Payload Configuration, Integration and Testing of the Deformable Mirror Demonstration Mission (DeMi) CubeSat

Adaptive optics is an imaging technique that has been used on many ground based telescopes to improve image resolution and reduce the effects of atmospheric turbulence. While adaptive optics has known uses on the ground, applying this technique to space telescopes has major advantages for exoplanet imaging, inter-satellite laser communication, high energy systems, and other military applications. The Deformable Mirror Demonstration Mission (DeMi) is a 6U CubeSat, that will demonstrate the use of adaptive optics, specifically a microelectromechanical system (MEMS) deformable mirror, in space. Not only will the DeMi mission characterize the deformable mirror on-orbit, the mission will also demonstrate deformable mirror control using closed loop image plane sensing and wavefront sensing on internal and external light sources. DeMi uses COTS components like Thorlabs mirrors, Pixelink complementary metal-oxide-semiconductor cameras, and a Boston Micromachines Corporation “multi” deformable mirror. DeMi is currently in the optical integration and testing stage. The payload design and assembly is being tested by assembling 3D printed payload components. Optical alignment and configuration is being tested by mounting the optical components to the 3D printed payload assembly. Current and future testing will inform payload design and payload assembly plan changes. DeMi is expected to launch winter of 2019

Deformable Mirror Demonstration Mission

The Deformable Mirror Demonstration Mission (DeMi) is a 6U cube satellite mission created to demonstrate the use of adaptive optics (AO), specifically a 140 actuator Microelectromechanical systems (MEMS) deformable mirror (DM), in space. While AO has been commonly used on ground based telescopes, it has many useful benefits in space. AO can be a critical difference in reaching the necessary contrast, of 1010, to image Earth-like exoplanets. It allows for corrections of optical imperfections and thermal distortions. These correction capabilities also allow launches of cheaper optics, and have further implications for use with inter-satellite laser communication and high energy applications. DeMi will use a closed-loop adaptive optics system, that incorporates a Shack- Hartmann wavefront sensor (SHWFS), DM, and CMOS cameras, in multiple mission operations to demonstrate the capabilities of this adaptive optics technique. DeMi will launch in to a low-Earth orbit in mid 2019. During its lifetime, DeMi will complete both internal and external observations. The internal observations will use a laser to characterize the DM and test the wavefront correction. The external observations will demonstrate the wavefront correction on stars

The Deformable Mirror Demonstration Mission (DeMi) CubeSat: optomechanical design validation and laboratory calibration

Coronagraphs on future space telescopes will require precise wavefront correction to detect Earth-like exoplanets near their host stars. High-actuator count microelectromechanical system (MEMS) deformable mirrors provide wavefront control with low size, weight, and power. The Deformable Mirror Demonstration Mission (DeMi) payload will demonstrate a 140 actuator MEMS deformable mirror (DM) with \SI{5.5}{\micro\meter} maximum stroke. We present the flight optomechanical design, lab tests of the flight wavefront sensor and wavefront reconstructor, and simulations of closed-loop control of wavefront aberrations. We also present the compact flight DM controller, capable of driving up to 192 actuator channels at 0-250V with 14-bit resolution. Two embedded Raspberry Pi 3 compute modules are used for task management and wavefront reconstruction. The spacecraft is a 6U CubeSat (30 cm x 20 cm x 10 cm) and launch is planned for 2019.Comment: 15 pages, 10 figues. Presented at SPIE Astronomical Telescopes + Instrumentation, Austin, Texas, US

Calibration and Testing of the Deformable Mirror Demonstration Mission (DeMi) CubeSat Payload

The Deformable Mirror Demonstration Mission (DeMi) is a 6U CubeSat that will operate and characterize the on-orbit performance of a Microelectromechanical Systems (MEMS) deformable mirror (DM) with both an image plane and a Shack-Hartmann wavefront sensor (SHWFS). Coronagraphs on future space telescopes will require precise wavefront control to detect and characterize Earth-like exoplanets. High-actuator count MEMS deformable mirrors can provide wavefront control with low size, weight, and power. The DeMi payload will characterize the on-orbit performance of a 140 actuator MEMS DM with 5.5 _m maximum stroke, with a goal of measuring individual actuator wavefront displacement contributions to a precision of 12 nm. The payload will be able to measure low order aberrations to l/10 accuracy and l/50 precision, and will correct static and dynamic wavefront phase errors to less than 100 nm RMS. The DeMi team developed miniaturized DM driver boards to fit within the CubeSat form factor, and two cross-strapped Raspberry Pi 3 boards are used as payload computers. We present an overview of the payload design, the assembly, integration and test progress, and the miniaturized DM driver characterization process. Launch is planned for late 2019

Thermomechanical design and testing of the Deformable Mirror Demonstration Mission (DeMi) CubeSat

