=========================================================== SKY & TELESCOPE'S NEWS BULLETIN - SEPTEMBER 15, 2000 =========================================================== For images and Web links for these items, visit http://www.skypub.com =========================================================== Drive around town or to the nearest star party and show your support of dark skies with the International Dark-Sky Association license- plate frame. The IDA -- an alliance of astronomy enthusiasts, lighting engineers, and city planners -- is leading the drive to replace bad lights with good ones. For every "Stars Up, Lights Down" license-plate frame sold, Sky Publishing (a lifetime corporate member of the IDA) will donate $3 to the IDA. To order yours, visit our online store at http://store.skypub.com/ or call 800-253-0245. ===========================================================
According to Tom Duxbury, who assumed the role of Stardust project manager last month, the bad images at first suggested that the camera was out of focus, that its optics were coated with some contaminant, or both. Essentially a telephoto lens with a 200-mm focal length, the camera combines wide-angle optics left over from the Voyager program with a 1,024-pixel-square CCD detector. Further tests ruled out bad focus, leaving a mystery coating as the cause of the blurry, indistinct views. Test images of the bright star Vega showed that the star's light was smeared over more than 100 pixels in the camera's detector.
Since April, the Stardust team has been struggling to learn what the contaminant is, why its there, and -- most importantly -- how to get rid of it. "We had hoped it was something with a lot of water in it, even ice," Duxbury explains. "But ice would have sublimated away into space by now." Most recently, the team tried heating the camera's CCD detector, in the hope that the stuff would vaporize and go elsewhere. A week of warm temperatures caused some improvement, but not much. Additional test images and heating cycles are planned.
Should the camera's view not clear up, Stardust's encounter with Comet Wild 2 will be affected. Right now plans call for the spacecraft to dash about 150 km from the sunlit side of the nucleus, far enough away to ensure that Stardust will survive the flyby yet close enough to get the precious dust particles and to permit high-resolution imagery of the nucleus. Blurred optics mean that the camera may not be able to spot the comet until just a few days ahead of time, which could jeopardize last-minute trajectory corrections and force the spacecraft to make its pass farther away. In that case, the hoped-for closeups of the nucleus, some resolving features only 10 meters across, would take a serious hit. "It'd be really disappointing if we can't get those high-quality images," says Donald Brownlee, Stardust's project scientist. Fortunately, he adds, the camera won't be needed for mission-critical activities until 2004 -- affording project engineers lots of time to attack the contamination problem.
There were five Deep Space Network (DSN) tracking passes during the past week. Commands were sent to the spacecraft to set the Command Loss Timer back to its original value of nine days. The spacecraft, due to interference from the Sun (solar conjunction), did not receive these commands last week, and they were retransmitted. Other commands were transmitted to the spacecraft to update the Small Forces, Earth ephemeris and Sun ephemeris files. These files contained updated information due to the trajectory and mass properties changes from the Deep Space Maneuver in January. All subsystems onboard the spacecraft are performing normally.
The spacecraft transitioned back to Gyro Based Attitude Mode with the Inertial Measurement Unit (IMU) powered on to provide high rate attitude data during the aerogel grid deployment. Also six images were taken with the Star Camera. These images will be analyzed to determine the health of the Star Camera and provide information concerning why the number of valid stars occasionally drops from 10 to 4 stars.
A historic milestone in planetary exploration was achieved by STARDUST this week. The aerogel collector was successfully deployed to begin its interstellar dust collection. The commanded timeline was followed precisely with the heat shield on the Sample Return Capsule (SRC) opening, followed by the shoulder motor moving the collector out of the SRC and then finally the wrist motor extending the collector fully to its collection position where it sticks above the spacecraft dust shielding and into the interstellar dust stream.
The deployment was confirmed during deployment with small torques detected by the attitude control system as well as the motors turning for the proper time duration. The final confirmation came with the shoulder and wrist microswitches being triggered when deployment was complete.
In the spacecraft's current orbit where it just came out of solar conjuction, its inertial velocity direction is about 49 degrees away from traveling directly with the interstellar dust stream. Over the next few months as the spacecraft orbit curves around the sun, the spacecraft motion will parallel the dust stream motion.
After the collector was fully deployed and all subsystems were verified to be operating normally, a command was sent to move the collector 49 degrees in the direction of closing to position the collector surface area normal to the interstellar dust stream flow. Every few weeks the wrist motor will be commanded to change this angle by a few degrees to keep the collector surface normal to the stream. Near the end of this first interstellar collection period, the collector will be fully deployed again. This historic collection will continue until 25 May 2000; however we are currently exploring extending this period by a few additional weeks.
There are no microswitches in between the full open and full close shoulder and wrist positions to tell us the exact position of the aerogel collector. Control and knowledge of this position during the next few months is achieved by commanding the wrist motor for a fixed length of time to provide the desired angle movement and then verify this movement from telemetered wrist motor operating data. To reach its current 49 deg offset angle, the wrist motor was power on for about 20 seconds, which was executed perfectly.
The collector has two sides of aerogel: side A for interstellar dust collection and side B for cometary dust collection. We control which side of the collector is exposed to a dust stream by orienting the spacecraft in inertial space. Currently the spacecraft is oriented with its dust shields pointing in the direction of its motion about the sun and the interstellar dust particles hitting the back side (side A) of the collector. The spacecraft orientation with be reversed relative to the Comet Wild 2 particle stream so that the dust shields will protect the spacecraft while the collector is extended above these shields, into the oncoming dust stream.
As its name indicates, the interstellar particles to be collected now are from outside of our solar system. There is a very tenuous dust cloud within our galaxy, the Milky Way, which our solar system is moving through. The direction of the interstellar dust is opposite to the motion of the sun, which drags the planets with it, relative to the particle media. Thus the dust motion is small relative to the solar system motion that is controlling the direction of interstellar dust passing through our solar system.
The interstellar dust stream was detected many years ago by earth orbiting spacecraft and earlier Pioneer and Voyager spacecraft have improved information on this stream. More recently the Ulysses and Galileo spacecraft have confirmed the stream direction as well as indicated that the density of particles in the stream is very low.=20 With the size of the STARDUST collector being only about 0.1 meter square, on the order of 100 such particles are expected to be collected during the 2 collection periods. The second collection period is in about two years, when again the spacecraft is traveling in the direction of the particle stream.
High praise goes to the spacecraft builder and flight operations team at Lockheed Martin Astronautics in Denver, Colorado for this successful deployment and the start of the sample collection. The interstellar particles will be returned to earth with the Wild 2 particles for detailed science analyses in 2006 after the SRC lands in the Utah Test and Training Range.
Following the successful deployment, three images were taken with the Navigation Camera. These images were taken through the Optical Navigation filter (widest bandwidth) with the calibration lamp on. Two images had an exposure time of 200 milliseconds and the third had an exposure duration of 1 second. These images will be analyzed to help determine the cause of the apparent decrease in Navigation Camera sensitivity observed when the last star images were taken in October.
