[meteorite-list] The Fiery Return of NASA's Space Dust Cargo

From: Gerald Flaherty <grf2_at_meteoritecentral.com>
Date: Wed Nov 30 20:22:18 2005
Message-ID: <002b01c5f615$9b85a3e0$6402a8c0_at_Dell>

Wow! what an incredible range of information potential this may
provide!!!!!!
Jerry
----- Original Message -----
From: "Ron Baalke" <baalke_at_zagami.jpl.nasa.gov>
To: "Meteorite Mailing List" <meteorite-list_at_meteoritecentral.com>
Sent: Wednesday, November 30, 2005 12:15 PM
Subject: [meteorite-list] The Fiery Return of NASA's Space Dust Cargo


>
> http://www.nasa.gov/centers/ames/research/exploringtheuniverse/stardust.html
>
> John Bluck
> NASA Ames Research Center, Moffett Field, Calif.
> Phone: 650/604-5026
> E-mail: jbluck_at_mail.arc.nasa.gov
>
> The Fiery Return of NASA's Space Dust Cargo
> November 29, 2005
>
> In search of clues about the origin of life on Earth and other secrets,
> a crew flying on a NASA DC-8 aircraft will study the small, speeding
> Stardust capsule returning from space early in 2006.
>
> Two years earlier, in January 2004, the Stardust spacecraft flew within
> 147 miles (236 kilometers) of the comet Wild 2 (VILT-TWO) and survived
> the high-speed impact of millions of dust particles and small rocks up
> to nearly two-tenths of an inch (one half centimeter) across. With its
> tennis-racket-shaped collector extended, Stardust captured thousands of
> comet particles.
>
> The returning Stardust capsule will strike Earth's atmosphere during the
> early morning darkness in mid-January 2006, at eight miles (12.8
> kilometers) per second ??" more than 10 times faster than a speeding
> bullet. That is fast enough to go from San Francisco to Los Angeles in
> only one minute. The DC-8 crew will face the daunting task of tracking
> and observing the 101-pound (45.7 kilogram) conical object as it hurtles
> through the atmosphere and slows before the spacecraft finally
> parachutes down in a Utah desert.
>
> Scientists aboard the DC-8 also will assess how well the Stardust
> capsule's heat shield protects its precious cargo of comet dust and
> interstellar grains.
>
> Though scientists will study this captured space dust for years to come,
> the separate team of researchers aboard the DC-8 will gather data only
> during the brief re-entry of the space capsule into Earth's atmosphere.
>
> The mini, Apollo-like capsule will shoot down through the air at the
> highest spacecraft re-entry speed into Earth's atmosphere ever,
> generating extremely high temperatures. The capsule's special
> carbon-based heat shield, developed at NASA Ames Research Center in
> California's Silicon Valley, will protect the priceless cargo of comet
> dust and interstellar grains. During this blistering re-entry, the DC-8
> crew will take surface-temperature and shock-radiation measurements of
> the heat shield as part of it burns away. Shock radiation is light
> emitted from extremely hot air. Scientists will study this light to
> learn how hot the capsule gets and what chemical reactions are taking
> place. These chemical reactions will result from of the violent breakup
> of air molecules that collide with vapor in front of the speeding capsule.
>
> At the same time as the DC-8 crew is flying its mission, amateur
> astronomers, willing to endure the cold of the bitter winter, may
> contribute to the study by simply photographing the incoming capsule,
> noting their global positions and later providing that information to
> mission scientists.
>
> One of the goals of the researchers aboard the DC-8 is to measure the
> capsule's re-entry brightness. Scientists expect it to peak at
> approximately the brilliance of Venus for roughly 90 seconds. The
> capsule will be brightest 37 miles (60 kilometers) high over the town of
> Carlin, Nev., as the spacecraft approaches. This will occur in the early
> morning cold and darkness on Sunday, Jan. 15, 2006, shortly before the
> spacecraft parachutes to a landing at 3 a.m. MST. The landing zone is a
> restricted area ??" the Utah Test and Training Range, located southwest of
> Salt Lake City.
