Multispectral Thermal Imager (MTI) Space Cryocooler Development, Integration, and Test

Abstract

This paper presents the selection rationale, development, flight qualification, flight integration, and characterization testing for the Multispectral Thermal Imager (MTI) cryocooler. The MTI program is a technology demonstration effort led by Sandia National Laboratories (SNL) under the sponsorship of the Department of Energy. As part of this effort, Sandia will build, deploy, and operate a small satellite, the core of which is a telescope and focal plane that is cooled to 75 Kelvin using a TRW supplied pulse tube cryocooler. This application, a milestone in the application of active cryocooling, is intended to demonstrate the utility of large capacity, non-split, cryocoolers for space missions.

The cooler for MTI is a near identical, tailored version of the TRW 6020 pulse tube cryocooler, a product of recent long life cooler technology advances, which can provide greater than 2 Watts of cooling at 60 Kelvin. The focal plane is under development at Santa Barbara Research Center (SBRC). Both items are one-of-kind products whose integration occurs in the later phases of the MTI system build, thereby posing potential schedule risks to the overall program success. The existence of a TRW 6020 pulse tube at the Air Force Research Laboratory (AFRL), and it’s similarity to the MTI cryocooler, allowed for characterization testing to be performed with a focal plane thermal mock-up to mitigate this risk. This test and the development of a new thermal strap design will also be presented.