Also, after the aerogel collector deployment, the spacecraft transitioned back to All Stellar attitude mode.
For more information on the STARDUST mission - the first ever comet sample return mission - please visit the STARDUST home page.
February 22, 2000
The aerogel collector was successfully deployed today to begin the interstellar dust collection. The commanded timeline was followed precisely with the heat shield on the Sample Return Capsule (SRC) opening, followed by the shoulder motor moving the collector out of the SRC and then finally the wrist motor extending the collector fully to its collection position where it sticks above the spacecraft shielding and into the cometary dust stream.
The deployment was confirmed during deployment with small torques detected by the attitude control system for the proper duration as well as the motors turning for the proper time duration. The final confirmation came with the shoulder and wrist microswitches being triggered when deployment was complete.
In the spacecraft current orbit where it just came out of solar conjuction, its inertial velocity direction is about 50 degrees away from traveling directly with the interstellar dust stream. Over the next few months as the spacecraft orbit curves around the sun, the spacecraft motion will parallel the dust stream motion.
After the collector was fully deployed today and all subsystems were verified to be operating nominally, a command was sent to move the collector 50 degrees in the direction of closing to position the collector surface area normal to the interstellar dust stream flow. Every few weeks we will command this angle by a few degrees to keep the collector surface normal to the stream. Near the end of this first interstellar collection period, the collector will be fully deployed again. The collection will continue until at least 25 May 2000; however we are currently exploring extending this period by a few additional weeks.
There are no microswitches in between the full open and full close positions to tell us the exact position of the aerogel collector. We will control this position during the next few months by commanding the wrist motor for a fixed length of time to provide the desired angle movement and verify this movement from telemetered wrist motor operating data. To reach its current 50 deg offset angle, the wrist motor was power on for about 20 seconds which was executed perfectly.
The collector has two sides of aerogel: side A for interstellar dust collection and side B for cometary dust collection. We control which side of the collector is exposed to by orienting the spacecraft in inertial space. Currently the spacecraft is oriented with its dust shields pointing in the direction of its motion about the sun and the interstellar dust particles hitting the back side (side A) of the collector. The spacecraft orientation with be reversed relative to the comet Wild 2 particle stream so that the dust shields will protect the spacecraft while the collector is extended above these shields into the oncoming dust stream.
As its name indicates, the interstellar particles to be collected now are from outside of our solar system. There is a very tenuous dust cloud within our galaxy, the Milky Way, which our solar system is moving through. The direction of the interstellar dust is opposite to the motion of the sun, which drags the planets with it, relative to the particle media. Thus the dust motion is small relative to the solar system motion that is controlling the direction of interstellar dust passing through our solar system.
The interstellar dust stream was detected many years ago by earth orbiting spacecraft and information on this stream has been improved by early Pioneer and Voyager spacecraft. More recently the Ulysses and Galileo spacecraft have confirmed the stream direction as well as indicated that the density of particles in the stream is very low. With the size of the STARDUST collector being only about 0.1 meter square, we expect to collect on the order of 100 such particles during the 2 collection periods. We have just started the historic first collection period and will perform the second collection period in about two years, when again the spacecraft is traveling in the direction of the particle stream.
High praise goes to the spacecraft builder and flight operations team at Lockheed Martin Astronautics in Denver, Colorado for this successful deployment and the start of this historic sample collection. The sample will be returned to earth for detailed science analyses in 2006 after the SRC lands in the Utah Test and Training Range.
For more information on the STARDUST mission - the first ever comet sample return mission - please visit the STARDUST home page.
19 February 2000
PASADENA, Calif. - Come Tuesday, February 22, the Stardust spacecraft will attempt to collect the speeding particles of interstellar dust that stream into our solar system from distant stars.
Armed with Aerogel, a wispy, glass foam, packed into the spacecraft's dust collector, Stardust will capture star stuff, acting like a bowl of Jell-O in a dust storm.
There were two Deep Space Network (DSN) tracking passes in the past week. All subsystems on board the spacecraft are performing normally.
During the first DSN pass no telemetry was received due to interference from the Sun - the angular separation from the Sun is only 1.4 degrees. A weak carrier was observed and the DSN was able to occasionally lock onto the telemetry subcarrier but never long enough to provide telemetry data. Although no data was captured, the fact that the spacecraft was there and transmitting at the correct data rate indicated that the spacecraft was healthy.
The second DSN pass provided data that confirmed the spacecraft was healthy. Commands were sent to the spacecraft to return the Command Loss Timer to its original value of nine days. The spacecraft, due to interference from the Sun, did not successfully receive these commands. They will be sent again during the next pass.
Preparation for the Aerogel deployment on February 22 is continuing The commands have been built and are in testing and review.
The All-Stellar performance continues to be monitored. The fuel usage remains at less than 3 grams/day. Analysis of the high rate attitude telemetry is on going.
The STARDUST Outreach team hosted the Southern California Space Explorer Teachers training workshop with other project personnel providing presentations on comets and the STARDUST Project.
Ken Atkins, the STARDUST Project Manager released a special 1 year STARDUST launch anniversary announcement.
For more information on the STARDUST mission - the first ever comet sample return mission - please visit the STARDUST home page.
STARDUST Commemorative Newsletter
February 7, 2000
The Stardust spacecraft blasted into space a year ago on February 7, 1999. Its destination - Comet Wild 2 (pronounced "Vilt 2"). Its mission -- to capture interstellar and comet particles before returning to Earth in 2006. Over the past year, the ship and its "sailors" have learned to voyage on the ocean of deep space. It is just now passing its farthest point from the sun (aphelion) on this leg of the journey. It takes radio signals, travelling at the speed of light, almost a half-hour to reach Earth after they leave the spacecraft.
There have been "storms" to sail through. The first attempt to move from gyro-stabilized control of the celestial attitude to pure star-referencing, found a software "bug" that caused the spacecraft to invoke its automatic fault protection. This placed Stardust in a "safe" mode to allow the controllers to troubleshoot and fix the problem. When the ship invokes the safing routine, it shuts down all unnecessary activities, including its telecommunication with Earth, and turns to the sun to ensure the lifeblood of solar energy floods its batteries and electronics with electricity. When it deems all is well, it sets up a plan to contact us on Earth, tell us what happened, and let us tell it what to do next. This routine, while carefully designed to protect the spacecraft, is still an "anxiety event" for the crew back on Earth. It's a bit like the feeling when your teenager is late coming home, and you get no phone call. The anxiety builds fear until the dutiful signal comes through. "I'm here!" "I'm O.K.!" Stardust and its crew have navigated three more safing events, all involving data handling by on-board software.
