How to Bring Home a Comet

On January 15, 2006, after more than 7 years and billions of miles of travel through space, the Stardust spacecraft will finally return to Earth with some precious cargo -- pristine samples of comet and interstellar dust. Stardust will provide the world's first opportunity to analyze preserved samples of the fundamental building blocks of our Solar System that formed 4.6 billion years ago.

Retrieving the Sample Return Capsule

During a brief but daring encounter with Comet Wild 2 on January 2, 2004, Stardust captured thousands of particles and began its arduous two-year journey back to Earth, where its Sample Return Capsule (SRC) will land in the Utah Test and Training Range (UTTR) within the Great Salt Lake Desert.

The SRC will reenter Earth's atmosphere and parachute toward the surface, touching down at approximately 3:15 AM on January 15, 2006. Upon its long anticipated landing, the SRC will separate from the parachute, which will float on its own to the ground several yards away from the landing site.

After the capsule's touch down, three helicopters will begin their complex task of retrieving Stardust's precious cargo. They will fly approximately 10 miles across the desert lakebed toward a UHF homing beacon emitted from the capsule. The first helicopter, flown by a commercial pilot, will lead the way; the second helicopter, a Blackhawk, will be flown by an Army Reserve pilot; and lastly, the third, flown by another commercial pilot, will bring up the rear of the helicopter fleet.

Accompanying the lead pilot will be UTTR's On-Scene Commander (OSCAR), as well as a safety specialist from Lockheed Martin, the aerospace corporation responsible for building the Stardust spacecraft. And in order to ensure the most efficient and safe retrieval of the capsule, the second helicopter will carry the recovery Operations Manager (RCO), a Science Co-Investigator (Co-I) and a curation representative and recovery specialist from Johnson Space Center (JSC).

Staggering their arrival to the landing site, the first helicopter's navigation will unveil the exact location of the capsule and will begin sweeping the SRC landing site with a spotlight to catch its reflection on the dark desert floor.

Once the helicopters set down, the team will then begin the process of preparing the SRC for its history-making analysis. First, a gas sample will be taken and stored for preliminary examination. Then, the SRC will be placed inside a handling fixture and double bagged to ensure that no Earthly materials touch the capsule and contaminate its contents. Then, the capsule will be flown to a prepared staging area cleanroom in a nearby hangar.

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Scientists Inspecting the Backup Aerogel Collector Grid

Just before entering the cleanroom, Lockheed Martin engineers, clad in "bunny suits" will remove the SRC from its double bags, and take two more gas samples from within the unopened capsule for further examination. Then, because the capsule is encased in thick SLA-561 ablator materials that protect it from the heat of reentry into Earth's atmosphere, the team will have to drill into these protective coatings to access and remove the 12 bolts from the backshell of the capsule.

This is the first time that the SRC will be opened after its ambitious encounter with Comet Wild 2 in 2004.

Deep inside the capsule is a canister that holds the samples--ancient comet and interstellar dust particles that could hold possible clues to the early origins of the Solar System. The canister loosely resembles an oversized tennis racket and contains cells filled with Aerogel-- a substance so light it almost floats in air. During the brief encounter with Comet Wild 2, the sample tray with the Aerogel cells was exposed to capture the prized particles, and then retracted into the canister for its long journey back to Earth.

With great anticipation, the team will then carefully remove the canister from the capsule.

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Scientists in the Cleanroom

Opening the Sample Return Canister

Stardust's Sample Return Canister will be opened at a curation facility at JSC in Houston, Texas. It is here where science will again make history as the very first pristine comet and interstellar dust samples will undergo extensive investigation and analysis.

The fine dust and rocks in comets are best studied on Earth where complex instruments can be used to fully study the materials at scales approaching atomic spatial resolution.

Working in the cleanroom, scientists will painstakingly activate and slowly open the canister, exposing the sample tray which holds the Aerogel and trapped particles.

As a precaution, team members are prepared to catch any Aerogel pieces that might have become loose during any part of Stardust's interstellar journey. The sample tray will then be secured to a stand, and the individual Aerogel capture cells will be removed from the sample tray with a cell-removal tool.

In order to minimize damage, each cell will be carefully removed and analyzed, paying particular attention to unique features, composition, size, and chemical properties. Each removed cell will be placed in an individually marked box.

The need for laboratory study of samples from the Solar System's most primitive bodies, was the inspiration for the NASA Stardust mission, the first NASA mission to return samples from space since the Apollo 17 Lunar mission in 1972.

These scientists will be the world's first to witness and analyze the fundamental building blocks of our Solar System and may be able to determine not only the origins of the Solar System from these samples, but also possibly the origins of life.