Thursday, July 31, 2008


NASA scientists have concluded that at least one of the large lakes observed on Saturn's moon Titan contains liquid hydrocarbons, and have positively identified the presence of ethane.
This makes Titan theonly body in our solar system beyond Earth known to have liquid on its surface.

Scientists made the discovery using data from an instrument aboard the Cassini spacecraft. The instrument identified chemically different materials based on the way they absorb and reflect infrared light. Before Cassini, scientists thought Titan would have global oceans of methane, ethane and other light hydrocarbons. More than 40 close flybys of Titan by Cassini show no such global oceans exist, but hundreds of dark lake-like features are present. Until now, it was not known whether these features were liquid or simply dark, solid material.

"This is the first observation that really pins down that Titan has a surface lake filled with liquid," said Bob Brown of the University of Arizona, Tucson. Brown is the team leader of Cassini's visual and mapping instrument. The results will be published in the July 31 issue of the journal Nature.

Ethane and several other simple hydrocarbons have been identified in Titan's atmosphere, which consists of 95 percent nitrogen, with methane making up the other 5 percent. Ethane and other hydrocarbons are products from atmospheric chemistry caused by the breakdown of methane by sunlight.

Some of the hydrocarbons react further and form fine aerosol particles. All of these things in Titan's atmosphere make detecting and identifying materials on the surface difficult, because these particles form a ubiquitous hydrocarbon haze that hinders the view. Liquid ethane was identified using a technique that removed the interference from the atmospheric hydrocarbons.

The visual and mapping instrument observed a lake, Ontario Lacus, in Titan's south polar region during a close Cassini flyby in December 2007. The lake is roughly 7,800 square miles in area, slightly larger than North America's Lake Ontario.

"Detection of liquid ethane confirms a long-held idea that lakes and seas filled with methane and ethane exist on Titan," said Larry Soderblom, a Cassini interdisciplinary scientist with the U.S.
Geological Survey in Flagstaff, Ariz. "The fact we could detect the ethane spectral signatures of the lake even when it was so dimly illuminated, and at a slanted viewing path through Titan's
atmosphere, raises expectations for exciting future lake discoveries by our instrument."

The ethane is in a liquid solution with methane, other hydrocarbons and nitrogen. At Titan's surface temperatures, approximately 300 degrees Fahrenheit below zero, these substances can exist as both liquid and gas. Titan shows overwhelming evidence of evaporation, rain, and fluid-carved channels draining into what, in this case, is a liquid hydrocarbon lake.

Earth has a hydrological cycle based on water and Titan has a cycle based on methane. Scientists ruled out the presence of water ice, ammonia, ammonia hydrate and carbon dioxide in Ontario Lacus. The observations also suggest the lake is evaporating. It is ringed by a dark beach, where the black lake merges with the bright shoreline. Cassini also observed a shelf and beach being exposed as the lake evaporates.

"During the next few years, the vast array of lakes and seas on Titan's north pole mapped with Cassini's radar instrument will emerge from polar darkness into sunlight, giving the infrared instrument rich opportunities to watch for seasonal changes of Titan's lakes," Soderblom said.

Launched in Oct. 1997, Cassini's 12 instruments have returned a daily stream of data from Saturn's system. The mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency.

For information on Cassini, visit:

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NASA's Lunar Science Institute at Moffett Field, Calif., has announced its first international affiliate partner for conducting lunar science activities. Canada's University of Western Ontario, London, Ontario, will represent the Canadian lunar science community as part of the newly established Canadian Network for Lunar Science and Exploration.

"We are tremendously excited about this partnership," said S. Pete Worden, director of NASA's Ames Research Center at Moffett Field, Calif. "With the large number of U.S. and international missions focused on the moon, this is absolutely the right step forward."

The institute, dedicated in April 2008 at Ames, will promote a new generation of research on and about the moon. It will support collaborative science, providing technical perspectives to NASA's
lunar missions and developing future scientific investigations.

"We are extremely proud of our status as the first NASA Lunar Science Institute affiliate outside of the United States," said Ted Hewitt, vice president of research and international relations for the University of Western Ontario. "We look forward to working with our colleagues throughout the institute's organization and at the Canadian Space Agency conducting this world-class research."

The institute has a major focus on developing the next generation of lunar science researchers and supporting a vigorous education and public outreach program focused on the moon.

"The moon has been Earth's cosmic partner for the last four billion years," said Gregory Schmidt, director of international partnerships and deputy director of the institute. "It is an honor to move forward in partnership with the Canadian science community in this next phase
of scientific exploration of the moon."

For information about the NASA Lunar Science Institute, visit:

For information about the University of Western Ontario, visit:

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Less than a month after launch, the NASA-French space agency Ocean Surface Topography Mission (OSTM)/Jason 2 oceanography satellite has produced its first complete maps of global ocean surface topography, surface wave height and wind speed.

