| Submit your comments on this article |
| India-Pakistan |
| Us and Indian lunar probes to jointly look for water on moon |
| 2009-03-02 |
| If things go well, India’s Chandrayaan-1 probe could be joining forces with two U.S. spacecraft to be launched later this year in looking for water on the Moon. The National Aeronautics and Space Administration plans to launch the Lunar Reconnaissance Orbiter (LRO) as well as the Lunar Crater Observation and Sensing Satellite (LCROSS) on an Atlas V rocket from the Kennedy Space Center in Florida. NASA’s LRO web site indicates that the launch is currently scheduled to take place no earlier than May 20. Whether or not water in the form of ice has accumulated in craters at the lunar poles remains an unsettled and controversial issue. One of the instruments on Chandrayaan-1, which is currently circling the Moon, is a compact imaging radar known as Mini-SAR. The radar was specifically developed by a team of U.S. scientists to look for signs of water-ice at the bottom of lunar craters that are permanently in shadow. A similar sort of radar, called Mini-RF, is flying on the LRO as well. In principle, the two radars — one on the Chandrayaan-1 and the other on the LRO — could be used together in what is known as a bistatic mode. In that mode of operation, the radar signal would be sent out from the instrument on one satellite and the return echo picked up by the radar on the other satellite. “Because both Chandrayaan-1 and LRO will be in lunar orbit at the same time, the Chandrayaan-1 Mini-SAR and LRO Mini-RF units were designed to operate cooperatively in a bistatic mode, with Chandrayaan-1 transmitting and LRO receiving in S-band radar data,” write Paul Spudis and others of the Mini-SAR team in a paper published in the latest issue of the journal Current Science. The bistatic mode could provide the best evidence for the presence of water-ice, Dr. Spudis told this correspondent when he was in India last year for the launch of Chandryaan-1. The LRO mission team has approached the Indian Space Research Organisation to explore possibilities for a bistatic experiment using their spacecraft and Chandrayaan-1, said J.N. Goswami, director of the Physical Research Laboratory, Ahmedabad, and principal scientist for Chandrayaan-1. The idea is scientifically interesting, Dr. Goswami said. “But we may be able to consider it only after preliminary results from radars on both satellites become available. Also, it is important that many of Chandrayaan-1’s primary science objectives are first completed.” Once the LRO and LCROSS satellites are put on course for the Moon, NASA intends to have the Atlas V rocket’s spent Centaur upper stage slam into a lunar crater. The impact is expected to throw up a large cloud of dust and debris that will rise high above the Moon’s surface, hopefully carrying traces of any water-ice that may be present. Travelling just minutes behind the Centaur stage, the LCROSS’ instruments will make measurements as the spacecraft passes through the plume of debris. The data will relayed back to Earth before the spacecraft too crashes into the Moon and creates a second debris plume. Instruments on Chandrayaan-1 may be able to take readings of the debris plumes if the spacecraft is in a suitable position when the impacts occur, Dr. Goswami said. |
| Posted by:john frum |