News & Analysis Physics World  January 2018

James Webb Space Telescope completes cryogenic testing

(NASA / Chris Gunn)

The $9bn James Webb Space Telescope (JWST) has completed its final round of cryogenic testing at NASA’s Johnson Space Center in Houston, Texas. The tests began last July when the spacecraft’s optical telescope and integrated science instrument module were sealed in a chamber, which is a huge cylindrical vacuum chamber 27 m tall and 17 m in diameter. There, it was cooled to temperatures as low as 11 K using cold helium gas and then put through a three-month testing programme to ensure that the JWST functions in an environment similar to space. The instrument module and optics will now be shipped to Northrop Grumman Aerospace Systems in Los Angeles, where it will be integrated into the JWST spacecraft. Once this is complete, the spacecraft will be subject to a final round of “observatory-level testing” before being launched in the spring of 2019. The telescope will then journey to Lagrange point 2, a location 1.5 million kilometres from Earth.

Hamish Johnston