The new data will help scientists monitor changes in global sea level and the distribution of heat in the ocean. This information is used to monitor climate change and ocean circulation, and to enable more accurate weather, ocean and climate forecasts. The data reveal patterns of sea level anomalies, which are used by scientists to calculate the speed and direction of ocean surface currents.

The new mission extends a 16-year continuous record of global sea level measurements begun in 1992 by the NASA/Centre National d'Etudes Spatiales (CNES) TOPEX/Poseidon mission and continued by the two agencies on Jason 1, launched in 2001. Data from TOPEX/Poseidon and Jason 1 shows that mean sea level has been rising by about .12 inches a year since 1993.

The new maps were generated from the first 10 days of data collected once the new satellite reached its operational orbit of 830 miles on July 4. OSTM/Jason 2 and its predecessor, Jason 1, now are flying in formation in the same orbit approximately 55 seconds apart, making nearly simultaneous measurements that are allowing scientists to precisely calibrate the new satellite's instruments. Comparisons of data from the two satellites on sea-level anomalies, significant wave
height and ocean wind speed all show very close correlation of all measured parameters.

"These initial observations from OSTM/Jason 2 compare very closely to those of Jason 1," said Lee-Lueng Fu, OSTM/Jason 2 project scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "To be able to collect such high-quality science data within a month of launch breaks previous records. It is also a direct reflection of how mature the field of satellite altimetry has become and of the seamless cooperation of our international team."

The satellite's first radar altimeter data were acquired just 48 hours after its launch on June 20 from Vandenberg Air Force Base, Calif., on a Delta II rocket. CNES processed the first test results, followed by more advanced data results a week after launch. The more advanced
results were produced after calculating the precise location of the satellite's preliminary orbits. The satellite, its instruments and ground segment all are functioning properly. After it has been fully calibrated and validated, the satellite will begin providing oceanographic products to users around the world.

OSTM/Jason 2 is an international endeavor, with responsibilities for satellite development and launch shared between NASA and CNES. CNES provided the OSTM/Jason 2 spacecraft, NASA provided the launch, and NASA and CNES jointly provided the primary payload instruments. CNES and the National Oceanic and Atmospheric Administration (NOAA) are responsible for satellite operations, while JPL is managing the mission for NASA. Data processing is being carried out by CNES, the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) and NOAA, depending on the type of product.

After on-orbit commissioning of OSTM/Jason 2 is completed, CNES will hand over mission operations and control to NOAA, which then will join with EUMETSAT to generate, archive and distribute data products to users worldwide.

For more information about OSTM/Jason 2, visit:

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Tuesday, July 29, 2008

NASA's Close-Up Images of 'Snow Queen' Show Changes

A distinctive hard-surface feature called "Snow Queen" beneath NASA's Phoenix Mars Lander visibly changed sometime between mid-June and mid-July, close-up images from the Robotic Arm Camera show.

Cracks as long as 10 centimeters, or about four inches, have appeared. A seven-millimeter (less than one-third inch) pebble or clod not seen there before has popped up on the surface. And some smooth texture on Snow Queen has subtly roughened. Phoenix's Robotic Arm Camera, or RAC, took its first close-up image of Snow Queen on May 31, 2008, the sixth Martian day, or sol, after the May 25 landing. Thruster exhaust blew away surface soil covering Snow Queen as Phoenix landed, exposing a hard layer comprising several smooth, rounded cavities.

"Images taken since landing showed these fractures didn't form in the first 20 sols of the mission," Phoenix co-investigator Mike Mellon of the University of Colorado, Boulder, said. "We might expect to see additional changes in the next 20 sols."

Mellon, who has spent most of his career studying permafrost, said long-term monitoring of Snow Queen and other icy soil cleared by Phoenix landing and trenching operations is unprecedented for science. It's the first chance to see visible changes in Martian ice at a place where temperatures are cold enough that the ice doesn't immediately sublimate, or vaporize, away. Phoenix scientists discovered that centimeter-sized chunks of ice scraped up in the Dodo-Goldilocks trench lasted several days before vanishing.

The Phoenix team has been watching ice in the Dodo-Goldilocks and Snow White trenches in views from the lander's Surface Stereo Imager as well as RAC, but only RAC can view Snow Queen near a strut under the lander.

The fact that RAC is attached to the robotic arm is both an advantage and a disadvantage. The advantage is that RAC can take close-ups of Snow Queen, while the Surface Stereo Imager can't see Snow Queen at all from the topside of the spacecraft. The disadvantage is that the robotic arm has so many tasks to perform that RAC can't be used for monitoring trench ice at some opportune times. Also, RAC hasn't been used to take up-close images of other icy places under the spacecraft cleared on landing because it would require the robotic arm to make a difficult and complex series of moves.

