Considered lost since 2009 when radio contact with it was lost, India’s Chandrayaan-1 spacecraft has been found orbiting the moon. The spacecraft has been found by NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California. Earlier, JPL’s calculations indicated that Chandrayaan-1 was circling some 200 kilometres above the lunar surface, but it was generally considered “lost.”
Chandrayaan-1 was India’s first mission to the moon, was launched successfully on October 22, 2008 from Sriharikota. ISRO says the “satellite made more than 3400 orbits around the moon and the mission was concluded when the communication with the spacecraft was lost on August 29, 2009”.
However, JPL was recently trying out new ways to find objects in space and it thought that due to its small size the lost Chandrayaan-1 was a perfect test candidate that would allow it to truly test its new techniques.
“Optical telescopes are unable to search for small objects hidden in the bright glare of the moon. However, a new technological application of interplanetary radar pioneered by scientists at NASA’s JPL can do so,” noted JPL in a note to media.
“We have been able to detect NASA’s Lunar Reconnaissance Orbiter (LRO) and the Indian Space Research Organization’s Chandrayaan-1 spacecraft in lunar orbit with ground-based radar,” said Marina Brozovic, a radar scientist at JPL and principal investigator for the test project.
Brozovic says that finding LRO was easy. But Chandrayaan-1 was a tricky object to locate in the lunar orbit because of its size. It is a cube “about five feet (1.5 meters) on each side — about half the size of a smart car”.
“Finding India’s Chandrayaan-1 required a bit more detective work because the last contact with the spacecraft was in August of 2009,” says Brozovic.
Apparently it also tricky to find objects near the moon because once a spacecraft is lost in the lunar orbit, it soon gets pulled in by the moon’s gravity and then crash lands.
“Finding a derelict spacecraft at lunar distance that has not been tracked for years is tricky because the moon is riddled with mascons (regions with higher-than-average gravitational pull) that can dramatically affect a spacecraft’s orbit over time, and even cause it to have crashed into the moon,” JPL notes. But then its calculations showed that Chandrayaan-1 was still in the orbit.
Based on their calculations, the scientists at JPL then used 70-meter antenna at NASA’s Goldstone Deep Space Communications Complex in California and 100-meter Green Bank Telescope in West Virginia to hunt for Chandrayaan-1. On July 2, 2016, the scientists got a response that showed the presence of Chandrayaan-1 around 160 kilometres above the moon’s north pole.
Although it is a pleasant surprise that India’s first lunar probe is still orbiting and is not exactly “lost” it may not have much operational significance for ISRO. The radio contact with the Chandrayaan-1 remains lost and it is not going to transmit any data or any contact with ground stations.
But for JPL, finding Chandrayaan-1 is a proof that it’s space object hunting techniques work. “Hunting down LRO and rediscovering Chandrayaan-1 have provided the start for a unique new capability. Working together, the large radar antennas at Goldstone, Arecibo and Green Bank demonstrated that they can detect and track even small spacecraft in lunar orbit,” noted JPL.