May 31, 2010

Japanese Asteroid Spacecraft On Its Way Home

The Hayabusa Japanese spacecraft, which is designed to return samples from an asteroid back to Earth, has completed an important step on its journey back.

The unmanned craft achieved the second and largest of four engine firings designed to guide the probe back home.

The probe visited the asteroid Itokawa in 2005 in order to capture soil during its journey.

However, the mission has been filled with technical glitches affecting the engines and communications with Earth.

It is still unclear whether the probe managed to grab material from Itokawa or not. 

The Japanese Space Agency (JAXA) said over the weekend that Hayabusa had successfully completed its second Trajectory Correction Maneuver (TCM), guiding the spacecraft to Earth's "outer rim."

According to JAXA, the craft is now about 4,700,000 miles from Earth, and is set to return on June 13.

At about 24,800 miles from our planet, the Hayabusa "mothership" will release its sample return capsule.

If the craft failed to pick up large samples from the asteroid, then the capsule may still contain some residues from Itokawa.

Researchers have already been able to study remote sensing data sent back to Earth by the spacecraft during its encounter with the asteroid.

Hayabusa was launched from the Kagoshima Space Center in Japan on May 9, 2003.

The spacecraft arrived on the asteroid in September 2005 and returned images of the potato-shaped asteroid's jagged terrain.

Hayabusa - which manes "Falcon" in Japanese - made two "touchdowns" designed to collect rocks and soil for return to Earth.  However, it apparently failed to fire a metal bullet designed to gather the samples.

Asteroids contain primordial material left over from the formation of the Solar System billions of years ago.

In 2005, a fuel leak left Hayabusa's chemical propellant tanks empty.  Because of this, engineers had to use the spacecraft's ion engines to guide the spacecraft home.

Ion thrusters have a low acceleration but are highly efficient.  This means that each trajectory correction takes much longer to complete than the typical chemical engines would.


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