CHENNAI: “The Chandrayaan-1 team is over the moon,” exulted M. Annadurai, Project Director, when the Moon Impact Probe of the spacecraft crashed on the lunar surface at 8.31 p.m. IST. The MIP ejected at 8.06 p.m.
When the 35-kg box-like scientific instrument crashed on the Moon on Friday night, India became the fourth country in the world to have put a probe on lunar soil. The other countries/agency which had done it earlier were Russia, the United States, Japan and the European Space Agency.
The MIP was a technological forerunner to Chandrayaan-2, which would soft-land a rover on the Moon in 2012-13. The three objectives were: to demonstrate India’s capability to impact an instrument at a pre-planned time and desired location on the Moon; to test the critical technologies required for soft-landing a rover on the Moon; and scientific exploration of the Moon at close range.
The MIP crashed at a place called the Shackleton crater in the south polar region of the Moon. The crater also is a possible site for future human missions to the Moon.
Riding piggyback on Chandrayaan-1, the MIP had three instruments. They were a video camera, a radar altimeter and a mass spectrometer. Commands went from the Spacecraft Control Centre (SCC) at the ISRO Telemetry, Tracking and Command Network (ISTRAC) at Bangalore to fire a spin-up motor on board the MIP for two seconds and separate it from the mother-spacecraft.
“After it is separated, the MIP starts spinning like a top. The aim behind spinning it like a top is to give directional stability to the MIP just like a top is stable when it is spinning,” explained B.R. Guruprasad, Public Relations Officer, ISRO. Then, the MIP’s retro-rockets were fired to reduce the speed of its descent. When the velocity was reduced, it followed a curved path towards the surface of the Moon, Mr. Guruprasad said. The MIP descended for about 25 minutes from its separation till it impacted on the Moon.
As the MIP was descending, its video-camera took pictures of the lunar surface. They would be useful in selecting a possible site for soft-landing Chandrayaan-2’s rover. Its altimeter measured the MIP’s altitude during every second of its descent. The mass spectrometer analysed the constituents of the Moon’s extremely thin atmosphere.
The Shackleton crater has an undulating terrain with hills and valleys. Since the valleys are in the Moon’s permanently shadowed regions, it could harbour water ice. The dust kicked up when the MIP crashed would be analysed to check whether it contained water ice. The probe died within a few seconds of its crash.Related stories: