The Indian Space Research Organisation (ISRO) is still attempting to re-establish communications with its Chandrayaan-3 mission鈥檚 moon lander and rover, but experts say hopes are fading as suspicions grow that the spacecraft have succumbed to brutally cold temperatures during the lunar night.
ISRO鈥檚 Vikram lander touched down on the surface on 23 August before releasing the Pragyan rover. Both craft successfully carried out their scientific experiments and transmitted data back to Earth, and the mission had already proven a great success.
But after the landing, senior engineers said they were confident that the craft would be able to survive the lunar night and carry out more work. Around two weeks after the mission began 鈥� one single period of lunar daylight 鈥� both devices went into 鈥渟leep mode鈥� and prepared for conditions as low as -238掳C that could destroy their electronic components.
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Following a long wait, the lunar terminator 鈥� the line between night and day 鈥� crossed the Chandrayaan-3 landing site around 22 September, bathing the craft in sunlight and theoretically allowing them to use their solar panels to charge their batteries and boot up their onboard computers once again. But there have been no signs of life.
ISRO tweeted on 22 September that it had been attempting to establish contact with the craft without success. Since then, it has provided no further updates and ISRO鈥檚 press office didn鈥檛 respond to a request for comment. On 25 September, former ISRO chief A. S. Kiran Kumar that the 鈥渃hances of reawakening are dimming with each passing hour鈥�.
at Cranfield University, UK, says it shouldn鈥檛 be considered a failure if Vikram and Pragyan don鈥檛 wake up, as the Chandrayaan-3 mission was designed to achieve its objectives in a single lunar day.
He says that designing craft to survive the vast temperature swings between lunar night and day, which can cause batteries and electrical components to literally crack as they expand and contract, can involve measures like adding radiation sources to provide warmth 鈥� but these also add complexity, cost and weight. Often, it is more pragmatic to land a leaner, simpler craft that quickly carries out science before the brutally cold nighttime temperatures destroy it, he says.
鈥淭o make sure it can survive is an enormous engineering challenge,鈥� says Cullen. 鈥淪o quite a few missions will be designed with no serious expectation of surviving the lunar light. And then if, by some chance, you do survive the lunar night, it鈥檚 a nice added-on extra.鈥�
鈥淚t would seem logical to assume that if it didn鈥檛 respond during its second lunar day, then, when it comes to the third lunar day, the chances of responding are significantly less,鈥� he says.
at the University of Leicester, UK, says it is now unlikely that the craft will reawaken. 鈥淵ou maybe expect some little bit of delay because things don鈥檛 warm up as fast as you鈥檇 like or, you know, there鈥檚 awkward shadows. But by now, I think you would have expected everything to have warmed up, so it sounds as though the cold was maybe too much.鈥�
But she says that the project should be considered a huge success. 鈥淭hey鈥檝e done everything they set out to do,鈥� says Casewell. 鈥淗ow inspirational is this for a nation that has a relatively young space programme? I think that is just phenomenal, that鈥檚 such an achievement.鈥�
