[meteorite-list] Hayabusa Heads Back to Earth

From: Walter Branch <waltbranch_at_meteoritecentral.com>
Date: Thu, 5 Feb 2009 18:22:42 -0500
Message-ID: <F4A4F776048A4C44B1E11A7ECE7BC882_at_walterdesktop>

>because the system was disarmed.

WHAT! The system was disarmed?

You mean someone actually forgot to arm the system before firing the pellet!

Am I reading this correctly?

Wouldn't it be funny if after the probe is recovered and any samples are
analyzed it is determined that
they exactly match the soil from the Australian outback (picture the thing
firing on impact).

Sort of like one of the early US unmanned probes (can't remember if it was
one of the Pioneer or Explorer series, or maybe Vanguard) that failed to
launch. It rose a few inches then settled back down onto the launch pad
(one part of a two part plug was shorter then the other) but the automatic
sequencer dutifully ejected the probe from the top of the rocket and it flew
through the air and went rolling into the bushes near the launch pad.

It was a little humorous until someone realized that a fully fueled rocket
was sitting on the launch pad with a parachute hanging from the top,
billowing in the wind.

Duh.

-Walter Branch

-----------------------------------------------------
----- Original Message -----
From: "Ron Baalke" <baalke at zagami.jpl.nasa.gov>
To: "Meteorite Mailing List" <meteorite-list at meteoritecentral.com>
Sent: Thursday, February 05, 2009 3:59 PM
Subject: [meteorite-list] Hayabusa Heads Back to Earth


>
> http://www.spaceflightnow.com/news/n0902/05hayabusa/
>
> Asteroid sampler spacecraft heads back to planet Earth
> BY STEPHEN CLARK
> SPACEFLIGHT NOW
> February 5, 2009
>
> Japan's Hayabusa probe, potentially loaded with the first rock samples
> from an asteroid, fired up one of its ion engines Wednesday to begin the
> second phase of the explorer's return voyage to Earth.
>
> Hayabusa ignited a single ion engine at 0235 GMT Wednesday to begin
> pulsing for up to 8,000 hours to finish guiding the spacecraft toward
> Earth, according to the Japan Aerospace Exploration Agency, or JAXA.
>
> The spacecraft's ion propulsion system has already completed than 31,000
> hours of operations since its launch in 2003.
>
> The probe carries four ion engines, but engineers believe some of the
> devices are not capable of long-duration firings. Officials designed a
> taxing return trajectory using a single engine to reduce the odds of a
> major failure.
>
> Despite the hard work of several dozen engineers, Hayabusa still faces
> more hurdles before making its scheduled parachuted landing in Australia
> in June 2010.
>
> "We are not so optimistic, but not so pessimistic," said Makoto
> Yoshikawa, Hayabusa project scientist.
>
> Officials said the ion engine must accelerate Hayabusa by nearly 900 mph
> by March 2010, when engineers will turn off the machine to begin the
> probe's final approach to Earth.
>
> "If the current status of Hayabusa (remains) until the final stage, we
> are sure that it will come back to the Earth," Yoshikawa said.
>
> The spacecraft still has enough xenon gas to power the ion engine and
> control its orientation in space, according to JAXA.
>
> "We are continuing to pay careful attention to our onboard equipment and
> are doing our utmost to operate the Hayabusa with the greatest care,"
> officials said in a statement.
>
> The craft's ion engines use microwave discharge to ionize xenon gas and
> accelerate the plasma to high speeds. The highly-efficient engines
> produce little thrust, but the devices can operate for months to propel
> the spacecraft across the solar system using small amounts of fuel.
>
> Hayabusa completed the first round of return trip ion engine operations
> in October 2007 after a burn lasting about four months.
>
> The mission's ground team refined operations plans since 2007 to
> increase the odds of Hayabusa's successful return, according to Yoshikawa.
>
> Scientists also devised methods to find Hayabusa's entry capsule after
> landing and created plans to transport the sample canister from
> Australia to a specially-outfitted science lab in Japan, Yoshikawa said.
>
> The science team is currently testing the mission's curation facility
> and discussing how to analyze asteroid samples returned by Hayabusa.
>
> But officials still are not sure if the 950-pound probe is actually
> carrying the priceless samples.
>
> Hayabusa spent three months near asteroid Itokawa in late 2005, studying
> the space rock and attempting a series of close approaches to collect
> bits of rock and dirt.
>
> A pellet was supposed to be fired into the surface of Itokawa to force
> the rocks through a funnel to guide the precious samples into a
> container for the voyage back to Earth.
>
> Those plans did not materialize in November 2005 and Hayabusa spent up
> to 30 minutes on the asteroid's surface during a failed retrieval
> attempt. Officials later reviewed telemetry data from a subsequent
> attempt and determined the pellet likely did not fire because the system
> was disarmed.
>
> Scientists hope some particles were funneled into the collection
> chamber, even if the pellet did not fire as planned.
>
> Engineers were forced to postpone the start of Hayabusa's return trip by
> a year after the mission was struck by a fuel leak and communications
> problems.
>
> Controllers labored to overcome the issues, which were compounded by the
> loss of two orientation-controlling reaction wheels and power cells in
> an electrical battery.
>
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Received on Thu 05 Feb 2009 06:22:42 PM PST


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