The Philae lander, which was the first spacecraft designed to land on a comet, failed to latch onto the surface, according to the scientists. It bounced off the frozen body and in doing so has likely scrapped the side of a crater as it came to rest on the nucleus of the comet.
As the scientists studied the data on the comet lander, more information came to light about the bumpy landing. The lander drifted for two hours and bounced off three times over the surface, before finally resting on the comet.
According to the Rosetta Lander Magnetometer and Plasma Monitor (ROMAP), which keeps a track on the lander, the spacecraft collided with a surface structure shortly after its first landing and might have grazed one of its legs.
Hans-Ulrich Auster of the Technische Universitat Braunschweig, in Germany, and Romap co-principal investigator, said, “Any motion of Philae in a magnetic field – even if it is small – can be seen by field changes in the measured magnetic field direction. We think that Philae probably touched a surface with one leg only – perhaps grazing a crater rim – and after that the lander was tumbling.”
ROMAP’s original role was to observe the comet’s magnetic field as it interacts with the solar wind. This despite the challenge that the orbitor (Rosetta) and the lander both create tiny magnetic fields of their own due to magnetic circuitry. ROMAP’s data is essential to see what the environment on comet is like. But during the landing, ROMAP was used to track Philae’s descent on the comet.
When it touched down at 10:34 a.m. EST on November 12, the lander was supposed to fire harpoons to secure itself to the comet’s surface. The mechanism unfortunately failed to activate. A flywheel in the lander was turned off by the control electronics, and its angular momentum was transferred to the vehicle. So for the next 40 minutes, the wayward spacecraft was spinning once every 13 seconds.
At 11:20 a.m. EST, the grazing collision happened. This made the rotation decrease to once every 24 seconds. At 12:25 p.m. EST and 12:31 p.m. EST, the final two touchdowns happened. Once the data from ROMAP, Comet Nucleus Sounding Experiment by Radiowave Transmission (CONCERT) probes and other instruments on the lander is received, only then the scientists can figure out exactly where Philae has landed on the comet.
Philae needs sunlight to recharge its battery through the solar panels. Unfortunately there isn’t adequate sunlight in its present landing spot. Scientists hope that Philae will come back to operation in March when the comet will go near the sun. Meanwhile, Rosetta continues to orbit the comet and send data and images from it.