James Webb Space Telescope scheduled to launch in 2021, the Telescope will orbit about 930,000 miles (1.5 million kilometers) away from Earth. The James Webb Space Telescope is the planned successor to the Hubble Telescope. The cost of the telescope has nearly doubled—to $9.7 billion—since 2009.
For months, inside the towering Building 29 here at Goddard Space Flight Center, the four scientific instruments at the heart of the James Webb Space Telescope have been sealed in what looks like a house-sized pressure cooker. A rhythmic chirp-chirp-chirp sounds as vacuum pumps keep the interior at a spacelike ten-billionth of an atmosphere while helium cools it to –250°C. Inside, the instruments, bolted to the framework that will hold them in space, are bathed in infrared light, focused and diffuse, in laserlike needles and uniform beams—to test their response.
When we look at a distant galaxy light years away, we aren’t seeing it in its most recent state. Its distance in light years translates to the number of years it takes for its light to arrive to Earth. For example, the closest galaxy to ours is the Canis Major Dwarf Galaxy which is 25,000 light-years away, so its light takes 25,000 years to reach Earth. The James Webb Space Telescope will detect infrared light that is 400 times fainter than current space-based telescopes can see.
James Webb Space Telescope contains 8-meter mirror would never fit inside a rocket fairing, so it would have to fold up for launch. The sunshield, too, would have to be collapsible and made of a superthin, lightweight membrane. And the telescope structure would have to be absolutely rigid but lightweight enough to limit the weight of the whole orbiting observatory to no more than 6 tonnes, just a few percent of the weight of a similar-size ground-based telescope.
Another critical technology, the microshutter array in the near-infrared spectrograph, also succumbed. This is a device the size of four postage stamps with a grid of 250,000 tiny flaps that can be opened selectively so that the instrument can take separate spectra from, 100 galaxies in a single field of view—the first such multiobject spectrograph to fly in space.
Webb’s infrared capabilities are also crucial for observing these galaxies. Light from distant galaxies will be stretched out by the expanding universe. By the time the light reaches our telescopes, its original wavelength will have shifted from the visible or ultraviolet to the infrared. Luckily, picking up infrared signals is right up Webb’s alley.
Young stars emerge from the dustiest pockets where it’s most challenging to see through. Thanks to Webb’s high infrared sensitivity and spectacular resolution, scientists might be able to sift through the dust to make out these infant stars with unprecedented detail. And Webb might help scientists figure out how the dust cooks up a star, why stars form in clusters and how planets form around a star.
Webb will be the first telescope of its kind in terms of its size, sensitivity and wavelength range altogether. With its capabilities, a good chance exists scientists will get to see something they’ve never seen before.
After successful completion of its final tests, NASA’s James Webb Space Telescope is seen here being prepared for shipment to its launch site. NASA plans to launch the James Webb Space Telescope into orbit Dec. 18, 2021, to serve as the premier deep space observatory for the next decade.
