Category: Missions

Artist’s impression of Stardust returning back to Earth. Image credit: NASA/JPL Click to enlarge
NASA’s Stardust mission is nearing Earth after a 4.63 billion kilometer (2.88 billion mile) round-trip journey to return cometary and interstellar dust particles back to Earth. Scientists believe the cargo will help provide answers to fundamental questions about comets and the origins of the solar system.

The velocity of the sample return capsule, as it enters Earth’s atmosphere at 46,440 kilometers per hour (28,860 miles per hour), will be the fastest of any human-made object on record. It surpasses the record set in May 1969 during the return of the Apollo 10 command module. The capsule is scheduled to return on Jan. 15, 2006.

“Comets are some of the most informative occupants of the solar system. The more we can learn from science exploration missions like Stardust, the more we can prepare for human exploration to the moon, Mars and beyond,” said Dr. Mary Cleave, associate administrator for NASA’s Science Mission Directorate.

Several events must occur before scientists can retrieve cosmic samples from the capsule landing at the U.S. Air Force Utah Test and Training Range, southwest of Salt Lake City. Mission navigators will command the spacecraft to perform targeting maneuvers on Jan. 5 and 13. On Jan 14 at 9:57 p.m. PST (12:57 a.m. EST on Jan. 15), Stardust will release its sample return capsule. Four hours later, the capsule will enter Earth’s atmosphere 125 kilometers (410,000 feet) over the Pacific Ocean.

The capsule will release a drogue parachute at approximately 32 kilometers (105,000 feet). Once the capsule has descended to about 3 kilometers (10,000 feet), the main parachute will deploy. The capsule is scheduled to land on the range at 2:12 a.m. PST (5:12 a.m. EST).

After the capsule lands, if conditions allow, a helicopter crew will fly it to the U.S. Army Dugway Proving Ground, Utah, for initial processing. If weather does not allow helicopters to fly, special off-road vehicles will retrieve the capsule and return it to Dugway. Samples will then be moved to a special laboratory at NASA’s Johnson Space Center, Houston, where they will be preserved and studied.

“Locked within the cometary particles is unique chemical and physical information that could be the record of the formation of the planets and the materials from which they were made,” said Dr. Don Brownlee, Stardust principal investigator at the University of Washington, Seattle.

NASA expects most of the collected particles to be no more than a third of a millimeter across. Scientists will slice these particle samples into even smaller pieces for study.

NASA’s Jet Propulsion Laboratory, Pasadena, Calif. manages the Stardust mission for NASA’s Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, developed and operates the spacecraft.

For information about the Stardust mission on the Web, visit http://www.nasa.gov/stardust .

Original Source: NASA News Release

The heavy-lift Ariane 5 ECA. Image credit: Arienspace. Click to enlarge
During the night of Wednesday, November 16 to Thursday, November 17, Arianespace placed two satellites into geostationary transfer orbit: the SPACEWAY 2 high-definition direct broadcast satellite for the American operator DIRECTV, and the TELKOM 2 communications satellite for the Indonesian operator PT Telekomunikasi Indonesia Tbk.

20th successful Ariane 5 launch, 10th in a row, record payload.

Today’s mission sets a new record for commercial launches: with over 8,000 kg. injected into orbit, the SPACEWAY 2 and TELKOM 2 satellites represent the heaviest dual payload ever launched.

Today, Ariane 5 is the only commercial launcher in service capable of simultaneously launching two payloads. Ariane 5 ECA offers a payload capacity of nearly 10,000 kg. into geostationary transfer orbit, giving Arianespace’s customers enhanced performance, flexibility and competitiveness through the best launch service in the world.

Today’s mission was the 20th successful launch of an Ariane 5, and the 10th successful launch in a row. One week after the successful launch of the Venus Express spacecraft by a Soyuz rocket from the Baikonur Cosmodrome, this confirms that Arianespace, with its complete family of launchers, offers the best launch solution for operators from around the world.