"I've made a list of hypotheses about what could be forming cracks in Snow Queen, and there are difficulties with all of them," Mellon said.

One possibility is that temperature changes over many sols, or Martian days, have expanded and contracted the surface enough to create stress cracks. It would take a fairly rapid temperature change to form fractures like this in ice, Mellon said.

Another possibility is the exposed layer has undergone a phase change that has caused it to shrink. An example of a phase change could be a hydrated salt losing its water after days of surface exposure, causing the hard layer to shrink and crack. "I don't think that's the best explanation because dehydration of salt would first form a thin rind and finer cracks," Mellon said.

"Another possibility is that these fractures were already there, and they appeared because ice sublimed off the surface and revealed them," he said.

As for the small pebble that popped up on Snow Queen after 21 sols -- it might be a piece that broke free from the original surface or it might be a piece that fell down from somewhere else. "We have to study the shadows a little more to understand what's happening," Mellon said.

The Phoenix mission is led by Peter Smith of The University of Arizona with project management at the Jet Propulsion Laboratory and development partnership at Lockheed Martin, located in Denver. International contributions come from the Canadian Space Agency; the University of Neuchatel; the universities of Copenhagen and Aarhus, Denmark; Max Planck Institute, Germany; and the Finnish Meteorological Institute.

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NASA hosted a meeting of space agencies from nine countries last week to discuss the next steps in the ongoing scientific exploration of the moon. The meeting laid the groundwork for a new generation of lunar science.

Discussions, led by NASA Headquarters officials, were held at NASA's Lunar Science Institute, located at the Ames Research Center at Moffett Field, Calif. Representatives from space agencies in Canada, France, Germany, India, Italy, Japan, the Republic of Korea, the United Kingdom, and the United States attended the meeting. During the meeting, attendees discussed cooperation on an international activity called the International Lunar Network (ILN). The network is designed to gradually place 6-8 fixed or mobile science stations on the lunar surface. The stations will form a second-generation robotic science network to replace hardware left by the Apollo Program to study the moon's surface and interior.

NASA plans to place its first two ILN landers on the surface of the moon in 2013-14. The landers are being developed under the Lunar Precursor Robotic Program at NASA's Marshall Space Flight Center. Huntsville, Ala.

The ILN is supported by NASA's Science Mission Directorate at the agency's headquarters in Washington. It was created in response to a 2007 report released by the National Research Council, which affirmed that the moon offers "profound scientific value" and "lunar activities apply to broad scientific and exploration concerns."

Representatives from space agencies considering participation in the ILN agreed on a statement of intent as a first step in planning. The statement marked an expression of interest by the agencies to study options for participating in a series of international lunar missions. The goal is to form a network of missions that will benefit scientists worldwide.

"We are tremendously excited by the enthusiasm shown for the ILN and lunar science more broadly," said Jim Green, director of the Planetary Science Division at NASA Headquarters. "This international activity will greatly extend scientific knowledge of the moon in a number of important areas."

The statement of intent does not completely define the ILN concept. The document leaves open the possibility for near and long-term evolution and implementation. Initially, participants intend to establish potential landing sites, interoperable spectrum and communications standards, and a set of scientifically equivalent core instrumentation to carry out specific measurements.

"We are in a new era of lunar exploration," said Jim Adams, deputy director of the Planetary Science Division at NASA Headquarters. "Scientific coordination of the international armada of missions being sent to the moon in the next decade will greatly leverage our scientific capabilities, and perhaps even more importantly, develop the next generation of lunar scientists."

International participation in specific ILN activities will be established by appropriate international agreements. Additional participants may join in the future when they are programmatically and financially ready. Participation in the ILN could include the contribution of landers, orbiters, instrumentation, or other significant infrastructure, such as ground segment elements or power supplies for surviving the lunar night.

For more information on NASA lunar activities, visit:

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NASA's Constellation Program has selected 11 companies and one university to independently develop concepts that contribute to how astronauts will live and work on the moon.

Each organization will conduct a 180-day study focused on a topic relevant to lunar surface systems. Selected organizations and topics are:

--Alternative Packaging Options: Oceaneering Space Systems of Houston
--Avionics: Honeywell International, Inc. of Glendale, Ariz,
--Energy Storage: ATK Space Systems Group of Brigham City, Utah,
Battelle Memorial Institute of Columbus, Ohio, and Hamilton
Sundstrand of Canoga Park, Calif.
--Minimum Habitation Functions: The Boeing Company of Huntington
Beach, Calif., ILC Dover of Frederica, Del., and University of
Maryland, College Park
--Regolith Moving Methods: Astrobotic Technology Inc. of Pittsburgh
and Honeybee Robotics of New York
--Software: The Charles Stark Draper Laboratory, Inc. of Cambridge,
Mass., and United Space Alliance of Houston

The awards total approximately $2 million, with a maximum individual award of $250,000.

