The James Webb Space Telescope has completed testing at temperatures below -411 degrees Fahrenheit, or 27 Kelvin. Credit: NASA/Goddard
Imagine building a car chassis without a blueprint or even a list of recommended construction materials.
In a sense, that's precisely what a team of engineers at the NASA Goddard Space Flight Center in Greenbelt, Md., did when they designed a one-of-a-kind structure that is one of 9 key new technology systems of the Integrated Science Instrument Module (ISIM). Just as a chassis supports the engine and other components in a car, the ISIM will hold four highly sensitive instruments, electronics, and other shared instrument systems flying on the James Webb Space Telescope, NASA's next flagship observatory.
From scratch — without past experience to help guide them — the engineers designed the ISIM made of a never-before-manufactured composite material and proved through testing that it could withstand the super-cold temperatures it would encounter when the observatory reached its orbit 1.5-million kilometers (930,000 miles) from Earth. In fact, the ISIM structure survived temperatures that plunged as low as 27 Kelvin (-411 degrees Fahrenheit), colder than the surface of Pluto.
"It is the first large, bonded composite spacecraft structure to be exposed to such a severe environment," said Jim Pontius, ISIM lead mechanical engineer.
...One of the first challenges the team tackled after NASA had named Goddard as the lead center to design and develop ISIM was identifying a structural material that would assure the instruments' precise cryogenic alignment and stability, yet survive the extreme gravitational forces experienced during launch.
An exhaustive search in the technical literature for a possible candidate material yielded nothing, leaving the team with only one alternative — developing its own as-yet-to-be manufactured material, which team members jokingly referred to as "unobtainium." Through mathematical modeling, the team discovered that by combining two composite materials, it could create a carbon fiber/cyanate-ester resin system that would be ideal for fabricating the structure's square tubes that measure 75-mm (3-inch) in diameter.
Doug McGuffey is pictured here standing next to the Integrated Science Instrument Module (ISIM) Flight Structure. Credit: NASA/Chris Gunn
...The James Webb Space Telescope (JWST) is a planned infrared space observatory and is the scientific successor to the Hubble Space Telescope. The JWST or Webb Telescope's main scientific goal is to observe the most distant objects in the universe beyond the reach of either ground based instruments or the Hubble. The JWST is a project of the United States space agency (NASA) with international collaboration from the European Space Agency and the Canadian Space Agency, including contributions from fifteen nations.
Originally called the Next Generation Space Telescope (NGST), it was renamed in 2002 after NASA's second administrator James E. Webb (1906–1992). Webb had headed NASA from the beginning of the Kennedy administration through the Johnson administration (1961–68), thus overseeing all the manned launches in the Mercury through Gemini programs, until just before the first manned Apollo flight.
Current plans call for the telescope to be launched on an Ariane 5 rocket in June 2014 (or mid 2015) on a five-year mission (10 year goal). The JWST will orbit the Sun in Earth's partial shadow , approximately 1,500,000 km (930,000 mi) on the far side of Earth at the L2 Lagrange point. Objects at the L2 point orbit the Sun in synchrony with the Earth, which allows JWST to use one radiation shield, positioned between the telescope and the Earth, to protect it from both the Sun's and the Earth's heat and light. It's also possible for the same shield to block moonlight, because the telescope is much further from Earth than the Moon is.
...Page last updated: 30 September 2010
by the UK Space Agency
MIRI being prepared for testing
The pioneering camera and spectrometer for the James Webb Space Telescope – the gigantic successor to the Hubble Telescope – is about to receive its first taste of the harsh conditions of space, without even leaving the UK.
The sophisticated instrument - designed to examine the first light in the Universe and the formation of planets around other stars – will shortly be put through its paces in the space test chamber at the Science and Technology Facility Council’s Rutherford Appleton Laboratory (RAL). The tests include ensuring it can survive the vibrations of a rocket launch and operate successfully in the cold vacuum of space.
The journey to space began a few months ago when the flight model of MIRI was integrated at RAL, from key parts that have been developed at institutes across Europe. Each of these parts of MIRI have already, separately, undergone exhaustive mechanical and thermal testing to make sure they can not only survive the rigours of a journey into space, but also remain operational for the life of the mission. Now the whole instrument will be tested using specially designed facilities developed at RAL to simulate the environment that the instrument will experience once in space.