Original Source: Arienspace News Release

An artist’s concept of twisted space-time around Earth. Image credit: NASA. Click to enlarge
Is Earth in a vortex of space-time?

We’ll soon know the answer: A NASA/Stanford physics experiment called Gravity Probe B (GP-B) recently finished a year of gathering science data in Earth orbit. The results, which will take another year to analyze, should reveal the shape of space-time around Earth–and, possibly, the vortex.

Time and space, according to Einstein’s theories of relativity, are woven together, forming a four-dimensional fabric called “space-time.” The tremendous mass of Earth dimples this fabric, much like a heavy person sitting in the middle of a trampoline. Gravity, says Einstein, is simply the motion of objects following the curvaceous lines of the dimple.

If Earth were stationary, that would be the end of the story. But Earth is not stationary. Our planet spins, and the spin should twist the dimple, slightly, pulling it around into a 4-dimensional swirl. This is what GP-B went to space to check

The idea behind the experiment is simple:

Put a spinning gyroscope into orbit around the Earth, with the spin axis pointed toward some distant star as a fixed reference point. Free from external forces, the gyroscope’s axis should continue pointing at the star–forever. But if space is twisted, the direction of the gyroscope’s axis should drift over time. By noting this change in direction relative to the star, the twists of space-time could be measured.

In practice, the experiment is tremendously difficult.

The four gyroscopes in GP-B are the most perfect spheres ever made by humans. These ping pong-sized balls of fused quartz and silicon are 1.5 inches across and never vary from a perfect sphere by more than 40 atomic layers. If the gyroscopes weren’t so spherical, their spin axes would wobble even without the effects of relativity.

According to calculations, the twisted space-time around Earth should cause the axes of the gyros to drift merely 0.041 arcseconds over a year. An arcsecond is 1/3600th of a degree. To measure this angle reasonably well, GP-B needed a fantastic precision of 0.0005 arcseconds. It’s like measuring the thickness of a sheet of paper held edge-on 100 miles away.

GP-B researchers invented whole new technologies to make this possible. They developed a “drag free” satellite that could brush against the outer layers of Earth’s atmosphere without disturbing the gyros. They figured out how to keep Earth’s penetrating magnetic field out of the spacecraft. And they concocted a device to measure the spin of a gyro–without touching the gyro.

Pulling off the experiment was an exceptional challenge. A lot of time and money was on the line, but the GP-B scientists appear to have done it.

“There were not any major surprises” in the experiment’s performance, says physics professor Francis Everitt, the Principal Investigator for GP-B at Stanford University. Now that data-taking is complete, he says the mood among the GP-B scientists is “a lot of enthusiasm, and a realization also that a lot of grinding hard work is ahead of us.”

A careful, thorough analysis of the data is underway. The scientists will do it in three stages, Everitt explains. First, they will look at the data from each day of the year-long experiment, checking for irregularities. Next they’ll break the data into roughly month-long chunks, and finally they’ll look at the whole year. By doing it this way, the scientists should be able to find any problems that a more simple analysis might miss.

Eventually scientists around the world will scrutinize the data. Says Everitt, “we want our sternest critics to be us.”

The stakes are high. If they detect the vortex, precisely as expected, it simply means that Einstein was right, again. But what if they don’t? There might be a flaw in Einstein’s theory, a tiny discrepancy that heralds a revolution in physics.

First, though, there are a lot of data to analyze. Stay tuned.

Original Source: NASA News Release

Cryosat launch. It crashed back to Earth shortly after. Image credit: ESA. Click to enlarge.
Mr Yuri Bakhvalov, First Deputy Director General of the Khrunichev Space Centre on behalf of the Russian State Commission officially confirmed that the launch of CryoSat ended in a failure due to an anomaly in the launch sequence and expressed his regret to ESA and all partners involved.

