Chandrayaan’s orbit raised again

With the fourth manoeuvre to raise the orbit of Chandrayaan-1 successful on Wednesday morning, Chandrayaan-1, India’s first spacecraft to the moon, is racing to reach two-thirds of the distance to the moon. The moon is about 3.84 lakh km away from the earth.
When engineers from the Indian Space Research Organisation’s (ISRO) Spacecraft Control Centre (SCC) at Bangalore radioed commands to Chandrayaan-1 on Wednesday, the spacecraft’s propulsion system swung into action and fired for three minutes from 7.38 a.m. This led Chandrayaan-1 into a highly elliptical orbit, whose apogee lay at 2,67,000 km and the perigee at 465 km. In this orbit, the spacecraft takes about six days to go round the earth once.
(The SCC, the nerve centre of operations under way now to take Chandrayaan-1 into the lunar orbit, is situated at ISRO Telemetry, Tracking and Command Network - ISTRAC - at Peenya in Bangalore).
M. Annadurai, Project Director, Chandrayaan-1, explained: “The spacecraft will keep moving. Chandrayaan-1 will take three days to reach this height (2.67 lakh km). Again, it will take three days to come back to the earth. So in this orbit, the spacecraft takes six days to go round the earth once.”
When the spacecraft reached the apogee of 2.67 lakh km, it would signify its crossing two-thirds of the distance to the moon. The next firing of the motor on board Chandrayaan-1 would take place late in the night of November 3 or early in the morning of November 4 to take it to the vicinity of the moon, Mr. Annadurai said. An ISRO press release said the health of Chandrayaan-1 was being continuously monitored from the SCC at ISTRAC with support from the two huge radars with diameters of 32 metres and 18 metres, installed at Byalalu village near Bangalore. “All systems on board the spacecraft are performing normally,” the release said.The ISRO’s Polar Satellite Launch Vehicle (PSLV-C11) put Chandrayaan-1 into its initial orbit of 22,866 km by 256 km on October 22.