LCROSS’s Impact On the Moon (October 9, 2009): What was It All About?

We’ve managed to achieve so many things but the Moon has always been a source of fascination for the entire world. Since time immemorial, man has always needed to find out what that silvery globe held on its surface. NASA has managed to go a bit deeper in finding some of the details about the Moon with its various manned and unmanned landings but the recent LCROSS impact on the Moon has had the whole world hopping.

Scientists have been inquisitive about the existence of water on the Moon. The idea is based on the facts that numerous collisions of comets with the Moon, over the past million and billions of years, may have resulted in sublimation of the water from the surface of those comets and may have settled in the deep craters near the Moon's poles. It is therefore possible that water ice might be present in the dark craters in its polar regions, at a temperature even lower than -170 ⁰C.

NASA decided that just sending probes to the surface of the Moon was not enough. The only way to get these answers was by actively collecting Moon dust and researching it to find out the chemical nature of the dust. One way to do this was by impacting or bombing the surface of the Moon’s deepest craters. This would create a cloud of dust that could be collected and analyzed for data. NASA decided to go one step

further and used the LCROSS impact on the Moon to help in finding out some amazing details in a matter of minutes.

With this objective, the twin impacts of LCROSS (Lunar CRater Observation and Sensing Satellite) and its booster smacked down hard on the surface of the Moon, on Friday, October 9, 2009 creating history.

{Image Source : above right : LCROSS Centaur: credit: NASA/Roger Arno; http://en.wikipedia.org/wiki/File:LCROSS_Centaur_1.jpg}

{Image credit : left : LCROSS spacecraft :http://www.nasa.gov/pdf/360020main_LRO_LCROSS_presskit2.pdf }

The actual launch of the LCROSS was a huge media event. There were three launch opportunities as the bad weather had made the

sky a little cloudy. The countdown began at 10 AM EDT and was aimed at a potential liftoff at 5:12 PM. When the weather cleared, LCROSS and the Lunar Reconnaissance Orbiter, along with its Centaur booster was launched into orbit aboard the Atlas-V rocket at 5:32 PM EDT, from Cape Canaveral Air Force Station, Florida.

{Image credit : This photo of LCROSS Launch has been taken from the video released by NASA on LCROSS Launch. Imagecourtesy of http://lcross.arc.nasa.gov/}

The LCROSS impact on the Moon was specially designed to ferret out would-be water sources on the Moon. Scientists have already stated that water has already been detected on the Moon and the news was confirmed by the Indian Chandrayaan-1 Moon probe. However, unless a viable source of frozen water is found, it’s going to be very difficult to actually support a colony on the Moon.

The main aim for finding water is that scientists will eventually be able to set up a Moon colony.The impact from the Centaur excavated approximately 350 tons of lunar dust and created a crated which was about 65 ft in diameter and 13 ft in depth. This was the largest impact ever from a man-made object on the Moon!

Image of LCROSS's impact.

{Image credit: Courtesy: NASA, LCROSS Mission Team}

The after-effects caused by the impact raised a plume of dirt in the lunar sky, which was used to search for the presence of water on the Moon. LCROSS impacted the bottom of the crater’s rim and exposed the dirt along the corner of the crater.

During the Centaur stage portion of the impact, a plume of dust was shot up, which was imaged by the LCROSS spacecraft as it followed the booster before it hit the Moon's surface itself. This plume of dust hopefully contained water ice. NASA scientists have received the data and have been analyzing it. If there was any water ice, hydrogen, organic material etc, all of it would have vaporized and the visible and infrared spectrometers would have provided data of the event for scientists to study.

On November 13, 2009, a report from NASA confirmed that there have been some evidence of the presence of water. A high angle plume of vapour and fine dust was detected along with a lower angle ejecta curtain of heavier material. Further confirmation was done from the emissions of the UV spectrum, which revealed the presence of hydroxyl fragments. Hydroxyl ions are produced by the break-down of water molecules by sunlight. However, the concentration and distribution of water and other compounds will be determined after further analysis.

{Image credit: left: MIR and UV Spectrometers Image of Centaur Crater: NASA, LCROSS Mission Team: Source: http://www.nasa.gov/images/content/392970main_LCROSS_9_full.jpg}

The truth is that thousands of objects impact the Moon everyday and most of the time there is no noticeable effect on the Earth. Most of the larger craters were caused by the impact of large asteroids on the Moon's surface. LCROSS impacted with a force of about 6 billion joules of energy, while an ordinary 10 kg meteorite will impact with a force of 8 billion joules—this is due to the meteorite's much higher velocity of about 40 km/s versus LCROSS's mass of about 2000 kg and velocity of about 2.5 km/s at impact.

The LCROSS team is working very closely with the LRO scientists and also some other space observatories. They are trying to extract the maximum information from the data obtained from the LCROSS impact. The analysis is still on. Let us see what secrets are lying within the deep craters of Moon!

http://lcross.arc.nasa.gov/

http://lcross.arc.nasa.gov/faq.htm

http://en.wikipedia.org/wiki/LCROSS

lcross.arc.nasa.gov/webcast.htm

www.youtube.com/watch?v=j-5t4de6jjI

http://www.youtube.com/watch?v=j-5t4de6jjI&feature=player_embedded#