India's Moon mission loses communication with lander

ISRO says it was barely 2.1 km away from touching down on the lunar South Pole.

Subhra Priyadarshini & Vanita Srivastava

doi:10.1038/nindia.2019.122 Published online 7 September 2019

A screen grab showing Prime Minister Narendra Modi consoling ISRO scientists after communication with Chandrayaan-2's lander was lost.

© DD

India's second moon mission Chandrayaan-2 lost communication with its lander today (7 September 2019), just minutes before its scheduled touch down. This dampens India's first scheduled soft landing on lunar soil as also the country's ambition of being the first to descend on the far side of the Moon.

Chandrayaan-2's lander Vikram, named after the father of India's space programme Vikram Sarabhai, lost communication with  the Indian Space Research Organisation (ISRO) centre in Bengaluru in the wee hours Indian time. ISRO chairperson Kailasavadivoo Sivan announced that Vikram, which nestled the six-wheeled robotic rover Pragyan, had lost contact with the ground station when it was just 2.1 km away from the Moon.

India's Prime Minister Narendra Modi, who was at the ISRO centre in Bengaluru to witness the historic landing, tried to cheer up the mission scientists, who wore a dejected look after communication to the lander was lost. "I am with you," Modi said before leaving the centre without making his scheduled address to the scientists. "This is no mean achievement...these are moments to be courageous," he later tweeted.

Earlier in the night, the mission control room resonated with thunderous applause when the lander's 'rough braking phase' lasting nearly 10 minutes went as planned. But soon after this, Vikram's trajectory started showing a dip with a sudden loss of signal.

ISRO cancelled a scheduled press conference as a spokesperson said data of the unforeseen event was being analysed. ISRO sources pointed to the possibility of Vikram having crash-landed but said this can only be confirmed after an ongoing investigation into the reason behind the loss of communication.

Tens of thousands of people across India woke up the night to watch the live telecast of the 1.4 tonne lander's scheduled touch down around 2.30 am India time.The nail biting finish, earlier described as the "15 minutes of terror" by Sivan, turned out to be just that for them. The descent   from 30 kilometers above the lunar surface to a spot between two craters, was supposed to take about 15 minutes and was the trickiest part of the mission.

After performing a series of complex manoeuvres, Vikram  embarked on its descent from  a height of 35 km above the lunar surface and gradually slowed its velocity from 1.6 km per second to 0 in 15 minutes for a controlled soft landing.

With the mission, India was hoping to join the elite space club of  United States, Russia and China to become the fourth country to land on the Moon. Chandrayaan-2 was launched on its 384,400 km voyage from the Satish Dhawan Space Center in Sriharikota, by GSLV Mk-III on 22 July  2019 after an aborted attempt on 19 July.

Chandrayaan-2 was armed with three modules — an orbiter, a lander and a rover —  and almost all the components were designed and fabricated in India. The spacecraft was ejected into an Earth parking orbit, before a series of manoeuvres raised  its orbit to a lunar transfer trajectory. On entering the Moon’s sphere of influence, the on-board thrusters slowed  down the spacecraft for a lunar capture. 

The lander was separated from the orbiter earlier this week. The Rs 1000 crore mission is looking to better understand the origin and the evolution of the Moon. The orbiter which weighs 2.4 tonnes, will be alive for  one year and will operate in a 100x100 km lunar polar orbit.