"Bringing the Flight Model MIRI to readiness for the testing is the culmination of several years hard work and dedication from the teams all around Europe along with the efforts from our US colleagues. The fact that we are now at that point is testament to the tremendous team spirit in the MIRI Consortium and there will be many people waiting to hear the test results" said John Thatcher, the MIRI European project manager from Astrium Ltd.
Dr David Parker, Director of Space Science and Exploration for the UK Space Agency, said, “MIRI is in for a tough old time in this mock space environment but we’re confident that this unique instrument is up to the job.”
He added, “With the UK playing a lead role in the instrument and the UK Astronomy Technology Centre being the overall science lead for it, this project is a great example of how the specialist skills of our UK scientists and space companies are being utilised for the biggest and most ambitious international space projects.”
...One of the jewels in MIRI's crown is the potential to observe star formation that has been triggered by an interaction between galaxies. Conventionally, the emission from such events is shrouded by gas and dust in interstellar space. This is not a problem for MIRI, as it’s extremely low temperature (colder than the temperature on Pluto) will allow it to penetrate these obstructions.
...The astronomers who will use MIRI and the Webb telescope are also particularly keen to explore the formation of planets around distant stars, another area where dust penetration becomes important. “MIRI is absolutely essential for understanding planet formation because we know that it occurs in regions which are deeply embedded in dust,” said Wright. MIRI's beam width of 6 microns allows the instrument to image 30-35 Astronomical Units (AU) of a protoplanetary disc. With most such discs thought to be hundreds of AU across, MIRI can build up highly resolved mosaics of these planetary nurseries in unprecedented detail. With its spectrometer, MIRI could even reveal the existence of water and/or hydrocarbons within the debris, paving the way for investigations into the habitability of other planetary systems.
sci.esa.int : MIRI in the cleanroom at RAL
Date: 08 Sep 2010
Copyright: MIRI European Consortium/RAL
The MIRI instrument pictured in the clean room at the Rutherford Appleton Laboratory, UK, during integration of the flight model, in Summer 2010.
sci.esa.int : Schematic diagram of the MIRI instrument
Date: 08 Sep 2010
The MIRI instrument pictured in the cleanroom at the Rutherford Appleton Laboratory, UK, during integration of the flight model, in Summer 2010.
Date: 14 Apr 2010
Copyright: University of Arizona
Overview of the MIRI instrument. The instrument is attached to the JWST Integrated Science Instrument Module (ISIM) by the CFRP hexapod (triangular structure at left).
Date: 14 Apr 2010
Copyright: University of Leicester, UK
NASAexplorer | October 01, 2010
A video snap shot showing JWST's Integrated Science Instrumnet Module (ISIM) structure inside Goddard's Space Environment Simulator after it completed cryogenic testing. The snap shot also shows engineers removing the ISIM and returning it to the clean room.
...REDONDO BEACH, Calif.,
Oct. 4, 2010 (GLOBE NEWSWIRE)
-- The first flight mirror segment for NASA's James Webb Space Telescope's (JWST) primary mirror has completed its final polishing process, the first of 18 segments that comprise the Observatory's 21 ft. primary mirror. Northrop Grumman Corporation (NYSE:NOC) is leading the design and development effort for the space agency's Goddard Space Flight Center.
"With the contributions of our JWST subcontractor L3-Tinsley, we've put forth a sustained effort over a number of years to achieve this milestone," said Scott Willoughby, Webb Telescope program manager for Northrop Grumman Aerospace Systems. "This is a significant step as we move toward completion of the mirror manufacturing process and into integration and test."
Performed at Tinsley Laboratories Inc. in Richmond, Calif., the optical fabrication process is one of the longest and most rigorous steps in mirror manufacturing. Each of the 18 primary mirror segments undergoes high precision grinding, aspheric polishing and testing to tolerances as tight as 20 nanometers, or less than a millionth of an inch.
Each mirror segment is polished and tested at least 30 times. After each polishing cycle, the mirror segment is cooled to 80K (-315 deg. F) in a liquid nitrogen chamber to test the polishing process, which ensures that when the mirror segment reaches cryogenic temperatures, it will change its shape into the exact optical prescription needed for the mission.
The mirror segment will next be sent to Quantum Coatings, Inc. in Moorestown, N.J., where a thin coat of gold is deposited on the mirror's optical surface to increase its reflective properties. The layer of gold measures 120 nanometers, a thickness of about a millionth of an inch or 200 times thinner than a human hair. The segment will next be shipped to Ball Aerospace where actuators will be added, and then on to NASA's Marshall Space Flight Center in Huntsville, Ala., for a cryotest at minus 400 degrees Fahrenheit (near absolute zero). The first mirror segment will be closely followed by the remaining 17 segments.
