The Space Dynamics Laboratory (SDL) at USU designed, built and delivered a cryogenic thermal subsystem that will cool the Roman Coronagraph Instrument on NASA’s Nancy Grace Roman Space Telescope. The coronagraph instrument will help scientists locate and identify exoplanets – planets that orbit stars outside of our solar system.
Matt Felt, the branch head for thermal technologies at SDL, said the instrument uses infrared cameras to detect these planets. To function at peak sensitivity, the infrared detectors must be cooled to about 161 degrees below zero.
“And to give you an idea of how cold that is. It's about 100 degrees colder than the coldest temperature that was measured up at Peter Sinks, up Logan Canyon,” Felt said.
The cryogenic thermal subsystem will draw heat away from the instrument using technology known as thermal straps.
“The thermal straps transfer heat from one location to another, without transferring any mechanical energy," Felt said. "If you're connecting to a camera that's really precisely aligned, if you also transfer force into that camera, you can change its alignment."
Felt said this technology was invented at SDL in the mid-90s. The cryogenic thermal subsystem for the Nancy Grace Telescope required further innovation.
“Each optical instrument in space typically has its own requirements.... And this was a challenging one too because they really pushed us on mass, we needed to keep our mass really low,” Felt said.
To conserve mass, SDL constructed thermal straps from sheets of pyrolytic graphite instead of metal. These sheets are about a third the width of a human hair and enable more heat transfer than metal thermal straps of the same size.
“There's a lot of fun things that can happen with those new materials. And it's neat to see the progress and development,” Felt said.
