The James Webb Space Telescope at L2
After launch, the James Webb Space Telescope will travel to its orbital destination. Webb will perform its science mission while orbiting a location in space, called the second Lagrange point, or L2 for short. L2 is located one million miles from Earth.
As Webb orbits L2, the telescope stays in line with Earth as it travels around the Sun. L2 is a point where the gravitational influences of the Earth and Sun balance the centripetal force of a small object orbiting with them.
The telescope's optics and instruments need to be kept very cold to be able to observe the very faint infrared signals of very distant objects clearly. This location is perfect for Webb's sunshield to block out light and heat from the Sun, Earth, and Moon. Unlike the Hubble Space Telescope, Webb's orbit keeps the spacecraft out of the Earth's shadow making L2 a thermally stable location for the observatory to operate at.
Webb will operate within its field of regard. The "field of regard" refers to the angles the telescope can move while staying in the shadow of the Sun. Each of Webb's instruments has its own field of view. The field of view is the area of sky an instrument can observe. Webb's fine steering mirror is moved so that an object can be observed by the different instruments. This prevents the whole telescope from having to repoint itself to do so.
The Webb Telescope’s commissioning process will be complete approximately six months after launch, at which time Webb start its science mission. Helping to uncover more of the mysteries of our Universe.
Please give credit for this item to:
NASA's Goddard Space Flight Center
- Aaron E. Lepsch (ADNET Systems, Inc.)