By Venkatachari Jagannathan, IANS,
Chennai : The earth orbit of India’s first lunar spacecraft will be raised to 267,000 km Wednesday, an official here said.
“The Chandrayaan spacecraft, orbiting at a distance of around 165,000 km apogee (farthest point from earth) will be raised Wednesday to around 267,000 km. As of now, everything is normal and as per our expectations,” Chandrayaan-1 project director M. Annadurai told IANS.
The third orbit-raising was done Oct 26 and the spacecraft was raised up to 164,600 km, instead of 199,277 km apogee as originally announced by the Indian Space Research Organisation (ISRO).
“The important date for us is Nov 3 when the final orbit manoeuvre will happen. Between Oct 22 and Nov 3 we have the leeway to carry out the orbit raising activity,” he said.
On Nov 3, the ISRO will take the spacecraft to 384,000 km apogee.
The subsequent firing of spacecraft motors will take it near the lunar orbit and it is expected to get into lunar orbit Nov 8.
During the lunar orbit, the spacecraft’s motors will be fired five times – called lunar burn – to take it to 100 km of the moon’s radius.
“We expect that to happen November 14 or November 15,” Annadurai said.
According to him the spacecraft has sufficient fuel on board.
“Going up, the spacecraft spends less fuel to travel the same distance,” he added.
On Oct 23, the spacecraft’s motors were fired for 18 minutes to take it to 37,900 km apogee.
Subsequently, the spacecraft motors were fired for 16 minutes and 9.5 minutes Oct 25 and Oct 26 respectively to take it to 74,715 km and 164,600 km respectively.
“On Wednesday we will fire the spacecraft motors for 190 seconds (3.17 minutes) to take it to 267,000 km. On Nov 3, the motor firing will be for around 150 seconds (2.5 minutes) to take the spacecraft to 384,000 km,” Annadurai said.
Till date, the spacecraft has expended around 340 kg of fuel of the lift off capacity of 819 kg.
The spacecraft’s motor firing Wednesday and Nov 3 would consume around 40-50 kg of fuel.
“Another 100 kg fuel might be expended to put Chandrayaan into its intended orbit near the moon, leaving sufficient quantities of fuel for the spacecraft to orbit for two years,” he added.