"These studies provide new ideas to help the Constellation Program develop innovative, reliable requirements for the systems that will be used when outposts are established on the moon," said Jeff Hanley, the Constellation Program manager at NASA's Johnson Space Center in Houston.

The recommendations from the studies will help determine packaging options, identify basic functions for lunar habitats, and conceptualize innovative avionics, computer software, energy storage ideas and equipment and techniques that could help preparation for the lunar outpost site.

The Constellation Program is building NASA's next generation fleet of spacecraft -- including the Ares I and Ares V rockets, the Orion crew capsule, the Altair lunar lander and lunar surface systems -- to send humans beyond low Earth orbit and back to the moon. NASA plans to establish a human outpost on the moon through a successive series of lunar missions beginning in 2020. Lunar surface systems may include habitats, pressurized and un-pressurized rovers, communication and navigation elements, electrical power control, and natural resource use.

For more information about NASA's Constellation Program, visit:

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Monday, July 28, 2008


The 2008 General Aviation Technology Challenge will be held Aug. 4-10 at the Sonoma County Airport in Santa Rosa, Calif. Competitors will demonstrate innovations resulting in aircraft that
are safer, less expensive and easier to operate, while having fewer negative impacts on the environment and communities surrounding airports.

This year's competition will feature the first Green Prize for aviation. The highlight of the week-long event will occur Saturday, Aug. 9, with the CAFE 400 - a 400-mile, cross-country air race that requires speed and efficiency.

The Comparative Aircraft Flight Efficiency (CAFE) Foundation based in Santa Rosa manages this challenge for NASA. The total purse for 2008 is $300,000, which will be divided among the following prizes:
- The Community Noise Prize
- The Green Prize (for the highest miles per gallon)
- The CAFE Safety Prize (for handling and electronic safety features)
- The CAFE 400 Prize
- The Quietest Light Sport Aircraft Prize

The General Aviation Technology Challenge is one of seven current NASA technology prize competitions. The prize program, which began in 2005, is known as Centennial Challenges in recognition of the centennial of powered flight. In keeping with the spirit of the Wright Brothers and other American innovators, Centennial Challenge prizes are offered to independent inventors who work without government support, including small businesses, student groups and individuals.

The prize competitions are targeted at a range of technical challenges that support NASA's missions in aeronautics and space. The goal is to encourage novel solutions from non-traditional sources. In the Centennial Challenge program, NASA provides the prize money, and each
of the competitions is managed by an independent organization. NASA's Innovative Partnerships Program Office manages the Centennial Challenges program. For more information on the Centennial Challenges, visit:

For information about NASA's Innovative Partnerships Program, visit:

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NASA and the University of Arizona, Tucson, will hold a media briefing Thursday, July 31, at 11 a.m. PDT, in the mission's Science Operations Center at the university. Briefing participants
will discuss the latest progress by NASA's Phoenix Mars Lander in exploring a site in the Martian arctic. Following its May 25 landing, Phoenix has been studying whether Mars' environment ever has been favorable for microbial life.

The briefing participants are: - Michael Meyer, chief scientist, Mars Exploration Program, NASA
Headquarters, Washington - Peter Smith, Phoenix principal investigator, University of Arizona,
Tucson - Victoria Hipkin, mission scientist for Phoenix Meteorological Station, Canadian Space Agency, Saint-Hubert, Quebec - Mark Lemmon, lead scientist for Phoenix Surface Stereo Imager, Texas A&M University, College Station

News media may participate by telephone during the question and answer portion of the briefing. Reporters should call NASA's Jet Propulsion Laboratory media office at 818-354-5011 before the briefing for instructions and the dial-in number.

The briefing will be carried live by NASA TV and on the Internet at:

For more information on the Phoenix mission, visit:

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A NASA concept for lifting and manipulating materials on the lunar surface will be demonstrated for reporters at NASA's Langley Research Center in Hampton, Va., on Friday, Aug. 1.

NASA's Lunar Surface Manipulation System recently completed a successful June field test on the lunar-like landscape of Moses Lake, Wash. The system is a lifting and precision positioning device that will be used on items ranging from large airlocks and habitats to delicate scientific payloads. The robotic manipulator incorporates features that could help astronauts during early lunar outpost construction and follow-on operations. The principles behind the device also are directly applicable to future operations on the Martian surface.

The system reporters will be able to view is full-scale and sized for unloading a lunar lander. Designed by NASA engineers and controlled by a remote computer, the manipulator resembles a lightweight crane, but has more capabilities. It can be operated autonomously, remotely
or manually in a backup mode, and can be configured to perform a multitude of tasks.

Media interested in attending the presentation and briefing should phone Keith Henry by noon EDT, July 31, at 757-864-6120 or 757-344-7211. Reporters should arrive at the Langley front gate parking lot by 9:30 a.m. for escort to the briefing and lab demonstrations.

