[meteorite-list] NEAR Shoemaker To Land On Eros On February 12

From: E.P. Grondine <epgrondine_at_meteoritecentral.com>
Date: Thu Apr 22 09:41:53 2004
Message-ID: <20010103201333.38578.qmail_at_web11601.mail.yahoo.com>

Hi -

    Any idea why they're making the "landing" now?
 Could this spacecraft continue to be operated,
returning more data, or is it nearing the end of its
consumables?

EP

--- Ron Baalke <baalke_at_zagami.jpl.nasa.gov> wrote:
>
>
>
http://www.space.com/scienceastronomy/solarsystem/near_landing_010103.html
>
> Asteroid Landing Draws Near
> By Leonard David
> space.com
> 02 January 2001
>
> WASHINGTON -- NASA has okayed a February 12
> controlled descent of the Near
> Earth Asteroid Rendezvous (NEAR) spacecraft onto the
> dust-laden, cratered
> and boulder-strewn surface of Asteroid 433 Eros.
>
> Ground controllers hope to fire spacecraft engines
> just prior to hitting the
> space rock, perhaps allowing NEAR to briefly bounce
> off Eros, relay
> last-minute science data, then plop itself down at a
> final resting spot.
>
> The spectacularly successful NEAR Shoemaker probe
> has been orbiting Eros
> since February 14, 2000. Since it began looping the
> tumbling space rock
> almost a year ago -- at a range of high and low
> altitudes over Eros -- the
> craft has amassed an asteroid photo gallery made up
> of 150,000 snapshots.
>
> Later this month, NEAR is set to make daring flybys
> of Eros. Pictures
> clicked during the maneuvers will show the greatest
> detail to date of
> various features on the celestial hunk.
>
> Downtime
>
> "Everything continues to go swimmingly," said Robert
> Farquhar, NEAR mission
> manager at the Johns Hopkins University Applied
> Physics Laboratory (APL) in
> Laurel, Maryland. "Right now, NEAR is doing just
> fine," he told SPACE.com.
>
> APL designed, built and is managing the NEAR mission
> for NASA.
>
> Now being orchestrated is a progression of
> low-altitude flybys of Eros by
> NEAR.
>
> The spacecraft is set to zoom down between January
> 24 and 28, skimming over
> the ends of the asteroid as it somersaults through
> space. NEAR may get as
> close as about 1.6 miles (2.5 kilometers) above the
> asteroid's surface,
> Farquhar said.
>
> Last October, NEAR whisked by Eros at approximately
> 3 miles (5.3 kilometers)
> above its surface, shooting over the asteroid at
> about 14 miles per hour (6
> meters per second).
>
> "What we have seen so far in the low orbits has
> merely whetted our appetite
> for more," said Andrew Cheng, NEAR project scientist
> at APL. "We went up
> close to have a better look at the surface than ever
> before, but we now see
> things we do not understand, and we need more
> information," Cheng said.
>
> Swoop and bounce
>
> NEAR's finale on February 12, swooping down and
> striking Eros, should give
> scientists photos that are 10 times better in
> resolution than anything
> received. Images from only 1,640 feet (500 meters)
> above the asteroid's
> surface are expected.
>
> By firing NEAR's rocket engines just before making
> asteroid contact, at a
> speed of 7 miles per hour (3 meters per second), the
> craft may hit, then
> bounce off Eros. Spacecraft cameras are to be busy
> during the risky
> controlled landing, the world's first touchdown on
> an asteroid.
>
> "But the uncertainty is pretty large. Who knows what
> NEAR will do," Farquhar
> said. "Even if it's a crash landing...it's a first
> landing," he said.
>
> NEAR was not built to be a lander. The spacecraft's
> set of delicate solar
> arrays and other hardware will likely succumb to any
> hard-hitting arrival.
>
> Surface surprises
>
> Scott Murchie, NEAR science team member at APL, said
> that landing on Eros is
> gravy, contrasted to the rich bounty of data already
> gleaned.
>
> "To be honest, with 150,000 images, nobody has had
> the chance to look at all
> of them in detail. We're constantly going back and
> discovering interesting
> details in images that we've taken months ago,"
> Murchie said.
>
> That in-depth survey of Eros has revealed numbers of
> surprises.
>
> "One thing we've found is that the surface layer is
> unexpectedly complex,"
> Murchie said. That surface covering, called
> regolith, is not dotted with as
> many smaller craters as expected, he said.
>
> Furthermore, the regolith appears relatively mobile,
> Murchie said, moving
> about like a fluid and has "ponded" in certain
> areas. "So there's a
> complicated geological story in the very small-scale
> surface features," he
> said.
>
> For Cheng, having more mysteries than answers simply
> means more work ahead.
>
> "Perhaps it will not be us, but some future
> scientists, who will unravel
> some of the mysteries we are studying. In any case,
> we are working hard to
> understand the surface of Eros," Cheng said.
>
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Received on Wed 03 Jan 2001 03:13:33 PM PST