It could be weeks before the Indian Space Research Organisation (ISRO) reveals what precisely prevented lander Vikram from making a smooth touchdown on the moon, but the most recent failure of a similar sort is Beresheet, a private moon mission by Israeli non-profit organisation SpaceIL. It crashed on the lunar surface on April 11.
Beresheet was launched aboard a Falcon rocket made by the U.S.-based Space X, and at $100 million (₹700 crore approximately), it was cheaper than Chandrayaan-2 that cost about $140 million (₹980 crore approximately). Beresheet’s journey lasted 49 days, compared to ISRO’s 46.
The Israeli spacecraft had a rocky journey through space. However, telemetry data suggested that the lander was performing well until about 500 metres from its scheduled touchdown on the moon. The gyroscope engine that keeps the spacecraft oriented and regulates its speed reportedly failed and given that the object was plummeting at nearly 500 kmph, was impossible to control by earth-bound scientists.
“The key challenge of landers is the large communication lag once it starts descending. The NASA’s Mars mission had its equivalent seven minutes of terror like the ISRO’s 15 minutes of today... This is a technological limitation that, even in principle, cannot be overcome,” according to Jatan Mehta, science writer and a former science officer with Team Indus, a private space-based company once set to launch a lander mission from India.
A key challenge with understanding what precisely went wrong with Vikram is that there is no ‘black box’ that can be retrieved or examined as in the case of a plane crash. Scientists can only rely on telemetry data that was beamed. “While complex, the causes can be determined though because landers everywhere have similar basic features — like a car,” Mr. Mehta reckoned.
China for its part has had the most recent successes with landers with its Chang’e 3 and Chang’e 4 in 2013 and 2018 both landing on the moon as planned.