For more information and images, visit:

For more information about NASA's Constellation Program, visit:

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NASA will hold a series of news media briefings Sept. 8 - 9 to preview the space shuttle's fifth and final servicing mission to the Hubble Space Telescope. NASA Television and the agency's Web site will provide live coverage of the briefings from the Johnson Space Center and the Goddard Space Flight Center in Greenbelt, Md. Questions also will be taken from other participating NASA locations.

Shuttle Atlantis' 11-day flight, designated STS-125, is targeted for launch Oct. 8 and will include five spacewalks to refurbish and upgrade the telescope with state-of-the-art science instruments. Replacing failed hardware on Hubble will extend the telescope's life into the next decade.

U.S. news media planning to attend the briefings at Johnson must contact the newsroom there at 281-483-5111 by Sept. 2 to arrange for credentials. All reporters who are foreign nationals must contact the newsroom by Aug. 8.

On Sept. 9, Atlantis' seven astronauts will be available for round-robin interviews at Johnson. Reporters planning to participate in-person or by phone must contact Gayle Frere at 281-483-8645 by Sept. 2 to reserve an interview opportunity.

Scott Altman will command Atlantis' crew, which includes Pilot Gregory C. Johnson, and Mission Specialists Andrew Feustel, Michael Good, John Grunsfeld, Megan McArthur and Mike Massimino. The spacewalkers are Good, Grunsfeld, Feustel and Massimino. McArthur is the flight engineer and lead for robotic arm operations.

Along with the briefings to preview the Hubble servicing mission at Johnson, media will have an opportunity during the afternoon of Sept. 8 to review new equipment being developed for NASA's Constellation Program. Constellation is building America's next human spacecraft,
which will fly astronauts to low Earth orbit, the moon and beyond. During the review, media will see items that include concepts of a new spacesuit, a pressurized rover vehicle for astronauts, and a mockup of the Orion crew capsule.

The schedule (all times are CDT) includes:

Monday, Sept. 8
7 a.m. - Video B-Roll Feed
8 a.m. - NASA Overview Briefing (from Goddard)
9 a.m. - Shuttle Program Overview Briefing (from Johnson)
10 a.m. - HST/SM 4 Program Overview (from Goddard)
11:30 a.m. - NASA TV Video File
Noon - HST/SM4 Science Overview (from Goddard)
1:30 p.m. - HST Program and Science Round-Robins (from Goddard; not on
1:30 p.m. - Constellation Program Preview (from Johnson, not on NASA

Tuesday, Sept. 9
8 a.m. - Video B-Roll Feed
9 a.m. - STS-125 Mission Overview (from Johnson)
10:30 a.m. - STS-125 Spacewalk Overview (from Johnson)
Noon - NASA TV Video File
1 p.m. - STS-125 Crew News Conference (from Johnson)
2 - 6 p.m. - STS-125 Crew Round-Robins (from Johnson; not on NASA TV)

For NASA TV streaming video, schedules and downlink information,

For the latest information about the STS-125 mission and its crew,

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Sunday, July 27, 2008

NASA's Lander Collects Icy Soil But Needs to Work on Delivery

NASA's Phoenix Mars Lander's robotic arm collected a more than adequate amount of icy soil for baking in one of the lander's ovens but will need to adjust how it delivers samples.

Engineers determined the rasping and scraping activity collected a total of 3 cubic centimeters of icy soil, more than enough to fill the tiny oven cell of the Thermal and Evolved-Gas Analyzer, or TEGA. However, images returned from the lander Saturday morning show that much of the soil remained lodged in the robotic arm's scoop after the attempt to deliver the sample to the TEGA.

"Very little of the icy sample made it into the oven," said Barry Goldstein, Phoenix project manager from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "We believe that the material that was intended for the targeted cell is the material that adhered to the back of the scoop."

Once the sample had been collected, the robotic arm tilted its scoop and ran the rasp motor several times in an attempt to sprinkle the sample into the oven whose doors were wide open. The final step was inverting the scoop directly over the doors. A screened opening over the oven measures about 10 centimeters (4 inches) long by 3 centimeters (1.5 inches) wide. The oven itself is roughly the size of an ink cartridge in a ballpoint pen.

The delivery sequence also included vibrating the screen several times, which would have aided delivery. TEGA detected that not enough sample was recorded as being in its oven, so the oven doors did not close.

The TEGA activities did not cause any short circuits with the equipment.

"The good news here is TEGA is functioning nominally, and we will adjust our sample drop-off strategy to run this again," Goldstein said.

Prior to the sample delivery, Phoenix's robotic arm made 16 holes in the hard ground with its motorized rasp tool and the scoop collected the rasped material and shavings left on the surface from the rasping action.

