Tag Archives: space telescope

Astronomers propose giant super Hubble replacement

A major university consortium that manages many ground- and space-based telescopes has proposed that a new giant optical space telescope be built to replace Hubble.

A report published today by the Association of Universities for Research in Astronomy in Washington, D.C., lays out the rationale for another orbiting observatory. It will have a mirror as big as 12 meters across, to both look for habitable planets around other stars and peer deep into the early aeons of the universe.

Hubble has a mirror 2.4 meters across, so this would be significantly larger. In fact, if built this new space telescope would make it bigger than any ground-based telescope that exists today.

As the article notes, the cost over-runs and delays of the infrared James Webb Space Telescope — which went from a $1 billion budget to $8 billion — will likely make Congress reluctant to fund a new giant project like this. Nonetheless, this report gives us a hint of where the astronomy community wants to head in future decades. For the past two decades they have poo-pooed the construction of a new and larger optical space telescope. It appears from this report that this culture is now changing.

Problems with the European Gaia space telescope

Shades of Hubble: The first data from Europe’s Gaia space telescope, launched to map a billion Milky Way stars, will be delayed 9 months while engineers grapple with several problems.

Gaia managers started taking test images early this year, but soon noticed three issues. For one, more light than anticipated is bending around the 10-metre sunshield and entering the telescope.

Small amounts of water trapped in the spacecraft before launch are being released now that the telescope is in the vacuum of space, and more ice than calculated is accumulating on the telescope’s mirrors. In addition, the telescope itself is expanding and contracting by a few dozen nanometres more than expected because of thermal variations.

Mission managers say the number of stars detected will remain the same even if these complications remain untreated, but the accuracy in measurements of the fainter stars will suffer.

Unlike Hubble, however, there is no way to send a shuttle and a team of astronauts to Gaia to fix it. And it sounds like these issues will have an impact on the telescope’s abilities to gather its intended data.

This story raises my hackles for another reason. Gaia was a very technically challenging space telescope to build, but it was far easier and less cutting edge than the James Webb Space Telescope. It also cost far less. What will happen when Webb gets launched later this decade? How likely is it to have similar issues? Based on a story I just completed for Sky & Telescope on the difficulties of building ground-based telescopes, I’d say Webb is very likely to have similar problems, with no way to fix them. The American astronomy community could then be faced with the loss of two decades of research because they had put all the eggs into Webb’s basket, and thus had no money to build anything else.

A private organization focused on preventing asteroids from impacting the Earth today announced its plans to build and launch an infrared space telescope by 2017.

A private organization focused on preventing asteroids from impacting the Earth today announced its plans to build and launch an infrared space telescope by 2017.

New exoplanets make astronomers long for a telescope to see them

The plethora of new exoplanet discoveries has astronomers longing for a telescope that can see them up close.

Astronomers need either a giant space telescope equipped with a device for blocking starlight, or an interferometer, consisting of several telescopes flying in formation. NASA did develop a proposal for such a space telescope, called Terrestrial Planet Finder, and the European Space Agency hoped to fly a similar mission called Darwin. But budgetary constraints have left both missions in limbo, unlikely to advance to the front of either agency’s queue until well into the next decade. At the conference, Traub raised the issue. “People are not thinking deeply about the distant future. People are wrapped up with what they’re doing right now,” he says. “Clearly, I’m concerned.”

Are astronomers finally going to push for a replacement for Hubble?

Astronomers are considering the merger two space missions to create a new optical/ultraviolet space telescope. The mission would be designed to do both deep cosmology and exoplanet observations.

The two communities would both like to see a 4–8-metre telescope in space that would cost in excess of $5 billion. “Our interests are basically aligned,” says [Jim Kasting, a planetary scientist at Pennsylvania State University]. Such a mission would compete for top billing in the next decadal survey of astronomy by the US National Academy of Sciences, due in 2020.

This story is big news, as it indicates two things. First, the 2010 Decadal Survey, released in August 2010, is almost certainly a bust. The budget problems at NASA as well as a general lack of enthusiasm among astronomers and the public for its recommendations mean that the big space missions it proposed will almost certainly not be built.
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