Preliminary analysis of the telemetry data indicates that the first stage performed nominally. The second stage performed nominally until main engine cut-off was to occur. Due to a missing command from the onboard flight control system the main engine continued to operate until depletion of the remaining fuel.

As a consequence, the separation of the second stage from upper stage did not occur. Thus, the combined stack of the two stages and the CryoSat satellite fell into the nominal drop zone north of Greenland close to the North Pole into high seas with no consequences to populated areas.

An investigating commission by the Russian State authorities has been established to further analyze the reasons for the failure, results are expected within the next weeks. This commission will work in close cooperation with a failure investigation board consisting of Eurockot, ESA and Khrunichev representatives.

This information is released at the same time by Eurockot and ESA.

Original Source: ESA News Release

Artist illustration of the Gravity Probe B satellite in orbit. Image credit: NASA/Stanford. Click to enlarge.
Almost 90 years after Albert Einstein first postulated his general theory of relativity, scientists have finished collecting data to put it to a new, different kind of experimental test.

NASA’s Gravity Probe B satellite has been orbiting the Earth for more than 17 months. It used four ultra-precise gyroscopes to generate the data required for this unprecedented test. Fifty weeks worth of data has been downloaded from the spacecraft and relayed to computers in the Mission Operations Center at Stanford University, Stanford, Calif. Scientists have begun the painstaking task of data analysis and validation, which is expected to take approximately one year.

“This has been a tremendous mission for all of us,” said Francis Everitt, Gravity Probe B principal investigator at Stanford. “With all the data gathered, we are proceeding deliberately to ensure everything is checked and re-checked. NASA and Stanford can be proud of what has been achieved so far.”

Launched on April 20, 2004, from Vandenberg Air Force Base, Calif., Gravity Probe B has been using four spherical gyroscopes to precisely measure two extraordinary effects predicted by Einstein’s theory. One is the geodetic effect, the amount by which the Earth warps the local space time in which it resides. The other, called frame-dragging, is the amount by which the rotating Earth drags local space time around with it.

“The completion of the GP-B mission is the culmination of years of hard work, training and preparation by the GP-B team,” said Tony Lyons, NASA GP-B program manager from NASA?s Marshall Space Flight Center in Huntsville, Ala.

“We are proud to have been associated with this extremely significant mission,” said Bob Schultz, Lockheed Martin’s Gravity Probe B program manager. “Working with Stanford and NASA, we formed a powerful team to develop the challenging technologies needed to take a giant step forward in helping understand Einstein’s theory of general relativity.”

The Marshall manages the Gravity Probe B program. Stanford conceived the experiment and is NASA’s prime contractor for the mission. Stanford was responsible for the design and integration of the science instruments and mission operations. The university has the lead for data analysis. Lockheed Martin Space Systems Company designed, integrated and tested the space vehicle and built some major payload components.

Original Source: NASA News Release

Solar power heats NASA space shield material. Image credit: Bill Congdon, Applied Research Associates. Click to enlarge
For the last two years, tests have been conducted at Sandia National Laboratories? National Solar Thermal Test Facility to see how materials used for NASA?s future planetary exploration missions can withstand severe radiant heating.

The tests apply heat equivalent to 1,500 suns to spacecraft shields called Advanced Charring Ablators. The ablators protect spacecraft entering atmospheres at hypersonic speeds.

The test facility includes a 200-ft. ?solar tower? surrounded by by a field of hundreds of sun-tracking mirror arrays called heliostats. The heliostats direct sunlight to the top of the tower where the test objects are affixed.

Under a work agreement, researchers at Sandia and Applied Research Associates, Inc. are conducting the tests for NASA Marshall?s In-Space Propulsion/Aerocapture Program. The R&D effort is tied to NASA?s plan for a future Titan mission with an orbiter and lander. Titan is Saturn?s largest moon.

The tests are led by Sandia solar tower expert Cheryl Ghanbari and Bill Congdon, project principal investigator for Applied Research Associates, Inc.

