 |
 |
||
 |
|
||
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
||||||||
 |
Planetary News: Stardust (2006)Stardust: Comet “Treasure” is RetrievedBy A.J.S. Rayl January 15, 2006
The Stardust capsule – which holds the world’s first samples from a comet ever returned to Earth – has been retrieved and is now in a clean room inside a hangar at the Michael Army Air Field. The capsule, which was reported to have bounced five times before it settled down near the middle of its landing ellipse early this morning on the Air Force’s Utah Test & Training Range, appeared to be in excellent shape, although the recovery crew did find pieces of the heat shield nearby. The salt and mud the capsule picked up on landing and any other possible contamination will be cleaned off. Then, at some point in the next day or two, technicians will open the capsule and remove the samples for a cursory examination before they are packed for shipment Tuesday to a special repository at the Johnson Space Center (JSC). “It’s hard to describe what it feels like to be at this point,” said Stardust principal investigator Don Brownlee at a post-landing press conference in Utah. “The most spectacular part of this mission for me happened about 5 minutes before it landed. We snuck outside and went down to the end of the fence, which is pretty far down range . . . and then we saw something up there and it looked like Mars, it was bright and a reddish color, but it was get brighter and moving . . . the Moon was up in the sky, a ghostly white color . . . but this other object was red by contrast . . . a meteor flying through the sky . . . and from our view, even though we knew this was coming from space it looked like it was climbing in the sky – and then we saw this glowing trail behind it.” Nodding to the video of the recovery team walking around the capsule at the landing site that playing on the monitors, Brownlee, of the University of Washington, Seattle, continued: “Inside this thing is our treasure – our sample from the early solar system, that truly contains stardust,” “We traveled almost 3 billion miles in space. We visited a comet, grabbed a piece of it, and it landed here this morning. It’s an incredible thrill.” At JSC, the team will further analyze, verify, and section the cosmic dust particles, which will be housed in the same building as the only other samples that we have brought back from another body – the Moon rocks, and other meteorites.
Since Wild 2 is believed to hail from the Kuiper belt, way out there close to the edge of the solar system, the comet samples are the world's first preserved samples of the fundamental building blocks of our solar system that formed 4.6 billion years ago. Unique chemical and physical data that may hold the record of the formation of the planets and the materials from which they were made are locked within these particles. “We will open capsule in two days and remove first samples a couple of days later,” Brownlee said. “What we want to compare [the samples] to most is the dirt that created meteorites . . . comparing the ones at edge of solar system and least changed to those that have come inside the solar system and have been modified by various processes. Here we’ve got samples for a comet that is least changed . . . it is a treasure . . . all the atoms in our bodies and Earth were in stardust before solar system formed . . . we are stardust . . . we’re still amazed.” All told, team members expect, if they’re lucky, they will get at least a thimbleful of the cosmic dust from the 101-pound capsule that is now the star of this $212 million dollar NASA Discovery mission. It sounds like an incredibly small amount, but inside that thimble-full the scientists are expecting to have about one million samples, most of them 10 to 20 microns in size. The scientists believe that in-depth terrestrial analyses of these samples will reveal not only a lot about comets, but about the earliest history of the solar system, and, perhaps -- because “we are all stardust” – a little something about ourselves. Once the sample processing procedures are completed, a small number of the samples will be isolated for a preliminary study, and the rest to be made available to scientists around the world for research. __________
The Stardust return capsule landed in pre-dawn darkness and windy conditions on the salt flats of the Utah range this morning at 3:10 a.m. local or Mountain Standard Time (MST) / 2:10 a.m. Pacific Standard Time (PST), two minutes early and intact. “All stations, we have touchdown,” announced Stardust Project Manager Tom Duxbury. You could hear the sighs of relief as they rippled out along the airwaves via the Internet and NASA TV. It was the conclusion of a 7-year, 4.63 billion kilometer (2.88 billion mile) round-trip journey to comet Wild 2 (pronounced Vilt two), which took Stardust around the Sun three times, beyond Mars and the asteroid belt -- as far out as half-way to Jupiter, and back in time 4.5 billion years to gather its precious treasure from the comet’s nucleus. At other points during its long cruise phases, Stardust spent 195 days collecting interstellar dust samples, particles from stars that flow from outer space into the solar system. The most intense moments during Stardust’s descent came when the instruments seemed not to show any indication that the stabilizing or drogue parachute opened when it should have at 32 kilometers (105,000 feet) – and no doubt minds raced back to September 2004 when Stardust’s sister mission, Genesis, crash landed because its parachutes failed to deploy. Stardust was literally on fire when it re-entered the Earth’s atmosphere. Traveling at 12.8 kilometers or 8 miles per second, more than 10 times faster than a speeding bullet or fast enough to go from San Francisco to Los Angeles in one minute, at a velocity greater than any human-made object on record, the comet chaser reached peak temperatures of around 4,900 degrees Fahrenheit and set a new record as the fastest returning spacecraft. Any fears that Stardust might also crash land, however, were laid to rest just minutes later when the main parachute opened on time at an altitude of about 3 kilometers (10,000 feet). The capsule’s dramatic slow down – and the chute -- could be seen via the long-range infrared cameras, as well as some of the ground observers. “All stations, the main chute is open. We’re coming down slowly,” announced Stardust Project Manager Tom Duxbury. At the landing area in Utah, and at the mission control room at the Jet Propulsion Laboratory (JPL) the cheers and applause drown the nominal silence. [As it turned out, later examination of the infrared video did clearly seem to clearly indicate the drogue chute had opened.]
