A View of Telescopes to Come

Though the Hubble Space Telescope is doing better than ever, thanks to last year's servicing mission by the space shuttle Atlantis, the fact remains that progress cannot be stopped. Increasingly large and advanced telescopes are on the drawing board for NASA, the European Space Agency (ESA), or various international collaborations. Each of these machines will put its predecessors to shame, and will cover wider portions of the electromagnetic spectrum than ever before.

“Each generation of telescopes you're launching into space is vastly more capable than the ones before, partly because of larger apertures but also because of better detectors. You're getting a double whammy,” told Space astronomer Rick Fienberg, who is also a press officer of the American Astronomical Society (AAS). Though the James Webb Space Telescope (JWST) is the only approved project so far – and scheduled to launch in a few years – there are other, larger observatories planned for 2015 and beyond as well.

They are massive, and are known as >giant space telescopes, as in larger than giant. They will cover wavelengths spanning from infrared to X-rays, and will be hundreds of times more advanced and sensitive than the instruments they are replacing. The JWST, for example, has a 21-foot (6.5-meter) primary mirror, which will provide it with the ability to collect about seven times more light than Hubble. At 22 meters in length, it dwarfs the famous observatory, which is only 13.4 meters.

But the JWST will in turn be made to look nearly insignificant by the Advanced Technology Large Aperture Space Telescope (ATLAST), which will feature an 8- to 16-meter-wide main mirror. It is scheduled to become NASA's flagship telescope somewhere in 15 to 25 years. Moving to other portions of the electromagnetic spectrum, we meet the Single Aperture Far-InfraRed observatory (SAFIR), which is destined to replace the NASA Spitzer infrared telescope, and the newly-launched ESA Herschel Space Observatory. SAFIR is planned to be about 1,000 times more sensitive than Spitzer.

As far as X-ray observations go, NASA, ESA and the Japanese Aerospace Exploration Agency (JAXA) are planning a joint effort, the International X-ray Observatory (IXO). Currently planned for launch in 10 to 11 years, the instrument will exceed the collecting area of existing telescopes of its kind by more than 20 times over, and will also employ cutting-edge technology that will prevent X-rays being absorbed into the mirrors themselves.

“Even when you build one today and launch one tomorrow, you're already thinking about the one that will come next and laying the groundwork. Otherwise you'll end up with a decade-long gap between missions,” Fienberg concludes.