Chandrayaan-1 reaches final orbital home
India’s first unmanned lunar spacecraft, Chandrayaan-1, today reached its final orbital home, about 100 km over the moon’s surface, after scientists carried out the last orbit-lowering operation.
The satellite will remain in this orbit for about two years and carry out a range of experiments. The final 60-second manouvere was carried out from a ground station in Bangalore exactly three weeks after the spacecraft began its voyage to the outer space from atop a polar rocket from Sriharikota.
“The journey part to the Moon is complete,” Project Director M Annadurai said. “We are eagerly awaiting the start of the experiments.”
Indian Space Research Organisation (Isro) said the next major event would be the release of the moon impact probe and its hitting the Moon’s surface. This is expected on Friday and scientists hope to get the first signals in about 20 minutes after the landing.
The entry of Chandrayaan-I into the final lunar orbit followed three orbit-reduction manoeuvres conducted during the past three days by firing its liquid engine, Bangalore-headquarted Isro said.
With this, Isro said, the carefully planned complex sequence of operations to carry Chandrayaan-1 from its Earth orbit to its intended lunar orbit had been successfully completed.
“As a result of these manoeuvres, the farthest point of the Chandrayaan-1 orbit from the moon’s surface was first reduced from 7,502 km to 255 km and finally to 100 km while the nearest point was reduced from 200 km to 182 km and finally to 100 km”, Isro said.
During these operations, Chandrayaan-1’s liquid engine, built by Liquid Propulsion Systems Centre, Thiruvananthapuram, has been fired a total of ten times.
From its present operational orbit, passing over the polar regions of the moon, the spacecraft will conduct chemical, minerological and photo-geological mapping of the moon with its 11 scientific instruments (payloads).
Two of these payloads -- Terrain Mapping Camera (TMC) and Radiation Dose Monitor (RADOM) - have already been switched on. TMC has successfully taken pictures of the Earth and the Moon.
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 with critical support from the antennas of Indian Deep Space Network (IDSN) at Byalalu on the outskirts of Bangalore.