[meteorite-list] Hayabusa Begins Daring Close EncouterWithAsteroid

From: K. Ohtsuka <ohtsuka_at_meteoritecentral.com>
Date: Wed Sep 14 21:17:17 2005
Message-ID: <000a01c5b993$224e1200$347e76da_at_LocalHost>

P.S. Color composite images (but still looks like b/w image) of Itokawa are
released in Japanese page,
but not yet in English page.

 http://www.isas.ac.jp/j/snews/2005/0914.shtml

Katsu O.

----- Original Message -----
From: "K. Ohtsuka" <ohtsuka_at_jb3.so-net.ne.jp>
To: "Meteorite Mailing List" <meteorite-list_at_meteoritecentral.com>
Sent: Thursday, September 15, 2005 9:45 AM
Subject: Re: [meteorite-list] Hayabusa Begins Daring Close
EncouterWithAsteroid


> Hello Jeff-san
> You can find Itokawa's latest image(s) at the following site:
>
> http://www.isas.ac.jp/e/snews/index.shtml
>
> K. Ohtsuka, Tokyo Meteor Network
>
> ----- Original Message -----
> From: "Jeff Kuyken" <info_at_meteorites.com.au>
> To: "Ron Baalke" <baalke_at_zagami.jpl.nasa.gov>; "Meteorite Mailing List"
> <meteorite-list_at_meteoritecentral.com>
> Sent: Thursday, September 15, 2005 9:02 AM
> Subject: Re: [meteorite-list] Hayabusa Begins Daring Close Encouter
> WithAsteroid
>
>
> > Hi List,
> >
> > Does anyone have a link to images that Hayabusa is sending back?
> >
> > Thanks,
> >
> > Jeff
> >
> >
> > ----- Original Message -----
> > From: Ron Baalke
> > To: Meteorite Mailing List
> > Sent: Thursday, September 15, 2005 9:27 AM
> > Subject: [meteorite-list] Hayabusa Begins Daring Close Encouter With
> > Asteroid
> >
> > http://www.spaceflightnow.com/news/n0509/14hayabusa/
> >
> > Probe begins daring close encounter with asteroid
> > BY STEPHEN CLARK
> > SPACEFLIGHT NOW
> > September 12, 2005
> >
> > A $100 million Japanese space explorer parked in the vicinity of an
> > enigmatic asteroid this week, allowing scientists to get a first glimpse
> > of the mid-sized rock that will become the source of the first samples
> > of such an object to ever be returned to Earth.
> >
> > After methodically tweaking its course - first by electrical ion
> > propulsion, then by conventional chemical thrusters - toward its target
> > over the past few months, the Hayabusa probe finally arrived at its
> > station keeping position some 12 miles from the asteroid early Monday.
> >
> > Officials timed the arrival by when the 1,000-pound craft's closure rate
> > relative to the object reached zero, indicating the probe was now
> > essentially anchored in the "gate position" located about 12 miles from
> > the space rock. That moment occurred as the spacecraft commanded its
> > maneuvering jets to fire one last time at about 0117 GMT Monday, or in
> > the late-morning hours in Japan.
> >
> > Hayabusa's ion drive propulsion system took a the leading role for the
> > rendezvous up until August 28, when control switched to the
> > liquid-fueled chemical thrusters. That milestone left the four ion
> > engines with a cumulative burn time of almost 26,000 hours, and the
> > system will be re-started once the probe embarks on the last leg of its
> > journey back to Earth.
> >
> > The delicate space ballet took place almost 200 million miles from
> > controllers on Earth, who left responsibility for the rendezvous to an
> > on-board navigation system that is designed to operate without ground
> > intervention.
> >
> > The goal of the mission is to study asteroid 1998 SF36 - later named
> > Itokawa in honor of an early Japanese pioneer in rocketry. The object
> > was discovered in September 1998 by a joint team consisting of
> > scientists from the U.S. Air Force, NASA, and the Massachusetts
> > Institute of Technology.
> >
> > Details about Itokawa have largely remained elusive in the seven years
> > since its discovery, but scientists now have a much clearer picture of
> > the potato-shaped asteroid estimated to measure 2,000 feet by around 900
> > feet. Its orbit stretches from inside Earth's out to a distance of 157
> > million miles from the Sun, making it a member of the Apollo class of
> > near-Earth asteroids that pose potential impact threats to our planet.
> >
> > Astronomers studied Itokawa via several ground-based telescopes during
> > its last Earth fly-by in 2001, and they found evidence that the asteroid
> > was brighter and more reflective than first expected. Scientists had a
> > difficult time predicting what Hayabusa would find as it closed in on
> > the object, and many questions were left unanswered.
> >
> > However, many of those issues can now be thoroughly remedied with the
> > new higher resolution images Hayabusa's optical asteroid multi-band
