Chandrayaan-1 reaches final orbit

Destination Moon
It is yet another historic day in India’s space odyssey. Chandrayaan-1 successfully reached its intended operational orbit at a height of about 100 km from the lunar surface. This followed a series of three orbit reduction manoeuvres during the past three days by repeatedly firing the spacecraft’s 440 Newton Liquid Engine.

As part of these manoeuvres, the engine was fired totally for about 16 minutes. As a result, the farthest point of Chandrayaan-1’s orbit (aposelene) from the moon’s surface was first reduced from 7,502 km to 255 km and finally to 100 km. The nearest point (periselene) was reduced from 200 km to 182 km and finally to 100 km.

With this, the carefully planned complex sequence of operations to carryChandrayaan-1 from Earth orbit to operational lunar orbit has been completed. During these operations, Chandrayaan-1’s liquid engine, built by Liquid Propulsion Systems Centre (LPSC), Thiruvananthapuram, was fired ten times. In its current orbit, Chandrayaan-1 takes about 2 hours to go round the moon once.

From this orbit passing over the moon’s polar regions, it will conduct chemical, mineralogical and photogeological mapping with 11 instruments (payloads). Two of them — Terrain Mapping Camera (TMC) and Radiation Dose Monitor (RADOM) — have already been successfully switched on. TMC has taken pictures of the Earth and the moon.

The next major event of the mission is the release of the Moon Impact Probe (MIP) and its landing on the moon’s surface.