Document Type

Conference Paper

Journal/Book Title/Conference

AIAA SCITECH 2026 Forum

Publisher

AIAA

Publication Date

1-8-2026

First Page

1

Last Page

9

Abstract

Thermal switches are a key enabling technology for spacecraft operating in extreme thermal environments. Whether surviving the lunar night, managing intermittent high-power loads from deep space communication systems, or dealing with other extreme thermal environments, high-performance thermal switches allow critical missions to operate beyond conventional thermal design limits. This paper presents the development, testing, and performance of a suite of passive thermal switches designed for both spacecraft- and subsystem-level thermal control. The suite includes: (1) traditional in-line switch placed between sensitive components and radiators; (2) compact designs suitable for integration into standard bolted joint interfaces to modulate the conductance between a temperature sensitive component and a thermal sink; and (3) an electronic board mounting design that varies the conductance to the electronics box or chassis. Variants 1 and 2 employ a combination of metals with high positive (Aluminum) and negative (ALLVAR) coefficients of thermal expansion (CTE), enabling reliable and repeatable switching over modest temperature gradients. Variant 3, the electronic board thermal switch, similarly uses a CTE mismatch for passive actuation over temperature but employs Ultem 1000 as the high CTE material and Invar as the low CTE material. This paper describes the various designs and presents initial test data along with discussion of future work to progress the maturity for space flight. These innovations promise enhanced survivability and adaptability for future space missions facing severe thermal challenges.

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