'That's where we basically shake it, to simulate the stresses it will encounter during launch.' They've just finished vibrational testing, Straughn said. The current environmental testing is taking place at Goddard. This spot is called the second Lagrange point, a 'gravitationally semi-stable point.' In other words, Straughn said, it's a pretty good place to park. While Hubble orbits the Earth, the JWST will be about a million miles away, orbiting the Sun along with the Earth. The first is its size: Webb's mirrors are six-and-a-half times as big as Hubble's-the primary mirror is made of 18 individual segments-while the telescope itself is the width of a tennis court (that's the size of its massive Sun shield) and more than three stories tall.Īside from the mirror and Sun shield, the JWST is comprised of science instruments (cameras and detectors to collect data) and a 'spacecraft bus' where the controls and electronics lie. Aside from being an infrared observatory, the JWST has two main differences from Hubble.

Nasa webb telescope tests