NASA finishes 100 days of cryogenic vacuum testing on Webb space telescope

JOHNSON SPACE CENTER, HOUSTON, Texas. On November 18, NASA unsealed the 40-metric-ton doors of a cryogenic test chamber at the Johnson Space Center, marking the end of a 100-day cryogenic test phase for the James Webb Space Telescope, to make sure that the telescope's sensitive instruments will work as expected in the cold, airless environment of space. The cryogenic test phase was an important step toward the launch and operation of the telescope, which is considered to be a replacement for the Hubble Space Telescope.

While some instruments had been tested previously in smaller cryogenic chambers, the recently completed test was the first time that the optics and instruments were tested at the same time.

A team from Harris Corp. helped safeguard the telescope while Houston was lashed by Hurricane Harvey during August 2017 and ensured that testing was uninterrupted. Harris has been involved in the design and test of the Webb telescope for 15 years, including designing and installing a multiwavelength interferometer system that aligned 18 mirror segments into a single 6.5-meter phased primary mirror to verify optical quality and placement. According to the Harris team, the 18 gold-plated hexagonal mirrors worked together as one reflective surface during the test.

Engineers at Harris also designed and installed the cryogenic test equipment, including a simulator to mimic the temperature of the sun, and built the structure that held and isolated the telescope during vibration and acoustic testing.

Although the Webb telescope was originally scheduled for launch in late 2018, has postponed the date to early 2019 to give the teams additional time to integrate all the elements of the telescope. Once in operation, the will be the largest observatory in space.

NASA’s James Webb Space Telescope sits inside Chamber A at NASA’s Johnson Space Center in Houston after having completed its cryogenic testing on Nov. 18, 2017. This marked the telescope’s final cryogenic testing, and it ensured the observatory is ready for the frigid, airless environment of space. Photo: NASA/Chris Gunn.

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