ISRO racing against time to salvage lander-rover

ISRO is racing against time to spring 'Vikram' back to life and salvage the lander-rover partof the Chandrayaan-2 mission.The lander Vikram, with rover 'Pragyan' tucked inside it, lost communication with the ground-stations during its final descent, just 2.1 kms above the lunar surface, minutes beforethe planned soft-landing in the early hours of Saturday.

ISRO (Indian Space Research Organisation) said on Sunday Vikram had a "hard-landing". The Bengaluru-headquarterd space agency on Tuesday again confirmed that the lander has been located on the lunarsurface by the on-board cameras of the Chandrayaan-2 orbiter which is circling the moon in its intended orbit.

"All possible efforts are being made to establishcommunication with (the) lander", ISRO further said in a tweet. A senior ISRO official associated with the mission said: "The images from the orbiter camera showed that Vikram is insingle piece lying on the lunar surface; not broken intopieces. it is in a tilted position. It's not in its four legs,as usual". This official added on condition of anonymity: "it's notupside down. It's lying on its side". 

ISRO officially did not comment on the condition of the lander. Chandrayaan-2 comprises an orbiter, lander (Vikram) androver (Pragyan). The mission life of the lander and rover is one Lunarday, which is equal to 14 earth days. ISRO Chairman K Sivan said on Saturday evening that thespace agency would try to restore link with the lander for 14days and it has been reiterating the resolve since then.

An ISRO official said Vikram hit the lunar surface at aplace about 500 metres away from where it was originally planned to touch-down. But there was no official word on this from ISRO. Sources said an ISRO team is trying to see if they canreorient the antennas of the lander in such a way that communication can be restored.

"Efforts are going on", they said. According to a senior ISRO official, orientation may have been lost during the final descent when velocity was reduced,due "sensor or on-board software or computer anomaly".

"A committee is looking into what has gone wrong. They will come out with answers soon", this official said. Meanwhile, flawless and precise launch and efficient management of the Chandrayaan-2 mission ---- till the lander 'Vikram' lost communication with ground-stations --, has paid rich dividends to the ISRO on the orbiter front.

The 2,379 kg orbiter whose mission life was designed tobe one year would now be able function for almost sevenyears. "Enough fuel is available with the orbiter. Up to (lunar)orbit insertion, we did not have any flaw. Additional fuelwhich was anticipated was not used at all. Everything went asper the plan. Additional fuel is available with us (on-boardthe orbiter)", an ISRO official said.

Another ISRO official said, "One of the limiting factoris on-board fuel availability. Because the performance ofGSLV-MK III (which launched the spacecraft) and efficient mission management, we have enough fuel for continuing it forward for seven years."  The space agency also said, the precise launch and mission management has ensured a long life of almost seven years instead of the planned one year for the orbiter.

ISRO had said 90 to 95 per cent of the Chandrayaan-2 mission objectives have been accomplished and it would continue to contribute to Lunar science , not withstanding the loss of communication with the Lander which hit lunar surface after failing in its planned attempt to soft-land in the early hours of Saturday.

Noting that Chandrayaan-2 mission was a highly complex one, which represented a significant technological leap compared to the previous missions of ISRO, the space agency said it brought together an orbiter, lander and rover to explore the unexplored south pole of the Moon.

This was a unique mission which aimed at studying notjust one area of the Moon but all the areas combining the exosphere, the surface as well as the sub-surface of the moonin a single mission, it added.