During this first year in space, Stardust has operated the Cometary and Interstellar Dust Analyzer (CIDA) and the Dust Flux Monitoring Instrument (DFMI). Both have worked well, but DFMI has a power supply with an oscillation. That means the crew has had to develop a way of compensating for this. Currently, the plan involves limiting its operating time and cycling it off and on. Testing of this technique will come late in the year. DFMI is currently "off." CIDA has collected data of some interest to the science team. Analysis is underway to determine if interstellar dust impacts occurred as the ship navigated "upwind" in the interstellar dust stream. With Stardust rounding the "mark" to sail back downwind toward Earth, the science team has turned the CIDA off.
As Stardust turned toward home, the crew commanded Stardust to fire on-board rockets to achieve the precise course for the Earth-swingby next January. The ship performed flawlessly in completing the three required rocket burns. In addition, the sample-return capsule (SRC) housing the Aerogel collector has been unlatched. This is in preparation for deployment of the collector in late February. Deployment will mark the beginning of the attempt to "catch" interstellar particles to bring home.
So, the adventure continues. It is bittersweet in that while Stardust sails on, its sister ships at Mars were lost. The trauma underscores the risks of voyaging into the unknown, attempting audaciously to know it. To know the unknown most often requires the birth pangs of failure. Earth's oceans are littered with the bones of the ships and sailors who brought us to the understanding of our planet we now enjoy. We sail its sky with the safety provided by the sacrifices of the Wrights, Lindberg, Doolittle, Yeager, Earhart, and many others. And we plunge into deep space on the shoulders of Newton, Kepler, Tsiolkovsky, Goddard, and Von Braun, with the physics of space and the fire of rockets.
Stardust has yet to meet its destiny. The unknown "landfall" of Wild 2 waits for the dawn of 2004. Nevertheless, the ship is "spaceworthy." The design is robust. A year of flight has made crew and ship a team. We know each other better in the arena of spaceflight. While we mourn our lost ships at Mars, we increase our vigilance and resolve. We have sailed the year from Cape Canaveral to First Aphelion.
I celebrate the spacecraft. I congratulate the crew.
Sail on, Stardust! May the "wind" be at your back! Happy birthday!
Dr. Kenneth L. Atkins
Project Manager,
STARDUST
All names submitted for the second microchip that will be carried on the STARDUST spacecraft are now online on our website:
http://stardust.jpl.nasa.gov/microchip/names2.html Thanks to those you who have participated. I've delivered the names to the Microdevices Lab here at JPL, and they will be etched onto a fingernail-size silcon chip using a technique called electron beam lithography. I'll keep you posted on its progress.
Ron Baalke
STARDUST Webmaster
June 18, 1998
http:/stardust.jpl.nasa.gov/microchip
To date, we have collected 327,000 names, and will continue to collect names until August 15, 1998. The names submitted up through June 5 (~200,000 names) are now listed online on the home page. We will periodically update the page with the latest submissions.
Bear in mind that this is our second name collection effort. Last fall, we've collected 136,000 names which have been inscribed onto the small chip and placed inside the spacecraft. Photos of the first microchip is available on the home page, along with a full name listing and the photos and letters added from the STARDUST project that have been included onto the chip.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ Pasadena, CA | The truth always turns out
/___| | | | ___/ | |/__ /| | to be simpler than you
|_____|/ |_|/ |_____|/ | thought. Richard Feynman
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
June 12, 1998
Stardust's prime mission is to return a sample of comet dust to Earth in 2006.
The "Send Your Name to a Comet" effort has drawn attention around the world as people submit their names to the Stardust web page via the Internet, said Aimee Whalen, public outreach coordinator for the Stardust Project at NASA's Jet Propulsion Laboratory in Pasadena, CA.
"People are excited at the idea of their names flying on the Stardust spacecraft," Whalen said. "By submitting their names to the microchip, participants become vicarious passengers on a space voyage that they can follow over the next seven years." The project hopes to exhibit the names in a museum after the comet sample has returned to Earth, she said.
The names are electronically etched onto a fingernail-size silicon chip at JPL's Microdevices Lab. Writing on the microchip is so small that about 80 letters would equal the width of a human hair. Once inscribed, the names can be read only with the aid of an electron microscope.
The web page and a project-sponsored network of educators across the country are two of the main efforts Stardust is using to bring information about the mission, its science plans and eventual discoveries to as broad an audience as possible.
Scientists have long sought a direct sample of a comet particle because these icy bodies are thought to be nearly pristine examples of the original material from which the Sun and planets were born 4.6 billion years ago. Stardust's mission is to travel to within 150 kilometers (100 miles) of the nucleus of Comet Wild-2 (pronounced "Vilt-2"), gather comet dust particles and deliver them back to Earth. En route to the comet, Stardust will attempt to capture interstellar particles that are believed to be blowing through the solar system. In January 2006, mission plans call for the Stardust sample return capsule to parachute to a designated landing spot in the Utah desert.
The first Stardust microchip, which contained 136,000 names collected last fall, has already been installed on the spacecraft, which is being assembled at Lockheed Martin Astronautics, Denver, CO.
Interest has heightened recently in Stardust and other NASA comet and asteroid projects with the promotion of Hollywood movies that center on fictional comet and asteroid impacts with Earth. Names are being gathered in cooperation with the National Space Society, Paramount Studios and Dreamworks Inc.
Names may only be submitted electronically and may be sent to the Stardust web page. Those submitting their names are granting permission for the Stardust project and its partners to use the names submitted in possible future exhibits and/or publications.
Stardust, managed for NASA's Space Science Division and is a collaborative partnership between the University of Washington, Lockheed Martin Astronautics, and JPL/Caltech. Stardust is the fourth mission to be chosen under NASA's Discovery Program of low-cost solar system projects, and follows the Mars Pathfinder, Near Earth Asteroid Rendezvous (NEAR) and Lunar Prospector missions. The goal of the Discovery Program is to launch many small missions that perform focused science with fast turn-around times, cost less than $150 million (in fiscal year 1992 dollars) to build, and are joint efforts with industry, small business and universities.
JPL is a division of the California Institute of Technology.
National Space Society
Paramount Pictures
May 7, 1998
(Washington, DC) -- May 7 -- The National Space Society, along with Paramount Pictures and DreamWorks Pictures, today announce a joint online campaign to collect one million names to be placed on board a spacecraft that will intercept an actual comet. The campaign, "Make an IMPACT," is being launched in time for tomorrow's nationwide release of the film, "DEEP IMPACT," and will continue through the summer or until the one million mark is met.
The spacecraft, STARDUST, is being prepared for launch by NASA and the Jet Propulsion Laboratory to intercept Comet Wild-2, collect samples and return to Earth. The names will be printed onto a microchip to be placed aboard the craft later this year. Already on the chip are the names of every member of the National Space Society, and the names of the cast and crew of "DEEP IMPACT." Names can be submitted by going to the National Space Society website at nss.org/impact or to the film's website at deep-impact.com.