“Genesis was a big blessing for us,” Duxbury said later at the press conference. “Based on Genesis’ experience, we re-examined everything, looked at all designs and testing and verified for ourselves that everything was working. We take our hats off to Genesis for making us much smarter, and much more sure when we came in.” The first of three helicopters was sent in moments after Stardust landed to begin the recovery operation of the return capsule. Despite having the coordinates, infrared instruments to scan the desert floor, and on and off beacon contact with the capsule, recovery operations crew members had some difficulty homing in on it. The range is large and the capsule small, but within 30 minutes they had locked on to the spacecraft, and landed. The second helicopter followed minutes later and the third followed suit minutes after that and the recovery was in full swing. The recovery team circled the capsule on foot, and visually examined it, then wrapped up or “bagged” it, lifted it onto a spacecraft gurney, and flew it to the clean room at the Michael Army Air Field, taking whatever precautions they could to reduce contamination. In the clean room, technicians were still examining the capsule when the press conference began. Now that the team has the comet and interstellar dust samples, they are going to have to search the grids for the comet and interstellar dust particles before they can analyze them. But the grains are so few and so tiny that the scientists expect that they will be completely lost within the cracked and imperfect surface of the aerogel collector that has spent 7 years in space. In fact, they expect they will be so embedded that the scientists are asking for the public's help to search for the interstellar dust via an Internet-based project called Stardust@home, inspired by the long-running Seti@home.
Stardust@home will be a hands-on activity, however, unlike SETI@home where one’s computer processed all the data. Scientists at the Space Sciences Laboratory at the University of California at Berkeley (UCB) will create "movies" of each tiny section of the aerogel collectors -- 1.6 million movies in all. Each of these movies will be sent electronically to volunteers around the world, who will inspect them for the telltale signs of interstellar dust particles. Since no one knows exactly what these dust tracks will look like, the human eye – and good old-fashioned human intelligence – will be better at spotting them than a computer program. Therefore, each volunteer scanner will need to pass a test by spotting tracks made in test samples. The Stardust@home team will also keep scanners vigilant by occasionally throwing into the mix a “ringer” – an artificially made track – to see if the volunteer scanners find it. As an official collaborator in the project, The Planetary Society has put out an all-call to recruit users. To be part of be part of Stardust@home, you will need an easily downloadable "virtual microscope" and some basic online training, and a desire to really do the research, according to Bruce Betts, the Society’s director of projects. The public can begin signing up with Stardust@home in mid-March. Meanwhile, the Stardust “mothership,” which performed a divert burn maneuver about 15 minutes after releasing the return capsule late Saturday night, is now in an orbit going around the Sun. Along for that ride is a microchip that contains the names of all Planetary Society members from around the world at the time of the mission’s launch, the first such collection of names from the public to have made a round trip to space and back. While that could be the end of it, the Stardust mothership could, theoretically, go back into the field and work some more, Duxbury and Brownlee said. Designed in the late 1980s, it features two complete sets of electronics – and, according to Duxbury, “probably has many years left.” It’s also still got 17 kilograms of propellant and thus could spend a lot of time in cruise mode, although it could not bring anything back because it’s used the one return capsule. Its fate rests in the hands of NASA. No matter what happens now, Stardust has met its mission objectives and delivered the bounty, an example, said Duxbury “of what a lot of hard work and a little luck” can achieve. It’s impossible at this point to truly understand the significance of these samples, but, as Brownlee noted, comets are “libraries” that store information. “And I expect textbooks in the future will have a lot more information on the formation of the solar system because of these samples.” |
||||||||||
 |
 |
||||||||||
[ what is this? ]