> > imaging camera has captured. The pictures show a contrast of rocky and
> > hilly terrain with smooth regions, but detailed analysis and sample
> > retrieval will be conducted before scientists can announce the results
> > of their detailed study.
> >
> > A first look at the new images appears to show a loose layer of dust and
> > dirt-like material covering the smooth surfaces of parts of the
> > asteroid, which is a surprise to some project officials.
> >
> > "According to a certain theory, small objects do not have regolith,"
> > said Hayabusa project manager Jun Kawaguchi. "But this asteroid seems to
> > have smooth portions that appear (to have) some regolith."
> >
> > Work with Hayabusa's science payload has already begun, with the
> > near-infrared and X-ray spectrometers now gathering measurements. The
> > craft's laser altimeter is also conducting observations to learn more
> > details about Itokawa's terrain.
> >
> > The pair of spectrometers will labor to determine the elemental and
> > mineral composition of Itokawa to help astronomers in their quest to
> > link asteroids and comets to meteorites that have fallen to Earth and
> > been recovered.
> >
> > "The analysis has just started and no conclusive results (are) given
> > until the measurements are detailed and analyzed," Kawaguchi told
> > Spaceflight Now.
> >
> > "When we talk about the shape just from impression and not from a
> > scientific point of view, the shape apparently looks like an object
> > (with many) smaller objects united. And also apparently, a small
> > (object) and some other objects are accreted with a larger one. These
> > are not interpreted at all and definitely have to wait for detailed
> study."
> >
> > Hayabusa will have to occasionally refine its position relative to the
> > asteroid because the object's gravity is too weak to keep the craft in a
> > stable stationary position.
> >
> > Controllers plan to order Hayabusa to close further toward Itokawa at
> > the end of September, when more precise science activities are
> > scheduled. Once in the "home position" under five miles from the
> > asteroid, remote sensing observations will continue as the object
> > completes one rotation about every 12 hours.
> >
> > A goal of the remote sensing phase will also serve to choose up to three
> > sites that are scientifically interesting and safe enough to bring the
> > fragile spaceship to the surface for sample retrieval passes beginning
> > in November. During each approach, a 16-inch funnel aboard Hayabusa will
> > make contact with the asteroid, followed by the firing of a small metal
> > pellet into the rocky crust at hundreds of feet per second.
> >
> > Rubble and dust ejected from the high-speed impact will make their way
> > through the funnel and into a chamber designed to carry the samples on
> > the return trip to Earth and through the fiery re-entry into the
> > atmosphere. Officials expect up to one gram - or two one-thousandths of
> > a pound - of material will be gathered.
> >
> > It is expected that the ground team will eventually choose two sites for
> > sample runs, leaving a third as a rehearsal to test the operation and
> > feasibility of the plan.
> >
> > Also during the first pass, Hayabusa will deploy a tiny 1.3-pound rover
> > known as MINERVA, which will leap, hop, and jump across the surface in
> > the extreme low-gravity environment. MINERVA carries three stereo
> > cameras for pictures, and a suite of six thermometers to measure
> > temperatures.
> >
> > Hayabusa - formerly known as MUSES-C - was launched on May 9, 2003,
> > aboard an M-5 rocket from Japan's Kagoshima launch site. The spacecraft
> > flew past Earth a year later to receive a gravity boost that aimed
> > Hayabusa toward this year's encounter with Itokawa.
> >
> > Time spent in the vicinity of asteroid Itokawa was reduced by a 2003
> > solar flare that slightly damaged the ability of Hayabusa's two solar
> > panels to produce electricity, which is vital to the operation of the
> > craft's primary ion propulsion system. The degradation caused the four
> > ion drive engines to produce less total thrust with less operating time,
> > delaying arrival from mid-summer until now.
> >
> > Plans call for Hayabusa to depart Itokawa in early December to begin its
> > trek back to Earth, culminating with a homecoming in June of 2007 by way
> > of parachuted landing at Woomera in the Australian outback.
> >
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Received on Wed 14 Sep 2005 09:16:43 PM PDT