The lander conducted these activities overnight Friday to Saturday, Pacific Time, during Martian morning hours of the mission's 60th Martian day, or sol. The Phoenix team planned Saturday to send the spacecraft commands to take images on Sunday, the mission's Sol 61, of areas around and under the TEGA instrument. The images by the Robotic Arm Camera would be a way to check for additional material that might have been released by the scoop on Sol 60.

The Phoenix mission is led by Peter Smith of the University of Arizona with project management at JPL and development partnership at Lockheed Martin, Denver. International contributions come from the Canadian Space Agency; the University of Neuchatel; the universities of Copenhagen and Aarhus, Denmark; Max Planck Institute, Germany; and the Finnish Meteorological Institute. For more about Phoenix, visit: and

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Friday, July 25, 2008

Hubble Instruments Slated for On-Orbit 'Surgery'

When astronauts visit the Hubble Space Telescope in October 2008 for its final servicing mission, they will be facing a task that has no precedence – performing on-orbit 'surgery' on two ailing science instruments that reside inside the telescope – the Space Telescope Imaging Spectrograph (STIS) and the Advanced Camera for Surveys (ACS).

Hubble was designed with servicing in mind, so its instrument bay doors are lined with handrails and, with custom tools, are relatively easy to open for the astronauts. The same cannot be said for the instruments themselves.

"The repair of STIS and of ACS in particular, involves techniques that the astronauts have never performed on Hubble, possibly never before anywhere," explained HST senior scientist Dave Leckrone at Goddard. "That is, to open up an instrument that was not designed to be opened up and actually pull out electronic printed circuit boards and replace them with new boards."

To accommodate these groundbreaking repairs, Hubble engineers and astronauts worked diligently to design special tools and procedures. Like doctors performing surgeries, preparation is imperative for success.

The Space Telescope Imaging Spectrograph

Astronauts installed STIS in Hubble in 1997 during Servicing Mission 2. Its main function is spectroscopy -- the separation of light into its component colors, or wavelengths, to reveal information about the chemical content, temperature, and motion of stars and gas. Among its many accomplishments, STIS confirmed the existence of super-massive black holes and was the first instrument ever to detect and analyze the atmosphere of a planet orbiting another star.

Although spectrographs like STIS generally do not produce the beautiful images that Hubble is famous for, the data they provide are absolutely essential to understanding the physical properties of the universe. It could be said that they put the "physics" in astrophysics.

After a long life of scientific discovery, STIS experienced a power supply failure in August 2004, causing it to suspend operations. NASA engineers were able to pinpoint exactly where and how the failure occurred by examining data from STIS and determined that the inoperable power supply resides on a printed circuit board housed within the instrument.

The Advanced Camera for Surveys

Installed during Servicing Mission 3B in 2002, ACS quickly became Hubble’s workhorse imaging camera. Designed to survey large areas of the sky at visible and red wavelengths, it had twice the field-of-view and a finer resolution than its predecessor, the Wide Field Planetary Camera 2. It quickly became Hubble’s most heavily used instrument and was responsible for many of the telescope’s most popular and dramatic images.

It took three failures to put ACS out of commission -- the first two were recovered by operating the instrument in different ways. To protect against failures, all Hubble instruments have some degree of "redundancy," meaning that there are duplicate parts that can perform the same function. If one part fails, another can be activated to restore the function.

When the first two failures occurred in 2006, the ground operations team was able to keep the entire instrument fully operational by using a redundant power supply. The final failure came in January 2007 when the backup power supply failed.

With less than two years until the final servicing mission, there would have been little time to develop procedures and tools needed to repair ACS had the team not already been preparing for a very similar task involving the repair of STIS. Designing a repair process for ACS became very workable by adapting the processes already under development for STIS repair.

Tool and Procedure Development

The repair of STIS and ACS presented a multitude of challenges during the development process. Engineers needed to work around three major issues: (1) safely getting access to the failed boards; (2) figuring a way to pull them out wearing the pressurized gloves; and (3) closing out the worksite when repairs are complete.

Knowing exactly what needs to be fixed is not enough to make repairs a piece of cake. To access the failed circuit boards on these two instruments, astronauts will have to remove 111 screws from the cover of STIS, and 32 screws from ACS, a time-consuming process in an environment where time is a scarce commodity.

To confront this challenge, Goddard engineers developed a high-speed power screwdriver with low torque, or twisting force. This combination of operational abilities means that the drill will speed up the removal process without breaking the screws and fasteners.

The sheer number of screws to be removed is not the only issue with gaining access to the circuit boards. Despite its mammoth size and giant status in space discovery, Hubble’s instruments are extremely delicate. Floating debris pose the threat of contaminating exposed electronics, so as astronauts open Hubble’s outer shell to make their repairs they must exercise extreme caution. Even tiny metal shavings resulting from the removal of one screw could be kryptonite to this super telescope.

