Chennai: After a historic first on Saturday, when Chandrayaan-1 was unshackled from earth's gravity and inserted into a lunar one, Indian scientists on Sunday carried out the first of four scheduled Lunar Orbit Reduction manoeuvres aimed at easing the orbiter into its designated circumpolar orbit 100 km above the moon's surface.
While the Saturday manoeuvre placed the Chandrayaan-1 into
a lunar orbit with an aposelene (farthest point from the moon)
of 7,502 km and a periselene (nearest point from the moon)
of 504 km, the Sunday manoeuvre brought down the latter to
200 km. The aposelene continues at 7,500 km.
An ISRO statement said the health, as well as the orbit, of the spacecraft was being closely monitored from the Spacecraft Control Centre of ISRO Telemetry, Tracking and Command Network (ISTRAC) in Bangalore, with crucial support from Indian Deep Space Network antennas at Byalalu. The spacecraft performance was normal it said.
The manoeuvre was carried out by firing the Moon Impact Probe's (MIP) engine for about a minute from 8.03 pm. Three similar manoeuvres, aimed at gradually reducing the periselene and aposelene of the Chandrayaan to intended altitudes, will be carried out over the coming days. If successful, they should place Chandrayaan-1 in a final circular orbit 100 km above the moon on 15 November.
As soon as these manoeuvres are over, ISRO will then eject the MIP from the Chandrayaan the same day. Once separated the MIP will then commence a 20-minute journey towards the lunar surface, beaming back video pictures to Bylalu before it crash lands.
The MIP will be India's flag bearer to the moon carrying the national colours painted on its side.
With the MIP concluding its journey, the Chandrayaan's remaining nine scientific payloads will come live, one after the other. The Terrain Mapping Camera has already been switched on and has beamed back its first pictures of the earth.