The Lunar Crater Observation and Sensing Satellite, or LCROSS,
successfully completed its most significant early mission milestone on
23 June with a lunar swingby and calibration of its science
instruments. The satellite will soon be searching for water ice in a
permanently shadowed crater at the moon's south pole. With the help of
the moon's gravity, LCROSS and its attached Centaur booster rocket
successfully entered into polar Earth orbit at 6:20 a.m. PDT on June
23. The maneuver puts the spacecraft and Centaur on course for a pair
of impacts near the moon's south pole on October 9.
"The
successful completion of the LCROSS swingby proves the science
instruments are functioning as expected. It is a testament to the hard
work and dedication of the entire team" said
Dan Andrews, LCROSS
project manager at NASA's Ames Research Center at Moffett Field, Calif.
"We are elated at the results from the maneuver and eagerly anticipate
the impacts in early October."
(photo at left: Daniel Andrews, LCROSS project manager at Ames Research Center; courtesy of NASA)During
its swing by the moon, the spacecraft's instruments were turned on and
calibrated by scanning three sites on the lunar surface. These sites
were the craters Mendeleev, Goddard C and Giordano Bruno. They were
selected because they offer a variety of terrain types, compositions
and illumination conditions. The spacecraft also scanned the lunar
horizon to confirm its instruments are aligned in preparation for
observing the Centaur's debris plume.
"Each instrument returned
good data that the science team will spend the next few weeks
analyzing," said
Anthony Colaprete, LCROSS project scientist at Ames.
"These data will ensure we are as prepared as possible for monitoring
and interpreting data we receive during impact."
LCROSS and
its attached Centaur upper stage rocket are now in a long, looping
polar orbit around Earth and the moon. Each orbit will be roughly
perpendicular to the moon's orbit around Earth and take about 37 days
to complete. Before impact, the spacecraft and Centaur will make
approximately three orbits.
LCROSS and the Centaur separately
will collide with the moon on October 9, creating a pair of debris
plumes that will be analyzed for the presence of water ice or water
vapor, hydrocarbons and hydrated materials. The spacecraft and Centaur
are targeted to impact the moon's south pole near the Cabeus region.
The exact target crater will be identified 30 days before impact, after
considering information collected by NASA's Lunar Reconnaissance
Orbiter and observatories on Earth.
Nine hours before impact,
about 54,000 miles above the surface, LCROSS and the Centaur will
separate. LCROSS will spin 180 degrees to turn its science payload
toward the moon and fire thrusters to create distance from the Centaur.
The spacecraft will observe the flash from the Centaur's impact and fly
through the debris plume. Data will be collected and streamed to Earth
for analysis. Four minutes later, LCROSS also will impact, creating a
second debris plume.
The LCROSS mission is providing mission
updates on Twitter at:
http://www.twitter.com/lcross_nasa. For more
information about NASA's LCROSS mission, visit:
http://www.nasa.gov/lcross.