://spacenews.com/nasa-plans-to-have-wfirst-reviews-complete-by-april/
 

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WFIRST work continues despite budget and schedule uncertainty

At a meeting of the Committee on Astronomy and Astrophysics of the National Academies’ Space Studies Board here March 27, NASA officials said WFIRST was on track to complete a review called Key Decision Point (KDP) B April 11, allowing it to enter Phase B of its development.

That came after an effort to reduce the mission’s cost to $3.2 billion triggered by an independent review in October. That review concluded WFIRST’s cost had grown to $3.9 billion, with potential additional increases of up to $300 million to meet a “Class A” risk classification used by large missions rather than the less-stringent Class B that WFIRST was operating under.

That cost-cutting is complete. “We did, in fact, come up with a baseline that fits at $3.2 billion, and retains in excess of 30 percent reserves in the lifecycle cost,” said Jeffrey Kruk, WFIRST project scientist, in a presentation at the meeting. That cost estimate is at the 50 percent confidence level, he said, the requirement for the KDP-B review.

Other cuts did affect the mission’s science, he acknowledged. The mission relaxed the performance requirements for detectors used by its primary wide-field instrument, although a decrease in operating temperature enabled by another design change will help reduce noise.

The biggest change, he said, is turning the other WFIRST instrument, a coronagraph, into solely a technology demonstration. “The direction to us was that we were being too ambitious” by adding science requirements to the instrument that informed its design, he said. “That had impacts in a lot of areas.”

http://spacenews.com/wfirst-work-continues-despite-budget-and-schedule-uncertainty/
 

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WFIRST’s second chance

There’s a saying often used in the space community that you’re not a real NASA mission until you’ve been threatened with cancellation. There is some truth to that: many NASA missions that ultimately were successful faced the threat of termination, either by the agency or Congress. For example, the new book Chasing New Horizons is filled with near-death experiences for the New Horizons mission to Pluto (see “Review: Chasing New Horizons”, The Space Review, April 30, 2018)

http://www.thespacereview.com/article/3497/1
 

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NASA Awards Contract for Space Telescope Mission
May 23, 2018 - CONTRACT RELEASE C18-017

NASA has awarded a contract to Ball Aerospace and Technologies Corporation, Boulder, Colorado, for the primary instrument components for the Wide Field Infrared Survey Telescope (WFIRST).

Called the Wide Field Instrument (WFI) Opto-Mechanical Assembly, the cost-plus-award-fee contract has a value of approximately $113.2 million. The period of performance is from May 2018 through June 2026.

Managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland, WFIRST is fully-funded for Fiscal Year 2018. Work will continue on the mission in this time period until appropriations for Fiscal Year 2019 have been determined.

The contract requires Ball Aerospace to design, analyze, develop, fabricate, integrate, test and evaluate the Wide Field Instrument Opto-Mechanical Assembly for the WFIRST mission. In addition, Ball will support the subsequent integration, test, evaluation, and validation of the WFI. Ball also will provide post-delivery support to payload and observatory integration and testing, and to prelaunch, launch and commissioning activities at the Mission Operations Center, and supply and maintain the instrument ground support equipment.

https://www.nasa.gov/press-release/nasa-awards-contract-for-space-telescope-mission-0
 

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NASA studying potential additional cuts in WFIRST

At a meeting July 24 of NASA’s Astrophysics Advisory Committee here, Jeff Kruk, project scientist for the Wide-Field Infrared Survey Telescope (WFIRST), said the project was asked by NASA Headquarters to study additional ways it could reduce costs for the spacecraft’s coronagraph instrument, which has already been downgraded to a technology demonstration.

“The only other shoe that might drop is that we’ve been asked to provide a study to headquarters on additional possible cost reductions to the coronagraph,” he said. “It’s not that we’ve been directed to do that, but we’ve been asked to present options.” That study is due late this year.

WFIRST has also lost some capability to its primary instrument, a wide-field imager. Kruk said that the Canadian Space Agency notified the project in the spring that it will not be able to contribute the Integral Field Channel, an element of that instrument that would perform spectra on discrete parts of the instrument’s field of view.

