The James Webb Space Telescope left Earth behind on Christmas Day in a launch that, to all outside observers, appeared flawless. Now, NASA has confirmed that the Ariane 5 rocket did indeed complete its task with extreme precision. In fact, the launch went so well that the observatory’s fuel reserves are showing a surplus. NASA says it’s on track to have enough fuel to support more than ten years of science operations.
NASA has spent about 20 years and $10 billion building the Webb telescope, which will pick up where Hubble left off. Hubble was launched in 1990 with a planned life span of 15 years, but it’s now more than 30 years old. Webb won’t be close enough to Earth for servicing missions, so it has to carry everything with it out past the orbit of the moon to the L2 Lagrange point. NASA designed Webb to last at least five years with ten years being the best-case.
The limiting factor for Webb is fuel. The Lagrange point is a region of gravitational stability where the observatory can remain with relatively little adjustment. However, it also needs fuel to get pointed in the right direction for observations. Once it can’t do that, astronomers on Earth will be out of luck.
NASA originally estimated that Webb would have enough fuel for ten years, but the Ariane 5 managed to deliver Webb into a perfect orbit. This saved Webb from burning through too much of its own fuel during the early stages of the mission — the solar panel even deployed ahead of schedule because the team designed this as an automated function based on orbital parameters. The first course correction maneuver also went perfectly, adding 20 meters per second to the spacecraft’s speed.
Webb will spend the next several weeks deploying as it coasts toward its final destination. NASA is working on deploying the sunshield, and the main communication antenna is already up. There are hundreds of little things that have to go right along the way, and then it will take months of testing and calibration before we get the first images. But the observations could go well beyond ten years thanks to the abundance of fuel remaining after launch.
Once it reaches L2, Webb will be able to see farther and with greater detail than Hubble. Not only does Webb have a comparatively enormous primary mirror, but its instruments are designed to see deeper into the infrared, revealing things that we cannot see in the visual spectrum. Webb is so powerful that it might even be able to detect artificial lights on nearby exoplanets — assuming there’s anyone living there to build artificial lights.