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NASA Probe Sees Solar Wind Decline

The 33-year odyssey of NASA's Voyager 1 spacecraft has reached a distant point at the edge of our solar system where there is no outward motion of solar wind. Now hurtling toward interstellar space some 17.4 billion...

Super-Earth Atmosphere

A team of astronomers, including two NASA Sagan Fellows, has made the first characterizations of a super-Earth's atmosphere, by using a ground-based telescope...

Kepler Discovers

NASA's Kepler spacecraft has discovered the first confirmed planetary system with more than one planet crossing in front of, or transiting, the same star...

Pulverized Planet

Tight double-star systems might not be the best places for life to spring up, according to a new study using data from NASA's Spitzer Space Telescope....

Dark Asteroids

NASA is set to launch a sensitive new infrared telescope to seek out sneaky things in the night sky -- among them, dark asteroids that could pose a threat to Earth....

Archive for February 2011

It may seem illogical, but boiling is a very efficient way to cool engineering components and systems used in the extreme environments of space.

An experiment to gain a basic understanding of this phenomena launched to the International Space Station on space shuttle Discovery Feb. 24. The Nucleate Pool Boiling Experiment, or NPBX, is one of two experiments in the new Boiling eXperiment Facility, or BXF.

Nucleate boiling is bubble growth from a heated surface and the subsequent detachment of the bubble to a cooler surrounding liquid. As a result, these bubbles can efficiently transfer energy from the boiling surface into the surrounding fluid. This investigation provides an understanding of heat transfer and vapor removal processes that happen during nucleate boiling in microgravity. Researchers will glean information to better design and operate space systems that use boiling for efficient heat removal.

Bubbles in microgravity grow to different sizes than on Earth. This experiment will focus on the dynamics of single and multiple bubbles and the associated heat transfer.

NPBX uses a polished aluminum wafer, powered by heaters bonded to its backside, and five fabricated cavities that can be controlled individually. The experiment will study single and/or multiple bubbles generated at these cavities. It will measure the power supplied to each heater group, and cameras will record the bubble dynamics. Analysis of the heater power data and recorded images will allow investigators to determine how bubble dynamics and heat transfer differ in microgravity.

"With boiling, the size and weight of heat exchange equipment used in space systems can be significantly reduced," said Vijay Dhir, the experiment's principal investigator at the University of California, Los Angeles. "Boiling and multiphase heat transfer is an enabling technology for space exploration missions including storage and handling of cryogenic, or extremely low temperature liquids, life support systems, power generation and thermal management."

"The cost of transporting equipment to space depends on the size and weight of the equipment," added David Chao, the project scientist from NASA's Glenn Research Center in Cleveland. "The knowledge base that will be developed through the experiment will give us the capability to achieve cooling of various components and systems used in space in an efficient manner and could lead to smaller and lighter spacecraft."

At 8:48 p.m. EST, space shuttle Discovery astronauts Steve Bowen and Alvin Drew will “campout” in the Quest airlock, preparing for Monday’s spacewalk. The airlock’s atmospheric pressure will be lowered to help purge nitrogen from Bowen and Drew’s bloodstreams, protecting them from “the bends” when they leave the airlock for the vacuum of space. The space station crew goes to sleep at 9:53 p.m. EST followed by Discovery’s crew at 10:23 p.m.

Discovery’s astronauts performed an inspection of the orbiter’s thermal protection system. They also checked out spacesuits and rendezvous tools in preparation for Saturday’s docking with the International Space Station, scheduled for 2:15 p.m. EST.

The crew configured shuttle systems for orbital operations and will install the centerline camera that will be used during alignment and rendezvous with the station. All of Discovery’s systems are performing well.

At 10:53 p.m., Discovery’s crew goes to sleep. Beginning at 11 p.m., NASA TV will play Flight Day 2 highlights hourly until the crew awakens at 6:53 a.m.

Space shuttle Discovery rode a brilliant trail of fire and smoke Thursday afternoon as it soared into orbit for an important mission to the International Space Station. The launch came after a last-minute technical glitch with the Air Force's Eastern Range that left only four seconds in the launch window and a practical limit of two seconds because of draining requirements with the external fuel tank.

"It was one more second than Mike Leinbach (shuttle launch director) needed to get the job done, so there was plenty of margin," said Mike Moses, chairman of the Mission Management Team. Still, he joked, "I could use a little less heart palpitations in the final seconds of the countdown."

Leinbach said launch simulations have conditioned the team of controllers to handle the pressures of last-second "go" decisions without jeopardizing a mission.

"This was one for the record books," Leinbach said. "It may have seemed a little rushed to people on the outside. It's a testament to the team that we have practiced for this."

The launch of the shuttle was not the only thing to happen in space exploration on launch day. Just as Discovery's tank finished being fueled, a cargo-carrying Automated Transfer Vehicle from the Eurpoean Space Agency docked to the station. The spacecraft, which carried no people, launched from South America last week on an Ariane V.

"This is a pretty tremendous day in spaceflight for us," said Bll Gerstenmaier, NASA's associate administrator for Space Operations. "For us to be sitting here today with both of these events occurring as they did is pretty amazing."

NASA's Mars Science Laboratory rover, Curiosity, will carry a next generation, onboard "chemical element reader" to measure the chemical ingredients in Martian rocks and soil. The instrument is one of 10 that will help the rover in its upcoming mission to determine the past and present habitability of a specific area on the Red Planet. Launch is scheduled between Nov. 25 and Dec. 18, 2011, with landing in August 2012.

The Alpha Particle X-Ray Spectrometer (APXS) instrument, designed by physics professor Ralf Gellert of the University of Guelph in Ontario, Canada, uses the power of alpha particles, or helium nuclei, and X-rays to bombard a target, causing the target to give off its own characteristic alpha particles and X-ray radiation. This radiation is "read by" an X-ray detector inside the sensor head, which reveals which elements and how much of each are in the rock or soil.

Identifying the elemental composition of lighter elements such as sodium, magnesium or aluminum, as well as heavier elements like iron, nickel or zinc, will help scientists identify the building blocks of the Martian crust. By comparing these findings with those of previous Mars rover findings, scientists can determine if any weathering has taken place since the rock formed ages ago.

