Moon landing drama: Play by play of ISRO losing communication with Chandrayaan 2's lander

ISRO Chairman K Sivan trying to re-establish contact with Chandrayaan 2's lander, VikramIANS
  • India attempted to soft land on the Moon's South Pole today but lost communication with Chandrayaan 2's lander, Vikram.
  • The first phase of the power descent operations went smoothly.
  • The Indian Space Research Organisation (ISRO) stated that it lost communication when Vikram was 2.1 kilometers from the lunar surface.

The Indian Space Research Organisation (ISRO) Chairman had repeatedly stated that the 15 minutes of parabolic descent will be the 'most terrifying' 15 minutes of India's mission to the Moon, Chandrayaan 2.

His warning held true as ISRO told communication with Chandrayaan 2's lander, Vikram, in the final moments of the power descent operation.

"Vikram lander was as planned and normal performance was observed up to an altitude of 2.1 km. Subsequently, the communication was lost. The data is being analysed," stated Sivan after no signals were being relayed from the Moon.

First phase of Vikram's descent goes smoothly

After seven weeks of travelling through space, Chandrayaan 2's lander — Vikram, started its power descent to the Moon at 1:38am Indian Standard Time (IST), 30 kilometers above the lunar surface.

It approached the lunar surface at a speed of 1,640 meters per second around 600 kilometers from the landing site. Two minutes after Vikram starting to drop, ISRO initiated the power descent operation.

The first phase of the descent is known as the 'rough breaking phase'. The lander was brought down from 30 kilometers to 7.4 kilometers above the lunar surface. Lasting ten minutes, lander's speed was reduced to 140 meters per second.

It required the brute force for all four of Vikram's engines to kill the spacecraft's velocity as it gets closer to the Moon.

Vikram manages to slow down even further

The second phase of Vikram's descent was the 'altitude and absolute navigation phase' was successfully completed reducing the speed to 86 meters per second over 98 seconds. The lander, at this point, was 5 kilometers from the Moon.

Immediately afterwards, the third phase — 'fine breaking phase' — kicked in which was supposed to take the lander even lower to an altitude of around 400 meters.

At the end of this phase, Vikram would no longer have any forward moving velocity — it can only perform a vertical descent.

Things start to go awry

Before the fourth phase of the launch, the 'terminal phase', could kick in — Vikram stopped sending data back to Earth.

Faces around the mission control operations room were tense as they awaited confirmation of the landing. At this point, the lander should be at a near zero velocity but the screen keeping tabs on the lander was frozen at 48.59 meters per second.

A lot can happen in 15 minutes

The landing window was only 15 minutes but there were no signals from Vikram even 10 minutes after the deadline passed. An ISRO executive was heard briefing Prime Minister Narendra Modi that the ISRO headquarters “was receiving signals only from the landing station.”

ISRO is yet to confirm whether or not it was able to re-establish communication with the lander.

Even though the lander and rover might not be able to send data back to Earth, the orbiter is still circling the Moon with its many high-tech instruments on board to collect information.
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