London, Jan 14: The James Webb Space Telescope (JWST) scheduled for launch on a European Ariane 5 from Kourou in 2013 has been designated as the Hubble Space Telescope’s successor.
Dr. John Mather, the senior project scientist on the JWST, said the telescope would primarily “extend the science that Hubble had pioneered”.
While Hubble gazed at the Universe in optical and ultra-violet wavelengths, JWST, named after a former NASA administrator will look primarily in the infrared.
"The infrared is where the new science seems to be, and where this mission has a special and unique advantage. Infrared astronomy is particularly important for understanding about the processes that went on in the early Universe,” said Dr. Mather.
“Distant objects in the Universe are moving away from us at very fast speeds - and this has an interesting effect on the light they emit. It gets shifted to longer wavelengths: the "red" part of the spectrum. The infrared is therefore essential to seeing the farthest - and therefore the earliest - objects to form in the Universe, a consideration that was one of the most important driving factors behind the design of the telescope.
"We know what the theories are predicting about these early objects, we know how bright and how far away they are supposed to be and what kind of telescope it would take to see them. So we said, 'it can't be a small telescope, it has to be a big one, and it has to work at certain infrared wavelengths'," he said.
Mather is now directing construction of the JWST at NASA’s Goddard Space Flight Center in Maryland.
The JWST boasts of huge mirrors and has a sunshield the size of a tennis court. Its primary mirror will be 6.6m (22ft) in diameter, compared to the Hubble's 2.4m (7.9ft) mirror. In fact it is so big that it has to be folded up to get it into the rocket fairing.
According to the BBC, the large shield has been designed to block light from the Sun, Earth and Moon that would otherwise heat up the telescope.
Dr. Mark Clampin, observatory project scientist for JWST, said the telescope has been “designed to operate at cryogenic temperatures, on the order of 40 Kelvin (-233C, -388F)”.
“By doing that, we get the background of the telescope down so that we're looking at red light coming from the early Universe," said Dr. Clampin.
"Hubble is a conventional telescope. It has a 2m primary mirror with a secondary mirror. JWST has a segmented primary mirror comprised of 18 individual elements. It gives us a lot more flexibility during its lifetime because we can actually tweak up the performance of the telescope,” he said.
"A lot of the technology builds on what we've done with Hubble, but takes it to the next level," he added.
According to astronomers, JWST will also be able to detect extrasolar planets through the transit technique and examine the formation of planetary systems, a phenomenon that has befuddled scientists for more than 50 years.
The telescope will also aim to shed light on the origins of life.
"We may be able to see something about the atmospheric chemistry of planets. If the planet's small enough, we may be able to learn about organic chemistry on an Earth-like object. We need luck on this one. We need people to go and survey all the nearby stars for planets and select the best targets. Maybe we'll get lucky," Dr. Mather added.