With further delays, Webb telescope at risk of seeing its rocket retired

Enlarge / An Ariane 5 rocket launches in December, 2017. (credit: Arianespace)

The most recent slippage of the James Webb Space Telescope, which now will launch no earlier than March, 2021, has raised some questions about how it will get into space. This is because NASA's chosen rocket for the mission, the proven Ariane 5 launcher, is likely to fly for only a few more years before it is phased out in favor of a newer, less expensive booster.

Back in 2015, when NASA formally reached an agreement with Arianespace to launch on the Ariane 5 rocket, the projected launch date was 2018. NASA partnered with the European Space Agency and its affiliated rocket company for the launch to keep costs down. Essentially, Europe provided a rocket in exchange for some of the observing time. The telescope's massive heat shield was then designed to fold 12 times to fit within the Ariane 5's payload fairing.

Last year, when the telescope's launch date was delayed into 2019, this was still no problem. But the telescope's launch has since been delayed twice more: first into 2020 and then into 2021. The Ariane 5 can still launch during these years. Further delays, however, may prove problematic.