Chandrayaan-2: Time running out to contact Vikram

There are just 11 more days for the Orbiter to re-establish communication link with the Lander Vikram that hard-landed on the lunar surface early Saturday morning. With the Lander and the Rover within a lot depends on its solar panels for it to stay alive. and once darkness engulfs, contact could be elusive.

On Tuesday, the Indian Space Research Organisation (ISRO) officially announced what has been public domain since Monday: “Vikram Lander has been located by the orbiter of #Chandrayaan2, but no communication with it yet. All possible efforts are being made to establish communication with lander.”

Since Vikram is now in a ‘tilted’ position with its orientation not vertical has made the efforts to contact all the more tough. If it had soft-landed on all its legs as originally planned, the antennas would have been upwards, facing the Orbiter, going around the Moon at an orbit of 100km X 100km.

ISRO scientists say although the Orbiter has been sending signals through its active communication channel, neither the Lander nor the Rover Pragyan within it have responded. Since the link had failed, Rover did not get the green signal to activate its solar panels.

The link failure also implies that Vikram and Pragyan, despite being embedded with multiple hi-tech modules to analyse the lunar surface data, cannot transmit any of that information back to ISRO's Earth stations through the Orbiter.

On the delay in making a formal announcement of Vikram’s location, ISRO sources had a rationale: Confirming and reconfirming the location from an altitude of 100km took time.

What Lander can do

Re-establishing contact with the Lander is critical to activate its key payloads. One of them is RAMBHA, an instrument to track the lunar ionosphere, measure ambient temperature near the lunar surface; and evolution of lunar plasma density near the surface under varying solar conditions.

Assigned for Lander is an experiment called ChaSTE to measure the vertical temperature gradient and thermal conductivity of the lunar surface. It consists of a thermal probe (sensors and a heater) that is inserted into the lunar regolith down to a depth of about 10 cm.

ILSA, an Instrument for Lunar Seismic Activity is also part of Vikram’s payload. It is a triple axis, MEMS-based seismometer that can detect minute ground displacement, velocity, or acceleration caused by lunar quakes.