"We are firm believers in the idea that, today, fact can be as spellbinding as fiction," said Ms. Pat Dasch, executive director for the National Space Society. "In this case, a film tells a fictional story of an impending comet collision while, in fact, NASA and JPL are preparing a craft to intercept a comet and learn more about it. We are very pleased to be partnering with Paramount on this project; with a one million name goal, we're committed to making a real 'impact.'"
The National Space Society is also producing a slide set for educators on comets and asteroids, featuring text prepared by leading scientists. The set will include several images from "DEEP IMPACT."
The National Space Society, founded in 1974, is an independent, nonprofit
space advocacy organization headquartered in Washington, DC. Its 23,000
members and 90 chapters around the world actively promote a spacefaring
civilization. Information on NSS and space exploration is available at
"DEEP IMPACT" is a contemporary action thriller about the chaos that ensues when it is discovered that a comet is on a deadly collision course with the Earth. DreamWorks Pictures and Paramount Pictures present "DEEP IMPACT," a Zanuck/Brown production, directed by Mimi Leder. The executive producers are Oscar-winner Steven Spielberg, Joan Bradshaw and Walter Parkes. The film is written by Michael Tolkin and Bruce Joel Rubin. DreamWorks SKG is a multi- faceted entertainment studio formed in October 1994 by Steven Spielberg, Jeffrey Katzenberg and David Geffen. Paramount Pictures is part of the entertainment operations of Viacom Inc.
April 29, 1998
http://stardust.jpl.nasa.gov/microchip/signup.html
Feel free to enter as many names as you like of your family, friends and coworkers.
___ _____ ___
/_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov
| | | | __ \ /| | | | Jet Propulsion Lab |
___| | | | |__) |/ | | |__ Pasadena, CA | The truth always turns out
/___| | | | ___/ | |/__ /| | to be simpler than you
|_____|/ |_|/ |_____|/ | thought. Richard Feynman
The Planetary Society
October 21, 1997
Working with the STARDUST Project, the Planetary Society is collecting names to be placed on a microchip that will be mounted on the STARDUST return capsule. This capsule is part of a spacecraft that will be rocketed into the tail of comet P/Wild-2, collect samples of the comet's tail, and then return to Earth in January 2006.
To join STARDUST on its journey, send your name, address, city, state, country, postal code, and age (optional) to:
STARDUST
The Planetary Society
65 North Catalina Avenue
Pasadena, CA 91106-2301
All entries must be received no later than Sunday, November 30, 1997. The Society will also be posting a form for members and others to submit their names on this web site.
Scientists consider comet P/Wild-2 to be a "fresh" comet. In 1974, it was deflected by Jupiter's gravitational action from an earlier orbit much farther out in the solar system. Samples from Wild-2 thus offer us an exciting glimpse of the best preserved fundamental building blocks out of which our solar system formed. And sample collection will make use of exciting new aerogel material, the lowest density solid material on Earth.
Fortuitously, a rare but opportune orbital design using an Earth gravity assist allows STARDUST to capture cometary dust intact -- and parent volatiles as well -- at the incredibly low relative speed of 6.1 kilometers (about 4 miles) per second. With the aid of onboard optical navigation, the flyby can take place at an encounter distance as close as 50 kilometers (31 miles) from the comet's nucleus, permitting the capture of the freshest samples from within the coma parent molecule zone. This rare trajectory imposes a very low post-launch fuel requirement and enables launch by a Delta 2 launch vehicle.
As an exciting bonus, STARDUST will also collect interstellar dust, recently discovered by Ulysses and confirmed by the Galileo mission. In addition, a particle impact mass spectrometer provided by Germany's DLR will obtain in-flight data on the compositon of both cometary and interstellar dust, especially the very fine particles.
Increasing the yield of science data, STARDUST's optical navigation will take images of the comet's nucleus. The spacecraft's dust shield will also provide coma dust spatial and temporal distribution, and the X-band transponder may provide an estimate of comet Wild-2's mass.
You can get more information on this mission to comet Wild-2 at the STARDUST Project's web site.
Ken Atkins
STARDUST Project Manager
The project completed a self-imposed, formal Risk Review on October 22. Standing Review Board Chairman Frank Carr used a subset of the board members to conduct this review. The Board examined the implementation processes, matching against the plan.
Cometary & Interstellar Dust Analyzer (CIDA) delivery date: Good News!! The ATLO (Assembly, Test & Launch Operations )team at Lockheed-Martin developed a work-around to allow schedule relief by implementing a structural end "frame" to keep one end of the spacecraft box open longer in the assembly flow. Thus, later access to the spacecraft interior makes a schedule matching possible for the CIDA electronics to be installed there.
Aerogel Production update: The Co-Investigator Team meeting last Friday validated the aerogel flight density profiles. Gun test reports by Johnson Space Center validated the collector thickness design and supported the validation for the flight-design density profiles.
The flight system assembly stand was moved into the Hi Bay Clean Room at Lockheed-Martin. The Launch Vehicle adapter face (with shields) and bottom of the flight spacecraft structure was also moved and mounted on the assembly stand as preparations begin for full system assembly.
A STARDUST briefing was provided to Kennedy Space Center Director Maj-Gen. Roy Bridges, USAF Ret., highlighting elements such as Earned Value-based Performance Management, electronic meeting room, etc.
Ken Atkins
STARDUST Project Manager
Welcome to the first Webpage Weekly Report. It is our hope to raise our STARDUST fans' interest and involvement by communicating some of the exciting progress and events on the project as we proceed toward our rendezvous with the Delta Rocket and blast-off toward Wild 2. Since this is the first report it is most appropriate to attempt initiating the reader at a start point. So, let's begin a little review.
Hopefully, you already know STARDUST was selected competitively from a field of 28 proposals as the winner of the #5 position in NASA's Discovery Program. The Discovery Program is NASA's series of relatively low-cost robotic missions aimed at doing planetary exploration faster, better and cheaper. After selection, the project team entered an intensive preliminary design phase (a.k.a. Phase B in the jargon). This period of about a year took us from November 1995 to September 1996. At that time a Preliminary Design Review (PDR) was held by NASA to validate the mission and spacecraft design maturity, match it with the Discovery budget constraints and decide whether the project was ready to proceed to the detail design and development phases (a.k.a. Phase C/D). We passed.
So for last year, from October 1996 to now, the team has been very busy completing hardware designs for the spacecraft components, buying or building those components, and also working on the software programs that will test it on the ground and operate it in flight. As the hardware and software are built they are then integrated and tested to be sure they work together as a team. So preliminary testing has been an important activity this year as well.