To avoid the debris issue, NASA engineers designed a fastener capture plate. Using the custom drill, astronauts will first remove four screws to install the transparent “capture plate” over the electronic access panel. Tiny, labeled holes in the plate will allow them to then insert the drill bit and remove screws as the capture plate contains them. When all of the screws have been removed, the entire capture plate can be released as one unit, safely taking the access panel and all debris with it.

The astronauts' second challenge is grasping the failed circuit boards once the access panel has been removed. The boards are thin and the astronaut’s suits, including their gloves, are bulky and pressurized to protect them from the space environment. If you were to put on a pair of thick, wool mittens and try to grab a single piece of paper from the middle of a stack, you might have some idea of how difficult and time-consuming the task is for astronauts. NASA engineers got around this issue by developing a special card extraction tool which will allow the astronauts to easily grab and remove the circuit boards using large handles made specifically for their gloves.

The last major challenge of the repair process involves closing the instruments back up after repairs are complete. To conserve time, engineers designed a simplified version of the access panels. Two lever-like latches will be all it takes for the astronauts to securely lock the new STIS cover into place. A new panel is not required for ACS because the new electronic cards have all been built into one box that easily slides into place and covers the open side of the instrument.

Appreciating a Complement

Because NASA will be installing similar instruments into Hubble during SM4, you may wonder what purpose it serves to fix STIS and ACS. The answer lies in their differing, but complementary, capabilities.

While the new Wide Field Camera 3 (WFC3) will expand Hubble’s high resolution and provide a wide field-of-view into the near ultra-violet and near infra-red regions of the spectrum, the ACS has a slightly higher discovery potential in the visible wavelengths of light. STIS is a two-dimensional spectrograph while the Cosmic Origins Spectrograph (COS) is a point-source ultra-violet spectrograph. These two spectrographs working in tandem would give astronomers a full, spectroscopic suite of instruments.

The improvements will add years of science to Indexing Card Extraction Tool (ICET) and provide a full 'toolkit' to astronomers around the world. "Personally, I think that's where the more exciting results will come from after this servicing mission," explained Leckrone, “the new ideas that astronomers have about how to use these wonderful instruments now that they’re all together in a set that is internally complementary.”

Making History Again

Hubble has been arguably the most well-known and successful telescope in NASA history, but it is not solely a pathfinder for the science it has yielded over the years. The processes and procedures carried out during servicing missions have also always been innovative.

Before Hubble, nothing launched into space had even been built to be serviced and upgraded on orbit. The telescope is close to making history again with the first on-orbit repairs of existing instruments. Should these repair tasks be successful, Hubble is expected to be 90 times more powerful than ever before.

"At the end of SM4, when the astronauts leave Hubble for the last time, we have a very good prospect that Hubble will be at the apex of its capabilities. It will be better than it's ever been before, which is quite awesome when you realize that it will be over eighteen years old as an observatory," Leckrone said.

Related link:

> Read the other stories in the "Next Stop: Hubble" series

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Phoenix Scoop Ready for Sampling

NASA's Phoenix Mars Lander's robotic arm scoop is primed and ready to collect a soil sample from the northern region of Mars to analyze for the presence of water and other possible ingredients.

Scientists and engineers on the mission Friday prepared plans to send Phoenix later in the day that would command the robotic arm to rasp the hard soil in the trench informally named "Snow White," collect the shavings and deliver them to an oven for analysis.

Images received on Earth Friday morning confirmed that the scoop had been cleared of anything collected during previous days' testing. The scoop went through a sequence of moves to dump any remaining material. At the same time, the Thermal and Evolved-Gas Analyzer (TEGA) was successfully prepared for the sample by purging it of any volatile materials.

"The successful completion of these preparatory activities clears the way for our next critical event, delivering the icy soil sample to TEGA," said Doug Ming, of NASA Johnson Space Center, Houston, the team's science lead for today's planning.

The Phoenix mission is led by Peter Smith of the University of Arizona with project management at JPL and development partnership at Lockheed Martin, Denver. International contributions come from the Canadian Space Agency; the University of Neuchatel; the universities of Copenhagen and Aarhus, Denmark; Max Planck Institute, Germany; and the Finnish Meteorological Institute. For more about Phoenix, visit: and

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At the edge of our solar system in December 2004, the Voyager 1 spacecraft encountered something never before experienced during its then 26-year cruise through the solar system — an invisible shock formed as the solar wind piles up against the gas in interstellar space. This boundary, called the termination shock, marks the beginning of our solar system's final frontier, a vast expanse of turbulent gas and twisting magnetic fields.

A NASA-sponsored team is developing a way to view this chaotic but unseen realm for the first time. Just as an impressionist artist makes an image from countless tiny strokes of paint, NASA’s new Interstellar Boundary Explorer (IBEX) spacecraft will build up an image of the termination shock and areas beyond by using hits from high-speed atoms that are radiating out of this region.