All NASA Mars rovers have carried a similar instrument – Pathfinder's rover Sojourner, Spirit and Opportunity, and now Curiosity, too. Improvements have been made with each generation, but the basic design of the instrument has remained the same.

"APXS was modified for Mars Science Laboratory to be faster so it could make quicker measurements. On the Mars Exploration Rovers it took us five to 10 hours to get information that we will now collect in two to three hours," said Gellert, the intrument's principal investigator. "We hope this will help us to investigate more samples."

Another significant change to the next-generation APXS is the cooling system on the X-ray detector chip. The instruments used on Spirit and Opportunity were able to take measurements only at night. But the new cooling system will allow the instrument on Curiosity to take measurements during the day, too.

The main electronics portion of the tissue-box-sized instrument lives in the rover's body, while the sensor head, the size of a soft drink can, is mounted on the robotic arm. With the help of Curiosity’s remote sensing instruments – the Chemistry and Camera (ChemCam) instrument and the Mastcam – the rover team will decide where to drive Curiosity for a closer look with the instruments, including APXS. Measurements are taken with the APXS by deploying the sensor head to make direct contact with the desired sample.

The rover’s brush will be used to remove dust from rocks to prepare them for inspection by APXS and by MAHLI, the rover’s arm-mounted, close-up camera. Whenever promising samples are found, the rover will then use its drill to extract a few grains and feed them into the rover’s analytical instruments, SAM and CheMin, which will then make very detailed mineralogical and other investigations.

Scientists will use information from APXS and the other instruments to find the interesting spots and to figure out the present and past environmental conditions that are preserved in the rocks and soils. "The rovers have answered a lot of questions, but they've also opened up new questions," said Gellert. "Curiosity was designed to pick up where Spirit and Opportunity left off."


In November 2010, the scientific journal Icarus published a paper by astrophysicists John Matese and Daniel Whitmire, who proposed the existence of a binary companion to our sun, larger than Jupiter, in the long-hypothesized "Oort cloud" - a faraway repository of small icy bodies at the edge of our solar system. The researchers use the name "Tyche" for the hypothetical planet. Their paper argues that evidence for the planet would have been recorded by the Wide-field Infrared Survey Explorer (WISE).

WISE is a NASA mission, launched in December 2009, which scanned the entire celestial sky at four infrared wavelengths about 1.5 times. It captured more than 2.7 million images of objects in space, ranging from faraway galaxies to asteroids and comets relatively close to Earth. Recently, WISE completed an extended mission, allowing it to finish a complete scan of the asteroid belt, and two complete scans of the more distant universe, in two infrared bands. So far, the mission's discoveries of previously unknown objects include an ultra-cold star or brown dwarf, 20 comets, 134 near-Earth objects (NEOs), and more than 33,000 asteroids in the main belt between Mars and Jupiter.

Following its successful survey, WISE was put into hibernation in February 2011. Analysis of WISE data continues. A preliminary public release of the first 14 weeks of data is planned for April 2011, and the final release of the full survey is planned for March 2012.

Frequently Asked Questions
Q: When could data from WISE confirm or rule out the existence of the hypothesized planet Tyche?
A: It is too early to know whether WISE data confirms or rules out a large object in the Oort cloud. Analysis over the next couple of years will be needed to determine if WISE has actually detected such a world or not. The first 14 weeks of data, being released in April 2011, are unlikely to be sufficient. The full survey, scheduled for release in March 2012, should provide greater insight. Once the WISE data are fully processed, released and analyzed, the Tyche hypothesis that Matese and Whitmire propose will be tested.

Q: Is it a certainty that WISE would have observed such a planet if it exists?
A: It is likely but not a foregone conclusion that WISE could confirm whether or not Tyche exists. Since WISE surveyed the whole sky once, then covered the entire sky again in two of its infrared bands six months later, WISE would see a change in the apparent position of a large planet body in the Oort cloud over the six-month period. The two bands used in the second sky coverage were designed to identify very small, cold stars (or brown dwarfs) -- which are much like planets larger than Jupiter, as Tyche is hypothesized to be.

Q: If Tyche does exist, why would it have taken so long to find another planet in our solar system?
A: Tyche would be too cold and faint for a visible light telescope to identify. Sensitive infrared telescopes could pick up the glow from such an object, if they looked in the right direction. WISE is a sensitive infrared telescope that looks in all directions.

Q: Why is the hypothesized object dubbed "Tyche," and why choose a Greek name when the names of other planets derive from Roman mythology?
A: In the 1980s, a different companion to the sun was hypothesized. That object, named for the Greek goddess "Nemesis," was proposed to explain periodic mass extinctions on the Earth. Nemesis would have followed a highly elliptical orbit, perturbing comets in the Oort Cloud roughly every 26 million years and sending a shower of comets toward the inner solar system. Some of these comets would have slammed into Earth, causing catastrophic results to life. Recent scientific analysis no longer supports the idea that extinctions on Earth happen at regular, repeating intervals. Thus, the Nemesis hypothesis is no longer needed. However, it is still possible that the sun could have a distant, unseen companion in a more circular orbit with a period of a few million years -- one that would not cause devastating effects to terrestrial life. To distinguish this object from the malevolent "Nemesis," astronomers chose the name of Nemesis's benevolent sister in Greek mythology, "Tyche."

JPL manages and operates the Wide-field Infrared Survey Explorer for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena.

Forty years after the first lunar rover rolled across the moon's surface, 84 teams of enterprising future engineers will demonstrate the same ingenuity and can-do spirit at the 18th annual NASA Great Moonbuggy Race, set for April 1-2 in Huntsville, Ala.
The event challenges high school and college students to design, build and race lightweight, human-powered rovers - "moonbuggies" - which address many of the same engineering challenges dealt with by Apollo-era lunar rover developers in the late 1960s.

Teams include U.S. high school, college and university students from 22 states and Puerto Rico; and international challengers from six countries, including returning teams from Canada, India and Germany and -- for the first time - racers from Ethiopia, Pakistan and Russia.

What would our solar system look like if visitors from other worlds took a series of pictures?

NASA's MESSENGER spacecraft did just that by piecing together the first portrait of our solar system from the inside looking out. Comprised of 34 images, the mosaic provides a complement to the solar system portrait--from the outside looking in--taken by Voyager 1 in 1990.

"Obtaining this portrait was a terrific feat by the MESSENGER team," says MESSENGER principal investigator Sean Solomon, of the Carnegie Institution of Washington. "This snapshot of our neighborhood also reminds us that Earth is a member of a planetary family that was formed by common processes four and a half billion years ago. Our spacecraft is soon to orbit the innermost member of the family, one that holds many new answers to how Earth-like planets are assembled and evolve."

MESSENGER's Wide Angle Camera (WAC) captured the images on Nov. 3 and 16, 2010. In the mosaic, all of the planets are visible except for Uranus and Neptune, which--at distances of 3.0 and 4.4 billion kilometers--were too faint to detect. Earth's moon and Jupiter's Galilean satellites (Callisto, Ganymede, Europa and Io) can be seen in the WAC image insets. The solar system's perch on a spiral arm of the Milky Way galaxy also afforded a beautiful view of a portion of the galaxy in the bottom center.

"The curved shape of the mosaic is due to the inclination of MESSENGER's orbit from the ecliptic, the plane in which Earth and most planets orbit, which means that the cameras must point up to see some planets and down to see others," explains imaging team member Brett Denevi of the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md. "The images are stretched to make it easier to detect the planets, though this stretch also highlights light scattered off of the planet limbs, and in some cases creates artifacts such as the non-spherical shape of some planets."

Assembling this portrait was no easy feat, says Solomon. "It's not easy to find a moment when many of the planets are within a single field of view from that perspective, and we have strong Sun-pointing constraints on our ability to image in some directions."

APL's Hong Kang, from MESSENGER’s guidance and control team, used the Jet Propulsion Laboratory's Solar System Simulator to pinpoint the relative positions of MESSENGER and the planets to determine if it was possible to see the planets from MESSENGER at any given time.

"I used the celestial coordinates of the planets at the time I wanted to observe them to verify with simulations that MESSSENGER could see each of the planets," Kang explains. "I also used a satellite tool kit to verify that we had the planets in the field of view of MESSENGER’s Mercury Dual Imaging System."

The MESSENGER team then had to determine how long the exposures needed to be for each planet.

"From exposure times that worked for previous imaging of stars with visual magnitudes similar to those of the planets, we chose exposure times that would allow us to obtain the appropriate number of counts (i.e., amount of light) in each planet image," explains APL's Nori Laslo, the mission's Operations Lead and Instrument Sequencer for MDIS.

"We decided to take images using both the Narrow Angle Camera and the Wide Angle Camera for each planet so that we would cover the sky surrounding the planets and also image the planets themselves at as high a resolution as possible," she adds. "I took all of these parameters, along with a variety of related settings, and began building the command sequence with the library of MDIS commands that we have to configure and control the camera system."

Robin Vaughan, who worked with Kang to coordinate the pointing and timing of the MDIS, also played a role in Voyager's portrait.

"I was working as an optical navigation analyst at JPL for the Voyager Neptune encounter," says Vaughan, the lead engineer for MESSENGER's guidance and control (attitude control) subsystem at APL. "I had to plan and generate the pointing commands for pictures of Neptune and its satellites against background stars that we used to improve our estimate of the spacecraft's trajectory leading up to the Neptune encounter. Voyager's solar system portrait was done a few years after that flyby and was coordinated by the imaging team. Our optical navigation image planning software was used to double check the pointing commands they had designed and confirm what they expected to see in each image."

Vaughan did the same thing for MESSENGER’s portrait, using Kang’s designs. "I used the SPICE trajectory files for the spacecraft generated by MESSENGER's navigation team, as well as routines in the SPICE toolkit, to write a software program that would identify windows when each of the planets would be visible to MDIS given the constraints on pivot angle and Sun keep-in zone for spacecraft attitude," she says.

From a technical standpoint, the MESSENGER portrait was a little more complicated than what was done for Voyager because we had to stay within the Sun keep-in constraints. "With Voyager so far out in the solar system, the Sun is much fainter and there were no constraints on the overall spacecraft attitude as far as the Sun was concerned," Vaughan says. "Being in the inner solar system, MESSENGER has to constantly keep the sunshade pointing toward the sun, which limits the periods when the different planets can be viewed even with the extra degree of freedom that MDIS has with its pivot capability."

Denevi says the experiment was humbling. "Seeing our solar system as just these little specks of light, it reminds you of how lucky we are that we've had the chance, through so many missions, to get up close and explore the incredible diversity and geology that each planet and moon displays," she says. "Mercury has been just a dot on the horizon for most of history, and we get to fill in the details and know it as a real world. What an amazing opportunity!"

During space shuttle Discovery's final spaceflight, the STS-133 crew members will take important spare parts to the International Space Station along with the Express Logistics Carrier-4.

Steve Bowen replaced Tim Kopra as Mission Specialist 2 following a bicycle injury on Jan. 15 that prohibited Kopra from supporting the launch window. Bowen last flew on Atlantis in May 2010 as part of the STS-132 crew. Flying on the STS-133 mission will make Bowen the first astronaut ever to fly on consecutive missions.

NASA astronaut Mark Kelly will resume training as commander of the STS-134 space shuttle mission on Monday, Feb. 7. With the exception of some proficiency training, Kelly has been on personal leave since Jan. 8 to care for his wife, congresswoman Gabrielle Giffords, who was critically wounded in a Tucson, Ariz. shooting.

"I am looking forward to rejoining my STS-134 crew members and finishing our training for the mission," Kelly said. "We have been preparing for more than 18 months, and we will be ready to deliver the Alpha Magnetic Spectrometer (AMS) to the International Space Station and complete the other objectives of the flight. I appreciate the confidence that my NASA management has in me and the rest of my space shuttle crew."
"We are glad to have Mark back," said Peggy Whitson, chief of the Astronaut Office at NASA's Johnson Space Center in Houston. "He is a veteran shuttle commander and knows well the demands of the job. We are confident in his ability to successfully lead this mission, and I know I speak for all of NASA in saying 'welcome back'.

