European Space Agency reported today that a solar panel on its Copernicus Sentinel-1A satellite was hit by a millimetre-size (0.04 inches) space particle in orbit on August 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, the agency said.
A sudden small power reduction was observed in a solar array of Sentinel-1A, orbiting at 700 km (434 miles) altitude, at 17:07 UTC on August 23. Slight changes in the orientation and the orbit of the satellite were also measured at the same time.
Following a preliminary investigation, the operations team at ESA’s control center in Darmstadt, Germany suspected a possible impact by space debris or micrometeoroid on the solar wing.
Detailed analyses of the satellite’s status were performed to understand the cause of this power loss. In addition, the engineers decided to activate 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.
The picture shows Sentinel-1A’s solar array before and after the impact of a millimetre-size (0.04 inches) particle on the second panel. The damaged area has a diameter of about 40 cm (15.7 inches), which is consistent on this structure with the impact of a fragment of less than 5 millimeters (0.19 inches) in size. Copyright: ESA
The power reduction is relatively small compared to the overall power generated by the solar wing, which remains much higher than what the satellite requires for routine operations.
“Such hits, caused by particles of millimeter size are not unexpected,” notes Holger Krag, Head of the Space Debris Office at ESA’s establishment in Darmstadt, Germany.
“These very small objects are not trackable from the ground, because only objects greater than about 5 cm can usually be tracked and, thus, avoided by maneuvering the satellites.
“In this case, assuming the change in attitude and the orbit of the satellite at impact, the typical speed of such a fragment, plus additional parameters, our first estimates indicate that the size of the particle was of a few millimeters.
“Analysis continues to obtain indications on whether the origin of the object was natural or man-made. The pictures of the affected area show a diameter of roughly 40 cm created on the solar array structure, confirming an impact from the back side, as suggested by the satellite’s attitude rate readings.”
This event has no effect on the satellite’s routine operations, which continue normally.
Featured image credit: ESA