Dan McGregor with a sunshield test article Northrop Grumman Lead Venting Analyst Dan McGregor with a sunshield test article as it is placed in the vacuum chamber at Aerospace Systems' test facility in Redondo Beach, Calif. Credit: Northrop Grumman Aerospace Systems
NASA's James Webb Space Telescope continues to make significant progress, successfully completing a series of sunshield vent tests that validate the telescope's sunshield design.
"While adequate venting is a design consideration for all spaceflight hardware, this was a particularly unique challenge for the sunshield given the large volume of trapped air in the membrane system at launch," said Keith Parrish, Webb telescope sunshield manager at NASA's Goddard Space Flight Center in Greenbelt, Md. "From the beginning of its development venting features have been a critical part of the overall sunshield design. Since we cannot vent test the actual flight article these test have shown the design works and the sunshield will vent safely on its way to orbit."
The sunshield on the Webb telescope will block the heat of the Sun and Earth from reaching the cold section of the Observatory. That's a critical function because the telescope and instruments must be cooled below 50 Kelvin (~-369.7 Fahrenheit) to allow them to see faint infrared emissions from astronomical objects. The sunshield consists of five layers of Kapton ®E with aluminum and doped-silicon coatings to reflect the sun's heat back into space.
Using flight-like sunshield membranes, the tests are designed to mimic the rapid change in air pressure the folded sunshield will experience the first minutes of launch. Several different folding configurations each underwent a series of 90-second depressurization tests and proved that the stowed sunshield will retain its shape during launch and allow trapped air to escape safely, both critical to sunshield deployment and performance.
Northrop Grumman Lead Venting Analyst Dan McGregor inspects a sunshield test article for the sunshield section on top of the spacecraft around the tower that supports the telescope. Credit: Northrop Grumman Aerospace Systems.
Northrop Grumman Corporation is leading Webb's design and development effort for NASA's Goddard Space Flight Center in Greenbelt, Md. The first tests were conducted the last week of August in vacuum chambers at Northrop Grumman Aerospace Systems' Redondo Beach facility. Another series of complementary tests were completed in October where air was injected into the stowed sunshield test article, and that provided more detailed data used in evaluating analytical models.
"This is another significant risk reduction activity that continues to move sunshield development forward," said Scott Willoughby, Webb Telescope program manager for Northrop Grumman Aerospace Systems. "We have demonstrated the effectiveness of our sunshield vent design."
Three critical full-scale sections of the sunshield were tested: the section on top of the spacecraft around the tower that supports the telescope; the vertical pallet structure that contains the folded sunshield membranes, and the intervening four-bar linkage area that is folded in an inverted V-shape. The flow paths are complex and the sunshield material, a tough plastic film, Kapton ®E, is only one to two thousandths of an inch thick and covers a surface area the size of a tennis court.
The James Webb Space Telescope is the world's next-generation space observatory and successor to the Hubble Space Telescope. The most powerful space telescope ever built, Webb will observe the most distant objects in the universe, provide images of the very first galaxies ever formed and see unexplored planets around distant stars.
The Webb Telescope is a joint project of NASA, the European Space Agency and the Canadian Space Agency.
For more information on the James Webb Space Telescope, visit:
These videos were developed to highlight the science that will be peformed by the James Webb Space Telescope. Read more about the visualizations in this NASA press release.
Here is a link to a YouTube playlist of all the videos:
...Nov 10th, 2010
by Nancy Atkinson
Artists concept of the James Webb Space Telescope in space. Credit: NASA
The price tag for NASA’s next big space telescope keeps rising and the launch date will likely be delayed as well. A new report from an independent panel on the James Webb Space Telescope reveals it will take about $6.5 billion to launch and run the telescope for its projected 10-year mission. The price had previously ballooned from $3.5 billion to $5 billion. Originally the telescope was slated to launch in 2007, but was pushed back to 2014. Now, the panel says, the earliest launch date would be in September 2015.
The panel, requested by Congress, said there appears to be no technical issues with the telescope, but budget and management problems are the reasons for the cost overruns and delays.
“There is no reason to question the technical integrity of the design or of the team’s ability to deliver a quality product to orbit,” said John Casani from the Jet Propulsion Lab, who chaired the panel. “The problems causing cost growth and schedule delays have been associated with budgeting and program management, not technical performance.”
