Larry Klaes (
Wed, 02 Jun 1999 15:28:39 -0400

>Resent-Date: Wed, 2 Jun 1999 09:48:54 -0700 (PDT) >Date: Wed, 2 Jun 1999 09:48:14 -0700 (PDT) >To: >From: John Bluck <> >Subject: news release - LUNAR PROSPECTOR SET TO MAKE SCIENCE "SPLASH" >Resent-From: >X-Mailing-List: <> archive/latest/201 >X-Loop: >Resent-Sender: > >June 2, 1999 >David Morse >NASA Ames Research Center, Moffett Field, CA >(Phone: 650/604-4724) > > >RELEASE: 99-36AR > >LUNAR PROSPECTOR SET TO MAKE SCIENCE "SPLASH" > >The mission of NASA's Lunar Prospector will end on July 31, 1999, when >ground controllers attempt to direct the spacecraft to impact the surface >of the Moon inside a permanently shadowed crater near the lunar south pole. > >This effort to gain additional science data about the Moon's composition >was proposed to NASA by an external team of scientists led by Dr. David >Goldstein of the University of Texas in Austin. Although the Lunar >Prospector spacecraft will weigh only 354 pounds (161 kilograms) at mission >end, the energy at impact will be the equivalent of crashing a two-ton car >at more than 1,100 miles per hour. > >Scientists hope that the direct impact into a lunar crater will liberate up >to 40 pounds of water vapor that may be detectable from ground- and >space-based observatories. A positive detection of water vapor or its >byproduct, OH, would provide definitive proof of what some scientists have >long suspected -- the presence of water ice in the lunar polar regions. > >"While the probability of success for such a bold undertaking is low, the >potential science payoff is tremendous," said Dr. Guenter Riegler, Director >of the Research Program Management Division in the Office of Space Science >at NASA Headquarters, Washington, DC. > >"External peer reviews of this plan have been very favorable, and we have >concluded that it is both technically and operationally feasible," Riegler >said. "Since the implementation costs are minimal and the mission is >scheduled to end anyway, it seems fitting to give Lunar Prospector the >chance to provide scientific data right up to the very end of its highly >successful mission." > >Lunar Prospector was launched on Jan. 6, 1998, with a one-year primary and >six-month extended mission to explore the lunar surface remotely. In March >1998, mission scientists announced that science instruments aboard Lunar >Prospector had detected sufficiently large quantities of hydrogen at the >lunar poles to infer the presence of water ice. In September, scientists >estimated that up to six billion metric tons of water ice may be buried in >the permanently shadowed craters of the Moon's poles. > >-more- > >-2- > >The current plan calls for a controlled impact of the Lunar Prospector >spacecraft in the early morning hours of July 31 directly into the Mawson >crater, located at the southern lunar pole. This crater is ideal for the >proposed experiment. It is only 31 to 38 miles (50 to 60 kilometers) across >and has a rim which is high enough to provide a permanent shadow, yet it is >low enough to provide for a suitable spacecraft impact trajectory. Data >from other observations suggest that the crater could contain a high >concentration of water ice. Finally, the crater is observable at impact >time from Earth-based observatories and orbiting platforms. > >"A positive spectral detection of water vapor or its photo-dissociated >byproduct, OH, would provide definite proof of the presence of water ice in >the lunar regolith," Goldstein said. However, scientists warn that the >failure to observe the desired signal does not mean that water ice is not >present. The model could be wrong, the spacecraft may not impact the >desired region or the impact energy may be insufficient to liberate an >observable plume of water vapor or OH. The overall probability of success >is estimated to be about 10 percent. > >Observing time has been granted at the University of Texas McDonald >Observatory and on the Hubble Space Telescope. It is also being sought at >other sites from which the Moon is clearly visible in the early morning >hours of July 31. > >Goldstein and his team will present a detailed description of their >proposal in the June 15 issue of "Geophysical Research Letters." > >Further information about Lunar Prospector can be obtained at the project >website at: > > >Lunar Prospector was the first of NASA's Discovery class of "faster, >better, cheaper" space exploration missions. The $63 million mission is >managed by NASA Ames Research Center, Moffett Field, CA. > > > -- end -- > > To receive Ames press releases via email, send an email with the >word "subscribe" in subject line to: > >To unsubscribe, send an email to: >with "unsubscribe" in subject line. Also, the NASA Ames Public Affairs >Home Page at URL, includes press releases and >JPEG images in AP Leaf Desk format minus embedded captions. > > > > > > >---- >John Bluck >Information Systems Liaison (Public Affairs) >NASA Ames Office of External Affairs >(voice 650-604-5026) (fax 650-604-3953) >Mail stop 204-12, email: >Moffett Field, CA, USA 94035-1000 >---- > > >

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