“This had been one of the central parts of the supernova program,” he said. “That is a significant change.” The instrument would have provided a “reasonably high quality” spectrum of each supernova studied to measure its redshift, or distance. Kruk said there was a “plausible path” to obtain that data instead through other observations of the supernova and its host galaxy.

https://spacenews.com/nasa-studying-potential-additional-cuts-in-wfirst/
 

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NASA’s Wide Field Infrared Survey Telescope (WFIRST) project has passed a critical programmatic and technical milestone, giving the mission the official green light to begin hardware development and testing.

 

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NASA’s Wide Field Infrared Survey Telescope (WFIRST) project has passed a critical programmatic and technical milestone, giving the mission the official green light to begin hardware development and testing.


Good news for the future of WFIRST.
 

Grey Havoc

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If they cut much more capability though, they may as well cancel the program outright.
 

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Flyaway

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Is now called the Nancy Grace Roman Telescope:


 

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Nancy Grace?

 

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The DoD gave NASA two sets of mirrors. Any idea if they're going to use the second set?
 

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Predictions of the Nancy Grace Roman Space Telescope Galactic Exoplanet Survey. II. Free-floating Planet Detection Rates*

Abstract
The Nancy Grace Roman Space Telescope (Roman) will perform a Galactic Exoplanet Survey (RGES) to discover bound exoplanets with semimajor axes greater than 1 au using gravitational microlensing. Roman will even be sensitive to planetary-mass objects that are not gravitationally bound to any host star. Such free-floating planetary-mass objects (FFPs) will be detected as isolated microlensing events with timescales shorter than a few days. A measurement of the abundance and mass function of FFPs is a powerful diagnostic of the formation and evolution of planetary systems, as well as the physics of the formation of isolated objects via direct collapse. We show that Roman will be sensitive to FFP lenses that have masses from that of Mars (0.1 M ⊕) to gas giants (M gsim 100 M ⊕) as isolated lensing events with timescales from a few hours to several tens of days, respectively. We investigate the impact of the detection criteria on the survey, especially in the presence of finite-source effects for low-mass lenses. The number of detections will depend on the abundance of such FFPs as a function of mass, which is at present poorly constrained. Assuming that FFPs follow the fiducial mass function of cold, bound planets adapted from Cassan et al., we estimate that Roman will detect ~250 FFPs with masses down to that of Mars (including ~60 with masses ≤ M ⊕). We also predict that Roman will improve the upper limits on FFP populations by at least an order of magnitude compared to currently existing constraints.

 

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The DoD gave NASA two sets of mirrors. Any idea if they're going to use the second set?

At first glance it seemed a bargain. Alas - as usual with NASA, its science projects, and their budget - the devil has been in the details. End result: not-so-good-bargain, after all.
 

Flyaway

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The DoD gave NASA two sets of mirrors. Any idea if they're going to use the second set?

At first glance it seemed a bargain. Alas - as usual with NASA, its science projects, and their budget - the devil has been in the details. End result: not-so-good-bargain, after all.
Having to store the mirrors apparently costs a lot, especially as they are still considered classified.
 

sferrin

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I don't believe anybody thinks that's the case.

Well, they certainly had me fooled when they talked about the FIA leftovers (that's what people were spitballing, at least) as "stubby Hubbles".

Well NASA is obviously using one of the sets in a telescope, so I'm not sure why some are so confused. Perhaps the confusion comes from thinking that anything different than Hubble is, by definition, not a telescope?
 

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I would agree you could save a lot of money IF these spare telescopes were:

-fully coated as required for the astronomy mission (almost certainly not)
-fully mounted and aligned for zero G in a space rated telescope body with the required sun shade/baffling
-modularly designed so an instrument package can simply bolt to the backplane of the primary housing

Otherwise, they could just have well dusted off the Hubble spare primary mirror (made by Kodak when they were still around). This mirror was built properly without the optical flaw in the flight primary. The cost to design/build a new telescope body, mount and align the mirrors to zero G conditions, and develop the mission science instruments will make the "savings" look very small.

spare Hubble primary
Spare Hubble Primary.jpg
 

sferrin

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I would agree you could save a lot of money IF these spare telescopes were:

-fully coated as required for the astronomy mission (almost certainly not)
-fully mounted and aligned for zero G in a space rated telescope body with the required sun shade/baffling
-modularly designed so an instrument package can simply bolt to the backplane of the primary housing

Otherwise, they could just have well dusted off the Hubble spare primary mirror (made by Kodak when they were still around). This mirror was built properly without the optical flaw in the flight primary. The cost to design/build a new telescope body, mount and align the mirrors to zero G conditions, and develop the mission science instruments will make the "savings" look very small.

