The 1.4-tonne lander has been lying silent on the moon’s surface since the early hours of Saturday.

For the fourth day on Tuesday, the Indian Space Research Organisation (ISRO) continued its efforts to reconnect with 1.4-tonne lunar lander Vikram, which has has been lying silent on the moon’s surface since the early hours of Saturday, the space agency confirmed on Tuesday in a short update.

Suspense continues on its status amidst many reports and speculations about its fate.

Is it bodily intact and can it still be revived? Has it fallen in a tilted position which might make salvage difficult? Are its antennas pointed in a favourable way towards the Chandrayaan 2 orbiter that is moving above the moon? Sources in the ISRO said they were struggling for these very answers.

“All we can say is that all efforts are on,” an official said on Tuesday. “You must understand that this is a very difficult time for us to be saying anything with conviction.”

After a three-day silence, the ISRO’s web updates page came alive. But it merely said, “Vikram lander has been located by the orbiter of Chandrayaan 2, but no communication with it yet. All possible efforts are being made to establish communication with the lander.”

Also Read Chandrayaan-2: VSSC scientists keep fingers crossed for establishing contact with Vikram

The orbiter continues to do its job, going around the moon at a distance of 100 km. For visual aids or eyes, it has (among its eight payloads) the 30-cm Orbiter High Resolution Camera or OHRC; and an infra-red spectrometer; and the Terrain Mapping Camera-2.

While the source of the images is not told to us, Dr. Sivan recently said the OHRC had the best resolution to date of any lunar mission.

The ISRO designed the orbiter, lander and the rover in such a way that the first one can “talk” with the Earth and the second one can talk with the Earth, the orbiter and rover Pragyan, while the third one can talk only with the lander.

Vikram lost its Earth link when it was 2.1 km and about 3 minutes from what would have been a historic first ever touchdown close to the lunar south pole.

Also Read Chandrayaan-2: A rapid dive to 15 minutes of terror

The lander and the rover are not expected to have signals after 14 earth days from September 7. The lunar night will begin and the spacecraft will have run out of solar power.

Deep space antennas

The ISRO is understood to be trying to call Vikram via the orbiter link but this could not be officially ascertained.

At such great planetary distances (of some 4 lakh km in this case,) space agencies use their deep space antennas to give and take signals from their spacecraft.

The ISRO has set up a 18-metre and 32-metre-diametre Indian Deep Space Network (IDSN) at Byalalu near here. The IDSN has been used for Chandrayaan 1 (2008-09) and the still working Mars Orbiter Missions (2013).

The ISRO, however, must tap NASA’s array of sensitive giant radio antennas set up globally to be continuously in touch with interplanetary missions. They are the DSNs operated by the Jet Propulsion Laboratories in California, Madrid and Canberra.