Re-Entry of Spacecraft Page 001

Uploaded on Jun 13, 2010

After traveling six billion kilometers in seven years, the Japanese space probe Hayabusa (meaning Peregrine Falcon) incinerated on re-entry after jettisoning a capsule expected to contain the first asteroid dust ever collected. The capsule parachuted to Earth near Woomera, the Australian Defence Force facility supporting the western world's largest defence systems test and evaluation range

Hayabusa, the $US200 million ($235.74 million) project launched in 2003, landed on the asteroid in 2005 and is believed to have collected samples of material from the surface that may shed light on the solar system's origin and evolution.
Scientists hope to study how and when the asteroid was formed, its physical properties, what other bodies it may have been in contact with, and how solar wind and radiation have affected it.

Hayabusa was originally due to return to Earth in 2007, but a series of technical glitches -- including a deterioration of its ion engines, broken control wheels, and the malfunctioning of batteries -- forced it to miss its window to manoeuvre into the Earth's orbit until this year.

If Hayabusa is indeed carrying asteroid samples, it would be only the fourth space sample return in history -- including moon matter collected by the Apollo missions, comet material by Stardust, and solar matter from the Genesis mission.

NASA Press Release below:

MOFFETT FIELD, Calif. -- A group of astronomers from NASA, the Japan Aerospace Exploration Agency (JAXA) and other organizations are flying to the other side of the world for a front row seat and a rare opportunity to study a spacecraft's targeted fiery descent through Earth's atmosphere.

A Douglas DC-8 airborne laboratory departed yesterday evening from NASA's Dryden Aircraft Operations Facility at Palmdale, Calif., carrying nearly 30 scientists and their instruments to Melbourne, Australia to make final preparations for the highly-anticipated return of JAXA's Hayabusa spacecraft. This luminous re-entry will mark the end of the spacecraft's seven-year journey to bring a sample of asteroid Itokawa back to Earth. Hayabusa is expected to fall to Earth over a vast, unpopulated area of Australia at approximately midnight locally, or 7 a.m. PDT, on Sunday, June 13, 2010. Earlier this week, JAXA announced it successfully completed the guidance of the Hayabusa spacecraft, so that it will land in the Woomera Prohibited Area in Australia.

"Hayabusa is hurtling toward Earth at an immense speed, comparable to that of an asteroid impact," said Peter Jenniskens, the observation campaign's principal investigator and a scientist at NASA's Ames Research Center, Moffett Field, Calif., and the SETI Institute, Mountain View, Calif. "The capsule that protects the asteroid sample will be only 6,500 feet ahead of the rest of the spacecraft, which will break into numerous pieces, essentially making it a man-made meteor."

Jenniskens and the team of astronomers onboard the DC-8 will have their instruments secured near the plane's specialized windows. This, paired with their altitude of 39,000 feet far above light pollution and clouds, will enable the scientists to study what happens when the spacecraft and sample return capsule heat up high in the atmosphere. When Hayabusa reaches an altitude of 190,000 feet, its heat shield will experience temperatures of more than 5,000 degrees Fahrenheit, while the gas surrounding the capsule will reach 13,000 degrees Fahrenheit - hotter than the surface of the sun.

The team's primary goal during the airborne mission is to study the Hayabusa capsule's re-entry to gain technological insight into the heat shield that designers and engineers can use while developing future exploration vehicles. Because of Hayabusa's unique heat shield material, shape and the tremendous interplanetary re-entry speed of 7.58 miles per second, scientists expect its descent will provide new, valuable information about heat shields for computer models of re-entry conditions. JAXA's Hayabusa is expected to be the second fastest man-made object to return to Earth; NASA's Stardust sample return capsule set the record re-entry speed of 7.95 miles per second in January 2006.

SOURCE: Wikipedia