NASA James Webb Space Telescope
We were having lunch with an astronomer the other day when the subject of the James Webb Space Telescope came up. Somewhat to our surprise, he was not particularly interested in the JWST. Nor was his lack of interest simply due to the instrument’s enormous cost and uncertain schedule. He was much more excited more excited about the new PLANETS telescope being built in Hawaii.

PLANETS, which stands for Polarized Light from Atmospheres of Nearby Extra-Terrestrial Systems, is designed to have a very high dynamic range. That means it can see dim objects that are close to very bright objects. The PLANETS telescope will allow astronomers to determine the atmospheric composition of exoplanets circling nearby stars.

Exoplanet research is one of the hottest fields in astronomy right now. Being able to determine atmospheric composition would be a big step forward. Right now, astronomers can tell little about exoplanets beyond size, mass, and basic orbital parameters. Determining atmospheric composition would provide important clues about surface composition including, possibly, the presence of life. (Free oxygen in the atmosphere would be a tell-tale sign.)

The JWST is not well-suited for exoplanet research. It is designed for infrared astronomy and deep-space cosmology. Since work started on JWST, there have been major advances in ground-based infrared astronomy. Space-based infrared astronomy has a big advantage, since the Earth’s atmosphere blocks many infrared wavelengths. Ground-based infrared astronomy is still possible, though, by looking through infrared windows at specific wavelengths, and the technology for ground-based telescopes has been advancing a lot faster than JWST has.

There’s an arms race going on between space-based and ground-based astronomy. Space-based astronomy is falling behind right now. It will continue to fall behind as long as instruments like JWST take decades to develop and build.

The PLANETS telescope is a relatively small instrument, just 1.9 meters (75 inches) in diameter. We couldn’t find any published cost figures for it, but instruments in this class generally cost millions, rather than billions, of dollars. The giant Thirty-Meter Telescope in Chile is expected to cost $300 million. (JWST is expected to cost at least $8.7 billion.)

Then there’s the Kilodegree Extremely Little Telescope, a small-aperture wide-field telescope which cost just $75,000. The KELT uses a Mamiya medium-format camera lens – an 80 mm f/1.9  or a 200 mm f/2.8 APO, depending on the observations to be performed. Despite its low cost and small size, KELT has already discovered some interesting exoplanets. This shows the power of modern technology, which is now within the reach of citizen scientists.

To put these costs into perspective, the amount of money being spent on JWST could buy 29 Thirty-Meter Telescopes or 116,000 KELTs. Unless this disparity is addressed, someone will start questioning why NASA is spending money on space-based astronomy.

Another interesting data point is the Atsa Suborbital Observatory being developed by Dr. Faith Vilas of the Planetary Science Institute and Dr. Luke Sollitt of The Citadel. This space telescope, which is designed to study objects close to the Sun, will fly on the XCOR Lynx Mark III. Lynx flights are currently selling for $97,000. So, the amount of money being spent on JWST would buy more than 89,000 flights of the Atsa Observatory – and that assumes the cost of Lynx flights wouldn’t drop at all due to the enormous flight rate!

Clearly, suborbital telescopes will not replace orbital (or ground-based) astronomy. It is obvious, though, that NASA and its political masters need to be smarter in how they spend their money if space-based astronomy is to win the technological arms race.

Written by Astro1 on September 30th, 2012 , Astronomy

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