The Space Shuttle Program baselined the STS-135 mission for a target launch date of June 28 at 3:48 p.m. EDT. It is NASA’s intent to fly the mission with orbiter Atlantis carrying the Raffaello multipurpose logistics module to deliver supplies, logistics and spare parts to the International Space Station. The mission also will fly a system to investigate the potential for robotically refueling existing spacecraft and return a failed ammonia pump module to help NASA better understand the failure mechanism and improve pump designs for future systems.

In late December, the agency’s Space Operations Mission Directorate requested the shuttle and International Space Station programs take the necessary steps to maintain the capability to fly Atlantis on the STS-135 mission. The Authorization Act of 2010 directs NASA to conduct the mission, and baselining the flight enables the program to begin preparations for the mission with a target launch date of June 28. The mission would be the 135th and final space shuttle flight.

Mission controllers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., have begun receiving the first of 72 anticipated images of comet Tempel 1 taken by NASA's Stardust spacecraft.

A news conference will be held at 12:30 p.m. PST (3:30 p.m. EST) to allow scientists more time to analyze the data and images.

Stardust-NExT is a low-cost mission that expands on the investigation of comet Tempel 1 initiated by NASA's Deep Impact spacecraft. JPL, a division of the California Institute of Technology in Pasadena, manages Stardust-NExT for NASA's Science Mission Directorate, Washington, D.C. Joe Veverka of Cornell University, Ithaca, N.Y., is the mission's principal investigator. Lockheed Martin Space Systems, Denver, built the spacecraft and manages day-to-day mission operations.

NASA's Stardust-NExT mission spacecraft is within a quarter-million miles (402,336 kilometers) of its quarry, comet Tempel 1, which it will fly by tonight. The spacecraft is cutting the distance with the comet at a rate of about 10.9 kilometers per second (6.77 miles per second or 24,000 mph).

The flyby of Tempel 1 will give scientists an opportunity to look for changes on the comet's surface since it was visited by NASA's Deep Impact spacecraft in July 2005. Since then, Tempel 1 has completed one orbit of the sun, and scientists are looking forward to discovering any differences in the comet.

The closest approach is expected tonight at approximately 8:40 p.m. PST (11:40 p.m. EST).

During the encounter phase, the spacecraft will carry out many important milestones in short order and automatically, as the spacecraft is too far away to receive timely updates from Earth. These milestones include turning the spacecraft to point its protective shields between it and the anticipated direction from which cometary particles would approach. Another milestone will occur at about four minutes to closest approach, when the spacecraft will begin science imaging of the comet's nucleus.

The nominal imaging sequence will run for about eight minutes. The spacecraft's onboard memory is limited to 72 high-resolution images, so the imaging will be most closely spaced around the time of closest approach for best-resolution coverage of Tempel 1's nucleus. At the time of closest encounter, the spacecraft is expected to be approximately 200 kilometers (124 miles) from the comet's nucleus.

The mission team expects to begin receiving images on the ground starting at around midnight PST. Transmission of each image will take about 15 minutes. It will take about 10 hours to complete the transmission of all images and science data aboard the spacecraft.

Live coverage on NASA TV and via the Internet begins at 8:30 p.m. PST from mission control at NASA's Jet Propulsion Laboratory in Pasadena, Calif. Coverage also will include segments from the Lockheed Martin Space System's mission support area in Denver. A post-flyby news conference is planned on Feb. 15 at 10 a.m. PST .

The live coverage and news conference will also be carried on one of JPL's Ustream channels. During events, viewers can take part in a real-time chat and submit questions to the Stardust-NExT team at: .

During its 12 years in space, Stardust became the first spacecraft to collect samples of a comet , which were delivered to Earth in 2006 for study. The Stardust-NExT mission is managed by JPL for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems in Denver built the spacecraft and manages day-to-day mission operations.

Here are five facts you should know about NASA's Stardust-NExT spacecraft as it prepares for a Valentine's "date" with comet Tempel 1. Feel free to sing along!

1. "The Way You Look Tonight" – The spacecraft is on a course to fly by comet Tempel 1 on Feb. 14 at about 8:37 p.m. PST (11:37 p.m. EST) -- Valentine's Day. Time of closest approach to Tempel 1 is significant because of the comet's rotation. We won't know until images are returned which face the comet has shown to the camera.

2. "It's All Coming Back To Me Now" – In 2004, Stardust became the first mission to collect particles directly from a comet, Wild 2, as well as samples of interstellar dust. The samples were returned in 2006 via a capsule that detached from the spacecraft and parachuted to the ground at a targeted area in Utah. Mission controllers then placed the still-viable Stardust spacecraft on a flight path that could reuse the flight system, if a target of opportunity presented itself. Tempel 1 became that target of opportunity.

3. "The First Time Ever I Saw Your Face" – The Stardust-NExT mission will allow scientists for the first time to look for changes on a comet's surface that occurred after one orbit around the sun. Tempel 1 was observed in 2005 by NASA's Deep Impact mission, which put an impactor on a collision course with the comet. Stardust-NExT might get a glimpse of the crater left behind, but if not, the comet would provide scientists with previously unseen areas for study. In addition, the Stardust-NExT encounter might reveal changes to Tempel 1 between Deep Impact and Stardust-Next, since the comet has completed an orbit around the sun.

4. "The Wind Beneath My Wings" – This Tempel 1 flyby will write the final chapter of the spacecraft's success story. The aging spacecraft approached 12 years of space travel on Feb. 7, logging almost 6 billion kilometers (3.5 billion miles) since launch. The spacecraft

is nearly out of fuel. The Tempel 1 flyby and return of images are expected to consume the remaining fuel.

5. "Love is Now the Stardust of Yesterday" – Although the spacecraft itself will no longer be active after the flyby, the data collected by the Stardust-NExT mission will provide comet scientists with years of data to study how comets formed and evolved.

A bonus round is something one usually associates with the likes of a TV game show, not a pioneering deep space mission. "We are definitely in the bonus round," said Stardust-NExT Project Manager Tim Larson of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "This spacecraft has already flown by an asteroid and a comet, returned comet dust samples to Earth, and now has almost doubled its originally planned mission life. Now it is poised to perform one more comet flyby."

