BENGALURU — Excitement is building up in Bengaluru, as India's moon lander eVikram braces for a slow descent and soft-landing near the moon's south pole in the wee hours of Sept. 7, followed by the rollout of its rover ePragyan for a stroll after dawn.
"A sort of countdown is underway for the grand finale of the Chandrayaan-2 mission for Vikram to touch down between 1:30-2:30 a.m. on Saturday in a maiden attempt and for Pragyan to step out of it 3-4 hours later to roll over the lunar surface," an official of the Indian Space Research Organization told IANS here Sept. 6.
Even as the nation gears up for the climax of the mission's 46-day voyage after its launch on July 22 from Sriharikota in Andhra Pradesh off the Bay of Bengal, hundreds of scientists and engineers have been working overtime at the space agency's Telemetry, Tracking and Command Network Centre (Istrac) in this tech hub's northern suburb for guiding Vikram to land gently between two huge craters and settle down before it opens the door for Pragyan to roll out.
"After the second de-orbiting on early Wednesday, the 1,471-kg Vikram has been elliptically spinning around the moon's north and south poles at a distance of 35 km x 101 km since then for the descent after 1:00 am. A command will be given to fire its four motors on-board for the lander's gradual descent motor at reduced velocity (speed). At 400 metres altitude, its sensors will capture the images of the surface hovering over it for 12 seconds for the final descent in 25 seconds and soft landing," the official said.
As Vikram descends from 100 meters altitude, all the four motors will be shut off while the central engine will be on till the touchdown. This is to minimise the rise of dust particles on the impact of Vikram's touchdown.
As there is no air in the moon's atmosphere, electrostatic forces from the lander's motors will emit particles that will settle down after some time.
"As the entire descent of Vikram will be visible on the display panels in the network centre through telemetry signals, we will get confirmation of the landing soon after its touchdown," said the official.
The signals will reach the network centre from Vikram through its orbiter spinning around the moon at 100 km away from its surface and via the space agency's Deep Space Network (DSN) at Bylalu, about 40 km southwest of Bengaluru.
"Commands will be given between 5-6 a.m. to open Vikram's door and roll out the 27 kg Pragyan in slow motion onto the surface, as the dust is expected to settle down in 3-4 hours after the lander's touch down," noted the official.
All going well, pictures of Vikram and Pragyan on the lunar surface near its south pole will reach the network centre by 7:00 a.m. for visual proof of the mission's success in its maiden attempt.
Cameras of Vikram and Pragyan will take the images of both and the region around their location and beam them to the network centre through its orbiter to the DSN for downloading them at the network centre in turn.
Prime Minister Narendra Modi flew here Sept. 6 to witness the historic landing of the Chandrayaan-2 mission's lunar lander Vikram with rover Pragyan in it on the moon the following day.
"Modi landed at the Yelahanka base of the IAF on the city's northern outskirts at 9.40 p.m. for an overnight stay at a star hotel, which is near to the space agency's network centre to witness Vikram's landing on the moon between 1.30-2.30 a.m.," an official told IANS here.
Governor Vajubhai Vala, Chief Minister B.S. Yediyurappa, city Mayor Gangambike Mallikarjun, Union Ministers D.V. Sadananda Gowda and Pralhad Joshi, ruling BJP's state unit President Nalin Kumar Kateel and top officials were present at the air base to welcome Modi, visiting the city for the first time after the recent Lok Sabha elections.
"Modi will drive to the Indian Space Research Organisation's (ISRO) Telemetry, Tracking and Command Network (Istrac) in the Peenya industrial area of the city's northwest suburb by 1.00 a.m. and return to the hotel after watching the landing by 3.00 a.m. for rest," added the VIP protocol official.
Modi will also interact with about 70 students from across the country at the network centre after Vikram's landing and address them.