Micro-Electro-Mechanical Systems (MEMS) Deformable Mirrors (DMs) enable precise wavefront control for optical systems. This technology can be used to meet the extreme wavefront control requirements for high contrast imaging of exoplanets with coronagraph instruments. MEMS DM technology is being demonstrated and developed in preparation for future exoplanet high contrast imaging space telescopes, including the Wide Field Infrared Survey Telescope (WFIRST) mission which supported the development of a 2040 actuator MEMS DM. In this paper, we discuss ground testing results and several projects which demonstrate the operation of MEMS DMs in the space environment. The missions include the Planet Imaging Concept Testbed Using a Recoverable Experiment (PICTURE) sounding rocket (launched 2011), the Planet Imaging Coronagraphic Technology Using a Reconfigurable Experimental Base (PICTURE-B) sounding rocket (launched 2015), the Planetary Imaging Concept Testbed Using a Recoverable Experiment - Coronagraph (PICTURE-C) high altitude balloon (expected launch 2019), the High Contrast Imaging Balloon System (HiCIBaS) high altitude balloon (launched 2018), and the Deformable Mirror Demonstration Mission (DeMi) CubeSat mission (expected launch late 2019). We summarize results from the previously flown missions and objectives for the missions that are next on the pad. PICTURE had technical difficulties with the sounding rocket telemetry system. PICTURE-B demonstrated functionality at >100 km altitude after the payload experienced 12-g RMS (Vehicle Level 2) test and sounding rocket launch loads. The PICTURE-C balloon aims to demonstrate 10 - 7 contrast using a vector vortex coronagraph, image plane wavefront sensor, and a 952 actuator MEMS DM. The HiClBaS flight experienced a DM cabling issue, but the 37-segment hexagonal piston-tip-tilt DM is operational post-flight. The DeMi mission aims to demonstrate wavefront control to a precision of less than 100 nm RMS in space with a 140 actuator MEMS DM.

The nanosatellite optical downlink experiment (NODE) implements a free-space optical communications (lasercom) capability on a CubeSat platform that can support low earth orbit (LEO) to ground downlink rates > 10 Mbps. A primary goal of NODE is to leverage commercially available technologies to provide a scalable and cost-effective alternative to radio-frequency-based communications. The NODE transmitter uses a 200-mW 1550-nm master-oscillator power-amplifier design using power-efficient M-ary pulse position modulation. To facilitate pointing the 0.12-deg downlink beam, NODE augments spacecraft body pointing with a microelectromechanical fast steering mirror (FSM) and uses an 850-nm uplink beacon to an onboard CCD camera. The 30-cm aperture ground telescope uses an infrared camera and FSM for tracking to an avalanche photodiode detector-based receiver. Here, we describe our approach to transition prototype transmitter and receiver designs to a full end-to-end CubeSat-scale system. This includes link budget refinement, drive electronics miniaturization, packaging reduction, improvements to pointing and attitude estimation, implementation of modulation, coding, and interleaving, and ground station receiver design. We capture trades and technology development needs and outline plans for integrated system ground testing.

The CubeSat Laser Infrared CrosslinK mission is a joint Massachusetts Institute of Technology (MIT), University of Florida (UF), and NASA Ames Research Center effort to develop laser communications (lasercom) transceivers. The terminals demonstrate full-duplex intersatellite communications and ranging capability using commercial components to enable future large constellations or swarms of nanosatellites as coordinated distributed sensor systems.CLICK will demonstrate a crosslink between two CubeSats that each host a < 2U lasercom payload. Range control is achieved using differential drag in Low Earth Orbit (LEO), with attitude controlled using a three-axis reaction wheel assembly and attitude sensors, including star trackers.The lasercom terminals are direct-detect and rate scalable, designed to achieve a 20 Mbps crosslink at ranges from 25 km to 580 km and operate full-duplex at 1537 nm and 1563 nm with 200 mW of transmit power and a 14.6 arcscecond (0.07 milliradian) full width half max (FWHM) beamwidth. The terminals also use a 976 nm, 500 mW, 0.75 degree FWHM beacon and a quadcell for initial acquisition, and a low-rate radio crosslink for exchanging orbit information.The payload transmitter is a master oscillator power amplifier (MOPA) with fiber Bragg grating for pulse shaping and MEMS fast steering mirror (FSM) for fine pointing, modeled after the MIT Nanosatellite Optical Downlink Experiment. The transceiver leverages UF's Miniature Optical Communications Transmitter (MOCT) including a chip-scale atomic clock (CSAC). The receiver implements both a time to digital converter (TDC) as well as pulse recovery and matched filtering for precision ranging.