IF things go as planned and the Moon Impact Probe (MIP) of Chandrayaan-1 crashes into lunar soil, that will be a truly proud day for India. The 29-kilogram instrument, which sits like a hat on top of the spacecraft, has the Indian tricolour painted on its sides. The MIP, built by the Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram, is one of 11 scientific instruments on the spacecraft and is a technological forerunner to India landing a rover on the moon as part of the Chandrayaan-2 mission in 2012-2013.
Soon after Chandrayaan-1 enters the lunar orbit at an altitude of 100 kilometres, commands will be radioed from the Spacecraft Control Centre (SCC) at ISTRAC, ISROs Telemetry, Tracking and Command Network in Bangalore, for the MIP to eject. After a 20-minute elliptical descent, the MIP will crash onto the moons surface.
The MIP has three instruments: a video camera, an altimeter and a mass spectrometer. During the 20-minute descent the video camera will take pictures of the moons surface, the altimeter will measure the altitude every instant of the MIPs descent, and the spectrometer will sniff the thin atmosphere above the moon to analyse what it is made of.
When the MIP crashes, the video camera will take pictures of the dust that is kicked up and radio them to the mother-spacecraft, which will relay it to the Indian Space Science Data Centre at Byalalu near Bangalore. The MIPs images will help decide where Chandrayaan-2s lander-cum-rover can soft-land on the moon.
ISRO Chairman G. Madhavan Nair said: The mass spectrometer is basically a particle analyser. The dust coming out on impact will be picked up by it, and if you get a sweep, you will again get a mineral composition on that. But the whole event is very short-lived. You have to keep your fingers crossed till you get the data.
But as far as the launch itself was concerned, Mission Director George Koshy said: We could not have asked for more. The Polar Satellite Vehicle PSLV-C11 is a rugged vehicle, and it put Chandrayaan-1 in a perfect initial orbit.
This is the 14th PSLV flight and the 13th success in a row. The PSLV-C11, also called PSLV-XL, is the PSLVs third variant with more powerful strap-on booster motors than the standard version. The other two are the standard version and the core-alone version without the strap-on motors.
S. Ramakrishnan, Director (Projects), VSSC, explained why it is called PSLV-XL: Each normal strap-on uses nine tonnes of solid propellants. But XL has 12 tonnes of propellants in each strap-on. We have also extended the length of the strap-ons from 10 metres to 13.5 m. That is why it is called XL extra long.
C. Venugopal, vehicle director, PSLV-C11, had absolute confidence in the XL version as the new motors had been tested on the ground. He called the PSLV a flexible vehicle that could fly different payloads. It is a robust vehicle. There is no doubt about that, he said.
Since 1994 the PSLV has put satellites in every conceivable orbit low-earth orbit, polar sun synchronous orbit, geosynchronous transfer orbit and now Chandrayaan-1 in a long elliptical orbit. The PSLV has also put in orbit multiple satellites in four missions, including 10 satellites on April 28, 2008. S. Satish, Director, Publications and Public Relations, ISRO, said: This is the ultimate that a launch vehicle can do. The PSLV is so versatile.
T.S. SubramanianCOMMents
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