The European Space Agency landed a probe on a comet this week.
Unfortunately, there were a couple of malfunctions. In the first, the “harpoon” that was to anchor the lander malfunctioned allowing it to bounce around a bit.
These revealed the astonishing conclusion that the lander did not just touch down on Comet 67P/Churyumov–Gerasimenko once, but three times.
The harpoons did not fire and Philae appeared to be rotating after the first touchdown, which indicated that it had lifted from the surface again.
Stephan Ulamec, Philae manager at the DLR German Aerospace Center, reported that it touched the surface at 15:34, 17:25 and 17:32 GMT (comet time – it takes over 28 minutes for the signal to reach Earth, via Rosetta). The information was provided by several of the scientific instruments, including the ROMAP magnetic field analyser, the MUPUS thermal mapper, and the sensors in the landing gear that were pushed in on the first impact.
The result of this mishap was that the lander, which was using solar energy to recharge batteries, was not positioned properly to absorb the very weak sunlight energy at that distance.
But then the lander lifted from the surface again – for 1 hour 50 minutes. During that time, it travelled about 1 km at a speed of 38 cm/s. It then made a smaller second hop, travelling at about 3 cm/s, and landing in its final resting place seven minutes later.
That is quite a move and the result has been a very limited experiment as the lander has now shut down due to low battery power.