Hayabusa Spots Asteroid Itokawa

http://www.isas.jaxa.jp/e/snews/2005...hayabusa.shtml

Hayabusa performed the Star Tracker imaging of Itokawa!
Japan Aeorospace Exploration Agency (JAXA)
August 15, 2005

For almost two years and three months after the launch in May of 2003,
Hayabusa spacecraft has traveled a long journey by way of Earth gravity
assist in May of 2004, and will make a world's first low thrust
rendezvous with a near-Earth asteroid Itokawa next month.

Hayabusa performed the Star Tracker imaging of Itokawa on July 29-30,
August 8-9 and August 12. Totally, 24 images were taken and the hybrid
navigation combining both radio and optical measurement was performed
and the results came out enough well to guide the spacecraft making a
final approach to the object. The optical navigation at very slow
approach speed under ion engines propulsion is what Hayabusa has
demonstrated for the first time. The exposure of Optical Navigation
Camera (ONC), a high resolution imager, is also planned one or two
weeks
later.

Hayabusa carries three reaction wheels aboard. There was an incident on
x-axis wheel, whose friction exceeded a driving torque on July 31 and
stopped. However, the spacecraft is designed equipped with
Double-Reaction-Wheel (DRW) mode software, and taking the advantage of
it, the spacecraft resumed the attitude stability and has been operated
normally. The project team is confident in accomplishing a series of
scientific observation including sample collection scheduled during the
proximity phase.

The spacecraft is, as of August 12th, at about 35,000 kilometer at the
very slow approach speed of 38 meters per second. This is peculiar to
the low thrust rendezvous that has not ever been experienced. The
spacecraft will turn off the ion engines at the distance of 3,500 km to
the object leaving intentional residual approach speed of 10 meters per
second that is scheduled decelerated via Reaction Control System
aboard.
And in the middle of September, Hayabusa comes to still with respect to
Itokawa at the distance of 20 km, Gate Position.

(This release is coordinated with NASA.)

1.Image of Asteroid Itokawa taken by HAYABUSA's Star Tracker #1
2.Predicted position and observed position of Asteroid Itokawa #2
3.Brightness of Asteroid Itokawa #3
4.The locus of Asteroid Itokawa #4

[Image}
1.Image of Asteroid Itokawa taken by HAYABUSA's Star Tracker
Image of Asteroid Itokawa

This shows the object conceived Itokawa moves amid stars and strongly
suggests this is not a star but a kind of planet.
The constellation over which the object is exposed is the Puppis
between
the Canis Major (Great Dog) and the Carina.
Itokawa may not be seen toward that direction from Earth, but seen via
radio toward the Sun, nearest of which Itokawa should be together with
Hayabusa spacecraft. Itokawa seen from Hayabusa has increased quite
rapidly its brightness up to the magnitude four.

[Chart]
2.Predicted position and observed position of Asteroid Itokawa

It draws loci of the Itokawa direction from Hayabusa. Where Itokawa was
exposed is plotted against the star map. Any object whose orbit
parameters are different from those of Itokawa should never have been
photographed. This simply indicates what is actually exposed is sure to
be the object we have sought so far, which is our target destination,
Itokawa.

Whenever the optical navigation is performed, the relative trajectory
has been updated and this process results in the loci corrected, so
that
the Itokawa direction should coincide with what was predicted. The
optical measurements were combined with the radio data obtained on the
ground. This sophisticated process is so called a hybrid navigation
technique. These results conclude we could successfully complete the
hybrid navigation task. The final portion of the locus was not
significantly corrected and this implies our predict has already been
enough accurate to guide the spacecraft to Itokawa.

[Chart]
3.Brightness of Asteroid Itokawa

The brightness intensity of the object conceived Itokawa is plotted
along with exposure time. The predict curve of it derives from the
shape
and rotation parameters determined last year, when Itokawa flew close
by
the Earth. It is of great importance to notice that this object's light
curve shows a beautiful fit for the predict. This indirectly proves
that
the object is Itokawa.

[Animation]
4.The locus of Asteroid Itokawa

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http://www.isas.jaxa.jp/e/snews/2005...hayabusa.shtml

Hayabusa performed the Star Tracker imaging of Itokawa!

translation about par with 60s era Japanese motorcyle owner's manuals!

translation about par with 60s era Japanese motorcyle owner's manuals!


I've seen worse. Here one could make sense of 98% of what they
wrote. I've seen some Japanese written English that is badly
garbled. And then there is English intended as decoration
(like on T shirts) and not to be read by an English speaker.

Seems that the Japanese education has a systemic set of errors
in their English language classes. And that noone wants to
lose face and own up to the problem....