The James Webb Space Telescope is facing possible cancelation due to the increasing cost of the project. But according to Matt Mountain and John Grunsfeld of the Space Telescope Science Institute, the telescope will provide an invaluable view of Earth-like worlds.
An estimated $3.5 billion has been spent on the JWST project, with about 3/4 of the construction and testing completed. If JWST is not canceled by Congress, it is scheduled to launch in 2018 on the European Space Agency’s Ariane V rocket.
Five years ago, the project was estimated to cost 2.4 billion dollars, but the latest reports peg the total at closer to 8.7 billion. The Independent Comprehensive Review Panel Report, issued in late 2010, said the main problem was that the necessary development costs had not been properly estimated, and the budget therefore had been unrealistic.
This is what James Webb can uniquely do. Let’s say these cubesats [small satellites designed to hunt for exoplanets] identify in the hundred or so stars that are close to us, based on transits [when a planet passes in front of its star], Earth-sized planets in habitable zones around those stars. That’s all we can learn. We may be able to learn how far away they are from their parent star, their mass and diameter. Those are all good things. And you say, gosh, that looks a lot like Earth. But does it have oceans? Does it have an atmosphere? Are there any chemical signs of interest there? That’s where James Webb comes in, and that’s what James Webb will be able to do with or without a star shade for a subset. The star shade expands that remarkably. It allows you to see the atmosphere of planets that are orbiting nearby stars.
The 18 mirror segments are made of polished beryllium and a thin coating of gold, which will give them optimal reflectance in the infrared. Image Credit: NASA/MSFC/David Higginbotham/Emmett Given