>
> "As the observer sees the approaching capsule, it will appear as a point
> of light," said Peter Jenniskens, principal investigator of the Stardust
> Sample Return Capsule Re-entry Observing Campaign. Jenniskens is a
> meteor astronomer at the SETI Institute, Mountain View, Calif. "After it
> passes the observer, the back of the capsule will be less bright, and it
> will quickly fade. Each observer will have a different experience,"
> Jenniskens added.
>
> The special carbon-based heat shield material designed to protect the
> Stardust capsule is a candidate for potential inclusion on NASA's next
> planned spaceship, the Crew Exploration Vehicle (CEV), NASA engineers
> say. This prospective future use is one reason they plan to study the
> Stardust capsule as it slams into Earth's atmosphere, and the shield
> rapidly heats due to friction with the air.
>
> "Our main interest is the performance of the heat shield and the
> chemistry that takes place in it as it vaporizes and erodes during the
> descent and re-entry," said Dave Jordan, a NASA Ames engineer and
> project manager for the capsule observation mission.
>
> The spacecraft will penetrate Earth's atmosphere as if it were a normal
> meteor, according to Jenniskens.
>
> "The capsule will be an artificial meteor that we can study for clues
> about how life's molecules may have first formed on Earth," Jenniskens
> said. "The carbon from the heat shield will react in the shockwave,
> making new molecules that would have seeded Earth at the time of the
> origin of life. The carbon in comet dust could have done the same,"
> Jenniskens ventured.
>
> After scientists examine the dust carried within the capsule, they may
> soon learn what carbon compounds are found in comet dust. The spacecraft
> flew through comet Wild-2's dust cloud and captured some of it in a very
> light substance, called 'aerogel.'
>
> "It's a little
> bit like collecting BBs by shooting them into Styrofoam," said Scott
> Sandford, an astrophysicist at NASA Ames and a Stardust mission
> co-investigator. "Some of the grains are likely to have exotic isotopic
> ratios that will give us an indication that we're looking at materials
> that aren't as old as the solar system, but are, in fact, older than the
> solar system," Sandford asserted.
>
> Another mission objective was to expose the spacecraft to the
> interstellar dust stream for 150 days to grab interstellar particles.
> After collecting the particles, the aerogel collector retracted into the
> capsule. Stardust will be the first mission to capture and return a
> substantial sample from outside Earth's moon system.
>
> Watching the Stardust re-entry
>
> The capsule will approach the landing zone from a westerly direction.
> The best opportunities for viewing the re-entry will be along Highway 80
> between Carlin, Nev., and Elko, Nev., and further east to the Utah
> border, where the capsule's front side can be observed before it passes
> over the observer on the ground. The peak brightness will decrease
> further from Carlin, lessening to about the brightness of Venus (+0
> magnitude) when seen from Boise, Idaho, and Salt Lake City. Viewing will
> not be as good at sites east of Carlin where the craft will be seen from
> behind.
>
> For certain viewing locations just north of the trajectory line, the
> capsule will appear to pass by the moon (above it, or below it,
> depending on the viewer's location). By choosing their positions
> carefully, some observers will be able to see the capsule pass in front
> of the moon. As seen by the naked eye, the capsule will disappear in the
> glare of moonlight, but by looking through telescopes, observers may see
> a tiny dot, perhaps trailed by a dark wake of dissipating heat shield
> material and hot air. The trail may form a thin line behind the capsule,
> especially near the point of peak brightness where ablation (erosion of
> the heat shield and dissipation of the heat that results from the
> friction of the heat shield with the atmosphere) is most intense.
>
> "If somebody could see that line, that would be fantastic, because it
> would tell us how much carbon is being lost by the heat shield at that
> moment," observed Jenniskens. "It would be better yet if several
> observers at different locations were to videotape the entry of the
> capsule appearing in front of the moon because then we could trace the
> ablation of the carbon along the capsule's trajectory, especially at
> locations between Carlin and Elko," he added. Videographers should fix
> the focus of their cameras at 'infinity,' because auto focus may be
> unreliable for nighttime recording, according to mission technicians.
>
> The best way to see the capsule pass in front of the moon would be with
> a large telescope at high magnification, according to Jenniskens. Due to
> the long viewing distances, the tiny capsule will appear as a dark dot,
> only 1-2 arcseconds across, but darker if the capsule is clearly
> visible. One arcsecond is 1/3600th of a degree.