Some of the key elements include the Aerogel collector that will go into the Sample Return Capsule to capture the comet and interstellar particles, the flight computers, the heat shields, the spacecraft particle shields, the cameras, radios, solar power system, propulsion, and the structures, mechanisms, and electronics that hook everything together. It's a pretty complex task involving about 200 engineers at Lockheed-Martin's Astronautics Co. in Denver, some 35 engineers at JPL, and about 15 U.S. mission scientists scattered around the country at universities and laboratories. That's not counting the Boeing Co. folks that are working to get our launch rocket ready and the folks in Germany building one of the "passenger" instruments, the Cometary and Interstellar Dust Analyzer (CIDA), described elsewhere on this website in more detail.
At this point in the project, we have completed virtually all the design work, have passed the so-called Critical Design Review (CDR) and are moving quickly toward the time when we begin to assemble, integrate and test everything working together as a full flight system. So in the weeks ahead you'll read about the accomplishments and challenges as we bring qualification units into the assembly and test environments in Denver. Soon we will have cameras on this website showing continuous time-lapse "stills" of the daily assembly processes as the project team brings the spacecraft toward its readiness to ship to Cape Canaveral for launch.
In this report, we will be sharing some of the details on that activity as it happens. You can be a participant by following our weekly or bi-weekly updates. So we begin here with some notes from our last two "weekly" reports that we send to our colleagues on the project and at NASA. And again, Welcome Aboard!
Aerogel Production update: 30 quartz molds for making cometary collector aerogel were received this week. These were of good form and the dimensions met the specifications. This indicates that the vendor is able to supply the needed mold size. These will be used next week along with the already-in-hand interstellar particle collector quartz molds to make a "pre-qual" production run of Aerogel in preparation for producing the qualification units for delivery to Lockheed-Martin Astronautics (LMA) during the first week in November. If successful, this will complete the qualification tests before Thanksgiving.
Cometary & Interstellar Dust Analyzer (CIDA) Working Meeting (Germany Sept 29 to Oct 1): The trip report showed good accomplishments in command and telemetry agreements. Also a number of software issues were resolved such as instrument startup and code files. Unfortunately the schedule mismatch on Assembly Test & Launch Operations (ATLO) delivery date was not resolved. Both ATLO team and the CIDA team are examining additional work-around options.
The Launch Vehicle Ground Ops Working Group met at Kennedy Space Center (KSC) on 10/7 & 8. Focus items included change of the spacecraft processing facility, communications plans, and safety procedures.
The spacecraft flight structure was disassembled in preparation for final installation of the thermal insulation and Nextel particle curtains in the Whipple shields. The Whipple shield composite structure details were completed and enough stand-off tubes were shipped by Spyrotech to assemble the Structural Thermal Model.
A "lessons-learned" session with Giotto (The European Space Agency's probe of Halley's comet in the 80's) personnel was held in Germany. Discussions on the health and history of Giotto showed very strongly that the STARDUST spacecraft design would have survived the Halley encounter. The Giotto fly-through speed at Halley was over 70 km/s.....an order of magnitude higher than the plan for STARDUST at Wild-2.
The 'Bill Nye the Science Guy' PBS TV production team did a STARDUST "shoot" at LMA Thursday, 10/9. Airing should be in November. Denver TV Channel 4 also interviewed LMA personnel on Monday, 10/6.
NASA Science News for Feb 5, 1999: Aerogel Rides Again - Aerogel will take its next ride into space on Stardust, which launches this weekend. With aerogel, scientists hope to capture dust from comet Wild's tail and return it to Earth. However, aerogel has many more applications, from super insulation to computing.
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
NASA's Stardust spacecraft successfully shot into a clear blue sky atop a Delta II rocket from Florida's Cape Canaveral Air Station at 4:04:15 p.m. EST (1:04:15 p.m. PST) today to become the first U.S. mission destined for a comet, and the first-ever spacecraft sent to bring a sample of a comet sample back to Earth.
The Stardust team reported that the spacecraft was in excellent health and that its power and temperature levels are normal. The spacecraft is in communication with NASA's Deep Space Network, and is controlled through the mission operations area at Lockheed Martin Astronautics, Denver, Colo., and monitored at NASA's Jet Propulsion Laboratory, Pasadena, Calif., where the mission is managed.
Sixty-six seconds after liftoff, the four solid rocket motors on the Delta were discarded and the first stage continued to burn until it shut down and fell away about 4 minutes, 30 seconds into the mission. A few seconds later, the Delta's second stage ignited and burned for about 5 minutes, cutting off at 9 minutes, 55 seconds into the mission. Almost immediately after the second-stage ignition, the fairing or nose-cone enclosure around the Stardust spacecraft was jettisoned.
After coasting for about 11 minutes, the second-stage engine restarted and burned for about 2 minutes. The third stage separated from the second stage 24 minutes, 27 seconds into the mission; the Star 37 third stage ignited 25 minutes, 4 seconds into the mission, burning for about 2 minutes. At 27 minutes, 19 seconds into the mission -- or 4:31:34 p.m. EST -- the Stardust spacecraft separated from the Delta's third stage, stopping its spinning by firing onboard thrusters. About 4 minutes after separation, Stardust's solar arrays began to unfold and pointed toward the Sun. The spacecraft's signal was successfully acquired by the NASA Deep Space Network complex in Canberra, Australia, 51 minutes after launch at 4:55 p.m. EST.
Stardust is on a flight path that will deliver it to Comet Wild-2 (pronounced "Vilt-2" on January 2, 2004. The spacecraft will gather particles flying off the nucleus of the comet. In addition, Stardust will attempt to gather samples from a stream of interstellar dust that flows through the solar system. Captured in a glass foam called aerogel, the comet and interstellar dust samples will be enclosed in a clamshell-like capsule that will be dropped off for reentry into Earth's atmosphere in January 2006. Equipped with parachutes, the capsule will float to a pre-selected spot in the Utah desert, where it will be retrieved and its contents delivered to scientists for detailed analysis.
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
February 3, 1999
Launch is scheduled at 4:06 p.m. Eastern time, with live coverage on NASA Television beginning at 2:30 p.m. Eastern. A post-launch briefing is planned to be broadcast on NASA Television at 6 p.m. Eastern.
Comets, which periodically grace our sky like celestial bottle rockets, are thought to hold many of the original ingredients of the recipe that created the planets and brought plentiful water to Earth. They are also rich in organic material, which provided our planet with many of the ready-to-mix molecules that could give rise to life. They may be the oldest, most primitive bodies in the solar system, a preserved record of the original nebula that formed the Sun and the planets.
"Scientists have long sought a sample directly from a known comet because of the unique chemical and physical information these bodies contain about the earliest history of the solar system," said Dr. Edward Weiler, NASA's associate administrator for space science. "Locked within comet molecules and atoms could be the record of the formation of the planets and the materials from which they were made."