A Successful Prime Mission

NASA's Stardust spacecraft was launched on Feb. 7, 1999, on a mission that would explore a comet as no previous mission had. Before Stardust, seven spacecraft from NASA, Russia, Japan and the European Space Agency had visited comets – they had flight profiles that allowed them to perform brief encounters, collecting data and sometimes images of the nuclei during the flyby.

Like those comet hunters before it, Stardust was tasked to pass closely by a comet, collecting data and snapping images. It also had the ability to come home again, carrying with it an out-of -this-world gift for cometary scientists – particles of the comet itself. Along the way, the telephone booth-sized comet hunter racked up numerous milestones and more than a few "space firsts."

In the first round of its prime mission, Stardust performed observations of asteroid Annefrank, only the sixth asteroid in history to be imaged close up. After that, Stardust racked up more points of space exploration firsts. It became the first spacecraft to capture particles of interstellar dust for Earth return. It was first to fly past a comet and collect data and particles of comet dust (hurtling past it at almost four miles per second) for later analysis. Then, it was first to make the trip back to Earth after traveling beyond the orbit of Mars (a two-year trip of 1.2 billion kilometers, or 752 million miles). When Stardust dropped off its sample return capsule from comet Wild 2, the capsule became the fastest human-made object to enter Earth's atmosphere. The mission was also the first to provide a capsule containing cometary dust specimens, speciments that will have scientists uncovering secrets of comets for years to come.

With such a high tally of "firsts" on its scoreboard, you'd think Stardust could receive a few parting gifts and leave the game. And an important part of the original spacecraft is currently enjoying retirement – albeit a high-profile one: Stardust's 100-pound sample return capsule is on display in the main hall (Milestones of Flight) of the Smithsonian's National Air and Space Museum in Washington. But the rest of NASA's most-seasoned comet hunter is still up there – and there is work still to be done.

"We placed Stardust in a parking orbit that would carry it back by Earth in a couple of years, and then asked the science community for proposals on what could be done with a spacecraft that had a lot of zeros on its odometer, but also had some fuel and good miles left in it," said Jim Green, director of NASA's Planetary Science Division.

Moving into the Bonus Round

In January 2007, from a stack of proposals with intriguing ideas, NASA chose Stardust-NExT (Stardust's Next Exploration of Tempel). It was a plan to revisit comet Tempel 1 at a tenth of the cost of a new, from-the-ground-up mission. Comet Tempel 1 was of particular interest to NASA. It had been the target of a previous NASA spacecraft visit in July 2005. That mission, Deep Impact, placed a copper-infused, 800-pound impactor on a collision course with the comet and observed the results from the cosmic fender-bender via the telescopic cameras onboard the larger part of Deep Impact, a "flyby" spacecraft observing from a safe distance.

"The plan for our encounter is to be more hospitable to comet Tempel 1 than our predecessor," said Joe Veverka, principal investigator of Stardust-NExT from Cornell University in Ithaca, N.Y. "We will come within about 200 kilometers [124 miles] of Tempel 1 and view the changes that took place over the past five-and-a-half years."

That period of time is significant for Tempel 1 -- it is the period of time it takes the comet to orbit the sun once. Not much happens during a comet's transit through the chilly reaches of the outer solar system. But when it nears perihelion (the point in its orbit that an object, such as a planet or a comet, is closest to the sun), things begin to sizzle.

"Comets can be very spectacular when they come close to the sun, but we still don't understand them as well as we should," said Veverka. "They are also messengers from the past. They tell us how the solar system was formed long ago, and Stardust-NExT will help us understand how much they have changed since their formation."

So the spacecraft that had traveled farther afield than any of its predecessors was being sent out again in the name of scientific opportunity. In between spacecraft and comet lay four-and-a-half years, over a billion kilometers (646 million miles), and more than a few hurdles along the way.

Your Mileage May Vary

"One of the challenges with reusing a spacecraft designed for a different prime mission is you don't get to start out with a full tank of gas," said Larson. "Just about every deep-space exploration spacecraft has a fuel supply customized to get the job done, with some held in reserve for contingency maneuvers and other uncertainties. Fortunately, the Stardust mission navigation team did a great job, the spacecraft operated extremely well, and there was an adequate amount of contingency fuel aboard after its prime mission to make this new comet flyby possible – but just barely."

Just how much fuel is in Stardust's tanks for its final act?

"We estimate we have a little under three percent of the fuel the mission launched with," said Larson. "It is an estimate, because no one has invented an entirely reliable fuel gauge for spacecraft. There are some excellent techniques with which we have made these estimates, but they are still estimates."

One of the ways mission planners can approximate fuel usage is to look at the history of the vehicle's flight and how many times and for how long its rocket motors have fired. When that was done for Stardust, the team found their spacecraft's attitude and translational thrusters had fired almost half-a-million times each over the past 12 years.

"There is always a little plus and minus with each burn. When you add them all up, that is how you get the range of possible answers on how much fuel was used," said Larson.

Fuel is not the only question that needs to be addressed on the way to a second comet encounter. Added into the mix is the fact a comet near the sun can fire off jets of gas and dust that can cause a change in its orbit, sometimes in unexpected ways, potentially causing a precisely designed cometary approach to become less precise. Then there are the distances involved. Stardust will fly past comet Tempel 1 on almost the opposite side of the sun from Earth, making deep-space communication truly, well, deep space. Add into the mix the Stardust spacecraft itself. Launched when Bill Clinton was in the White House, Stardust has been cooked and frozen countless times during its trips from the inner to outer solar system. It has also weathered its fair share of radiation-packed solar storms. But while its fuel tank may be running near-empty, that doesn't mean Stardust doesn't have anything left in the tank.

"All this mission's challenges are just that – challenges," said Larson. "We believe our team and our spacecraft are up to meeting every one of them, and we're looking forward to seeing what Tempel 1 looks like these days."

The Final Payoff

Larson, Veverka and the world will get their chance beginning a few hours after the encounter on Monday, Feb. 14, at about 8:56 p.m. PST (11:56 p.m. EST), when the first of 72 bonus-round images of the nucleus of comet Tempel 1 are downlinked.

