Microfabricated Thermal Switches for Emittance Control

Beasley, Malcolm; Firebaugh, Samara L.; Edwards, R. Lawrence; Keeney, Allen C.; Osiander, Robert

doi:10.1063/1.1649565

Cited by 6 publications

(4 citation statements)

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“…A small supplemental battery would be used to meet peak power demands (maximum of 17. 8 We) during LIBS, Raman spectrometry and communication events. In addition to this baseline design, three alternate RPS concepts were considered that could generate enough power to eliminate the need for a battery.…”

Section: Alternate Rps Power Systemsmentioning

confidence: 99%

Exploring Europa with a Surface Lander Powered by a Small Radioisotope Power System (RPS)

Abelson

Shirley²

2005

AIP Conference Proceedings

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Europa is a high-priority target for future exploration because of the possibility that it may possess a subsurface liquid ocean that could sustain life. Exploring the surface of this Galilean moon, however, represents a formidable technical challenge due to the great distances involved, the high ambient radiation, and the extremely low surface temperatures. A design concept is presented for a Europa Lander Mission (ELM) powered by a small radioisotope power system (RPS) that could fly aboard the proposed Jupiter Icy Moons Orbiter (JIMO). The ELM would perform in-situ science measurements for a minimum of 30 Earth days. The primary science goals for the Europa lander would include astrobiology and geophysics experiments and determination of surface composition. Science measurements would include visual imagery, microseismometry, Raman spectroscopy, Laser Induced Breakdown Spectroscopy (LIB s), and measurements of surface temperature and radiation levels. The ELM spacecraft would be transported to Europa via the JIMO spacecraft as an auxiliary payload with an extended duration cruise phase (up to 13 years). After arriving at Europa, ELM would separate from JIMO and land on the moon's surface to conduct the nominal science mission. In addition to transportation, the JIMO mothership would be used to relay all lander data back to Earth, thus reducing the size and power requirement of the lander communications system. Conventional power sources were evaluated and found to be impractical for this mission due to the extended duration, low level of solar insolation (-3.7% of Earth's), the low surface temperatures (as low as 85K), and the 1.75 days of eclipse every Europa day. In contrast, a small-RFS would enable the ELM mission by powering the lander and keeping all key instrumentation and subsystems warm during the cruise and landed phases of the mission. The conceptual small-RPS is based on the existing General Purpose Heat Source (GPHS) module using thermoelectric conversion. This would generate 225 Wt (thermal) and 10.1 We (electric) at the end of the mission, and would provide a 145% energy margin. A small rechargeable lithium-ion battery would be used to handle peak load demands during the short-duration communication events and while using the higherpower instrumentation (LIBS and Raman). In summary, small-RPS technology could enable an exciting, scientifically valuable Europa lander mission designed to verify the existence of a subsurface ocean, and to search for signs of past or present life.

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Section: Alternate Rps Power Systemsmentioning

confidence: 99%

Exploring Europa with a Surface Lander Powered by a Small Radioisotope Power System (RPS)

Abelson

Shirley²

2005

AIP Conference Proceedings

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“…A thermal switch relies on non-thermal parameters such as electric field, electrochemical potential, or pressure, to alter the device thermal conductance [5]. Several technologies have been reported for thermal switching, including liquid metal actuation [7,8], ion intercalation between layered materials [9], externally biased phase change materials [10], and micro-electro-mechanical systems (MEMS) [11][12][13][14]. However, these devices have typically low thermal switching ratios or slow operation, which limits their potential use.…”

Section: Introductionmentioning

confidence: 99%

“…These novel devices operate at low voltage (∼1-4 V with most close to ∼2 V) and could be reduced to nanoscale dimensions, operating at lower power and higher frequency. In comparison, similar thermal switches have been made with electrostatically collapsible metal membranes [11][12][13][14], however their utility is limited by high operating voltages, from 12 V to 126 V, in part due to the thickness of the metal membranes used. In contrast, graphene is an electrically and thermally conductive two-dimensional (2D) layer of carbon atoms that is ∼3.35 Å 'thick,' with the highest intrinsic tensile strength, stiffness, and in-plane thermal conductivity (2000-4000 W m −1 K −1 when suspended) of any material, comparable only to that of carbon nanotubes and diamond [15,16].…”

Section: Introductionmentioning

confidence: 99%

Graphene-based electromechanical thermal switches

et al. 2021

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Thermal management is an important challenge in modern electronics, avionics, automotive, and energy storage systems. While passive thermal solutions (like heat sinks or heat spreaders) are often used, actively modulating heat flow (e.g. via thermal switches or diodes) would offer additional degrees of control over the management of thermal transients and system reliability. Here we report the first thermal switch based on flexible, collapsible graphene membranes with low operating voltage (∼2 V) and thermal switching ratio up to ∼1.3. We also employ active-mode scanning thermal microscopy to measure the device behavior and switching in real time. A compact analytical thermal model is developed for the general case of a thermal switch based on a double-clamped suspended membrane, highlighting the thermal and electrical design challenges. System-level modeling demonstrates the thermal trade-offs between modulating temperature swing and average temperature as a function of switching ratio. These graphene-based thermal switches present new opportunities for active control of fast (even nanosecond) thermal transients in densely integrated systems.

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“…Beasley et al (2004) describes an alternative approach in which the membrane is fabricated as a micro-electromechanical system (MEMS). The first issue concerns the high DC voltages required achieve good conductive heat transfer between the membrane and the spacecraft skin.…”

Section: Introductionmentioning

confidence: 99%

Electrostatic Switchable Appliqué

Biter¹,

Hess²,

Oh³

2005

AIP Conference Proceedings

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In this paper, the development of a second generation electrostatic radiator (ESR) is described. This device consists of a different operational structure and materials than the first generation ESR. The second generation ESR employs a less insulating membrane than the previous device. Additionally, the insulator has been moved from the membrane to the rigid substrate. This construction results in significantly reduced operating voltages compared to the first generation device. The construction also permits easier fabrication which permits the device to be applied to the spacecraft as an appliqué. This paper discusses the current state of development of the ESR appliqué, its construction and results from laboratory thermal vacuum performance testing.

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Microfabricated Thermal Switches for Emittance Control

Cited by 6 publications

References 0 publications

Exploring Europa with a Surface Lander Powered by a Small Radioisotope Power System (RPS)

Exploring Europa with a Surface Lander Powered by a Small Radioisotope Power System (RPS)

Graphene-based electromechanical thermal switches

Electrostatic Switchable Appliqué

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