Moon Impact Probe 
Polar Satellite Vehicle (PSLV-C11)
If all goes well, Chandrayaan-1 spacecraft, to be launched by the Polar Satellite Vehicle (PSLV-C11) on October 22 at 6.20 a.m. from the Sriharikota space port, will reach the lunar orbit on November 8, according to M.Y.S. Prasad, Associate Director, Satish Dhawan Space Centre, Sriharikota.
About 1,000 engineers and technicians of the Indian Space Research Organisation (ISRO) have rolled up their sleeves and are working hard for the past two months to ensure a flawless launch. The 52-hour countdown will begin on October 20 at 4 a.m.
On Saturday, the PSLV-C11, which is 44.4 metres tall and weighs 316 tonnes, looked majestic in the huge Vehicle Assembly Building (VAB) of the state-of-the-art second launch pad on the Sriharikota island. As it gleamed in white and brown colours, the VAB’s massive doors, in contrast, shone in speckled grey.
“All checks on the vehicle are completed. The vehicle is now ready to receive the satellite,” declared T. Subba Reddy, Manager, Second Launch Pad, when journalists visited the complex.
A few kilometres away, Chandrayaan-1 spacecraft, which weighs 1,380 kg, is undergoing a battery of tests to test its flight-worthiness.
The spacecraft will be moved to the VAB on October 14 and married up with the PSLV-11. The “marriage ceremonies” such as filling Chandrayaan-1 with propellants and gas, and cobbling of the heat-shield which protects the spacecraft through searing heat when the rocket climbs through the atmosphere, will be performed over the next four days. On October 18 will begin the extremely slow journey of the rocket with the spacecraft, as if it were a temple chariot with the deity, from the VAB to the launch pad.
The PSLV, which stands on a mobile platform, will be wheeled on rail tracks to the launch pad, also called the umbilical tower, which is one km away. A powerful hydraulic bogey system will slowly pull the vehicle. The one-km journey will take two hours!
“The movement of the vehicle to the launch pad will take place on October 18. There will be minimum four days of work on the launch pad. The launch will take place on October 22 at 6.20 a.m., provided the weather supports us,” said M.C. Dathan, Director, Satish Dhawan Space Centre, Sriharikota.
However, V. Krishnamurthy, the Range Safety Officer for the mission, is a confident man. “Rains do not matter. The launch vehicle is rain-proof. It can get drenched and we can still launch,” he asserted.
The PSLV had lifted off earlier when it was pouring over the island. Only a cyclone would pose a problem to the launch on time. Since this was the time when the north-east monsoon set in, Mr. Krishnamurthy said ISRO had formed a team of weather specialists who would be in Sriharikota six days before the launch.
Depending on their inputs, ISRO would take a decision on when to ignite the rocket.
Chandrayaan-1 will carry 730 kg of propellants. About 600 kg of these propellants will be used to put the spacecraft into lunar orbit at an altitude of 100 km. The spacecraft will have a mission-life of two years and use up 70 kg of propellants during this period, Mr. Prasad said.
Chandrayaan-1 has 11 scientific payloads — five from India and six from abroad. The payloads from abroad includes those from NASA, the European Space Agency and Bulgaria. The payloads will map the chemicals and minerals on the moon, and also prepare a 3-diemensional map of the entire lunar surface. The mission will also give clues on the early origin of the moon.
Mr. Prasad said, “We will be able to confirm whether there is water on the surface of the moon near the Poles with the help of the Chandrayaan mission.” Water on the moon was first identified by a NASA mission called Clementine. Based on that, NASA concluded that there could be a possibility of water in the moon’s South Pole, he added.
Moon Impact Probe
S. Satish, Director, Publications and Public Relations, ISRO, said an important Indian payload on the Chandrayaan-1 was the Moon Impact Probe (MIP). When the spacecraft reached the lunar orbit at an altitude of 100 km, the MIP would eject from Chandrayaan. As the MIP sped towards the moon’s surface, its video-camera would take pictures of the lunar surface.
Its altimeter would measure the instantaneous altitude from the moon. A third instrument, a mass spectrometer, would sniff the tenuous atmosphere above the moon. V. Seshagiri Rao, Deputy Director, Range Operations, Sriharikota, said each payload on the Chandrayaan, was subjected to different tests at Sriharikota.
Source: http://www.hindu.com/2008/10/12/stories/2008101260901000.htm
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