Solar power heats NASA space shield material. The tests apply heat equivalent to 1,500 suns to spacecraft shields. (Photo courtesy of Bill Congdon, Applied Research Associates, Inc.)
Download 300dpi JPEG image, ?solar-heat.jpg,? 376K (Media are welcome to download/publish this image with related news stories.)The tests are designed to simulate atmospheric heating of spacecraft that enter Titan, including low levels of convective heating combined with relatively high levels of thermal radiation.

The primary ablator candidates for the Titan mission are low-density silicones and phenolics, all under 20 pounds-per-cubic-foot density.

To date, more than 100 five-inch diameter samples have been tested in the solar environment inside the tower?s wind tunnel using a large quartz window.

Congdon says because of Titan?s relatively high radiation environment, some initial concerns had to be put to rest through testing. He says radiation might penetrate in-depth within the ablator, causing an increased ?apparent? thermal conductivity and degrading insulation performance.

?Radiation could also generate high-pressure gasses within the ablator leading to spallation,? Congdon says.

?We have been testing at the solar tower to see how the candidate Titan materials can withstand the expected range of heating conditions,? Ghanbari says. ?Titan has a nitrogen-rich atmosphere and nitrogen is used in the tests to similarly reduce ablator oxidation, while energy from the sun-tracking heliostats is focused on the samples.?

Congdon says ground tests are necessary to understand and model surface ablation of the materials that will be severely heated during Titan entry.

During thermal radiation testing conducted in the solar tower, all of these concerns were addressed and found not to be a problem for the ablators of interest.

About the tests

The National Solar Thermal Test Facility consists of an eight-acre field of 220 solar-collection heliostats and a 200-ft.-tall tower that receives the collected energy at one of several test bays. A single heliostat includes 25 mirrors that are each four feet square. Total collection area of 220 heliostats is 88,000-square feet.

Because the heliostats are individually computer controlled, test radiation can be a shaped pulse as well as a square wave in terms of intensity vs. time, says Ghanbari.

Test samples are mounted high in the receiver tower, and the heliostats direct the sunlight upward to irradiate the sample surface. The samples are mounted in a water-cooled copper plate inside the wind tunnel with a quartz window that allows entry of the concentrated radiation.

Exposure is controlled by a fast-moving shutter and by pre-programmed heliostat movement. Radiation flux is calibrated before and after each test by a radiometer installed to occupy the same position as the test sample. Cooling effects from imposed surface flows are calibrated via a flat-plate slug calorimeter.

The materials are subjected to square pulse environments at flux levels of 100 and 150 W/cm2 for time periods that far exceed predicted flight durations for such high heating. They are also tested to ?exact? flux vs. time environments (simulating actual flight conditions) using programmed heliostat focusing at the solar tower facility.

The material samples are installed in the tower?s wind tunnel and exposed to the solar beam at flux levels up to 150 W/cm2, which is approximately 1,500 times the intensity of the sun on earth on a clear day. During exposure, air blows past the sample at about mach 0.3 with a high-speed nitrogen sub-layer close to the sample surface.

Ghanbari says tests can be conducted only during about four hours midday bracketing solar noon. Haze, clouds, and high winds that affect the heliostats can degrade test conditions.

Current results

?All of the candidate materials showed no spallation and very good thermal performance to these imposed environments,? Congdon says. Recently, five 12-inch by 12-inch panel samples were tested on top of the tower. Up to 20 additional 12-inch panels will be tested late in the summer followed by testing of 2-foot by 2-foot panels later in the year.

Additional tests for convective heating have been conducted on identical material samples at the Interaction Heating Facility (IHF) at NASA?s Ames Research Center.

Origianl Source: Sandia National Labs

20-meter solar sail. Image credit: NASA/MSFC Click to enlarge
NASA has reached a milestone in the testing of solar sails — a unique propulsion technology that will use sunlight to propel vehicles through space. Engineers have successfully deployed a 20-meter solar sail system that uses an inflatable boom deployment design.

