India’s first moon mission, Chandrayaan-1 has been considered lost since August 2009. Recently, NASA’s Jet Propulsion Laboratory used a new interplanetary radar technology to find the spacecraft, which has stayed out of radio contact for a significant amount of time. Using a ground based radar, the organization has been able to spot NASA’s Lunar Reconnaissance Orbiter [LRO] and the Indian Space Research Organization’s Chandrayaan-1 spacecraft in lunar orbit.
It is a difficult task for optical telescopes to detect small objects in the bright glare of the moon. Previously, small asteroids have been detected several million miles from the Earth, using the interplanetary radar. However, researchers lacked confidence on the world’s most robust radar to detect an object so small, and as far away as the moon. NASA found the LRO relatively easy, as they had the mission’s navigators and the precise orbit data to where it was located. The fact that the last contact with Chandrayaan-1 was made in August 2009, made Nasa’s job of finding the spacecraft relatively challenging.
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Chandrayaan-1 was launched on October 22, 2008, and successfully placed in a polar orbit around the moon on November 8, 2008. India became the fourth country to touch the moon by placing the Moon Impact Probe on the lunar surface on November 14, 2008. Evidence pointing to the existence of water on the lunar surface was spotted by Indian scientists by analyzing the soil samples collected from the impact probe.
Calculations suggested that the spacecraft was still circling some 200 km above the lunar surface. The scientists aimed the radar at a point above the moon’s north pole and waited for the satellite to pass the radar beam. The spacecraft was predicted to complete one orbit around the moon every two hours and 8 minutes. During the four hours of observation, something that had a radar signature of a small spacecraft did cross the beam twice. Timings between the detections were noted, and it matched the time Chandrayaan-1 would have taken to complete one orbit and return to the same position above the moon’s pole. After taking seven more readings over the next three months, it was confirmed that the vehicle was indeed the long lost Chandrayan-1.
It was a really taxing task for the JPL team to find a dormant spacecraft around the moon, as the path could have varied, or even crashed on the moon over time. Towards the end of 2018, India will witness the launch of its second moon mission, Chandrayaan-2.