>
> Moving at many times the speed of sound, the capsule will take only two
> to three video frames to appear to pass by the moon.
>
> When the Stardust capsule does not appear to be near the moon, observers
> should look for 'chemi-luminance,' a faint glow in the wake of the
> capsule. This glow may be created by chemical reactions between the hot
> air in the capsule's wake and ozone in the air.
>
> According to scientists, observers using the naked eye will likely see
> the capsule as a very bright pinpoint of pink-white light. This color is
> the signature of excited atoms and molecules in the shock wave formed as
> the capsule strikes the atmosphere, according to George Raiche of NASA
> Ames.
>
> Light emission is caused by violent breakup of the air molecules that
> collide with the speeding capsule. For the most part, these molecules
> are oxygen and nitrogen atoms and ionized nitrogen molecules, Jenniskens
> noted. Ablation products could cause violet light resulting from
> chemical reactions between carbon and air.
>
> "What the re-entry of the capsule will tell us is how those carbon
> compounds might be chemically changed when comet dust enters Earth's
> atmosphere. Life's molecules need nitrogen and oxygen combined so that
> they can become useful ingredients for living things," Jenniskens said.
>
> In effect, the capsule will be an artificial meteor that we can study
> for clues about how life's molecules may have first formed on Earth,
> according to Jenniskens. "This will be the first time we will have
> scheduled observation of a manmade object entering the planet's
> atmosphere at speeds comparable to natural fireballs," he noted.
>
> While most of this chemistry happening at high speed is very quick,
> complex and elusive, it is possible to recognize the most brightly
> radiating compounds in this fiery process and to look for clues about
> what conditions the molecules must endure.
>
> Finally, the conical spacecraft will drop straight down over the
> restricted zone in Utah, floating down by parachute.
>
> Once the capsule has landed in Utah, researchers will collect debris
> from the surface of the shield and study how much of the heat shield was
> lost during re-entry. "This is called an ablative heat shield," said
> Michael J. Wright of NASA Ames, another scientist working on the
> project. "By vaporizing some of the material from its surface, the heat
> shield vapor carries some of the heat from friction away from the
> capsule, keeping the payload cool," Wright explained.
>
> After they recover the capsule and its precious cargo, scientists will
> transport the space dust to a laboratory at NASA Johnson Space Center,
> Houston, for analysis.
>
> "The sample(s) brought back from comet Wild-2 will tell us is what
> carbon compounds are in cometary dust," Jenniskens observed.
>
> "There'll be a small team of us at Johnson Space Center who will assess
> what we actually got back from the comet so we can verify we did get a
> useful sample," Sandford said. "A small portion of the samples will then
> be used to make a preliminary study of the returned material. After the
> preliminary examination is complete, all the samples will be made
> available to the general scientific community for more detailed study.
> My guess is people will be asking for and working on these samples for
> decades to come."
>
> Besides NASA Ames and the SETI Institute, several other institutions are
> partners in the NASA DC-8 airborne study: the University of Alaska at
> Fairbanks; the University of Utah at Logan; Sandia National
> Laboratories; Los Alamos National Laboratories; the Aerospace
> Corporation; the U.S. Air Force Academy; Kobe University, Japan; and
> Stuttgart University, Germany. The University of North Dakota operates
> the DC-8 aircraft for NASA.
>
> Amateur astronomers who wish to submit photographic, video or other data
> to Jenniskens will find directions and more information about the
> airborne campaign at:
>
> http://reentry.arc.nasa.gov
>
> The Stardust spacecraft was launched on Feb. 7, 1999, from Cape
> Canaveral Air Station, Fla., aboard a Delta II rocket. NASA's Jet
> Propulsion Laboratory, Pasadena, Calif., manages Stardust, a part of
> NASA's Discovery Program of low-cost, highly focused science missions.
> For more information about Stardust and a background audio interview
> with Sandford, visit:
>
> http://stardust.jpl.nasa.gov
>
> http://www.nasa.gov/centers/ames/multimedia/audio/sdust/sdust.html
>
>
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Received on Wed 30 Nov 2005 08:21:50 PM PST