On 13 June, the Japan Aerospace Exploration Agency’s (JAXA’s) Hayabusa mission will re-enter the Earth’s atmosphere and parachute down to land in the Woomera Prohibited Area, Australia. Only once it has been recovered will mission scientists be able to tell if it has successfully returned a sample of asteroid Itokawa.
Launched in 2003, Hayabusa was already something of a marvel. Powered by ground-breaking Ion engines, the probe was to rendezvous with Itokawa in 2005, then land, scoop up samples and return to Earth. Unfortunately, the little probe suffered disaster after disaster and it is a miracle that it has continued to operate after so many setbacks.
First, a solar flare damaged the Solar panels, reducing the electrical power available to run onboard systems. Then, while attempting to land on Itokawa, one of the manoeuvring thrusters was damaged, leading to almost complete failure of guidance systems. Having regained control by using the solar panels as Solar Sails, the ion engines began failing. Now, with only one of the four engines remaining and a primitive makeshift navigation system in place, Hayabusa is finally limping home almost three years late.
The plucky little probe’s survival is a credit to the Japanese space program, and we can look forward to seeing what science is revealed when the samples are retrieved.
The Planetary Society has more information here: http://www.planetary.org/blog/article/00002450/