Two NASA Lunar Spacecraft Operating Well; Poised For Moon-Mapping And Lunar-Crash Missions
Lunar Impacts Set For Oct. 9
Two NASA spacecraft are healthy and ramping up their systems, poised for pioneering lunar missions that will net key information for future manned U.S. explorations and settlements on the moon.
One craft is the Lunar Reconnaissance Orbiter, or LRO, while the other is the Lunar Crater Observation and Sensing Satellite, or LCROSS.
They will perform functions ranging from mapping the moon, examining it for the best landing sites for manned missions, and to find frozen water, focusing on a permanently shadowed crater at the moon’s south pole.
Water is more valuable than gold for any extended human presence on the moon or another planet, because water, the universal solvent, is also the universal sustainer of life.
By itself, water provides drinking water for astronauts and irrigation for growing crops. (Bringing the enormous weight of a two-year supply of food to, say, Mars would be highly impractical.)
Further, water is H2O, hydrogen and oxygen. That means oxygen to breathe for astronauts, and for crops. And the hydrogen provides fuel for heating homes and offices in a lunar encampment, and for powering moon buggies for astronauts to tour the lunar landscape. Further, hydrogen can be fuel for electrical power generation critical to light, communications, computers and more. And the best part of any water on the moon is that NASA doesn’t have to buy rockets to move even one ounce of aqua from Earth to the pale orb.
After a four and a half day journey from the Earth, the LRO entered orbit around the moon. Engineers at Goddard Space Flight Center in Greenbelt, Md., confirmed the spacecraft’s lunar orbit insertion at 6:27 a.m. ET Tuesday.
During transit to the moon, engineers performed a mid-course correction to get the spacecraft in the proper position to reach its lunar destination. Since the moon is always moving, the spacecraft shot for a target point ahead of the moon. When close to the moon, LRO used its rocket motor to slow down until the gravity of the moon caught the spacecraft in lunar orbit.
"Lunar orbit insertion is a crucial milestone for the mission," said Cathy Peddie, LRO deputy project manager at Goddard. "The LRO mission cannot begin until the moon captures us. Once we enter the moon’s orbit, we can begin to build up the dataset needed to understand in greater detail the lunar topography, features and resources."
A series of four engine burns over the next four days will put the satellite into its commissioning phase orbit. During the commissioning phase each of its seven instruments is checked out and brought online. The commissioning phase will end approximately 60 days after launch, when LRO will use its engines to transition to its primary mission orbit.
For its primary mission, LRO will orbit above the moon at about 31 miles, or 50 kilometers, for one year. Spacecraft instruments will help scientists compile high resolution, three-dimensional maps of the lunar surface, and also survey it at many spectral wavelengths.
The satellite will explore the moon’s deepest craters, examining permanently sunlit and shadowed regions, and provide understanding of the effects of lunar radiation on humans. LRO will return more data about the moon than any previous mission.
LCROSS Set For Mission
Meanwhile, LCROSS completed its most significant early mission milestone Tuesday with a lunar swingby and calibration of its science instruments. The satellite will search for frozen water in a permanently shadowed crater at the lunar south pole.
Aided by lunar gravity, LCROSS and its attached Centaur booster rocket successfully entered into polar Earth orbit at 9:20 a.m. ET June 23. The maneuver puts the spacecraft and Centaur on course for a pair of impacts near the lunar south pole.
"Successful completion of the LCROSS swingby proves the science instruments are functioning as expected," said Dan Andrews, LCROSS project manager at Ames Research Center at Moffett Field, Calif.
During its swing by the moon, LCROSS 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 at about 7:30 a.m. ET Oct. 9, creating a pair of debris plumes that will be analyzed for the presence of frozen water 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 LRO 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.
For more information about the LRO mission, please visit:
http://www.nasa.gov/lro on the Web.
The LCROSS mission is providing mission updates on Twitter at:
For more information about the LCROSS mission, please visit:
http://www.nasa.gov/lcross on the Web.