Samples of the 500m (1,630ft)-wide Itokawa asteroid were collected by the Japan Aerospace Exploration Agency’s (JAXA) $170 million Hayabusa probe on 25 November, but its planned return to Earth could be jeopardised by a thruster leak, writes Tim Furniss.
Launched on Japan’s three-stage M-V solid fuel rocket from JAXA’s Kagoshima launch site on 9 May 2003, the spacecraft landed for the second time at 22:07 GMT on 25 November (07:00 Japan Standard Time on 26 November) and fired a 5g (0.176oz) metal ball into Itokawa’s surface at a speed of 1,850kt (1,000km/h).
This created a small cloud of material, which was collected in a re-entry capsule on the main craft. In June 2007 at about 200,000km (124,000 miles) from Earth, that capsule will be released and enter the atmosphere directly at a speed of 2.3 million ft/min (12km/s), landing in the Australian outback.
The probe has had a propellant leak from a thruster since its second launch from the asteroid. A lack of fuel or inability to achieve the correct attitude could jeopardise the return flight, expected to begin in December.
The spacecraft reached the asteroid on 12 November, but did not make its first landing for a further week. The first touchdown occurred at about 21:00 GMT on 19 November when Hayabusa bounced twice, came to a stop for about 30min, and then took off.
The spacecraft also attempted to drop a 600g micro-rover, called Minerva, on to Itokawa. This was to have used an internal weight to move itself across Itokawa’s surface while taking pictures and measuring the temperature. But Minerva was released at the wrong time and missed the asteroid.
Hayabusa is the world’s first probe to land on an asteroid and take off again.
Source: Flight International
