Japanese probe pulls alongside asteroid

I didn't even know Japan was doing this kind of mission! Well, fingers crossed!

Bringing Japan's most complex space mission near its climax, a probe is within 12 miles of an asteroid almost 180 million miles from Earth in an unprecedented rendezvous designed to retrieve rocks from its surface.

The Hayabusa probe, launched in May 2003, will hover around the asteroid for about three months before making its brief landing to recover the samples in early November. The asteroid is located between Earth and Mars.

Full story here

Seanie.

The space probe Hayabusa has finished an exciting excursion around the asteroid Itokawa. The spacecraft position during the latter half of
October. see www.isas.jaxa.jp/e/snews/2005/0929.shtml .


After reaching the sub-solar point
www.isas.jaxa.jp/e/snews/2005/1027_itokawa.shtml , Hayabusa
started to travel out of the ecliptic plane to observe the polar
regions of Itokawa. One of the images shows the southern hemisphere of Itokawa.


Due to the low altitude and solar elevation angles, there is detailed
topography in the high-latitude regions. There are boulders on
Muses-Sea see: www.isas.jaxa.jp/e/snews/2005/0922_itokawa.shtml ,
which looked very smooth in previous observations.

Imagine one of these boulders flying in space. If it came to the Earth's vicinity, we would observe it as a tiny independent near-Earth asteroid.

It has long been conjectured that meteorites are fragments of asteroids delivered to the Earth's surface, but it remains to be proven. The samples of Itokawa collected and returned by Hayabusa could provide the first direct evidence of the link between asteroids and meteorites.

Eamonn A

They're great images Eamonn.

Do you know if the engineers have figured out a workaround to the problem the probe suffered. I can't remember exactly what it was... But it involved limiting its fuel supply so it could make it back to Earth...

Dave

So far the project looks positive for touchdown and flyback to Earth.

Current Status of Hayabusa and Events Scheduled in November.

Hayabusa arrived at the target asteroid Itokawa on September 12th
of this year and performed detailed scientific observation so far by
varying its relative position around Itokawa.

Hayabusa carried two reaction wheels, were lost on
July 31st and October 3rd, and its attitude has been maintained by a
single wheel together with the chemical engines aboard, while the
spacecraft has been operated normally.

In order that the flight can be carried out and completed until the
return to the Earth, the fuel consumption required for stabilizing the
attitude has to be reduced, and a strenuous effort has been poured to
devise the strategy including a number of firing tests in vacuum on the
ground. A new control scheme making the firing impulse enough small has
now been developed assuring the attitude control resolution to be well
managed. This assures the fuel amount required is adequate within that
remains. The on-orbit function test was already conducted and it was
verified functioning by the actual flight hardware and software aboard.
The Hayabusa project team will conclude the flight operation until the
return to the Earth is feasibly performed, as long as the existing
instruments and hardware aboard continue working normally as they are.

The proximity operation assumed in November consists of one
Rehearsal Descent plus two Touching-downs for sampling. They are
scheduled as follows:

1. Rehearsal Descent November 4th,
2. 1st Touching-down for sampling November 12th,
3. 2nd Touching-down for sampling November 25th.

There are several Rehearsal and Touching-down sites candidates.

Eamonn A

Does it have imaging capabilities?

Deirdre Kelleghan
IAS
www.irishastrosoc.org

Deirdre,

Hayabusa has a camera on board and succeeded in observing the 'Opposition Surge' a few days ago. One interesting characteristic of the image recorded at a phase angle of <1 degree is the patchy nature of the bright spots across the topography of (25143) Itokawa.

Normally observations of the opposition effect for asteroids are
disk-averages since the surface features are not resolved. [Not sure how
low phase-angle observations of this object compare with NEAR-Shoemaker's of (433) Eros.] In this case we get the chance to see something special.

It may be that the surface regolith of Itokawa varies depending on location
such that different areas have markedly different multiple light-scattering
properties: another form of surface differentiation to watch out for. Why
this should happen is of interest and may indicate that the surface is
relatively young such that space-weathering has not yet given it an even
texture. Alternatively, could be that pools of dust that sink into or are
shaken into hollows have much finer structure / interstices than the
regolith on the 'higher' ground.

The appearance of Itokawa captured at very low phase-angle is unusual.

Eamonn A