NASA Unveils Hubble's Successor
dalutong writes "BBC News has an article detailing NASA's replacement for the much-loved Hubble telescope. The $4.5 billion telescope will be placed in orbit 1.5 million km from Earth and will be almost three times the size of the Hubble. It is set to launch in 2013. They also plan to service the Hubble in 2008."
Although it will see further than Hubble, JWST will see infrared, so that we still need Hubble for the visible and ultraviolet.
An servicing the Hubble is judged to be so risky that NASA originally did not plan to do it. Now they intend to do it, but with a backup shuttle in orbit in case the first one gets into trouble.
I think Gaia probe is more interesting, and it is planned to be launched in 2011 not in 2013 as JWST
The most important aspect here might also be the fact that space expansion is a local event. On a large enough "distance", the speed of that event, if we just tried to add together the relative expansion per unit length, would exceed c. It can certainly approach it. There is/should be matter much farther away than the 2 * 15 bly "bubble" that would be the theoretical maximum of matter simply going in all directions at the point of Big Bang.
Why does this need a sunshield at all? The article says that the telescope should be parked in the 2nd Lagrangian point L2, which is 1.5 Gm from the Earth and should be permanently shaded from sunlight. Isn't the whole point of sending something to L2 that it is not exposed to the sun? Also, how is the energy supply supposed to work? Anyone out there who can shed some light on these questions?
ignatius