Chennai, Sep 7 (IANS): "It is going to be 15 terrifying minutes", said K.Sivan, Chairman, Indian Space Research Organisation (ISRO) speaking about the Indias Moon lander Vikram's landing operations.

Sivan's words turned true towards the end of Vikram's landing process after it tumbled and regained its posture and then lost its communication links with ISRO.

Here are the "terrifying" moments:

* 1.38 a.m. Lander Vikram begins its descent from at altitude of 30 km from the lunar surface at a velocity of 1,680 metres per second (m/s).

* The rough braking operations began to kill the lander's velocity. The velocity started to come down to 1,300 m/s, to 760 m/s and further lower.

* 1.50 a.m. Rough or brute braking phase got over. The lander Vikram was at an altitude of about 5 km. The fine breaking phase began.

* When the lander was at an altitude of about 3 km, there was a slight deviation from its plotted path. The Vikram had tumbled and regained its position. The results of fine breaking phase were awaited.

* 2 a.m. There was silence and unease at the mission control centre.

* 2.07 a.m. Communication between lander and Chandrayaan-2 orbiter switched on. ISRO Chairman Sivan briefed Prime Minister Narendra Modi at the mission control centre about the problem.

* 2.10 a.m. ISRO Chairman Sivan gave the bad news. He said the performance of the lander was as per the plan till it was 2.1 km away from its designated landing spot on the Moon's South Pole. After that communication links got snapped.

Then the mood turned gloomy at ISRO.