Scientists at Nasa's Jet Propulsion Laboratory said it required "more detective work" to find Chandrayaan-I after they spotted Nasa's Lunar Reconnaissance Orbiter (LRO).
Chandrayaan-1, which was launched on October 22, 2008, by the Indian Space Research Organisation (ISRO), got lost in space on August 29, 2009, after the power system on the spacecraft failed, ending all communication between ground station and the spacecraft. A new technological application of interplanetary radar by scientists at NASA's Jet Propulsion Lab could be a major boon in solving the problem seeing as it just found a lost spacecraft orbiting the moon.
The space agency has historically had a lot of trouble detecting objects that are orbiting around our own moon, something that becomes essentially impossible when referring to small objects in the moon's bright glare. The radars have been used by scientists to locate distant asteroids still, there was a doubt about finding the Chindrayaan which is nearly as far as the Moon. "Ground-based radars could possibly play a part in future robotic and human missions to the moon, both for a collisional hazard assessment tool and as a safety mechanism for spacecraft that encounter navigation or communication issues". At that time, ISRO had come to the conclusion that the spacecraft must have developed some malfunction and crashed into the Moon. The only lead they had to go on was the spacecraft's last known orbit from 2009, which was a polar orbit, so the beam was focused on the moon's north pole hoping the spacecraft would pass by. But less than a month later, Indian space scientists had lost all contact with the country's first lunar probe.
Nasa's Moon Mineralogy Mapper, one of the 11 instruments onboard Chandrayaan-I, and Isro's Moon Impact Probe (MIP), discovered water on the lunar surface.
Using this data, scientists updated the orbital predictions for the silent satellite.
"It turns out that we needed to shift the location of Chandrayaan-1 by about 180 degrees or half a cycle from the old orbital estimates from 2009", Ryan Park, manager of the JPL's solar system dynamics group, said in the release. The dormant Chandrayaan-1 was predicted to complete one orbit around the moon every two hours and 8 minutes and when the signature of a small spacecraft crossed the beam, the team knew they had found what they were looking for.
It is hoped that this new method of object detection using multiple ground-based radar antennas can be put to good use in the future.
The father of India's moon mission, Krishnaswamy Kasturirangan, said, "To be declared lost and then found after eight years is a great accomplishment". The orbiter is a cube about five ft (1.5 m) on each side, which makes it a very tricky target. "Hunting down LRO and rediscovering Chandrayaan-1 have provided the start for a unique new capability".