L’Garde, Inc. of Tustin, Calif., deployed the system at the Space Power Facility — the world’s largest space environment simulation chamber — at NASA Glenn Research Center’s Plum Brook Station in Sandusky, Ohio. L’Garde is a technology development contractor for the In-Space Propulsion Technology Office at NASA’s Marshall Space Flight Center in Huntsville, Ala. NASA’s Langley Research Center in Hampton, Va., provided instrumentation and test support for the tests.

Red lights help illuminate the four, outstretched triangular sail quadrants in the chamber. The sail material is supported by an inflatable boom system designed to unfold and become rigid in the space environment. The sail and boom system is extended via remote control from a central stowage container about the size of a suitcase.

L’Garde began testing its sail system at Plum Brook in June. The test series lasted 30 days.

Solar sail technologies use energy from the Sun to power a spacecraft’s journey through space. The technology bounces sunlight off giant, reflective sails made of lightweight material 40-to-100-times thinner than a piece of writing paper. The continuous sunlight pressure provides sufficient thrust to perform maneuvers, such as hovering at a fixed point in space or rotating the vehicle’s plane of orbit. Such a maneuver would require a significant amount of propellant for conventional rocket systems.

Because the Sun provides the necessary propulsive energy, solar sails require no onboard propellant, thus increasing the range of mobility or the capability to hover at a fixed point for longer periods of time.

Solar sail technology was selected for development in August 2002 by NASA’s Science Mission Directorate in Washington. Along with sail system design projects, the Marshall Center and NASA’s Jet Propulsion Laboratory in Pasadena, Calif., are collaborating to investigate the effects of the space environment on advanced solar sail materials. These are just three of a number of efforts undertaken by NASA Centers, industry and academia to develop solar sail technology.

Solar sail technology is being developed by the In-Space Propulsion Technology Program, managed by NASA’s Science Mission Directorate and implemented by the In-Space Propulsion Technology Office at Marshall. The program’s objective is to develop in-space propulsion technologies that can enable or benefit near- or mid-term NASA space science missions by significantly reducing cost, mass and travel times.

For more information about solar sail propulsion, visit:
http://www.inspacepropulsion.com

For more information about L’Garde, Inc. and its solar sail system, visit:
http://www.lgarde.com/

Original Source: NASA News Release

Artist illustration of the position of the twin Voyager spacecraft. Image credit: NASA/JPL. Click to enlarge.
NASA’s Voyager 1 spacecraft has entered the solar system’s final frontier. It is entering a vast, turbulent expanse where the Sun’s influence ends and the solar wind crashes into the thin gas between stars.

“Voyager 1 has entered the final lap on its race to the edge of interstellar space,” said Dr. Edward Stone, Voyager project scientist at the California Institute of Technology in Pasadena. Caltech manages NASA’s Jet Propulsion Laboratory in Pasadena, which built and operates Voyager 1 and its twin, Voyager 2.

In November 2003, the Voyager team announced it was seeing events unlike any in the mission’s then 26-year history. The team believed the unusual events indicated Voyager 1 was approaching a strange region of space, likely the beginning of this new frontier called the termination shock region. There was considerable controversy over whether Voyager 1 had indeed encountered the termination shock or was just getting close.

The termination shock is where the solar wind, a thin stream of electrically charged gas blowing continuously outward from the Sun, is slowed by pressure from gas between the stars. At the termination shock, the solar wind slows abruptly from a speed that ranges from 700,000 to 1.5 million miles per hour and becomes denser and hotter. The consensus of the team is that Voyager 1, at approximately 8.7 billion miles from the Sun, has at last entered the heliosheath, the region beyond the termination shock.

Predicting the location of the termination shock was hard, because the precise conditions in interstellar space are unknown. Also, changes in the speed and pressure of the solar wind cause the termination shock to expand, contract and ripple.