Stardust is the first U.S. mission dedicated solely to a comet and will be the first to return extraterrestrial material from outside the orbit of the Moon. Stardust's main objective is to capture a sample from a well-preserved comet called Wild-2 (pronounced "Vilt-2").
The spacecraft will also collect interstellar dust from a recently discovered flow of particles that passes through our solar system from interstellar space. As in the proverbial "from dust to dust," this interstellar dust represents the ultimate in recycled material; it is the stuff from which all solid objects in the universe are made, and the state to which everything eventually returns. Scientists want to discover the composition of this "stardust" to determine the history, chemistry, physics and mineralogy of nature's most fundamental building blocks.
Because it would be virtually impossible to equip a spacecraft with the most sophisticated lab instrumentation needed to analyze such material in space, the Stardust spacecraft is more of a robotic lab assistant whose job it is pick up and deliver a sample to scientists back on Earth. The spacecraft will, however, radio some on-the-spot analytical observations of the comet and interstellar dust.
"The samples we will collect are extremely small, less than a micron, or 1/25,000th of an inch, in size, and can only be adequately studied in laboratories with sophisticated analytical instruments," said Dr. Donald C. Brownlee of the University of Washington, principal investigator for the Stardust mission.
"Even if a ton of sample were returned, the main information in the solids would still be recorded at the micron level, and the analyses would still be done a single grain at a time."
Stardust will meet up with Comet Wild-2 on January 2, 2004. A gravity assist flyby of Earth will put Stardust on a trajectory that will allow it to capture cometary dust intact at a low relative speed of 6.1 kilometers per second (about 13,600 miles per hour). An onboard camera will aid in navigating the spacecraft as close as about 150 kilometers (100 miles) from the comet's nucleus, permitting the capture of the freshest samples from the heart of the comet.
Dressed for survival behind armored shields, Stardust will document its 10-hour passage through the hailstorm of comet debris with scientific instruments and the navigation camera. On approach to the dust cloud, or "coma," the spacecraft will flip open a tennis-racket-shaped particle catcher filled with a smoke- colored glass foam called aerogel to capture the comet particles. Aerogel, the lowest-density material in the world, has enough "give" in it to slow and stop particles without altering them too much. After the sample has been collected, the aerogel capturing device will fold down into a return capsule, which closes like a clamshell to enclose the sample for its safe delivery to Earth.
In addition, a particle impact mass spectrometer will obtain in-flight data on the composition of both cometary and interstellar dust, especially very fine particles. The optical navigation camera should provide excellent images of the dark mass of the comet's nucleus. Other equipment will reveal the distribution in both time and space of coma dust, and could give an estimate of the comet's mass.
On January 15, 2006, a parachute will set the capsule gently onto the salt flats of the Utah desert for retrieval. The scientifically precious samples can be studied for decades into the future with ever-improving techniques and analysis technologies, limited only by the number of atoms and molecules of the sample material available. Many types of analyses now performed on lunar samples, for example, were not even conceived at the time of the Apollo missions to the Moon.
Comets are small, irregularly shaped bodies composed of a mixture of grains of rock, organic molecules and frozen gases. Most comets are about 50 percent water ice. Typically ranging in size up to about 10 kilometers (6 miles) in diameter, comets have highly elliptical orbits that bring them close to the Sun and then swing them back out into deep space. They spend most of their existences in a deep freeze beyond the orbit of Pluto - far beyond the Sun's dwindling influence, which is why so much of their original material is well-preserved.
When a comet approaches within about 700 million kilometers (half billion miles) of the Sun, the surface of the nucleus begins to warm, and material on the comet's nucleus heats and begins to vaporize. This process, along with the loss of rocky debris or other particles that fly off the surface, creates the cloud around the nucleus called the coma. It is the glowing, fuzzy coma that appears as the head of a comet when one is observed from Earth. A tail of luminous debris and another, less apparent, tail of gases flow millions of miles beyond the head in the direction away from the Sun.
Comet Wild-2 is considered an ideal target for study because, until recently, it was a long-period comet that rarely ventured close to the Sun. A fateful pass near Jupiter and its enormous gravity field in 1974 pulled Comet Wild-2 off-course, diverting it onto a tighter orbit that brings it past the Sun more frequently and also closer to Earth's neighborhood. Because Wild-2 has only recently changed its orbit, it has lost little of its original material when compared with other short-period comets, so it offers some of the best-preserved comet samples that can be obtained.
Stardust was competitively selected in the fall of 1995 under NASA's Discovery Program of low-cost, highly focused science missions. As a Discovery mission, Stardust has met a fast development schedule, uses a small Delta launch vehicle, is cost-capped at less than $200 million, and is the product of a partnership involving NASA, academia and industry.
Principal investigator Brownlee is well-known for his discovery of cosmic particles in Earth's stratosphere known as Brownlee particles. Dr. Peter Tsou of NASA's Jet Propulsion Laboratory, Pasadena, CA, an innovator in aerogel technology and maker of aerogel, serves as deputy investigator. JPL, a division of the California Institute of Technology, manages the Stardust mission for NASA's Office of Space Science, Washington, DC. Dr. Kenneth L. Atkins of JPL is project manager. The spacecraft is designed, built and operated by Lockheed Martin Astronautics, Denver, CO. JPL provided the spacecraft's optical navigation camera, and the Max Planck Institute of Germany provided the real-time dust composition analyzer.
NASA Television is broadcast on the satellite GE-2, transponder 9C, C band, 85 degrees west longitude, frequency 3880.0 MHz, vertical polarization, audio monaural at 6.8 MHz.
ROYAL ASTRONOMICAL SOCIETY
PRESS INFORMATION NOTE
2 February 1999
INFORMATION ON CONTACTS AND ILLUSTRATIONS IS GIVEN AT THE END OF THIS RELEASE.
Stardust is currently set for launch on Saturday, February 6. After a five year voyage to reach its target, Stardust will fly past the comet in January 2004. Approaching at a speed of 6 km/s (14,000 mph), Stardust will capture the tiny dust particles that make up the comet's tail, eventually returning them to Earth in January 2006. In order to avoid damaging the fragile particles, panels of aerogel - sometimes called 'solid smoke' because of its extreme lightness - will be exposed to the dust stream and used to entrap them.
The overall dust environment around the comet will also be studied in detail. One of the instruments used to measure the characteristics of this dust is a sensitive dust detection system.
This Large Area Momentum Sensor (LAMS) is mounted on Stardust's front bumper shield. The circular shield, which consists of three layers, is used to protect the vulnerable spacecraft from high speed impacts. At the rear of the shield is a set of microphones, designed by Kent in collaboration with the University of Chicago. These will listen to the 'sound' of the dust particles as they strike the spacecraft.
The microphone attached to the back of the external aluminium layer will record impacts from smaller particles. Larger grains which penetrate the aluminium will be detected by a second microphone fixed to a layer of Nextel cloth. The number of impacts on the shield will be counted from the number of electrical pulses picked up by the Kent sensors, while the voltage of each pulse will enable particle mass to be calculated.
