The probe first visited Otokawa in 2005, but ran into some difficulty after a technical error in its hardware resulted in it being unable to communicate with Earth for an extended period of time. After a long period of held breaths and waiting to see if the satellite would be able to recover it is now heading back
to Earth with a possible interesting cargo in tow. Scientists are suggesting that if the probe was a success, it will be able to bring back material from the asteroid and give us a clear view of a sampling of its composition. Of course without any way to confirm if it actually acquired the sample from the asteroid, scientists will have to depend on its safe arrival back on Earth in order to confirm whether or not it contains pieces of Itokawa.
After a leak in the rocket engines emptied out the tanks, the Hayabusa was prepared and used its ion engine thrusters to carry it the rest of the way home. There was some doubt that an ion based engine would work, but the solar sails turned light into electricity, which was then turned into a stream of ions which propelled the craft forward to its destination, albeit far slower.
The second Trajectory Correction Maneuver successfully guided the spacecraft on a course for Earth's "outer rim." The hope is it will be able to move from that position to the Earth's surface and give us insight into the resources of a slow moving nearby asteroid.
But the entire vessel will not be entering Earth's atmosphere. As Jaxa officials explained, the only part that is necessary will be the "sample return capsule" which will be jettisoned from the craft before it enters the atmosphere. The probe will at this point have shed most of its original body and return to Earth with its mission accomplished after five long years. The touchdown of the craft was never captured on film, but it did so amid the mathematical estimations and sensors from Jaxa's ground control in 2005. And prior to its return mission it spent another two years actually getting from Earth to the asteroid. On May 09, 2003 the "Falcon" was launched from Kagoshima Space Center after years of planning and research. Clearly, this is the final stage in a great number of scientific achievements. And soon we will know if it actually paid off with a sample from an asteroid.
But even if it doesn't, the craft still made great discoveries from far off as it scanned the surface and studied it electronically. Ultimately, whether the Hayabusa was a success, it has already proven it was worth the funding based on the data it sent back. Now we just have to see if it is worth more.
