How Hubble would look with the addition of an 8-meter mirror. Photo: Spaceflight Now/HST10X study

A volunteer group of scientists, engineers and shuttle experts believe the Hubble Space Telescope could be equipped with an 8-meter primary mirror, giving NASA what amounts to a new space observatory for half the cost of a new spacecraft.

"An 8-meter class enhancement to HST would provide the capability to do things like detect Earth-like planets orbiting nearby stars at distances up to 10 parsecs," the study team wrote.

Spectroscopic analysis of such planets to detect signs of atmospheric oxygen -- "a sure sign of life," the team said -- would be possible for targets within five parsecs of Earth. In addition, an upgraded telescope also would confirm or deny whether Hubble already has seen into and beyond the era of galaxy formation.

An 8-meter space telescope also could detect Cepheid variables to a distance of 100 million parsecs -- the current limit is 20 Mpc -- and could even detect the signatures of planets forming inside protoplanetary disks.

A simulation that compares the resolution of a HST WFPC2 dithered image (left) with an HST10X exposure of the antenna galaxy. The image with WFPC2 resolution shows little more than the fact that the galaxy is asymmetrical, and has color gradients from the center to edge. In contrast, the simulated HST10X image shows the merger of two nucleated galaxies, and reveals dust and bright knots of star formation throughout the two merging galaxies. Photo: HST10X study

"It is clear from the results of the investigations that augmenting HST to an 8-meter class observatory is feasible, will have much less detrimental impact than previously thought, and will cost of order less than half that of a new spacecraft," the study team concluded.

There's only one problem: NASA did not directly participate in the 1999 study and has no plans to upgrade Hubble, focusing instead on its Next Generation Space Telescope project, a spacecraft targeted for launch around 2007.

Anne Kinney, director of NASA's Origins Program, told Astronomy Now she admired the effort that went into the analysis, but gave it little chance of ever becoming reality.

Kinney said in an email that even if Hubble was equipped with a new mirror, many of its critical components are now decades old. Throw in the cost of a shuttle upgrade mission -- between $400 million and $500 million -- and the project loses much of its appeal.

"There was no knowledge at headquarters about this initiative," Kinney said. "Likewise, there is no support of this initiative at HQ. The problem is that by 2010, the components in [the telescope] will be 30 years old.

"It is a question of which basket you are going to put your eggs in since there are not limitless funds: Building a new telescope with greatly enhanced science capabilities, or refurbishing an aging facility."

While it may be technically feasible to upgrade Hubble, "putting something heavy at the end of a space-borne telescope and then expecting the gyros to be able to turn it and point it and control its vibrations is not easy," Kinney said.

How to build HST10X >