UKC team member Dr. Mark Burchell said, "Using the special facilities in our laboratory, we have been able to recreate the high speed impacts on a mock-up of the Stardust spacecraft. This allowed us to test the microphones which will 'listen' to the impacts on the real spacecraft as it flies past the comet."
Dust particles ejected by comets are thought to have been preserved in almost pristine condition since our Solar System formed some 4,600,000,000 years ago. Professor Tony McDonnell, Director of the Unit for Space Sciences, pointed out that "since comets are probably the most primitive objects in our Solar System, this is a very important mission which will greatly extend our understanding of them and of the conditions out of which our Solar System developed".
Also involved in the team is postgraduate student Bryan Vaughan, who will be basing his doctorate thesis on the University of Kent Stardust research.
The University of Kent involvement with this NASA mission is funded by a grant from PPARC, the UK Particle Physics and Astronomy Research Council.
Stardust is a prelude to an even more ambitious European Space Agency mission called Rosetta. A number of UK groups are involved in this mission, including the University of Kent, the Open University, and Rutherford Appleton Laboratory. Scheduled for launch in 2003, Rosetta will actually land a probe on the surface of a comet, but not until the year 2011!
NOTES.
Stardust will be the first spacecraft ever to bring cometary material back to Earth for analysis by scientists worldwide. Its main objective is to collect return particles flying off the nucleus of Comet Wild-2. It will also bring back samples of interstellar dust, including the recently discovered dust streaming into the Solar System from other stars. Ground-based analysis of these samples after their return in January 2006 should yield important insights into the evolution of the Sun and planets, and possibly into the origin of life itself.
Other objectives are to take pictures of the comet, count the comet particles striking the spacecraft, and produce real-time analyses of the composition of the material ejected by the comet.
Stardust is the fourth of NASA's low-cost Discovery missions.
Further details can be found on the World Wide Web as follows:
UKC STARDUST home page
UKC Space Activities
NASA STARDUST Home Page
University of Washington
Feb. 1, 1999
Stardust is scheduled to launch from Cape Canaveral, Fla., at 1:07 p.m. PST, and UWTV will provide live coverage. The mission, selected in 1995 by NASA as part of its Discovery series, aims to capture particles from comet Wild 2 (pronounced Vilt 2) and return them to Earth for analysis in laboratories at the UW, NASA and around the world. There's much to be learned, Brownlee said.
"People have long suspected that comets played a role in the origin of life. No one really knows this because no one knows how life began. But we do know that comets are the most carbon-rich materials in the solar system, and we know they're full of organic compounds and they fall on the Earth all the time. Even now we have tens of thousands of tons of comet particles landing on the Earth every year," he said.
Even though microscopic comet particles blanket open spaces such as parks and football stadiums every year, those particles don't tell the same story as ones collected from a comet such as Wild 2, Brownlee said. That's because Wild 2 only recently started orbiting close enough to the sun to make the mission feasible, so there hasn't been time enough for the sun's heat to destroy the characteristics of particles that have been preserved in a cryogenic deep freeze of space for billions of year.
In 1980, Brownlee and NASA first considered a mission to capture comet particles. In that case, the target would have been Halley's comet, but the idea proved unworkable. Various technological advances and a bit of celestial luck changed that. Before 1974, Wild 2 traveled outside the orbit of Jupiter. But a close encounter with Jupiter that year altered the comet's trajectory, bringing it close enough to make Stardust possible. The spacecraft's encounter with the comet in early 2004 will take place just outside the orbit of Mars, 242 million miles from Earth on the other side of the sun.
The mission is the first since Apollo 17 in 1972 to return extraterrestrial samples to Earth, and it is the first to bring back samples from beyond the orbit of the moon. Scientists will study the returned comet particles in the hope of understanding how life evolved on Earth. The planet probably was formed without water and without carbon or nitrogen, the building blocks of life. "The building blocks of life have long been thought to have come from further out in the solar system, out further away from the sun, and these would be materials from asteroids and comets," Brownlee said.
Stardust will have journeyed 3.1 billion miles before it parachutes into the Utah desert in early 2006. During its encounter with Wild 2, a tennis-racquet shaped collector, sheathed with a wispy substance called aerogel, will be extended to collect comet grains when the spacecraft is within 100 miles of the comet's icy core. A high-power antenna will transmit close-up pictures, and sensitive equipment will gather data about the comet.
The mission is a collaboration of the UW, NASA, NASA's Jet Propulsion Laboratory at the California Institute of Technology in Pasadena, Calif., and Lockheed Martin Astronautics in Denver. Other key members of the team are The Boeing Co., Germany's Max-Planck-Institut für extraterrestrische Physik, the NASA Ames Research Center and the University of Chicago.
Brownlee expects information gathered by Stardust to shed light on how the solar system and the universe evolved. The mission also could have implications on astrobiology, the search for life beyond Earth. The UW this fall will begin the first doctoral program in astrobiology to train people to look for life on other celestial bodies, such as Mars and Europa, a moon of Jupiter.
"From the astrobiology standpoint, we're interested in what kind of organic materials actually exist and how much there is and whether this played a role (in the formation of life)," Brownlee said. "Now this may be an impossible problem. We can study astrobiology and we can investigate how life might have formed, but no one was there taking notes when life formed.
"You have things ... before there was life and things after there was life but the real records aren't there," he said. "But by insight on this, you can at least look at what the starting materials were. So that's what Stardust is going to do, look at the starting materials, what was around in the solar system before life existed on Earth."
The name "Stardust" seemed appropriate because of the nature of the project and the fact that people can relate to that name, Brownlee said. A recent radio interview ended with a few bars of the song "Woodstock" by Joni Mitchell, which includes the lyrics: "We are stardust, we are golden, we are 2 billion-year-old carbon." That's an appropriate thought, Brownlee said.
"Comets are a vehicle that brings organic materials to the Earth. Many of the carbon atoms in our bodies were in comets early in the history of the solar system. So one of the bylines of the Stardust mission is that we are stardust. Our bodies are actually made of stardust."
Science aside, there's a hint of romanticism about this mission. That's why, come Saturday, it won't be "Woodstock" but instead the soft strains of Hoagy Carmichael's "Stardust" drifting through the launch area.
NASA News
National Aeronautics and Space Administration
John F. Kennedy Space Center
Nov. 12, 1998
Stardust will be the first spacecraft ever to bring cometary material back to Earth for analysis by scientists worldwide. Comets are believed to contain the original building blocks of the planets and perhaps of life itself. Early in Earth's history, comets laden with water ice slammed into the planet, maybe providing the source of our oceans. When Stardust returns its pristine comet samples, scientists will be able to examine for the first time the key ingredients of the original recipe that created the planets.
