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FROM A NASA/AMES PRESS
RELEASE
 July 31,
1999: Lunar Prospector, "the little spacecraft that
could," can't anymore. As a room full of viewers and observatories
from around the world looked on, the LP Mission Control team
successfully ended the Lunar Prospector mission at 2:52:00.8
a.m. PDT on July 31 when the spacecraft slammed into a deep crater
near the south pole of the moon.
Right: Artist Duane Hilton's rendering
of NASA's Lunar Prospector spacecraft.
No visible debris plume was reported and it may be several days
before data from ground- and space-based observatories and telescopes
can be analyzed to determine if any water vapor was liberated
by the impact.
For more science news and images from
Lunar Prospector visit
LunarImpact.com
Mission Control at NASA's Ames Research Center indicated that
they are confident the small, spin-stabilized spacecraft hit
its intended target precisely. The failure to reacquire a signal
from the vehicle at the time it would have emerged from the dark
side of the moon is proof that impact occurred. The absence of
a visible debris plume is not a negative result. In fact, it
increases the likelihood that the spacecraft impacted deep into
the intended target crater.
The final sequence of events for Prospector began at
1:17 a.m. PDT when the Mission Control team successfully loaded
a 60-minute pre-programmed countdown into Prospector's internal
clock to initiate the final burn sequence. At 2:00 a.m. PDT,
final loss of signal from Prospector occurred, as planned, when
the spacecraft passed behind the moon for the last time. Alan
Binder, Lunar Prospector Principal Investigator observed, "we
don't want to hear from Prospector again - if we do, we've missed
our mark." He was not to be disappointed.
The scheduled 4 minute 36.5 second burn was executed behind the
moon at 2:17 a.m. "Prospector's engines should be burning
full -- preparing to de-orbit," said Binder. "It is
now hurtling towards its destiny at approximately 1.7 kilometers
per second on a ballistic trajectory that will take it to its
target crater."
The spacecraft's key scientific instruments
continued to send data until the very end when signal was lost.
"Once again, Prospector has done everything we have asked
of it," said Binder. "This mission provided ten times
better data than we expected. The spacecraft performed flawlessly
to its very end. Scientists will be analyzing the tremendous
volume of valuable data obtained for years to come," he
concluded.
Analysis of data obtained during the mission-end experiment will
be ongoing for days, and possibly weeks, to come. At the completion
of that analysis, scientists will have a much better idea if
Prospector has, in fact, provided the definitive evidence of
water ice on the moon that they were seeking. A positive result
may have the potential to open up expanded possibilities for
solar system exploration. Failure to prove conclusively that
water ice exists in the lunar polar regions by no means suggests
that it is absent, according to mission scientists. It simply
means that this particular bold experiment, acknowledged as high
payoff but also with low probability of success, has not provided
the conclusive evidence that was being sought.
Please visit the Lunar Prospector
project web site from NASA/Ames and the Lunar
Prospector impact page from UT Austin for more information
about Lunar Prospector's crash into the Moon. See also: LunarImpact.com
for more science news and images.
Lunar Prospector was the first of NASA's competitively selected
"faster, better, cheaper" Discovery-class missions.
The $63 million mission is managed by NASA Ames Research Center,
Moffett Field, CA. |
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Web Links |
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Lunar
Prospector in Eclipse
-- The July 28, 1999 partial lunar eclipse poses a last-minute
threat to Lunar Prospector. , July 28, 1999, NASA Space Science
News
Bracing
for Impact
-- Astronomers prepare to observe the crash of Lunar Prospector
on July 31, 1999. Includes observing hints for amateurs, July
21, 1999, NASA Space Science News
Destined
for a Watery Grave
-- NASA scientists have decided to send Lunar Prospector crashing
into the Moon's south pole in search of water, June 4, 1999,
NASA Space Science News
Zeroing in on Lunar Ice -- Astronomers explore the
Lunar Prospector crash site using radar, June 4, 1999, NASA Space
Science News
Lunar Prospector set to make
science "splash"
-- NASA/Ames press release
NASA Press Release (3 September
1998) --
announcing enhanced estimate of quantity of water on the Moon
NASA Press Release (5 March
1998) --
announcing the detection of ice on the Moon
Lunar
Prospector Home Page
-- from NASA/Ames
Ice on the Moon -- informative article about
lunar water -- where it is and how to find it.
Lunar Prospects -- Astronomy Picture of the
Day, Sep. 18, 1998
Impact Moon -- Astronomy Picture of the
Day, Mar. 26, 1999
The Nine Planets: the Moon -- from SEDS
More
NASA Space Science News |
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