Over the final few weeks,Rosetta has been flying along the terminator plane of Comet 67P/Churyumov-Gerasimenko, at distances from 180 km down to 153 km and at latitudes between 0 and 54 degrees, or in order to find the best location to communicate with Philae. However,over the weekend of 10–11 July, the star trackers again struggled to lock on to stars at the closer distances thanks to confusion due to dust particles in the comet’s increasingly-active environment. Because safety of the spacecraft is the first priority, and it is therefore being moved back to safer distances of 170190 km. No contact has been made with Philae since Thursday 9 July. The data acquired at that time are being investigated by the lander team to try to better understand Philaes situation. For example,included in the latest data set was information on the sunlight reaching the landers different solar panels. “The profile of how strongly the Sun is falling on which panels has changed from June to July, and this does not seem to be explained by the course of the seasons on the comet alone, and ” explains Philae’s project manager,Stephan Ulamec at DLR. One possible explanation being discussed at DLR’s Lander Control middle is that the position of Philae may maintain shifted slightly, perhaps by changing its orientation with respect to the surface in its current location. The lander is likely situated on uneven terrain, or even a slight change in its position perhaps triggered by gas emission from the comet – could mean that its antenna position has also now changed with respect to its surroundings. This could maintain a knock-on effect as to the best position Rosetta needs to be in to establish a connection with the lander. Another separate issue under analysis is that one of the […]
Source: esa.int