Over the next three weeks-plus, the James Webb Space Telescope will play out an unfurling and deployment in deep space unlike anything this world has seen before.
It took decades to perfect the observatory — a segmented telescope on a heat shield the length of a tennis court that was squeezed for launch into a rocket payload compartment less than 30 feet in diameter. The unfurling has begun and will continue over 25 more days, with 50 major deployments and 178 release mechanisms to set the pieces free.
The process has been likened to the undoing of an origami creation, or like the opening of a massive, many-featured Swiss army knife but without a human to pull the parts out.
Adding to the stress of these days, the JWST will be much further out into space than the Hubble Space Telescope, which is in a very close orbit around the Earth at an altitude of about 340 miles. The JWST will be over 930,000 miles away from Earth at the stable orbital point called the second Lagrange point 2 (L2) — way too far away for any manual fixes or upgrades like the ones accomplished by astronauts for the Hubble.
Four days after liftoff, the observatory has unfurled some of its solar panels, has deployed some of the pallet that will hold the sunshield and has extended the tower assembly about 6 feet from its storage space. Here is a video from the Goddard Space Flight Center illustrating all the steps needed to make JWST whole:
And here is a more detailed depiction of the many stages of deployment, what is being deployed and how.
JWST will have the largest telescope mirror ever sent into space — 21 feet in diameter compared with the Hubble’s 8-foot diameter. Because it is so large, it had to be divided into 18 hexagonal segments of the lightweight element beryllium, each one roughly the size of a coffee table. Together, the segments must align almost perfectly, moving in alignment within a fraction of a wavelength of light.
Webb mission systems engineer Mike Menzel, of NASA’s Goddard Space Flight Center, said in a deployment-explaining video called “29 Days on the Edge” that every single releases and deployment must work.… Read more