The Deformable Mirror Demonstration Mission (DeMi) is a 6U CubeSat that will operate and characterize the on-orbit performance of a Microelectromechanical Systems (MEMS) deformable mirror (DM) with both an image plane and a Shack-Hartmann wavefront sensor (SHWFS). Coronagraphs on future space telescopes will require precise wavefront control to detect and characterize Earth-like exoplanets. High-actuator count MEMS deformable mirrors can provide wavefront control with low size, weight, and power. The DeMi payload will characterize the on-orbit performance of a 140 actuator MEMS DM with 5.5 μm maximum stroke, with a goal of measuring individual actuator wavefront displacement contributions to a precision of 12 nm. The payload is designed to measure low order aberrations to λ/10 accuracy and λ/50 precision, and correct static and dynamic wavefront phase errors to less than 100 nm RMS. The thermal stability of the payload is key to maintaining the errors below that threshold. To decrease mismatches between coefficients of thermal expansion, the payload structure is made out of a single material, aluminum 7075. The gap between the structural components of the payload was filled with a thermal gap filler to increase the temperature homogeneity of the payload. The fixture that holds the payload into the bus is a set of three titanium flexures, which decrease the thermal conductivity between the bus and the payload while providing flexibility for the payload to expand without being deformed. The mounts for the optical components are attached to the main optical bench through kinematic coupling to allow precision assembly and location repeatability. The MEMS DM is controlled by miniaturized high-voltage driver electronics. Two cross-strapped Raspberry Pi 3 payload computers interface with the DM drive electronics. Each Raspberry Pi is paired to read out one of the wavefront sensor cameras. The DeMi payload is ~4.5U in volume, 2.5 kg in mass, and is flying on a 6U spacecraft built by Blue Canyon Technologies. The satellite launch was on February15,2020 onboard a Northrop Grumman Antares rocket, lifting off from the NASA Wallops Flight Facility. We present the mechanical design of the payload, the thermal considerations and decisions taken into the design, the manufacturing process of the flight hardware, and the environmental testing results

MEMS Deformable Mirrors for Space-Based High-Contrast Imaging

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.DARPA; NASA Space Technology Research FellowshipOpen Access JournalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

The Deformable Mirror Demonstration Mission (DeMi) On-Orbit Analysis

The Deformable Mirror Demonstration Mission (DeMi) is a 6U CubeSat mission to demonstrate the use of a 140 actuator microelectromechanical system (MEMS) deformable mirror (DM) and a closed-loop adaptive optics (AO) system in space. DeMi launched to the International Space Station (ISS) on the NG-13 Cygnus resupply mission on February 15, 2020 and was deployed from the ISS into a 51° inclination, 423 km average altitude low-Earth orbit on July 13, 2020. The expected mission lifetime of DeMi was 6 months, however DeMi continues to be operational 9 months post deployment. During its lifetime, DeMi has completed several internal observations with the DM and both imagers using the internal laser source. The team is now working toward external observations of stars and demonstrations of closed-loop wavefront control. The biggest driver of mission success is spacecraft and component health. Looking at spacecraft data over time helps to characterize spacecraft performance and inform adjustments to the lifetime estimate. Additionally, telemetry analysis can alert the operations team of anomalies and provide useful information for resolving those anomalies. This thesis analyzes the spacecraft telemetry received between July 13, 2020 and April 4, 2021 and discusses trends and anomalies in the data. This work provides an overview of spacecraft and payload on-orbit health to date and provides recommendations on paths forward for anomaly resolution.S.M

Optical modeling and testing of the Deformable Mirror Demonstration Mission (DeMi) CubeSat payload

© 2019 SPIE. The Deformable Mirror Demonstration Mission (DeMi) is a 6U CubeSat that will characterize the on-orbit performance of a Microelectromechanical Systems (MEMS) deformable mirror (DM) with both an image plane wavefront sensor and a Shack-Hartmann wavefront sensor (SHWFS). Coronagraphs on future space telescopes will require precise wavefront control to detect and characterize Earth-like exoplanets. High-actuator count MEMS deformable mirrors can provide wavefront control with low size, weight, and power. The DeMi payload will characterize the on-orbit performance of a 140 actuator MEMS Deformable Mirror (DM) with 5.5 μm maximum stroke, with a goal of measuring individual actuator wavefront displacement contributions to a precision of 12 nm. The payload will be able to measure low order aberrations to λ/10 accuracy and λ/50 precision, and will correct static and dynamic wavefront phase errors to less than 100 nm RMS. We present an overview of the payload design, the assembly, integration, and test process, and report on the development and validation of an optical diffraction model of the payload. Launch is planned for late 2019

Optical modeling and testing of the Deformable Mirror Demonstration Mission (DeMi) CubeSat payload

The Deformable Mirror Demonstration Mission (DeMi) is a 6U CubeSat that will characterize the on-orbit performance of a Microelectromechanical Systems (MEMS) deformable mirror (DM) with both an image plane wavefront sensor and a Shack-Hartmann wavefront sensor (SHWFS). Coronagraphs on future space telescopes will require precise wavefront control to detect and characterize Earth-like exoplanets. High-actuator count MEMS deformable mirrors can provide wavefront control with low size, weight, and power. The DeMi payload will characterize the on-orbit performance of a 140 actuator MEMS Deformable Mirror (DM) with 5.5 mu m maximum stroke, with a goal of measuring individual actuator wavefront displacement contributions to a precision of 12 nm. The payload will be able to measure low order aberrations to lambda/10 accuracy and lambda/50 precision, and will correct static and dynamic wavefront phase errors to less than 100 nm RMS. We present an overview of the payload design, the assembly, integration, and test process, and report on the development and validation of an optical diffraction model of the payload. Launch is planned for late 2019.This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]