The launch of the James Webb will require technological cunning unequaled in the post-Apollo era. The base of the telescope, a six-layer sunshade, is roughly as long and wide as a tennis court. It will sit well beyond the moon, in a special pocket of gravity one million miles from Earth. Rather than orbit the Earth and whirl daily into the hot face of the sun, the Webb will use the combined gravity of the two to hide in a fixed position within the Earth’s shadow. Its 18 hexagonal mirrors, made of beryllium and coated in 24-carat gold, will operate at temperatures near absolute zero — the point at which all motion ceases — in order to remain sensitive to the faint infrared emanations of deep space. In this way movement in the heavens may be likened to sound, of which Emerson wrote, “Let us be silent, that we may hear the whispers of the gods.” Upon arriving in space, the Webb will attempt an unprecedented feat of reverse origami: It will emerge bundled from the tip of an Ariane rocket and slowly unfurl its shade, mirrors, and instruments, becoming in the process the world’s largest space observatory, its seeing power 100 times that of the Hubble. The stakes for this metamorphosis are high, for even with tomorrow’s technology, repair at such a remove from Earth will be impossible. If for any reason the Webb should fail after launch, it will be left to idle in space, out of reach, a stillborn in the void.

via http://www.3quarksdaily.com/3quarksdaily