"IBEX will let us make the first global observations of the region beyond the termination shock at the very edges of our solar system. This region is critical because it shields out the vast majority of the deadly cosmic rays that would otherwise permeate the space around the Earth and other planets," says Dr. David J. McComas, IBEX principal investigator from the Southwest Research Institute (SwRI) in San Antonio, Texas. "IBEX will let us visualize our home in the galaxy for the first time and explore how it may have evolved over the history of the solar system. Ultimately, by making the first images of the interstellar boundaries neighboring our solar system, IBEX will provide a first step toward exploring the galactic frontier."

Space is not empty. The sun exhales a thin, hot wind of electrically conducting gas, called plasma, into space at about a million miles per hour. This solar wind forms a large plasma bubble, called the heliosphere, in space around the Sun. Beyond the orbit of Pluto, the solar wind gradually slows as it interacts with inflowing neutral gases from interstellar space, and then abruptly drops in speed at a thin, invisible boundary around our solar system called the termination shock.

A simple kitchen demonstration illustrates how this shock forms. When water runs at high speed from a kitchen faucet down to the bottom surface of the sink, the water hitting this surface first flows quickly and smoothly away from the impact point, but then runs into a circular boundary with slower, more turbulent flow beyond this boundary.

In the kitchen sink demonstration, the circular boundary is the termination shock. The turbulent region beyond the shock boundary corresponds to a layer in the outer heliosphere of turbulent plasma flows and magnetic fields called the heliosheath. The boundary of this turbulent layer with the interstellar plasma environment, not so easily seen in the kitchen sink experiment because of the turbulence, is called the heliopause. The heliopause is the end of our solar system’s frontier. Beyond that is interstellar space.

IBEX will make pictures of the heliosheath region and determine the termination shock’s strength. It will also discover what happens when the solar wind clashes with interstellar space by observing how the solar wind is flowing in the heliosheath and how the interstellar gas interacts with the heliopause. IBEX will determine how high-speed atoms are accelerated within the termination shock and heliosheath.

A cosmic game of tag allows IBEX to make its pictures. First, some background on the players: an atom needs to be electrically charged to feel magnetic force and be influenced by the magnetic fields in space. Normally, the positive electric charges in the central part of the atom, called the nucleus, are balanced by an equal number of negatively charged electrons swirling around it. In this case, the atom is electrically neutral overall and does not respond to magnetic fields. However, sometimes an atom gains or loses an electron. The electric charges are no longer in balance; gaining an electron gives the atom an extra negative charge, while losing an electron leaves the atom with a positive charge. The charged atom, called an ion, can now be deflected or accelerated by magnetic fields.

Most of the ions in interstellar space are deflected around our solar system by the magnetic field carried by the solar wind. Energetic neutral atoms (ENAs) are created when low-energy neutral atoms floating in from the interstellar medium "tag" energetic protons that are gyrating around the magnetic field lines in the solar wind. They charge exchange (since opposite charges attract, an electron jumps from the neutral atom to the positively charged proton if the two pass each other very closely). The proton now has an electron to balance its charge, and it becomes an Energetic Neutral Atom. The ENAs that happen to be pointing in the direction of Earth at the moment of charge-exchange will then propagate back in toward the Earth where IBEX can detect them.

Since the ENAs no longer feel magnetic force, they travel in a nearly straight line, only slightly deflected by the sun's gravity. Their straightforward path allows ENAs that hit IBEX's two sensors to be traced back to their origin near the termination shock. This lets the IBEX team gradually build up a picture of the termination shock using the incoming neutral atoms, since the majority of Earthward-directed ENAs are believed to result from heating of the solar wind as it crosses the termination shock. Six months into the mission, IBEX will have observed the entire sky, and will reveal the global structure of the heliosheath and termination shock for the first time.

IBEX is scheduled to be launched on a Pegasus rocket on October 5, 2008. It needs to go beyond the region of space controlled by Earth's magnetic field, called the magnetosphere, because this region generates radiation and the same high-speed atoms (ENAs) that IBEX will use to make its pictures. To avoid contamination from local ENAs produced in the magnetosphere, IBEX's orbit will take it up to 200,000 miles from Earth.

"The solar system's frontier is billions of miles away, so it's difficult for us to go there, but interesting things happen at boundaries, and with IBEX, we will see them for the first time," said Dr. Robert MacDowall, IBEX Mission Scientist at NASA's Goddard Space Flight Center in Greenbelt, Md.

The IBEX mission is funded by NASA's Small Explorer program. It is a PI-led mission being run by SwRI, which is responsible for all aspects of the mission. Orbital Science Corporation in Dulles, Virginia, is SwRI’s sub-contractor for the IBEX spacecraft and also provides the Pegasus launch. The Explorer Project Office at NASA Goddard oversees all Small Explorer missions, including IBEX.

> IBEX News and Multimedia

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