All images of the comet will be taken by the spacecraft's navigation camera – an amalgam of spare flight-ready hardware left over from previous NASA missions: Voyager (launched in 1977), Galileo (launched in 1989), and Cassini (launched in 1997). Each image will take about 15 minutes to transmit. The first five images to be received and processed on the ground are expected to include a close up of Tempel 1's nucleus. All data from the flyby (including the images and science data obtained by the spacecraft's two onboard dust experiments) are expected to take about 10 hours to reach the ground.

Stardust-NExT is a low-cost mission that will expand the investigation of comet Tempel 1 initiated by NASA's Deep Impact spacecraft. JPL, a division of the California Institute of Technology in Pasadena, manages Stardust-NExT for the NASA Science Mission Directorate, Washington, D.C. Joe Veverka of Cornell University, Ithaca, N.Y., is the mission's principal investigator. Lockheed Martin Space Systems, Denver Colo., built the spacecraft and manages day-to-day mission operations.

NASA will host several live activities for the Stardust-NExT mission's close encounter with comet Tempel 1. The closest approach is expected at approximately 8:37 p.m. PST . on Feb. 14, with confirmation received on Earth at about 8:56 p.m. PST .

Live coverage of the Tempel 1 encounter will begin at 8:30 p.m. PST on Feb. 14 on NASA Television and the agency's website. The coverage will include live commentary from mission control at NASA's Jet Propulsion Laboratory in Pasadena, Calif., and video from Lockheed Martin Space System's mission support area in Denver.

Two Russian cosmonauts will step outside the International Space Station on Wednesday, Feb. 16. They will install and retrieve experiments on the Russian segment of the complex and deploy a small ham radio satellite. NASA Television coverage of the spacewalk will begin at 6:45 a.m. CST.

Expedition 26 Flight Engineers Dmitry Kondratyev and Oleg Skripochka, wearing their Russian Orlan spacesuits, will emerge from the Pirs Docking Compartment airlock for the second time in four weeks at about 7:15 a.m.

During the nearly six-hour spacewalk, they will install two experiments. One will collect information useful in seismic forecasts and earthquake predictions, and the second will look at gamma splashes and optical radiation during terrestrial lightning and thunderstorms. The spacewalkers also will retrieve a pair of panels exposed to space as part of an experiment to identify the best materials for building long-duration spacecraft.

The cosmonauts also will deploy an experiment called ARISSat-1, or Radioskaf-V, a boxy 57-pound nanosatellite that houses congratulatory messages commemorating the 50th anniversary of Yuri Gagarin's launch to become the first human in space. The ham radio transmitter will enable communications with amateur radio operators around the world for three to six months. It is the first of a series of educational satellites being developed in a partnership with the Radio Amateur Satellite Corp.; the NASA Office of Education International Space Station National Lab Project; the Amateur Radio on the International Space Station working group; and RSC-Energia.

The spacewalk will be the second for Kondratyev, who will wear the spacesuit marked with red stripes, and the third for Skripochka, who will wear the suit with blue stripes.

NASA's Stardust spacecraft marked its 12th anniversary in space on Monday, Feb. 7, with a rocket burn to further refine its path toward a Feb. 14 date with a comet.

The half-minute trajectory correction maneuver, which adjusts the spacecraft's flight path, began at about 1 p.m. PST (4 p.m. EST) on Monday, Feb. 7. The 30-second-long firing of the spacecraft's rockets consumed about 69 grams (2.4 ounces) of fuel and changed the spacecraft's speed by 0.56 meters per second (1.3 mph).

NASA's plan for the Stardust-NExT mission is to fly the spacecraft to a point in space about 200 kilometers (124 miles) from comet Tempel 1 at the time of its closest approach. During the encounter, the spacecraft will take images of the surface of comet Tempel 1 to observe what changes have occurred since a NASA spacecraft last visited.

Along with the high-resolution images of the comet's surface, Stardust-NExT will also measure the composition, size distribution and flux of dust emitted into the coma, and provide important new information about how comets evolve.

Stardust was launched on Feb. 7, 1999. This current Stardust-NExT target is a bonus mission for the comet chaser, which flew past comet Wild 2 in 2004 and returned particles from its coma to Earth.

While its sample return capsule parachuted to Earth in January 2006, mission controllers were placing the still-viable spacecraft on a path that would allow NASA the opportunity to re-use the already-proven flight system if a target of opportunity presented itself. In January 2007, NASA re-christened the mission "Stardust-NExT" (New Exploration of Tempel), and the Stardust team began a four-and-a-half year journey for the spacecraft to comet Tempel 1. The spacecraft has traveled more than 3.5 billion miles since launch.

On Feb. 6th, NASA's twin STEREO probes moved into position on opposite sides of the sun, and they are now beaming back uninterrupted images of the entire star—front and back.

"For the first time ever, we can watch solar activity in its full 3-dimensional glory," says Angelos Vourlidas, a member of the STEREO science team at the Naval Research Lab in Washington, DC.

Each STEREO probe photographs half of the star and beams the images to Earth. Researchers combine the two views to create a sphere. These aren't just regular pictures, however. STEREO's telescopes are tuned to four wavelengths of extreme ultraviolet radiation selected to trace key aspects of solar activity such as flares, tsunamis and magnetic filaments. Nothing escapes their attention.

"With data like these, we can fly around the sun to see what's happening over the horizon—without ever leaving our desks," says STEREO program scientist Lika Guhathakurta at NASA headquarters. "I expect great advances in theoretical solar physics and space weather forecasting."

Consider the following: In the past, an active sunspot could emerge on the far side of the sun completely hidden from Earth. Then, the sun's rotation could turn that region toward our planet, spitting flares and clouds of plasma, with little warning.

"Not anymore," says Bill Murtagh, a senior forecaster at NOAA's Space Weather Prediction Center in Boulder, Colorado. "Farside active regions can no longer take us by surprise. Thanks to STEREO, we know they're coming."

NOAA is already using 3D STEREO models of CMEs (billion-ton clouds of plasma ejected by the sun) to improve space weather forecasts for airlines, power companies, satellite operators, and other customers. The full sun view should improve those forecasts even more.

