Lockheed Martin [LMT] scientists were able to triple the power density of a satellite micro-cryocooler by significantly improving the compressor motor design.
Lockheed Martin Advanced Technology Center Research Scientist Jeffrey Olson said Monday in an email improving the cryocooler compressor motor design allows the High Power Microcooler to operate at a high frequency of 140 hertz (Hz) compared to 40-60 Hz for other space cryocoolers. Olson said this increases the input power capability.
Cryocoolers are critical elements of a satellite payload that cool highly-sophisticated electronics like satellite sensors and cameras to allow them to perform properly. Cryocoolers can chill instruments to as low as -320 degrees Fahrenheit. Lockheed Martin said in a statement small cryocoolers mean more affordable satellites and launches.
Olson said the improved compressor motor design also allows for highly-effective heat sinking of the compressor, permitting greater input power into the small compressor volume. Additionally, Olson said the cryocooler coldhead is thermodynamically optimized to operate at high-input power and high frequency.
The High Power Microcooler, Olson said, is available now following rigorous environmental testing in company labs that simulate the space environment. He said Lockheed Martin developed this technology so that future systems can consider this cooling option and design and that the company looks forward to its first flight “soon.”
Olson said instruments primarily chilled by cryocoolers are infrared (IR) sensors found in a wide variety of applications, for tasks like space imaging, aircraft targeting pods and naval missile systems. But cryocoolers are also used in some X-ray and gamma ray detectors, Olson said, and they also have uses for on-site resource utilization. Olson said this includes freezing carbon dioxide from the Martian atmosphere for use as a raw material in oxygen generation.
Olson said Lockheed Martin is briefing several customers on the High Power Microcooler technology for air-, sea- and space-based applications. The High Power Microcooler is designed for continuous operation over a lifespan in excess of 10 years, according to the company.
Lockheed Martin said the High Power Microcooler’s previous design was already the lightest in its class. The new product delivers more than 150 watts per kilogram, which the company called a significant advancement from the 30-60 watts per kilogram rating most space-rated cryocoolers deliver.
The High Power Microcooler also weighs less than a pound, which is less than half the weight of similar cooling systems. Olson said several parts make up a cryocooler: the coldhead, which is about 125 mm long, and the compressor at about 90 mm long. He said the coldhead can be repackaged to a smaller envelope, depending on a customer’s needs (Defense Daily, Aug. 25).