So ask yourself why they're doing what they're doing. Here, let me help you:

 

fredymac

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So ask yourself why they're doing what they're doing. Here, let me help you:



The Wikipedia link says using a spare NRO telescope mirror

“.... provided important political momentum to the project, even though the telescope represents only a modest fraction of the cost of the mission and the boundary conditions from the NRO design may push the total cost over that of a fresh design.”

which was my point. I don’t think (or at least hope) nobody would propose a follow on Hubble just because a spare primary exists. WFIRST proposals may have sidetracked themselves using the spare mirror argument rather than sticking with a telescope design optimized for the requirements. If mapping dark energy effects is important, it can compete directly on that basis.
 

sferrin

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So ask yourself why they're doing what they're doing. Here, let me help you:



The Wikipedia link says using a spare NRO telescope mirror

“.... provided important political momentum to the project, even though the telescope represents only a modest fraction of the cost of the mission and the boundary conditions from the NRO design may push the total cost over that of a fresh design.”

which was my point. I don’t think (or at least hope) nobody would propose a follow on Hubble just because a spare primary exists. WFIRST proposals may have sidetracked themselves using the spare mirror argument rather than sticking with a telescope design optimized for the requirements. If mapping dark energy effects is important, it can compete directly on that basis.

Fair enough.
 

Byeman

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They are:
-fully mounted and aligned for zero G in a space rated telescope body with the required sun shade/baffling
-modularly designed so an instrument package can simply bolt to the backplane of the primary housing
 

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A little digging.

WFIRST wavelengths are 0.5-2.0 microns or visible to near IR. I have no idea what wavelengths NRO likes for the spy sats. Overcoated Gold is the default coating for IR.

4:05 mark shows primary.

So, they probably will disassemble/debond optics, strip and maybe recoat, then remount although with modified hardware.

The main telescope body (sunshade,baffles, power, science etc etc) will be all new. Pointing sensors will be totally different as will gyro/stabilization requirements. New baffles means any existing mounting structures need to be modified or replaced to match replacements. That alone would mean you would want to yank the optics to keep them protected from damage.

Edit: found this other picture of the dismounted primary so I guess they already did. The people in the red hairnets are NASA.
WFIRST primary.jpg
 

Byeman

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The main telescope body (sunshade,baffles, power, science etc etc) will be all new. Pointing sensors will be totally different as will gyro/stabilization requirements. New baffles means any existing mounting structures need to be modified or replaced to match replacements. That alone would mean you would want to yank the optics to keep them protected from damage.
Power, sunshield, science, pointing sensors, gyro/stabilization requirements, etc are not part of the telescope, but part of the spacecraft.
 

fredymac

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Power, sunshield, science, pointing sensors, gyro/stabilization requirements, etc are not part of the telescope, but part of the spacecraft.


Telescope design is driven by the ambient light environment it faces, sensor formats and dwell times, waveband of interest, and any geometric constraints imposed by mechanical requirements. Since you apparently know what the KH-ll follow on spysat technical specifications included, you should give specific numbers to these.

Regarding the coating, if I had been a program manager, I imagine hardening against future laser attacks might have been a requirement and I might have proposed making the optics transparent to the waveband of greatest threat which would be something like 0.95 to 1.15 microns. This would make the coating a dielectric with a notch window. To the human eye, the coating would still look like silver (if visible wavelengths were still the main area of interest). Of course I have no idea if this was considered since I have no access to spysat design information.
 

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From the article:

"Development of the mirror is much further along than it would typically be at this stage since the mission leverages a mirror that was transferred to NASA from the National Reconnaissance Office. The team modified the mirror’s shape and surface to meet Roman’s science objectives. "


Which means the mirror was put into a grinding machine to generate a different aspheric profile. After that, the mirror is repolished to bring the surface figure into specification and achieve the necessary surface smoothness. At least they didn't have to cut the radius of curvature starting from a blank but machining to core out the center hole, edge the mirror to the exact diameter, and do whatever lightweighting desired on the rear is generally low risk and a small part of the fabrication budget. Of course, its not exactly just bolt on the science package either.
 
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