Chandrayaan-2’s Vikram lander hard landed as reduction in velocity during its descent did not match with the designed parameters, the government said on Thursday, throwing more light on the ISRO’s dashed hopes of making a soft landing on the lunar surface in its maiden attempt.

In a written reply to a question in the Lok Sabha, Jitendra Singh, Minister of State in the Prime Minister’s Office who looks after the Department of Space, said the first phase of descent was performed nominally from an altitude of 30 km to 7.4 km above the moon’s surface and the 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 metres of the designated landing site,” he said.

Mr. Singh, however, said most components of technology demonstration, including the launch, orbital critical manoeuvres, lander separation, de-boost and rough braking phase were successfully accomplished.

With regards to the scientific objectives, all the eight state-of-the-art scientific instruments of the orbiter were performing according to the design and providing valuable scientific data. Due to the precise launch and orbital manoeuvres, the mission life of the orbiter was increased to seven years, he said.

‘Data from orbiter reviewed’

Data received from the orbiter was being provided continuously to the scientific community, he said, adding the same was recently reviewed in an all-India user meet organised in New Delhi.

The indigenously developed Chandrayaan-2 comprising the orbiter, the lander and a rover was successfully launched onboard the indigenous GSLV MK III-M1 Mission on July 22.

After accomplishing four earth-bound manoeuvres and trans-lunar injection, the spacecraft was successfully inserted into the lunar orbit on August 20. A series of moon-bound manoeuvres were then carried out to achieve a lunar orbit of 119 x 127 km.

Vikram was separated, as planned, from the orbiter on September 2, 2019. After two successful de-orbiting manoeuvres, a powered descent of the lander was initiated on September 7 to achieve soft landing on the Moon surface.

The ISRO is planning to launch Chandrayaan-3 probably in November next year.

Quelle: The Hindu