Home / Science / Just keep it simple: The former isro-scientist explains what has led to Chandrayaan-2's Vikram crash India News

Just keep it simple: The former isro-scientist explains what has led to Chandrayaan-2's Vikram crash India News



As Moonlight Night kicks off on early Saturday, hopes of restoring communication with Indian mission Chandrayaan-2 Vikram Lander seem almost over with their 14-day missionary life.

On September 7, Lander Vikram lost contact with the ground station, just minutes before the planned landing on the moon, with the rover Pragyan on its final descent, just 2.1 km above the lunar surface.

A former official of the Indian Space Research Organization (ISRO) suggested keeping the technology simple; freeze the mission profile and change at the last moment; Carrying out simulation tests at the highest possible level – these are some findings from the crash landing of the Indian lunar lander Vikram.

Speaking to IANS, the official said: "The space technology itself is complicated and one should not add more complications like the Lander Vikram. For example, the four throttle motors that work simultaneously are a technical challenge. Then there's the fifth engine in the middle. "

Previously known to the ex-officer that the GSLV-Mk III rocket (Geosynchronous Satellite Launch Vehicle) was available for the mission, the spacecraft could have been developed with a powerful single engine rather than five engines.

"Ideally, a lunar lander of this type should have a single engine of 3,500 Newton (N). This would have avoided the complexity of managing the four throttled motors working together. Other nations had used a powerful single engine as they landed their craft on the moon. Before landing on the lunar surface, the single engine would be switched off and the lander would have landed gently.

See also: Chandrayaan 2: 90-95% Achieved Goals, ISRO Chief K Sivan Says

The mission profile changed at the last minute and was off the original plan departed.

"Originally, it was planned to launch the spacecraft Chandrayaan-2 together with the lander with GSLV-Mk II, which can carry a weight of two tons".

After a while, the fifth engine was added at

"This in turn increased the spacecraft's weight and changed the other specifications that GSLV-Mk II did not support. It was then decided to launch Chandrayaan-2 with a higher capacity GSLV-Mk III. "

Originally, the idea was to first turn off all four throttle motors and drop the lander slowly. "The idea was to drop the lander 2 meters per second from a height of 10 meters," he added.

"After the introduction of the fifth engine there was a software change. How well it was tested is not known.

The ISRO must simulate different things and scenarios with the available data. It should also check and simulate what actions were not carried out and what results they had adopted, "said another retired official who preferred to remain anonymous to IANS.

In his opinion, ISRO has to check if there is a simulation before starting any known deviation was overlooked or canceled.

"ISRO should also examine the extent to which various failure modes have been simulated. ISRO needs to respond to these details. It would take a considerable amount of time to come to a conclusion, "he added.

Space experts had told IANS that in the event of a loss of data, it is assumed that the satellite is suddenly changing altitude. If the target / satellite experiences a large angular rotation, the communication link will normally break off.

In your opinion, the reason for the failure of the communication link could be the wrong input loaded into the lander.

In other words, the failure of the communication link with Vikram could be due to sudden disturbances – in The Vikram was designed to land on its four legs at a speed of about 7 km / h on the lunar surface. Due to some complications that the lander faced just minutes before touchdown, the Vikram could have hit the lunar surface at a much higher speed than expected.

"The Vikram has a maximum landing tolerance of 5 meters per second. But it seems the landing speed has been very high in recent times, "the retired official added.

"In the case of Vikram's landing, it is not known at what point no return was possible – at which point the descent could not be stopped or changed, or at what deepest or nearest point on the lunar surface the lander could be manipulated. " said.

Former ISRO officials said the Indian Space Agency has received various technical data from this mission that will be useful for its future course of action. He also added, "There should be Plan B when something goes wrong with Vikram and it's not known if it's activated."

Chandrayaan 2, originally scheduled for July 15, was launched eleven hours earlier take off, start, take off, drive off because of a technical problem. After the problem was resolved in about a week, India's second lunar mission was launched by Sriharikota aboard the GSLV Mk III at 2:43 pm on July 22.

India's second moon mission has cost less than half the budget of Hollywood Blockbusters Avengers Endgame & # 39 ;. The total cost of the Chandrayaan 2 mission is estimated at $ 124 million, including $ 31 million for the launch and $ 93 million for the satellite.

(Contributed by Agencies)

First published:
September 21, 2019 06:36 IST


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