The moon is over 238,000 miles from earth and we haven't been back there in nearly 40 years. The James Webb Space Telescope, long-delayed successor to Hubble, is nearly 4X as far away, so if anything goes wrong it can't be fixed. Everything must go right. And so far, it has. 

After a mid-course correction that lasted about 5 minutes, Webb is at its final orbit around L2, the second Sun-Earth Lagrange point.

Lagrangian points allow a spacecraft to "hover" in space, because gravitational forces and the orbital motion of a body can be in balance. L2 is behind our planet if we look from the sun and in that spot JWST orbits the Sun at the same rate as the Earth so it is stable.

JWST won't be alone out there, other missions like Darwin and Gaia will also be around L2.