NASA’s next eye in the sky: the Webb space telescope
Author Jacqueline Detwiler Illustration James Provost
Since launching in 1990, NASA’s Hubble Space Telescope has undertaken the study of topics no less ambitious than the formation of planets and the age of the universe—which means its successor practically has to snap a picture of God to make it out from under the Hubble’s shadow. Unsurprisingly, NASA is throwing many millions of dollars of brand-new technology into its next imaging satellite, the James Webb Space Telescope, scheduled to launch in 2018. Using a mirror the size of a swimming pool to capture light from the farthest reaches of the universe, the Webb is expected to be so powerful that it will be able to see the heat signature of a bumblebee from the distance of the moon; hopefully, it will enable scientists to peer at the very beginning of time. Here’s how they’ll build it.
1. Much of the technology for the James Webb Space Telescope had to be invented from scratch—most notably, extra-sensitive infrared detectors that will search for light beyond the red end of the visible rainbow on the electromagnetic spectrum. The distant bodies that the Webb aims to discover are much easier to detect in this range.
2. To ensure that the Webb’s own infrared light doesn’t interfere with even the faintest signals from space, the satellite must be kept extremely cold, just a little above absolute zero. An orbit around a specific point called L2 will keep it in an appropriately chilly spot: one million miles away from Earth and constantly on the far side of the sun.
3. To further protect its massive mirror from heat and light, the Webb will be shielded on the side nearest to Earth and the sun by a shade the size of a tennis court. The mirror and shade won’t fit into a rocket in their open state, so both will be designed to fold up for launch and expand once the telescope is in orbit.