Stardust is to collect particles flying off the nucleus of comet Wild 2 in January, 2004. It will also bring back samples of interstellar dust including the recently discovered dust streaming into the solar system from other stars. The spacecraft will send back pictures of Wild 2, count the bullet-like comet particles striking the spacecraft, and produce real-time analyses of the composition of the material coming off the comet. A unique substance called aerogel is the medium that will be used to catch and preserve comet samples. When Stardust swings by Earth in January 2006, the samples encased in a re-entry capsule will be jettisoned and parachute to a pre-selected site in the Utah desert.
The length of the Stardust main bus is 5.5 feet (1.7 meters), about the size of an average office desk. The spacecraft weighs 849 pounds (385 kilograms). It is being processed in NASA's Payload Hazardous Servicing Facility (PHSF) located in the KSC Industrial Area. Among the processing activities to be performed are installation and testing of the solar arrays, final installation and testing of some spacecraft instruments followed by an overall spacecraft functional test. The spacecraft can then be fueled and mated to the Star 37 solid propellant upper stage booster.
Meanwhile, at Complex 17, the Delta II rocket will be undergoing erection and prelaunch checkout by Boeing. The first stage is scheduled to be installed into the launcher on Jan. 5, 1999. Four solid rocket boosters will be attached around the base of the first stage the next day. The second stage will be mated atop the first stage on Jan. 8, and the spacecraft fairing will be hoisted into the cleanroom of the pad's mobile service tower Jan. 11.
Stardust will be transported to Complex 17 on Jan. 28 for hoisting aboard the Delta rocket on Pad A and mating to the second stage. After the spacecraft undergoes state of health checks, the fairing can be placed around it three days later. Launch is currently targeted for Feb. 6 at 4:08 p.m. EST. The 20-day launch opportunity ends Feb. 25.
Stardust is built by Lockheed Martin Astronautics, Denver, Co., under a NASA contract managed by Jet Propulsion Laboratory, Pasadena, Ca. It is the fourth NASA Discovery mission to be chosen following Mars Pathfinder, the Near Earth Asteroid Rendezvous (NEAR), and the Lunar Prospector. The goal of NASA's Discovery Program is to launch many smaller missions with shorter development time that perform focused science at lower cost.
University of Washington
June 29, 1998
Stardust will blast off from Cape Canaveral, Fla., in February. It will be the fourth mission in NASA's Discovery series, which captured public imagination a year ago with Mars Pathfinder. It will be the first mission since Apollo to return samples of space material to Earth for analysis.
UW professor Donald Brownlee, the principal investigator for the project, expects to find clues about the formation of the solar system and perhaps the universe itself.
"We hope to understand how comets were formed and what they're made of," he said. "We expect them to be the preserved building blocks of the outer planets."
Brownlee began considering such a mission in1980. The idea was explored seriously five years later when Halley's comet approached Earth, but it was deemed unworkable then.
For Stardust's 7-year, 3.1-billion-mile journey, solar panels will power the spacecraft to encounter Wild 2, a comet that altered course in 1974 after a close encounter with Jupiter. Now instead of circling among the outer planets in our solar system, Wild 2 (pronounced vihlt 2) travels among the inner planets. It was discovered in 1978 during its first close approach to Earth.
Wild 2's recent arrival to the planetary neighborhood makes the $200 million Stardust mission possible. In 2004, the craft will pass about 75 miles from the main body of the comet. That's close enough to trap small particles from the comet's coma, the gas-and-dust envelope surrounding the nucleus. A camera built for NASA's Voyager program will transmit the first-ever close-up comet pictures back to Earth. Though the encounter will last about 12 hours, Brownlee says the really intense activity will be over in a matter of minutes.
The collection system will extend from the spacecraft and trap particles as they collide with it. To prevent damaging or altering the particles - each smaller than a grain of sand and traveling as much as nine times the speed of a bullet fired from a rifle - the collector uses a unique substance called aerogel. Often called "frozen smoke," aerogel is a transparent blue silica-based solid that is as much as 99.9 percent air. It is as smooth as glass, something like plastic foam without the lumps. A block the size of a person weighs less than a pound but can support the weight of a small car.
On the trip to Wild 2, the aerogel-equipped collection panel will be deployed to trap interstellar particles traveling in space. During the encounter with the comet, some 242 million miles from Earth, the opposite side of the panel will gather bits of comet dust. Trapped particles will leave a telltale trail through the aerogel that scientists will follow to find the grains and extract them. Upon leaving the comet, the collection panel will retract into its capsule.
Once the Stardust capsule parchutes into Utah's Great Salt Desert in 2006, the particles it collects will go to Johnson Space Center in Houston and then be parceled out to various research facilities, including the University of Washington. Because comets are about equal parts ice and dust, Brownlee believes the particles will be cryogenically preserved interstellar dust left from the birth of the solar system some 4.6 billion years ago. Such grains can be found only in the outer solar system, he believes, because heat has destroyed them nearer the Sun.
Brownlee's previous work collecting cosmic dust particles led to their being named Brownlee particles. Cosmic dust was brought back to Earth on Gemini missions in the 1960s. Later, high-flying U2 planes and balloons gathered particles from different levels in the atmosphere, and space dust even has been collected from the ocean floor. "A comet mission is the logical extension," Brownlee said.
The project is being carried out by a consortium that includes the Jet Propulsion Laboratory and Lockheed Martin Astronautics. When it came to picking a name, Brownlee said, it just seemed appropriate to select "Stardust," the title Hoagy Carmichael put on a popular tune that since has been recorded by numerous artists, including Willie Nelson and Ringo Starr.
"I liked it because most spacecraft missions had weird, bizarre names. They were acronyms for something," he said. "This isn't an acronym for anything. It's just a name that people know."
In fact, NASA collected 130,000 names for one microchip already loaded on the Stardust spacecraft, and more than 200,000 names have been placed on a second. The names are etched electronically on a chip the size of a fingernail, with writing so small that 80 letters will fit into the width of a human hair and an electron microscope is needed to read them.
University of Washington Astronomy Professor Donald Brownlee, the father of the Stardust mission, said plans are to place the chips in a museum when the spacecraft returns to Earth in early 2006. He hopes they will go to the Smithsonian Institution.
The drive to gather names for the mission has gotten new emphasis with the recent release of the movie Deep Impact, a science-fiction thriller about a comet colliding with Earth, and the imminent release of "Armageddon," about an asteroid colliding with Earth. Paramount Studios and and the DreamWorks SKG, which collaborated on "Deep Impact," are promoting the gathering of names.
The only way to submit a name for inclusion on a chip is through Stardust's web page. Submitting a name automaticallygrants permission for the name to be used in future exhibits and publications by the Stardust collaboration, which includes the UW, NASA, the Jet Propulsion Laboratory and Lockheed Martin Astronautics.
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