The most persuasive evidence that Voyager 1 crossed the termination shock is its measurement of a sudden increase in the strength of the magnetic field carried by the solar wind, combined with an inferred decrease in its speed. This happens whenever the solar wind slows down.

In December 2004, the Voyager 1 dual magnetometers observed the magnetic field strength suddenly increasing by a factor of approximately 2-1/2, as expected when the solar wind slows down. The magnetic field has remained at these high levels since December. NASA’s Goddard Space Flight Center, Greenbelt, Md., built the magnetometers.

Voyager 1 also observed an increase in the number of high-speed electrically charged electrons and ions and a burst of plasma wave noise before the shock. This would be expected if Voyager 1 passed the termination shock. The shock naturally accelerates electrically charged particles that bounce back and forth between the fast and slow winds on opposite sides of the shock, and these particles can generate plasma waves.

“Voyager’s observations over the past few years show the termination shock is far more complicated than anyone thought,” said Dr. Eric Christian, Discipline Scientist for the Sun-Solar System Connection research program at NASA Headquarters, Washington.

The result is being presented today at a press conference in the Morial Convention Center, New Orleans, during the 2005 Joint Assembly meeting of Earth and space science organizations.

For their original missions to Jupiter and Saturn, Voyager 1 and sister spacecraft Voyager 2 were destined for regions of space far from the Sun where solar panels would not be feasible, so each was equipped with three radioisotope thermoelectric generators to produce electrical power for the spacecraft systems and instruments. Still operating in remote, cold and dark conditions 27 years later, the Voyagers owe their longevity to these Department of Energy-provided generators, which produce electricity from the heat generated by the natural decay of plutonium dioxide.

Original Source: NASA/JPL News Release

Scientists have closely examined four Genesis spacecraft collectors, vital to the mission’s top science objective, and found them in excellent shape, despite the spacecraft’s hard landing last year.

Scientists at NASA’s Johnson Space Center (JSC) in Houston removed the four solar-wind collectors from an instrument called the concentrator. The concentrator targets collected solar-oxygen ions during the Genesis mission. Scientists will analyze them to measure solar-oxygen isotopic composition, the highest-priority measurement objective for Genesis. The data may hold clues to increase understanding about how the solar system formed.

“Taking these concentrator targets out of their flight holders and getting our first visual inspection of them is very important,” said Karen McNamara, Genesis curation recovery lead. “This step is critical to moving forward with the primary science Genesis was intended to achieve. All indications are the targets are in excellent condition. Now we will have the opportunity to show that quantitatively. The preliminary assessment of these materials is the first step to their allocation and measurement of the composition of the solar wind,” she said.

The targets were removed at JSC by a team from Los Alamos National Laboratory, Los Alamos, N.M., where the concentrator was designed and built.

“Finding these concentrator targets in excellent condition after the Genesis crash was a real miracle,” said Roger Wiens, principal investigator for the Los Alamos instruments. “It raised our spirits a huge amount the day after the impact. With the removal of the concentrator targets this week, we are getting closer to learning what these targets will tell us about the sun and our solar system,” he added.

The Los Alamos team was assisted by JSC curators and Quality Assurance personnel from NASA’s Jet Propulsion Laboratory in Pasadena, Calif. Curators at JSC will examine the targets and prepare a detailed report about their condition, so scientists can properly analyze the collectors. The targets will be imaged in detail and then stored under nitrogen in the Genesis clean room.

Genesis was launched Aug. 8, 2001, from Cape Canaveral Air Force Station, Fla., on a mission to collect solar wind particles. Sample collection began Dec. 5, 2001, and was completed April 1, 2004. After an extensive recovery effort, following its Sept. 8, 2004, impact at a Utah landing site, the first scientific samples from Genesis arrived at JSC Oct. 4, 2004.

Original Source: NASA News Release