For several years I’ve been reading about the Hubble Space Telescope’s successor, the Next Generation Space Telescope (now renamed the James Webb Telescope). I’d always assumed that it’d simply be a bigger, more expensive version of the Hubble – hardly anything worth writing home about.
I was wrong; the people at NASA have been busy and came up with a truly astonishing plan. The Webb Telescope will have a primary mirror over twice the size of Hubble’s at six metres in diameter – this poses a problem because there is no rocket in existence or being planned that could take a solid mirror that size into space. Instead they’ll construct the mirror as 36 different segments and unfold them in space.
The telescope will also have a deployable sunshield the size of a tennis court. As a result, the Webb Telescope will be big, but it’ll only weigh half as much as the Hubble.
It’ll take three months for the Webb telescope to get to its destination, L2 orbit – 1.5 million kilometres away from Earth and way outside the orbit of the Moon. NASA claims it can do all of this for less than a third of the price of Hubble. I don’t think many people appreciate how ambitious the plan is – putting a telescope the size of the Webb into L2 orbit and deploying two large and delicate structures has never been done successfully before. I’m glad to see that at least someone at NASA still has the guts to be adventurous.
(The telescope’s homepage has an endearingly bad design; the FAQ is not endearing though – it’s a bit of a nightmare trying to find all the information).