BepiColombo material samples after testing

Sample degradation after BepiColombo lifetime testing for ceramic reflective-surface thermal control materials. Only the central circle of each sample is exposed during testing, the border of each square revealing the original hue. Testing took place at 450˚C with UV radiation equivalent 10 times the sun for 25 000 hours under high vacuum conditions. The smaller the difference between the centre and the edge, the more successful the test.