Chandrayaan-1 orbit to be raised to 267,000 kilometres in fourth manoeuvre

Chennai: In its fourth orbit-raising manoeuvre for the Chandrayaan-1 spacecraft, ISRO will today further raise the earth orbit of India's first lunar spacecraft to 267,000 kilometres.

Chandrayaan-1 project director M Annadurai was quoted as saying that the Chandrayaan-1 spacecraft, which has been orbiting at a distance of a little under 165,000 kilometre (apogee) would be further raised to around 267,000 kilometres. He reiterated that till now, everything has progressed normally and as per expectations.

The spacecraft's third orbit-raising manoeuvre was done on Sunday, with the ISRO command and control centre firing Chandrayaan-1's liquid engine for 550 seconds on Sunday morning at around 0700 hours, which manoeuvred the satellite closer to its destination orbit. 

ISRO sources say that the date to mark on the calendar was 3 November, which is when the final orbit manoeuvre will happen. The 3 November manoeuvre will see ISRO take the spacecraft to 384,000 kilometres apogee, and the subsequent firing of spacecraft's motors will take closer to its lunar orbit. 

Chandrayaan-1 is expected to assume lunar orbit sometime around 8 November. Thereafter, the spacecraft's motors would be fired five times in a lunar burn that would take it to its final destination orbit of 100 kilometres of the moon's radius, which is expected to take place sometime around 14 – 15 November.

ISRO will fire Chandrayaan-1's motors for 190 seconds, or 3.17 minutes today, to take the spacecraft to 267,000 kilometres apogee. The 3 November firing will be for an estimated duration of around 150 seconds, or 2.5 minutes, that will take the spacecraft to 384,000 kilometres.