James Webb Observatory to undergo additional testing


NASA's James Webb Observatory will be undergoing additional testing as the combined optics and science instruments of the telescope are now out from their shipping containers.

NASA engineers will be performing final testing at Northrop Grumman Aerospace Systems in Redondo Beach, California, before it travels to the launch site in Kourou, French Guiana. The science payload recently arrived at Northrop after testing at NASA's Johnson Space Center in Houston.

Webb's combined optics and science instruments, the science payload, is the half of the observatory that includes Webb's iconic, 6.5-meter (21.3-foot), golden primary mirror.

The integrated spacecraft and sunshield will soon undergo its own launch environment tests to prove it is ready to be combined with the science payload. Then, additional testing will be performed to guarantee the fully assembled observatory will successfully operate in its orbit at the second Sun-Earth Lagrange point (L2).

The science payload was already separately proven to be able to withstand the rigors of launch and operate as expected at cryogenic temperatures through tests last year at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and at Johnson. Making sure every element of Webb functions correctly before it gets to space is critical, because at that orbit it will be beyond the reach of any servicing missions.

These final tests at Northrop are critical to making sure the fully assembled observatory deploys and operates as expected in space. Deployment is the most critical part of Webb's journey to L2. To reach space, the telescope must fold origami-style inside its Ariane 5 rocket for launch. Once in space and detached from the rocket's payload adaptor, Webb will unfold its sunshield and deploy its mirrors, including its highly complex primary mirror. It will be the first space telescope to complete such an intricate process.

Opening Webb's tennis court-sized, five-layered sunshield is one of the most technically challenging parts of deployment. The sunshield must delicately fold around the telescope for launch and then carefully open in space.

Opening the sunshield requires that about 100 actuators, tiny motors that control the delicate motions of deployment, correctly fire. The sunshield must deploy successfully to ensure the mirrors and science instruments of Webb stay cold enough to be able to detect the extremely faint light of far-away planets, stars and galaxies.