"With this nice global model, we can now track solar storms heading toward other planets, too," points out Guhathakurta. "This is important for NASA missions to Mercury, Mars, asteroids … you name it."
NASA has been building toward this moment since Oct. 2006 when the STEREO probes left Earth, split up, and headed for positions on opposite sides of the sun (movie). Feb. 6, 2011, was the date of "opposition".
The new view could reveal connections previously overlooked. For instance, researchers have long suspected that solar activity can "go global," with eruptions on opposite sides of the sun triggering and feeding off of one another. Now they can actually study the phenomenon. The Great Eruption of August 2010 engulfed about 2/3rd of the stellar surface with dozens of mutually interacting flares, shock waves, and reverberating filaments. Much of the action was hidden from Earth, but plainly visible to the STEREO-SDO fleet.

"There are many fundamental puzzles underlying solar activity," says Vourlidas. "By monitoring the whole sun, we can find missing pieces."

Researchers say these first-look whole sun images are just a hint of what's to come. Movies with even higher resolution and more action will be released in the days and weeks ahead as more data are processed. Stay tuned!

NASA Deputy Administrator Lori Garver visited Boulder, Colo. today to meet with entrepreneurs and discuss innovations in space exploration and technology development critical to America's future in space.

Garver toured the facilities of Sierra Nevada Corporation, a company with wide involvement in developing technologies for space exploration. The company's Dream Chaser vehicle is under development with support from NASA's Commercial Crew Development (CCDev) Program to provide crew transportation to and from low Earth orbit.

"It's a pleasure to see commercial space making rapid progress in Colorado," Garver said. “As NASA becomes more nimble, companies like Sierra Nevada and others will help the U.S. out-innovate, out-educate and out-build any competitor in the world”.

As NASA focuses on a renewed program of technology development to reach destinations farther in the solar system, it will continue a vigorous program of human spaceflight aboard the International Space Station and foster a growing commercial space industry with the capability to produce jobs and economic benefits.

“We are extremely pleased to

be working with NASA in the development of our Dream Chaser Orbital Space Vehicle," said Mark N. Sirangelo, head of Sierra Nevada's Space Systems Group. "The extensive knowledge, terrific support and expertise NASA is providing have enabled us to advance our program significantly. We are now ahead of schedule and in production of our first flight vehicle because of NASA and the CCDev program."

The NASA Authorization Act of 2010, passed with strong bipartisan support, calls on NASA to pursue commercial access to space and extend the life of the space station to at least 2020. Along with these goals, the act directs the agency to open multiple pathways to innovate and develop new capabilities for the exploration missions of the future.

Robonaut 2, NASA's dexterous humanoid robot, will make its television debut on Super Bowl Sunday, Feb. 6, 2011. Millions of viewers will be able to watch the state-of-the-art robot during a General Motors segment to air during the Super Bowl pre-game show on the Fox network.

Robonaut 2, or R2, was developed and built by NASA and General Motors via a Space Act Agreement. Using the latest technology, it's a new humanoid robot capable of working side-by-side with people. Using leading edge control, sensor and vision technologies, future R-2s could assist astronauts during hazardous space missions and help GM build safer cars and plants.

The two organizations, with the help of engineers from Oceaneering Space Systems of Houston, developed and built the current iteration of Robonaut. Robonaut 2, or R2, is a faster, more dexterous and more technologically advanced robot. Its capabilities include the use of fully-functional hands and arms to do work beyond the scope of prior humanoid machines.
Robonaut 2 in satellite news

Like its predecessor Robonaut 1, R2 is capable of handling a wide range of tools and interfaces, but R2 is a significant advancement over its predecessor. R2 is capable of speeds more than four times faster than R1, is more compact, is more dexterous, and includes a deeper and wider range of sensing.

Advanced technology spans the entire R2 system and includes: optimized overlapping dual arm dexterous workspace, series elastic joint technology, extended finger and thumb travel, miniaturized 6-axis load cells, redundant force sensing, ultra-high speed joint controllers, extreme neck travel, and high resolution camera and IR systems. The dexterity of R2 allows it to use the same tools that astronauts use and removes the need for specialized tools just for robots.

One advantage of a humanoid design is that Robonaut can take over simple, repetitive, or especially dangerous tasks on places such as the International Space Station.

Scientists using NASA's Kepler, a space telescope, recently discovered six planets made of a mix of rock and gases orbiting a single sun-like star, known as Kepler-11, which is located approximately 2,000 light years from Earth.

"The Kepler-11 planetary system is amazing," said Jack Lissauer, a planetary scientist and a Kepler science team member at NASA's Ames Research Center, Moffett Field, Calif. "It’s amazingly compact, it’s amazingly flat, there’s an amazingly large number of big planets orbiting close to their star - we didn’t know such systems could even exist."

In other words, Kepler-11 has the fullest, most compact planetary system yet discovered beyond our own.

"Few stars are known to have more than one transiting planet, and Kepler-11 is the first known star to have more than three," said Lissauer. "So we know that systems like this are not common. There’s certainly far fewer than one percent of stars that have systems like Kepler-11. But whether it’s one in a thousand, one in ten thousand or one in a million, that we don’t know, because we only have observed one of them."

All of the planets orbiting Kepler-11, a yellow dwarf star, are larger than Earth, with the largest ones being comparable in size to Uranus and Neptune. The innermost planet, Kepler-11b, is ten times closer to its star than Earth is to the sun. Moving outwards, the other planets are Kepler-11c, Kepler-11d, Kepler-11e, Kepler-11f, and the outermost planet, Kepler-11g, which is twice as close to its star than Earth is to the sun.

"The five inner planets are all closer to their star than any planet is to our sun and the sixth planet is still fairly close," said Lissauer.

If placed in our solar system, Kepler-11g would orbit between Mercury and Venus, and the other five planets would orbit between Mercury and our sun. The orbits of the five inner planets in the Kepler-11 planetary system are much closer together than any of the planets in our solar system. The inner five exoplanets have orbital periods between 10 and 47 days around the dwarf star, while Kepler-11g has a period of 118 days.

"By measuring the sizes and masses of the five inner planets, we have determined they are among the smallest confirmed exoplanets, or planets beyond our solar system," said Lissauer. "These planets are mixtures of rock and gases, possibly including water. The rocky material accounts for most of the planets' mass, while the gas takes up most of their volume."

