Lost Chandrayaan-1 found orbiting Moon by NASA
Scientists at NASA have detected that India’s first lunar probe, Chandrayaan-1, which was considered lost is still orbiting the moon. This was achieved by using a new ground based radar technique.
Scientists at Jet Propulsion Laboratory (JPL) have located the spacecraft which is still circling some 200 km above the lunar surface.
Along with Chandrayaan-1, NASA has also detected its Lunar Reconnaissance Orbiter(LRO). Though finding LRO was relatively easier as NASA was working with the mission’s navigators and had precise orbit data.
Whereas finding Chandrayaan-1 required higher efforts as the last contact with the spacecraft was in August 2009.
The Indian Government on November 2003 approved ISRO’s proposal of the first Indian Moon Mission which was named Chandrayaan-1. It is very small, cuboid in shape and about 1.5 m in length on each side.
The ISRO lost communication with Chandrayaan-1 on August 29, 2009, almost a year after it was launched.
Objectives of the Chandrayaan-1 mission:
- High-resolution remote sensing of the moon
- Prepare a three-dimensional atlas with high spatial and altitude resolution of both near and far side of the moon
- Conducting chemical and mineralogical mapping of the entire lunar surface
Challenges faced in detection of the spacecraft:
- Finding a spacecraft at lunar distance that has not been tracked for years is tricky because the moon is riddled with mascons
- Mascons are regions with higher-than-average gravitational pull
- These regions can dramatically affect a spacecraft’s orbit and even cause its crash into the moon.
How was it detected:
- Although the interplanetary radar has been used to observe small asteroids there was uncertainty among researchers whether an object of this size could be detected as far away as the moon
- A powerful beam of microwaves was send towards the moon. The radar echoes that bounced back from the lunar orbit were received by the Green Bank Telescope
- Though the spacecraft was generally considered lost, but the radar team utilized the fact that since the spacecraft is in the polar orbit around the moon, so it would always cross the lunar poles on each orbit
- An object that had radar signature of a small spacecraft was observed. The timings matched the time it would take Chandrayaan-1 to complete one orbit and return to the same position
- The team used data from the return signal to estimate velocity and the distance to the target. This information was then used to update the orbital predictions for Chandrayaan-1.