India's Chandrayaan-1 spacecraft reaches its final orbit

India’s Chandrayaan-1 spacecraft successfully reached its final operational orbit around the Moon on 12 November 2008. The spacecraft is now circling the Moon at an altitude of about 100 km.

After being captured into lunar orbit on 8 November, the spacecraft performed three orbit reduction manoeuvres. As a result, the farthest point of Chandrayaan-1’s orbit (aposelene) from the Moon’s surface was first reduced from 7502 to 255 km and then finally to 100 km. The nearest point of the orbit to the Moon (periselene) was reduced from 200 km to 182 km and finally to 100 km.

In this final orbit, the spacecraft flies over the lunar poles and takes about two hours to circle the Moon once.

The spacecraft will perform chemical, mineralogical and photo-geological mapping of the surface, using its 11 scientific instruments. Three of these, the C1XS and SIR-2 X-ray and infrared spectrometers, respectively, and the SARA atom analyser, were provided by Europe through ESA.

The next major event for the mission is the release of Moon Impact Probe (MIP) from the spacecraft and its impact on the Moon’s surface. The impact will provide information on lunar surface properties, and is planned to take place in the next few days, once Chandrayaan-1 selects a proper impact site from orbit.

After the impact, the mission will continue with remote-sensing studies in orbit.

Provided by ESA