Hayabusa (MUSES-C)
The first sample-return mission to an asteroid.
This Japanese spacecraft was launched by ISAS
(Institute of Space and Astronautical Science) on May 9, 2003 and used solar-electric
propulsion to rendezvous with asteroid Itokawa
(1998 SF36) in September 2005. Hayabusa ("peregrine falcon") –
previously known as MUSES-C – "parked" about 20 km away
from its target on Sep. 12 and immediately began mapping and carrying out
measurements to determine the asteroid's surface composition. For several
weeks it relied on autonomous navigation and guidance while its optical
navigation camera, lidar, laser range finder, and fan-beam sensors gathered
topographic and range information about the object's surface. At the end
of September, it approached to about 7 km from the 630-meter-long asteroid
and made a more detailed map. After building a three-dimensional model of
the asteroid during this mapping phase, the Hayabusa project team decided
on suitable sites for surface exploration. Minerva mini-lander
During its initial descent to the surface in November 2005 (see below),
Hayabusa deployed a coffee-can-sized mini-lander named Minerva, which weighs
a mere 519 grams. Taking advantage of the very low gravity at Itokawa, this
solar-powered, box-shaped vehicle was intended to hop along the surface
of the asteroid, relaying images from its cameras to Hayabusa whenever the
two spacecraft were in sight of each other. Minerva was intended to become
the first successful "space hopper". Sample collection
and return
To capture samples, Hayabusa was meant to utilize a fabric horn. In November
2005, the spacecraft descended toward the asteroid and briefly (for just
a second or so) allowed the cone to make contact with the surface. On each
occasion, a small pyrotechnic charge fired a bullet into the surface at
300 m/s and fragments of the impact were intended to be captured by the
horn and funneled into a sample container. On each of the sampling attempts
the spacecraft began its approach at some distance from the asteroid, moved
in to collect the sample, and then backed off to the same distance. The
samples, with a total mass of about one gram, were to have been held inside
a separate reentry capsule.
After a few months exploring Itokawa, the spacecraft was meant to fire its
engines to begin its cruise back to Earth. In the final phase of the mission,
the reentry capsule is intended to be detached from the main spacecraft
at a distance of 300,000 to 400,000 km from the Earth and then coast on
a ballistic trajectory, reentering the Earth's atmosphere in July 2007.
All being well, the capsule and its tiny cargo was to have landed via parachute
near Woomera, Australia.
Latest news
Mar. 8, 2006: Contact with Hayabusa, which
had been lost in Decemeber 2005, is restored. Uncertainty remains, however,
over whether the probe will be able to return to Earth and whether it captured
samples of the asteroid as intended. Sep. 13, 2005:
Hayabusa successfully approached to within 20 km (12 miles) of Itokawa to
begin the initial observing phase. (See entry on Itokawa
for photos of the asteroid). Related entry
comet
and asteroid missions Related categories
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