After a historic but awkward comet landing, the robot probe Philae is now stable and sending pictures - but there are concerns about its battery life...Launched in 2004, the European Space Agency (Esa) mission hopes to learn about the origins of our Solar System...It has already sent back the first images ever taken on the surface of a comet...Esa's Rosetta satellite carried Philae on a 10-year, 6.4 billion-km (4bn-mile) journey to Comet 67P/Churyumov-Gerasimenko, which reached its climax on Wednesday.