The money to cover the overruns will require $250 million more in NASA’s FY 2011 and 2012 budget. But with the current state of affairs in the country and Congress, it is likely other programs will suffer or be cut in order to pay for JWST.
...By Amy Klamper
Space News Staff Writer
posted: 10 November 2010
05:59 pm ET
WASHINGTON — NASA's James Webb Space Telescope (JWST) is expected to cost at least $1.5 billion more than current estimates and its launch will be delayed a minimum of 15 months, according to an independent review panel tapped to investigate escalating costs and management issues with the next-generation flagship astronomy mission.
U.S. Sen. Barbara Mikulski (D-Md.) called for the independent review in June to identify the root causes of cost growth and schedule delays on the JWST.
"The Webb telescope will now cost $6.5 billion, $1.5 billion more than the estimate included in NASA's February 2010 budget request, Mikulski wrote in a Nov. 10 letter to NASA Administrator Charles Bolden after reading the Oct. 29 report. "Its launch will be delayed by over a year, from June 2014 to September 2015."
What Golden and the others did not consider was that a 4m scope could have been launched years ago and at a fraction of the cost, since a one-piece mirror could have been used rather than the complex deployment system. Several duplicates could have been launched at little additional cost, so observing time would be already be much greater than the Webb will ever provide. Diffraction limit would be slightly lower but it could be used for visible light astronomy as well. We would have learned a great deal by now, at a lower cost. And operational experience would make the next evolutionary step less expensive. Sometimes it's better to take things one step at a time. As it is, NASA must cancel something to keep Webb on track. I would have to suggest Orion as a candidate, since it is redundant to Dragon and CST-100.Like Hubble, Webb has fallen behind its original schedule and is well over its planned budget, but Webb itself has also grown. When planning started in 1996, NASA had set aside $500 million to build a 4 m telescope with one instrument. Then former NASA administrator Dan Goldin suggested aiming for 8 m, and astronomers added more instruments. By the time the first requests for proposals were issued in 2001, the construction budget of the bigger and better instrument was around $2 billion. Later changes in NASA accounting added a few hundred million dollars to the budget, and last year overruns and delays added about another $1 billion. NASA now estimates the complete lifecycle cost-including about $1 billion in operations-will be $4.5 billion, not counting an Ariane V launch being supplied by the European Space Agency in 2013.
But Mather says the program has stayed on budget and on schedule since last year’s changes. Key technologies are being tested to meet milestones at the end of this year. The primary-mirror segments, which have the longest lead times, are already in production. And mindful of the fiasco of Hubble’s misshapen primary mirror, NASA has planned an end-to-end test to check how the fully assembled Webb transmits light on the ground before launch.
By Keith Cowing
Posted Friday, November 12, 2010
The James Webb Space Telescope (JWST) project started under NASA Science Mission Directorate (SMD) Associate Administrator Ed Weiler. Virtually all of its chronic and unabated cost increases and schedule slips have occured under Weiler's watch either at NASA HQ or at NASA GSFC. When former SMD AA Alan Stern tried to bring the escalating costs of programs such as JWST and Mars Science Laboratory (MSL) under control, in 2008, multiple NASA sources note that Chris Scoelese and Ed Weiler maneuvered to force Stern's resignation, in a classic NASA "shoot the messenger" move, with Weiler taking Stern's place within barely a week.
Meanwhile in a statement prepared for Bolden, it is evident that the agency is in complete denial when it comes to the severity of its escalating costs for government projects. Didn't the recent election sent a rather clear message from the electorate with regard to their dissatisfaction with out of control government spending? Add in the soaring overruns on MSL (another Weiler managerial fiasco) and National Polar-orbiting Operational Environmental Satellite System (NPOESS) - a project managed for the agency by Chris Scolese, and you see three large fiscal black holes sucking away at all the other things the agency is supposed to be doing for science, and exploration.
Bolden's response? He wants Weiler and Scoelese to spend more time watching JWST. These two have presided over years of cost growth and schedule delays that have damaged multiple projects within SMD, and which now threaten to damage the Agency's reputation as a whole. Perhaps it is Weiler and Scoelese that need to be changed out ...
This latest cost increase/schedule delay happened throughout Charlie Bolden's entire tenure with both Scolese and Weiler overseeing this program at NASA HQ under Bolden's direct, daily management. Perhaps Gen. Bolden doesn't realize his connection to the collective mismanagement of these projects is itself becoming as clear as the vacuum of space ...
...Source: NASA HQ
Posted Friday, November 12, 2010