NASA Delays James Webb Space Telescope Again to May 2020


The James Webb Space Telescope (JWST) has seen its fair share of delays (and then some), but we had every reason to expect it would finally launch in about a year. However, NASA now says it needs more time to test the telescope before sending it into space. The latest delay pushes the JWST launch to around May of 2020.

The James Webb Space Telescope is intended as the successor to Hubble, which is now more than 25 years old. Hubble was last services during one of the final Space Shuttle missions, and there are no plans to make another visit. When it stops working, that will be the end of the mission. The JWST was already supposed to be in space at this point, but it’s a complicated project costing more than $8 billion to date. NASA wants to get it right, and that has led to the latest delay.

NASA completed construction of the Webb telescope in late 2016, but that was just the beginning of launch prep. The team has meticulously inspected the giant 270 square foot mirror, which is composed of 18 hexagonal beryllium coated panels. That’s more than five times larger than Hubble’s mirror. NASA even locked the JWST mirror in a vacuum chamber and exposed it to low temperatures to make sure it would operate correctly in space. After that test, we thought all systems were go.

Webb will be much farther away than Hubble at the Earth-Sun L2 Lagrangian point. That means we likely will not be able to repair the telescope if something does go wrong. NASA says it has a few more loose ends to tie up before it’s comfortable launching the telescope. For example, the JWST needs to fold up to fit inside the payload bay of an Ariane 5 rocket, and then deploy itself once it’s in space. Scientists worry that its large and complicated sun shield could snag and end up damaged. Over 180 components need to work perfectly for the sun shield to deploy. The telescope needs to remain protected from the sun so it can take delicate infrared readings from distant objects. NASA also points to problems with a transducer in the propulsion system that require additional testing.

Previously, we expected the JWST to launch in the Spring of 2019. NASA’s new target of May 2020 is still just an estimate. Another delay could still push it back even further. When the James Webb Space Telescope does finally begin operating, it will offer unparalleled views of the universe that could help us study exoplanets, star formation, and more.