The Indian government has provided an explanation of why the Chandrayaan-2’s Vikram lander crashed into the lunar surface on Sept. 2. The Times of India reports:
In a written reply to a question in the Lok Sabha, Jitendra Singh, the minister of state in the Prime Minister’s Office, who looks after the department of space, said the first phase of descent was performed normally from an altitude of 30 kms to 7.4 kms above the moon’s surface and velocity was reduced from 1,683 metres per second to 146 metres per second.
“During the second phase of descent, the reduction in velocity was more than the designed value. Due to this deviation, the initial conditions at the start of the fine braking phase were beyond the designed parameters. As a result, Vikram hard-landed within 500 meters of the designated landing site,” he said.
Singh reported, however, most components of technology demonstration, including the launch, orbital critical maneuvers, lander separation, de-boost and rough braking were successfully accomplished.
Vikram was India’s first attempt to land on the moon. The vehicle carried a small surface rover named Pragyan that would have been deployed on the surface.
The lander and the rover each carried three instruments that were designed to operate for the two-week lunar day.
ISRO has not made the results of its investigation into the landing failure public. The Chandrayaan-2 orbiter continues to return data.
ISRO has said it plans to send another lander to the surface. The vehicle could be launched by the end of 2020.