According to Lissauer, Kepler-11 is a remarkable planetary system whose architecture and dynamics provide clues about its formation. The planets Kepler-11d, Kepler-11e and Kepler-11f have a significant amount of light gas, which Lissauer says indicates that at least these three planets formed early in the history of the planetary system, within a few million years.

A planetary system is born when a molecular cloud core collapses to form a star. At this time, disks of gas and dust in which planets form, called protoplanetary disks, surround the star. Protoplanetary disks can be seen around most stars that are less than a million years old, but few stars more than five million years old have them. This leads scientists to theorize that planets which contain significant amounts of gas form relatively quickly in order to obtain gases before the disk disperses.

The Kepler spacecraft will continue to return science data about the new Kepler-11 planetary system for the remainder of its mission. The more transits Kepler sees, the better scientists can estimate the sizes and masses of planets.

"These data will enable us to calculate more precise estimates of the planet sizes and masses, and could allow us to detect more planets orbiting the Kepler-11 star," said Lissauer. "Perhaps we could find a seventh planet in the system, either because of its transits or from the gravitational tugs it exerts on the six planets that we already see. We’re going to learn a fantastic amount about the diversity of planets out there, around stars within our galaxy."

A space observatory, Kepler looks for the data signatures of planets by measuring tiny decreases in the brightness of stars when planets cross in front of, or transit, them. The size of the planet can be derived from the change in the star's brightness. The temperature can be estimated from the characteristics of the star it orbits and the planet's orbital period.

The Kepler science team is using ground-based telescopes, as well as the Spitzer Space Telescope, to perform follow-up observations on planetary candidates and other objects of interest found by the spacecraft. The star field that Kepler observes in the constellations Cygnus and Lyra can only be seen from ground-based observatories in spring through early fall. The data from these other observations help determine which of the candidates can be identified as planets.

Kepler will continue conducting science operations until at least November 2012, searching for planets as small as Earth, including those that orbit stars in the habitable zone, where liquid water could exist on the surface of the planet. Since transits of planets in the habitable zone of solar-like stars occur about once a year and require three transits for verification, it is predicted to take at least three years to locate and verify an Earth-size planet.

"Kepler can only see 1/400 of the sky," said William Borucki of NASA’s Ames Research Center, Moffett Field, Calif., and the mission’s science principal investigator. "Kepler can find only a small fraction of the planets around the stars it looks at because the orbits aren’t aligned properly. If you account for those two factors, our results indicate there must be millions of planets orbiting the stars that surround our sun."

Kepler is NASA's tenth Discovery mission. Ames is responsible for the ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory, Pasadena, Calif., managed the Kepler mission development. Ball Aerospace and Technologies Corp., Boulder, Colo., was responsible for developing the Kepler flight system, and along with the Laboratory for Atmospheric and Space Physics at the University of Colorado, is supporting mission operations. Ground observations necessary to confirm the discoveries were conducted at the Keck I in Hawaii; Hobby-Ebberly and Harlan J. Smith 2.7m in Texas; Hale and Shane in California; WIYN, MMT and Tillinghast in Arizona, and the Nordic Optical in the Canary Islands, Spain.

During space shuttle Discovery's final spaceflight, the STS-133 crew members will take important spare parts to the International Space Station along with the Express Logistics Carrier-4.

Steve Bowen replaced Tim Kopra as Mission Specialist 2 following a bicycle injury on Jan. 15 that prohibited Kopra from supporting the launch window. Bowen last flew on Atlantis in May 2010 as part of the STS-132 crew. Flying on the STS-133 mission will make Bowen the first astronaut ever to fly on consecutive missions.

STS-134 Update:
Astronaut Rick Sturckow will serve as a backup commander for the STS-134 space shuttle mission to facilitate continued training for the crew and support teams during STS-134 Commander Mark Kelly's absence. Kelly's wife, Congresswoman Gabrielle Giffords, was critically wounded in a shooting on Jan. 8 in Tucson, Ariz. Kelly remains commander of the mission, which is targeted for launch on April 19 from NASA's Kennedy Space Center in Florida.

STS-135 Update:
The Space Shuttle Program baselined the STS-135 mission for a target launch date of June 28 at 3:48 p.m. EDT. It is NASA’s intent to fly the mission with orbiter Atlantis carrying the Raffaello multipurpose logistics module to deliver supplies, logistics and spare parts to the International Space Station. The mission also will fly a system to investigate the potential for robotically refueling existing spacecraft and return a failed ammonia pump module to help NASA better understand the failure mechanism and improve pump designs for future systems.

In late December, the agency’s Space Operations Mission Directorate requested the shuttle and International Space Station programs take the necessary steps to maintain the capability to fly Atlantis on the STS-135 mission. The Authorization Act of 2010 directs NASA to conduct the mission, and baselining the flight enables the program to begin preparations for the mission with a target launch date of June 28. The mission would be the 135th and final space shuttle flight.

You see a lot of smiles around the E-1 Test Stand at John C. Stennis Space Center these days. Engineers involved in testing Aerojet's AJ26 rocket engine for Orbital Sciences Corporation's Taurus II space launch vehicle have good reason to smile.

In fact, they have several good reasons given that the partnership between NASA, Orbital and Aerojet is off to such an impressive start. Two successful tests of an AJ26 engine that will power the first stage of Orbital's Taurus II rocket recently wrapped up at Stennis. The two tests were so successful that Orbital engineers decided a planned third test was unnecessary. The AJ26 engine used in the testing was removed from the E-1 stand on Jan. 24, and will be returned to Aerojet in Sacramento, Calif. to be refurbished and used on an upcoming Taurus II mission.
The same day the engine was removed, the first flight engine was installed to begin regularly planned "acceptance testing" at Stennis. The AJ26 flight unit will be tested in February, and then delivered to Orbital at the Wallops Flight Facility launch site in Virginia for integration with the rocket's first stage core.

Orbital's Taurus II rocket will first be used to carry out commercial cargo supply mission to the International Space Station. Orbital is developing the cargo logistics system under the joint Commercial Orbital Transportation Services research and development project with NASA, and is scheduled to carry out the first of eight cargo missions under the Commercial Resupply Services contract beginning in early 2012.