Chandrayaan-1 settles into operational lunar orbit

Bangalore: ISRO has confirmed that Chandrayaan-1, India's lunar probe has successfully settled into its intended operational orbit at a height of about 100 km from the lunar surface. It said this was achieved following a series of three orbit reduction manoeuvres conducted over the preceding three days.

The orbiters' 440 Newton Liquid Engine was repeatedly fired for a cumulative duration of about sixteen minutes during these manoeuvres, which progressively reduced the farthest point of the orbit (aposelene) from 7,502 km to 255 km and eventually to 100 km, even as the nearest point (periselene) was reduced from 200 km to 182 km and eventually to 100 km.

With this, the space agency said, the carefully planned complex sequence of operations to carry Chandrayaan-1 from its initial earth orbit to its intended operational lunar orbit with the use of its liquid engine has been successfully completed. In its present operational orbit, Chandrayaan-1 spacecraft takes about two hours to go round the moon once.

In the course of these operations, Chandrayaan-1's liquid engine built by Liquid Propulsion Systems Centre (LPSC), Thiruvananthapuram, has been fired a total of ten times successfully.

From this operational circular orbit of about 100 km height passing over the polar regions of the moon, it is intended to conduct chemical, mineralogical and photo geological mapping of the moon with Chandrayaan-1's 11 scientific instruments (payloads). Two of those 11 payloads – Terrain Mapping Camera (TMC) and Radiation Dose Monitor (RADOM) – have already been successfully switched on.

The TMC has already beamed back pictures of the earth and the moon.

The next major event of Chandrayaan-1 mission planned in the coming days is the release of Moon Impact Probe (MIP) from the spacecraft and its eventual hard landing on the moon's surface.

It may be recalled that after its successful launch by PSLV-C11 on 22 October into an initial earth orbit, Chandrayaan-1 spacecraft proceeded towards moon and successfully entered into an elliptical orbit around that celestial body on 8 November 2008.

Since its launch, the spacecraft's health and orbit have been continuously monitored from the Spacecraft Control Centre of ISRO Telemetry, Tracking and Command Network (ISTRAC) with critical support from antennas of Indian Deep Space Network (IDSN) at Byalalu.