The Path to Validation
The developers shortlisted the optical PTFE from Berghof Fluoroplastics very early on due to its unique bidirectional reflection behaviour. The first examinations showed that the version with the lowest reflectivity would be particularly suitable for the requirements of this mission. In order to be validated as "space flight material", however, it had to go through further comprehensive tests, among others regarding long-term resilience under vacuum in various thermal scenarios, abrasion behaviour, electrical conductivity and influences of high-energy particle radiation.
"The Bidirectional Reflectance Distribution Function of black PTFE is fantastic. It meets our mission requirements."
In the end, black optical PTFE by Berghof Fluoroplastics convinced the NASA developers and engineers. Applied on a large part of the surface of the optical instruments and other surface parts of the satellite, it now enables the measuring systems to work without interferences so that the satellite will be able to land safely on the asteroid.
The recorded images will be impressive, as has been proven even before the actual mission target, when the optical instruments recorded the Earth and moon together in one photograph for the first time. The result can be seen here:
The Next Steps
In August 2018, the satellite will catch up with asteroid "Bennu" on its orbit and start surveying. The latest updates on the mission will be published on: