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]

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

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]

Operations Update for the Deformable Mirror Demonstration Mission (DeMi) CubeSat

The Deformable Mirror Demonstration Mission (DeMi) CubeSat payload is a miniature space telescope designed to demonstrate Microelectromechanical Systems (MEMS) Deformable Mirror (DM) technology in space for the first time. MEMSDMscanprovidehigh-precisionwavefrontcontrolwithasmallformfactor,lowpowerdevicewiththe potential to be a key technology option for future space telescopes requiring adaptive optics. Applications of MEMS DMs in space include high-contrast imaging and optical communications. The DeMi payload contains a 140-actuator MEMS DM from Boston Micromachines Corporation whose performance can be measured with both an image plane wavefront sensor and a Shack Hartmann wavefront sensor (SHWFS). The key DeMi mission goals are to measure individual actuator wavefront displacement contributions to a precision of 12 nm and correct both static and dynamic wavefront errors in space to less than 100 nm RMS error. The DeMi mission has raised the Technology Readiness Level (TRL) of MEMS DM technology from a 5 to a 9. This paper summarizes payload data from the first year of in-space operations after briefly summarizing the DeMi optical payload design, calibration, integration and environmental testing results. Ground testing data shows that the DeMi SHWFS can measure individual actuator deflections on the MEMS DM to within 10 nm of interferometric calibration measurements and ground and space data can meet the 12 nm precision requirement for actuator deflec- tion voltages between 0-120 V [1]. Individual actuator measurements from space operations show the MEMS DM actuating in space with similar performance and measurement uncertainty to ground data. Differences between re- peated measurements of individual actuators have a standard deviation of 3-16 nm. Data from inital wavefront control experiments show the DeMi payload correcting wavefront errors in space to less than 150 nm RMS