ESA schedules James Webb Space Telescope for October 2018 launch

 

 US, Canadian, and European space agencies have been working on the James Webb Space Telescope (JWST) in one form or another since the 1990s. The scope and capabilities of the telescope have evolved considerably over that time, but it looks like a launch date may finally be set. The European Space Agency (ESA) has finalized a contract to send the Webb Telescope up on an Ariane 5 heavy rocket in October of 2018.
Getting the JWST into space isn’t as simple as putting a satellite into low-Earth orbit, and the Ariane 5 is one of the few vehicles capable of it. For the telescope’s sensitive instruments to operate as intended, it must be positioned at the Earth-Sun L2 Lagrange point. That’s 930,000 miles (1.5 million kilometers) from Earth. By comparison, Hubble orbits at an altitude of just 347 miles. When placed in the Lagrange point, the telescope will orbit in synchronicity with Earth. Thus, it will maintain a constant distance and be able to use a single shield to block the light from Earth and the Sun. The shield is still quite large (12×18 meters), so it will have to be folded 12 times to fit in the Ariane 5 payload capsule. The 6.5 meter segmented mirror will also be folded up inside the capsule.

The Araine 5 has been flying missions since the mid 1990s, and it has a solid track record. Through its various configurations over the years, the Ariane 5 has made 79 successful launches. Of the small handful of failures and partial failures (four in all), none took place with the current version of the rocket. It has been used to launch a number of important missions in the past, including the Planck observatory and the comet-chasing Rosetta spacecraft.
Scientists and engineers are still assembling the JWST and getting its mirrors in place, but once it’s ready to go, it will be packed inside the upper stage of the Ariane 5 launch vehicle. The rocket consists of a main stage, upper stage, and two solid rocket boosters (SRBs). At lift off, the SRBs will fire with 7,080 kilonewtons of force. They will burn for just 130 seconds before detaching and falling into the ocean. The main stage with its Vulcan 2 engine will carry the payload into space with a lower max thrust of just 1,390 kilonewtons. The main stage is jettisoned after the craft is out of the atmosphere, allowing the upper stage to maneuver into position and deploy the payload.

When the JWST is operational, it will pick up where the aging Hubble Space Telescope is leaving off. The primary mirror on the Web will be considerably larger and capable of higher resolution images. It will be powerful enough to detect the light from the first stars and galaxies that formed after the Big Bang. Exoplanets, brown dwarfs, and internal nebula structures are also fair game. Many of the JWST’s instruments are geared toward infrared astronomy, so it will also take over primary duties from the Spitzer Space Telescope. Everything is (finally) on track for a bright future in space-based telescopes.