MDI man designed ‘cool’ space telescope device

Ralph Longsworth

BAR HARBOR — This past Christmas Day, a NASA rocket lifted off from Europe’s Spaceport in French Guiana carrying the James Webb Space Telescope, the largest and most sophisticated space observatory ever built. 

Ralph Longworth, a long-time summer resident of Pretty Marsh who now lives at Birch Bay Village in Bar Harbor, was part of the team that made the telescope possible. 

The telescope, which NASA boldly states “will reveal the birthplaces of the stars,” is now in orbit around the Earth. 

NASA says the telescope will offer scientists around the world “the opportunity to observe galaxy evolution, the formation of stars and planets, exoplanetary systems and our own solar system in ways never before possible. 

“After alignment and calibration of the mirrors and instruments, the telescope will be ready for science operations in summer of 2022.” 

To work most effectively, the telescope’s sensors that detect the infrared light emitted perhaps billions of years ago must be super-chilled to minus 448 degrees Fahrenheit – about 11 degrees above absolute zero. Keeping the sensors at that temperature is a cryocooler, a component of which Longsworth designed. 

“The people at Northrop Grumman who built the cooler asked me to design the heat exchanger that is used to carry gas down from room temperature to the low temperature that’s circulated to the detectors,” Longworth said. 

The telescope’s infrared sensors are built to detect radiation that originated with the Big Bang some 13.8 billion years ago. 

“They can see back to several million years after the Big Bang, farther back in time than we have been able to look before,” Longsworth said. “The radiation is very weak, and you can only see it because it is extremely cold. The wavelengths are very long, so you have to have very cold sensors to detect it.” 

According to NASA, “The James Webb Space Telescope’s optics and scientific instruments need to be cold to suppress infrared background ‘noise.’ Moreover, the detectors inside each scientific instrument, which convert infrared light signals into electrical signals for processing into images, need to be cold to work just right.” 

The cryocooler on the telescope is a many-generations advancement over a cooling device – called a pulse tube refrigerator – that Longsworth designed and built as a young scientist at Syracuse University in the early 1960s. He said later versions of that refrigerator were used for many years to cool the magnets on MRI machines. 

“The other big application has been for creating ‘high vacuums’ that are widely used in the semiconductor industry because they run at low temperatures,” Longsworth said. 

He spent much of his career with Sumitomo Cryogenics of America in Allentown, Pa., and he is still a consultant for the company. When Sumitomo’s research and development labs were renovated a few years ago, they were named the Ralph C. Longsworth Technology Center. 

Reflecting a lifetime of scientific invention, Longsworth holds, either by himself or with colleagues, more than 70 patents or patents pending. 

The James Webb Space Telescope is named for a former NASA administrator. 

Dick Broom

Dick Broom

Reporter at Mount Desert Islander
Dick Broom covers the towns of Mount Desert and Southwest Harbor, Mount Desert Island High School and the school system board and superintendent's office. He enjoys hiking with his golden retriever and finding new places for her to swim. [email protected]

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