It’ll Be A Christmas Launch for JWST

The James Webb Space Telescope rolled out to its launch pad today, ready for flight on Christmas Day. The high altitude winds that postponed the launch from December 24 are forecast to be acceptable on Saturday and Arianespace gave the go-ahead for the Ariane 5 rocket and its $10 billion payload to make the trek to their final spot on Earth. Weather or technical issues could always disrupt plans again, but at this moment, the long-awaited launch is at 7:20 am ET on December 25, 2021.

JWST is a joint project among NASA, the European Space Agency and the Canadian Space Agency. ESA is providing the launch at no cost to NASA as part of its contribution.

The French launch services company Arianespace launches Ariane rockets from Kourou, French Guiana on the northeast coast of South America. NASA and ESA photographers provided splendid pictures of the rollout from the ground and the air.

JWST has taken more than 20 years and $10 billion to get to this point, and even after launch will have quite a ways to go before scientists get their first taste of the exciting data the 6.5 meter diameter infrared telescope will collect.

The 32-minute launch window opens at 7:20 am ET. Once JWST leaves the pad, it is on its own. The first two critical actions must take place automatically — deployment of the solar panels 33 minutes after launch and the first mid-course correction engine burn 12.5 hours after launch.

It will take 29 days for JWST to reach its destination at the Sun-Earth Lagrange Point-2 (SEL-2) a million miles (1.5 million kilometers) from Earth. The telescope had to be folded to fit inside the Ariane 5 fairing and during its trip to L2 it must unfold itself in carefully choreographed steps. JWST has 344 single points of failure and 80 percent are associated with deployment. NASA calls it 29 Days on the Edge. Once at L2, many more steps are required before the telescope is ready to begin observations. From launch to operations is a total of six months.

But successful launch and solar array deployment are the sine qua non of the mission. Those must go right for anything else to happen. Everyone will be holding their breath Christmas morning, and not because of what Santa may have left under the tree.