09 October,2009 10:19 AM IST | | Agencies
A US rocket is to crash into the moon Friday in an experiment scientists hope will provide data about ice hidden in the perpetually dark lunar craters.
Astronomers around the world are prepared to capture the impact of the Lunar Crater Observation and Sensing Satellite (LCROSS) into the moon's Caebus crater at 1130 GMT. The rocket will deliberately crash into the moon, kicking up a plume of dust that scientists hope to analyse for traces of water that they believe are abundant in the cold, shadowy craters.
The impact is designed to mimic that of the large, natural asteroids that slam into the moon several times a month. The probe belonging to the US space agency NASA is targeting a 100-km wide, 4-kilometre deep crater and is timed to strike when lighting conditions are ideal for observing the impact. The 585-km craft will hit the moon at about 9,000 km per hour creating at impact crater about 2 metres deep.
Despite the concerns of some naysayers in the blogosphere, the moon will not be harmed by the event. "The impact has about a million times less impact on the moon than a passenger's eyelash falling to the floor of a 747 during flight," said Daniel Andrews, LCROSS project manager.
The total event - from impact until the dust settles - will last just 120 seconds, but scientists say the experiment will produce valuable information to be collected on nine instruments, including five cameras that capture images in colour, thermal and near-infrared images.
Simultaneously, images of the impact will be captured by the companion Lunar Reconnaissance Orbiter, a satellite now circling the moon, as well as the Hubble Space Telescope and terrestrial telescopes. The composition of the material kicked up by the impact will help scientists deduce whether water is present.
When seen from the ground with an amateur telescope, the dust cloud will amount to a dim shimmer across a shadow adjacent to the crater. NASA says the best way to watch is at the parties being hosted by astronomy societies or online at the NASA website.
Data from three deep-space missions late last month revealed that there are small, but widespread amounts of water across the entire surface of the moon. That announcement is seen as complementing, not preempting, the LCROSS mission.
Astronomers said before the impact that new data from $79-millionLCROSS mission will complement the earlier findings because water is believed to be much more abundant in the craters. The findings could aid future manned missions to the moon, which could establish long-term outposts.
NASA scientists said that it is possible for frozen water to have remained in the moon's craters for billions of years, because the bottoms of the craters are never reached by sunlight and protect any ice from evaporation into the thin lunar atmosphere.
