[meteorite-list] Crap. Hayabusa lander misses.

From: Darren Garrison <cynapse_at_meteoritecentral.com>
Date: Sat Nov 12 14:25:31 2005
Message-ID: <bigcn1h1gnekaenf2i8s28tr540emeqif6_at_4ax.com>

http://www.msnbc.msn.com/id/10013920/

Asteroid-hopping robot misses its mark
MINERVA mini-probe floats in space; Hayabusa mothership is safe

By James Oberg
NBC News space analyst
Special to MSNBC
Updated: 1:45 p.m. ET Nov. 12, 2005


Japan's Hayabusa probe successfully performed a close approach to the surface of the asteroid
Itokawa on Saturday, clearing the way for an attempt to land and retrieve soil samples next week.

"We performed the touchdown test with success," mission managers reported on the Web site of the
Japan Aerospace Exploration Agency, or JAXA.

However, Japan's Kyodo news agency quoted space officials as saying that an attempt to send a
mini-robot called MINERVA to the asteroid's surface met with failure.

The 1.3 pound (600-gram) MINERVA, whose name stands for Micro/Nano Experimental Robot Vehicle for
Asteroid, was designed to hop gently across Itokawa's surface. Three small TV cameras were supposed
to take pictures, while temperature sensors would have provided insight into the texture of the
soil.

The hopper robot was deployed at 3:24 p.m. Japan time, from a distance of about 180 feet (55
meters). Hayabusa ?was able to establish radio contact with the free-flying MINERVA,? according to
the JAXA report. But at the later update, officials said the small probe was now expected to drift
away from Itokawa and not fall to the surface as planned. Its batteries are expected to be exhausted
in a day or two.

Meanwhile, the Hayabusa mothership has safely returned to its home position, about 4 miles (6.4
kilometers) distant from the asteroid.

Delicate maneuvers
Preliminary indications pointed to a problem with the delicate maneuvers behind MINERVA's
deployment.

While awaiting the ground command to deploy MINERVA, the Hayabusa mothership was under autopilot
control to maintain a set distance above the surface. As it drifted up or down to a range limit,
Hayabusa fired small gas thrusters to stay within the designated interval.

According to Junichiro Kawaguchi, a JAXA scientist, the deployment command happened to arrive at
Itokawa during a period when Hayabusa was drifting away from the surface. Since the escape velocity
associated with the asteroid's faint gravitational pull is so small ? about one-half of a mile per
hour (20 centimeters per second) ? MINERVA was sent on a flight path that took it away from the
asteroid.

Kyodo quoted Kawaguchi as saying the mission team tried to make sure that the deployment signal
would arrive while Hayabusa was descending. For some reason, this did not work.

The asteroid is currently falling inward toward the sun and is crossing Earth?s orbital path, but on
the far side of the sun. At that range (about 180 million miles or 290 million kilometers), the
travel time for a radio message is 16 minutes each way.

"It is very disappointing that it did not work out nicely," Kawaguchi was quoted as saying. "We
found out various things about the asteroid, so we will study the data and hope it will lead to the
successful landing of Hayabusa [on Nov. 19]."


The sample retrieval has always been the main scientific thrust of the project, and observers
believe that the disappointment surrounding MINERVA may actually help contribute to a better
understanding of the challenge of landing the entire spacecraft successfully next week.

?The apparent loss of Minerva is a disappointment,? Louis Friedman, executive director of the
California-based Planetary Society, said in an e-mail message to MSNBC.com, ?but it in no way
diminishes the admirable mission that JAXA carried out. They are doing something that no one else
has tried in space; and the achievements of rendezvous engineering and close-up science are already
truly remarkable.?

NBC News space analyst James Oberg spent 22 years at NASA's Johnson Space Center as a Mission
Control operator and an orbital designer.

? 2005 MSNBC Interactive
? 2005 MSNBC.com
Received on Sat 12 Nov 2005 02:29:31 PM PST