ESA engineers discovered that a solar panel on the Copernicus Sentinel-1A remote-sensing satellite was hit by a millimeter-sized particle on Aug. 23, 2016. Thanks to onboard cameras, ground controllers were able to identify the affected area. So far, there has been no effect on the satellite's routine operations.
At the time of suspected impact, a sudden small power reduction as well as slight changes in the orientation and orbit of the satellite were measured.
Following a preliminary investigation, engineers activated the board cameras to acquire pictures of the array. These cameras were originally carried to monitor the deployment of the solar wings, which occurred just a few hours after launch in April 2014, and were not intended to be used afterward. Following their switch-on, one camera provided a picture that clearly shows the strike on the solar panel.
Such hits, caused by particles of millimeter size, are not unexpected, noted Holger Krag, head of the ESA Space Debris Office in Darmstadt, Germany. Analysis continues to obtain indications on whether the origin of the object was natural or man-made.