WASHINGTON — The cryogenic cooling system intended to chill one of the James Webb Space Telescope’s four primary science instruments is still causing problems for contractor Northrop Grumman and remains the top risk to an on-time launch in 2018, the Government Accountability Office said in its latest annual review of the roughly $9 billion NASA astrophysics mission.

“The project continues to face major technical challenges building the cryocooler that have significantly delayed delivery of key components, have made it the driver of the project’s overall schedule or the project’s critical path, and required the use of a disproportionate amount of project cost reserves,” GAO wrote in a report released Dec. 15 and titled “James Webb Space Telescope Project Facing Increased Schedule Risk with Significant Work Remaining.”

As recently as 2013, the cryocooler was scheduled to arrive at NASA’s Jet Propulsion Laboratory for acceptance testing in January 2014. Now, GAO said, the cryocooler assembly now will not arrive until at least April 2015, a date that could slip to November 2015.

JWST cryocooler. Credit: Northrop Grumman
JWST cryocooler. Credit: Northrop Grumman

Northrop Grumman “is very unlikely to meet the current April 2015 delivery date and the compressor assembly is projected to be as late as November 2015, if past performance trends continue,” GAO said.

Northrop Grumman Aerospace Systems, Redondo Beach, California, is building the crycooler under a contract that is separate from the company’s roughly $3.5 billion JWST prime contract.

Northrop got the cryocooler contract from the Jet Propulsion Lab in 2006. The deal, which runs through March 1, 2016, is now worth about $150 million, according to data provided by NASA spokeswoman Veronica McGregor Dec. 11 in response to a Freedom of Information Act request filed by SpaceNews.

The cryocooler contract has twice been modified, most recently in 2012, because of ongoing manufacturing difficulties at Northrop Grumman’s facility in Redondo Beach. Since 2012, NASA’s costs on the contract have risen 120 percent, while the project’s head count has roughly tripled to 110 workers, according to GAO reports released in January and April.


The cooling system is meant to keep the telescope’s European-built Mid-Infrared Instrument chilled to its operational temperature of about minus 255 degrees Celsius.

JWST is expected to cost some $8.8 billion to build, launch and operate for a five-year primary mission at a gravitationally stable Lagrange point some 1.5 million kilometers from Earth. The infrared successor to the visible-spectrum Hubble Space Telescope. JWST is easily the largest NASA science mission in development. Launch is scheduled for October 2018 aboard a European Ariane 5 from Europe’s equatorial spaceport in Kourou, French Guiana.

Dan Leone is a SpaceNews staff writer, covering NASA, NOAA and a growing number of entrepreneurial space companies. He earned a bachelor’s degree in public communications from the American University in Washington.