( CNN ) Is Philae still alive ? The answer to this particular cosmic cliff-hanger was left unresolved towards the end of last year . The tiny space probe bounced across the surface of Comet 67P before touching down away from its intended landing zone . It returned plenty of data from the surface but ended up in a shady spot where there was n't enough sunlight to keep it powered -- so then it went to sleep and nothing has been heard since November . In the months since , mission scientists have not been able to pinpoint its exact resting place . But now the comet-chasing mother ship Rosetta -- in orbit around 67P -- is to begin listening for signs that the lander has survived the cold and dark . Scientists at the European Space Agency ( ESA ) , which is leading a consortium that includes NASA to find out more about the composition of comets and how they interact with the Sun , believe that if enough sunlight falls on Philae 's solar panels it could revive . As the comet gets closer to the Sun and more light illuminates the lander , the chances improve . Lander system engineer Laurence O'Rourke told CNN that Philae needs 5.5 watts of power to reboot itself , nine watts to switch on the receiver to accept communications and 19 watts to activate its transmitter and allow two-way communication with the orbiter . Modern energy-saving domestic light bulbs consume 20 watts or lower so it does n't need much to re-establish contact . On Tuesday , @ ESA_Rosetta tweeted : `` Excited ! I have some opportunities to listen for @ philae2014 to find out if he 's awake ! '' Rosetta and Philae 's love affair on Twitter . On the Rosetta mission blog , lander project manager Stephan Ulamec says : `` It will probably still be too cold for the lander to wake up , but it is worth trying . The prospects will improve with each passing day . '' The mission website adds that Philae could already have woken up but does not yet have sufficient power to communicate with Rosetta . It says Rosetta will transmit to Philae between March 12 and March 20 , listening for a response . Problems began for the lander when devices designed to anchor Philae to the surface failed . The gravity is so weak that without the harpoons intended to fire from the feet , the probe bounced across the comet . However , the mishap could prove to be a happy accident . O'Rourke explained that as the comet nears the Sun , Philae 's original landing spot would have exposed it to temperatures that would have burned out its electronics . In that position it most likely would have died by now . From lander pictures , mission controllers think Philae , which is about the size of a washing machine , is tucked up underneath a cliff face , affording it some shade . Beginning Thursday , mission controllers will send what O'Rourke described as `` blind commands '' to Philae in the hope that the lander has enough power to receive instructions even if it ca n't respond . Philae will be told to save power for the transmitter . O'Rourke admits that it 's a `` long shot '' but the team will try again in April if this attempt fails . If Philae revives it could be witness to an amazing show as the comet makes its closest approach to the Sun in August . `` I think we are going to see some amazing images at that point , '' said O'Rourke . Even if Philae never wakes up , all is not lost . The mission has detected organic chemicals on the comet surface , though full details of that discovery have yet to be revealed . And the Rosetta mission is already changing perceptions of comets . O'Rourke says instead of a comet being a dirty snowball he now thinks of it as being `` an icy dirtball . '' He described discoveries of dust and large `` boulders '' circling the comet after they were blown off by the Sun during previous orbits , and an image that appears to show a structure the size of a football pitch that has been lifted and then deposited next to the hole . `` The Rosetta mission is not just about the lander . It 's about orbiting and following a comet -- watching it wake up and then go to sleep again , finding the secrets held by comets . Every day is a new discovery , '' he said . Scientists have already applauded the mission 's success to date . `` The Rosetta radar experiment will reveal for the first time how a comet is put together , '' cosmochemist Denton S. Ebel told CNN in November . CNN Interactive : Rosetta and its mission . Opinion : How comet mission helps search for alien life .
CNN is to begin listening for signs that the lander has survived the cold and dark . From lander pictures , mission controllers think Philae is tucked up underneath a cliff face . Philae has already detected organic chemicals on the comet surface .