Lunar smackdown set for Friday
On Friday morning October 9th, two spacecraft will crash into the Moon. The target is crater Cabeus near the south pole. The collisions are part of the Lunar Crater Observation and Sensing Satellite (LCROSS) mission. The planned outcome of this lunar smackdown will allow scientists to confirm if water ice lies hidden within permanently shadowed craters.
Following the Apollo missions, interest in returning to the Moon became a low priority. But that all changed in 1999 when NASA’s Lunar Prospector detected the presence of hydrogen in the lunar polar regions. Most recently, the Cassini and Deep Impact probes along with India’s Chandrayaan-1 lunar orbiter obtained compelling evidence that the hydrogen may exist as water ice near the Moon’s poles.
LCROSS mission hardware has three main components. The Lunar Reconnaisance Orbiter (LRO), the Sheperding Spacecraft and a Centaur rocket stage. Once in space, the LRO separated and traveled to lunar orbit. The Sheparding Spacecraft, in tandem with the Centaur rocket stage, began a series of elongated orbits around Earth to line up with the target impact site.
The first impact will occur at approximately 5:31AM as the empty Centaur rocket stage strikes the lunar surface. Next, the Sheperding Spacecraft will dive through the debris plume to sample impact ejecta with its sensors and relay findings back to Earth. Then, it too will crash into the lunar surface four minutes later. Following the demise of the Centaur rocket and the Shepherding Spacecraft, instruments onboard the LRO will survey and map the impact sites.
Working to get some background on the mission, I checked the world wide web. Not surprisingly, I found some provocative claims that NASA is going to “bomb” or “blow-up” the Moon. Concerns that international treaties will be violated or that life on Earth will perish as a consequence of the LCROSS impacts are unfounded and unneccesarily alarming.
The truth is that the Moon, and other solar system bodies, have been constantly bombarded since the early days of their formation. Just how did the Moon get all those craters anyway? And the United States is not the only country to launch this type of mission. The history of lunar impact missions dates back to the dawn of the space age. In September 1959, the Soviet Union won bragging rights by crashing Luna 2 into the Moon. Since then, space agencies from China, Europe, India and Japan have all followed suit.
Impact timing is ideal for Hawaii, but it will also be possible to see the event in states across the Mountain and Pacific time zones. NASA Education and Public Outreach lead for LCROSS, Brian Day says “We expect the debris plumes to be visible through mid-sized backyard telescopes—10 inches and larger. The initial explosions will probably be hidden behind crater walls, but the plumes will rise high enough above the crater’s rim to be seen from Earth.”
On Friday, NASA -TV will begin coverage of the LCROSS impacts at 4:30AM. An updated viewer’s guide can be found online at http://science.nasa.gov/headlines/y2009/05oct_lcrossvg.htm
