Heavenly Idea
Astronomy professor Robert Fesen is sick of clouds. "Astronomical observing is highly dependent on clear skies," he says. "When it's cloudy, students keep asking me, 'Professor, is it gonna clear up?' like I'm the weather man or something."
Fesen can't change the weather, so he is developing a specialized balloon craft that would raise telescopes and other scientific payload above the clouds. NASA thinks he may be onto something. The space agency granted $250,000 to help him get his idea get off the ground.
What Fesen has in mind is a space catamaran: a payload platform suspended between two helium-filled balloons that would hover 22 miles above the Earth. At that altitude the craft would sit above 99 percent of the earth's atmosphere, yet still be positioned a thousand times closer to Earth than satellites.
Named Januus, after the twofaced Roman god, the craft would offer clearer views of space than ground-based telescopes can provide, and at a price far cheaper than the Hubble Space Telescope. Looking downward, the craft could also provide views and measurements of Earth with far greater resolution than satellites. An added advantage of the stationary catamaran would be the ability to carry out continuous studies. The Hubble Space Telescope, for example, orbits Earth every 96 minutes, so it can only target a particular area for less than an hour.
Fesen and colleagues at NASA, the Department of Defense and the Southwest Research Institute are working out Janus' engineering and aeronautic kinks. Prototypes of the torpedo-shaped balloons have already been made from a clear, lightweight nylon. To counter the effects of high- altitude winds, the balloons have been outfitted with solar-powered propellers (Janus would drift with the winds at night, then sprint into position during the day). Fesen estimates that Januswill be able to carry some 750 pounds of payload, so he and the other scientists on the team are eagerly watching advances in miniaturizing computers and lightweight telescopic mirrors.
Launching the catamaran would be relatively easy: fill the balloons with helium and propel the craft into position. Stratospheric conditions, which include carbon monoxide and ultraviolet light, degrade the fabric. So Fesen expects that Janus would need to be brought back to Earth every six to 12 months to replace the balloons. But since the goal is to make Janus as re-usable as possible, Fesen is looking for ways to effect a reverse launch by releasing helium and ballast. "An elegant recovery is the Achilles heel," says Fesen.
Assuming that technological problems can be solved, Fesen estimates that the future price tag of a Janus catamaran would be about $2 million. While not exactly cheap, the cost is a fraction of the astronomical price the next generation of space telescopes is likely to carry. He expects Janus will prove affordable to astronomers, earth scientists and even the telecommunications industry. Fesen hopes Janus' promise will help the project break through more immediate financial clouds. "If we have luck with funding," says Fesen, "we could be flying in five years."
Janus the space catamaran
