The US Air Force Academy of Physics has built FalconSAT-7, a membrane solar telescope to be deployed from a
3U CubeSat in LEO. The primary optic is a 0.2m photon sieve – a diffractive element consisting of billions of tiny
circular dimples etched into a Kapton sheet. The membrane its support structure, secondary optics, two imaging
cameras and associated control, recording electronics are packaged within half the CubeSat volume. Once in space
the supporting pantograph structure is deployed, extending out and pulling the membrane flat under tension. The
telescope will then be directed at the Sun to gather images at H-alpha for transmission to the ground. We will
present details of the optical configuration, operation and performance of the flight telescope which has been made
ready for launch in early 2017.
FalconSAT-7 (FS-7), a 3U CubeSat solar telescope, is the first-ever on-orbit demonstration of a lightweight deployable membrane primary optic that is twice the size of the host spacecraft. The telescope payload consists of the deployment structure, optical, electronic subsystems and occupying 1.5 U, while the rest of the volume is used for the bus, including satellite power, control, communications with the ground, etc. The deployment subsystem provides membrane deployment, positioning and tension with high precision for proper imaging, while the optical subsystem includes secondary optics with a camera to record images of the Sun at H-alpha. The electronics subsystem is used to control the primary optics deployment, focusing, image storage and transfer to the bus etc. We conducted an end-to-end flight optical subsystem test and a series of tests of the corrosion of the photon sieve due to atomic oxygen. The flight model build will be completed by October 2015with a launch date set for September 2016.