Active Optical Correctors for Large Inflatable Telescopes

Lesser, David; Graves, Logan R.; Walker, Christopher K.

doi:10.1109/tthz.2019.2918553

Cited by 3 publications

(2 citation statements)

References 16 publications

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“…Our iron-based superelastic alloys have small critical stress changes at lower temperatures (Fig. 2B), which means that alloys such as our 3Cr alloy have potential for use as springs for unfolding telescopes (35), exploration rover tires (36), and vibration control system of spacecraft, as well as applications in lunar infrastructure development (37).…”

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confidence: 99%

Iron-based superelastic alloys with near-constant critical stress temperature dependence

Noguchi

et al. 2020

Science

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Shape memory alloys recover their original shape after deformation, making them useful for a variety of specialized applications. Superelastic behavior begins at the critical stress, which tends to increase with increasing temperature for metal shape memory alloys. Temperature dependence is a common feature that often restricts the use of metal shape memory alloys in applications. We discovered an iron-based superelastic alloy system in which the critical stress can be optimized. Our Fe-Mn-Al-Cr-Ni alloys have a controllable temperature dependence that goes from positive to negative, depending on the chromium content. This phenomenon includes a temperature-invariant stress dependence. This behavior is highly desirable for a range of outer space–based and other applications that involve large temperature fluctuations.

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confidence: 99%

Iron-based superelastic alloys with near-constant critical stress temperature dependence

Noguchi

et al. 2020

Science

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“…Deformable mirrors which actively change shape at sub-wavelength precision have a wide array of applications in space, such as future missions to image Earth-like exoplanets (Levine et al, 2009;Stapelfeldt et al, 2014;Pueyo et al, 2019;Ruane et al, 2019;Gaudi et al, 2020;Kasdin et al, 2020), correction of scattered light imaging of dim debris disks (Chakrabarti et al, 2015;Cook et al, 2015;Sirbu et al, 2015;Douglas et al, 2018;Maier et al, 2020), reconfigurable telescopes (Underwood et al, 2015), and error correction for deployable or inflatable apertures (Dolkens et al, 2019;Lesser et al, 2019). Micro-electromechanical systems (MEMS) Deformable Mirror (DM)s are included in designs for many future exoplanet imaging missions due to relatively high actuator counts which allow correction of high-order spatial errors, and low Size, Weight, and Power (SWaP) (Pueyo et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Small Mirrors for Small Satellites: Design of the Deformable Mirror Demonstration Mission CubeSat (DeMi) Payload

Douglas

Allan

Morgan

et al. 2021

Front. Astron. Space Sci.

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The Deformable Mirror Demonstration Mission (DeMi) is a technology demonstration CubeSat to test a 140 actuator micro-electromechanical system (MEMS) deformable mirror in low-Earth orbit. Such mirrors can provide precise wavefront control with low size, weight, and power per actuator. Hence, they have the potential of improving contrast in coronagraphs on future space telescopes. In the DeMi payload, a Shack Hartmann lenslet array based wavefront sensor monitors the deformable mirror, illuminated by either an internal 636 nm laser diode or external starlight. This work describes the instrument design drivers and CubeSat implementation, and briefly illustrates operation on orbit by comparing ground-based measurements of a displaced actuator to an on-orbit measurement using the internal laser source. The 6U CubeSat was launched on February 25, 2020 and deployed from the International Space Station on July 13, 2020.

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A lightweight strain glass alloy showing nearly temperature-independent low modulus and high strength

Liu

Tang

et al. 2022

Nat. Mater.

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Fast development of space technologies poses a strong demand for elastic materials that are lightweight, strong, but compliant to achieve high density of elastic energy storage, and such properties need to be temperature-insensitive in space environments [1][2][3][4] . However, existing materials do not meet this demand.Here we report a lightweight magnesium-scandium (Mg-21.3 at. % Sc) alloy meeting this demand. It is as light and compliant as organic-based materials like bones and glass ber reinforced plastics, but stronger than them [5][6][7] ; thus, it exhibits a record-high elastic energy density ~0.5 kJ/kg among various metallic and organic-based composite materials at a moderate stress level of 200 MPa 8,9 . Importantly, the performance can persist for 1 million stress cycles and over a wide temperature range from ambient to cryogenic temperatures. Its exceptional properties stem from a strain-glass transition. In-situ microstructure observations during cooling show strain-glass nanodomains continuously form from the matrix phase, which enables low modulus, high strength, fatigue-resistance, and temperature-insensitivity.The lightweight strain-glass Mg-Sc alloy may nd applications in space technologies and other elds such as orthopedics 1,9-11 . Main TextMagnesium alloys have the lowest density (ρ ~2 g/cm 3 ) among all metallic structural materials, being comparable with a number of organic-based natural or arti cial materials like bones, hard wood and glass ber reinforced plastics (GFRP) 6,7,12,13 . Therefore, they have the potential to be a solution to various lightweight elastic components in space technologies such as tires, springs and seals 1-3 . These applications require a high weight-speci c elastic energy density (i.e., elastic energy per unit weight) under a moderate stress level (e.g., ~200 MPa) 4,8,9 and such a property needs to be insensitive to temperature changes (e.g., 290-120 K in Mars) 4 . As the weight-speci c elastic density U is de ned as U=σ 2 /2ρE, where σ denotes the stress and E the elastic modulus, a promising candidate material needs to possess a combination of low density, low modulus and high strength, together with the property stability over a wide temperature range. However, existing Mg-alloys are challenged by a trade-off relation between elastic modulus and strength (see Fig. 1) [14][15][16][17][18][19][20][21][22][23][24][25][26] , which precludes achieving low modulus and high strength simultaneously; meanwhile the desired property stability over a wide temperature range is challenged by the inevitable hardening of metallic bonding with decreasing temperature.Recently, shape-memory effect and superelasticity have been reported in a Mg-20.5 at. % Sc (Mg-20.5Sc) shape-memory alloy (SMA), as a result of a martensitic transformation 27 . Although the large superelasticity provides a possibility for lightweight elastic energy storage, the Mg-20.5Sc alloy possesses the same drawbacks of other SMAs 28 -the inherent temperature sensitivity of superelasticity and thus a narrow wo...

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Active Optical Correctors for Large Inflatable Telescopes

Cited by 3 publications

References 16 publications

Iron-based superelastic alloys with near-constant critical stress temperature dependence

Iron-based superelastic alloys with near-constant critical stress temperature dependence

Small Mirrors for Small Satellites: Design of the Deformable Mirror Demonstration Mission CubeSat (DeMi) Payload

A lightweight strain glass alloy showing nearly temperature-independent low modulus and high strength

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