The US space agency announced on Wednesday that the James Webb Space Telescope’s (JWST) tripod structure had successfully unfolded and latched into place. As an animated NASA tweet showed, only one arm of the 25-foot-tall tripod actually had to move, folding out from behind the massive primary mirror, which remained folded underneath it.
The secondary mirror is necessary for focusing the light captured by the massive primary mirror onto the small instruments at its center, which effectively function as the telescope’s “camera.”
Another set of smaller mirrors inside the “camera” further focus the image.
"Another banner day for JWST," said Bill Ochs, NASA’s program manager for the Webb telescope. "We actually have a telescope."
Earlier this week, the Webb telescope deployed its five-layered, tennis court-sized sun shield, which will ensure the telescope only gets the clearest images of deep space. However, it won’t be taking any such pictures until it’s arrived at a stable orbital position called the L2 Langrangian point, where the Earth’s and the Sun’s gravities are balanced against one another.
The gold-covered primary mirrors of the James Webb Space Telescope, revealed in the cleanroom at NASA Goddard.
© Flickr / NASA's James Webb Space Telescope
Webb must also unfold its primary mirror, which is seven times larger than the Hubble’s at 21 feet 4 inches across, and focus it down to nanometer accuracy - a process that will take at least a month. It’s composed of 18 separate hexagonal mirrors made of beryllium substrate and coated with a microscopically thin layer of gold to ensure maximum reflectivity.
Once it’s ready, Webb will peer its massive eye into ultra-deep space which, because nothing travels faster than light, allows scientists to glimpse the earliest moments of the universe more than 13.5 billion years ago.
The satellite was launched into space on December 25, 2021.