High Altitude Airship. (Photo credit: Wikipedia)Sometimes the edge of space can almost be as good as space itself - that is, when it comes to telescopes riding airships at the top of Earth's tenuous and rarefied stratosphere.
High Altitude Stratospheric Airships (HAAs), until now largely the purview of defense-related research, may ultimately find their rightful place as vehicles of science and industry.
At least that's the hope of Sarah Miller, an astronomer and Chancellor's ADVANCE Fellow at the University of California at Irvine.
Miller and colleagues are hoping to turn a February 2014 Keck Institute for Space Studies (KISS) workshop on the potential uses of stratospheric airships for science into a NASA-sponsored challenge to make HAAs a viable astronomical observing platform.
'The military has tried and failed to develop a vehicle, because they tried to move from a [stratospheric] 'Kitty Hawk'[-type] situation to a ' Boeing 747' on extremely aggressive timescales that were all doomed to fail,' said Miller, one of the workshop study's co-leads. 'But astrophysics, cosmology, and earth and atmospheric sciences all motivate the development of these vehicles. So, we could actually see them succeed over the next decade.'
Jason Rhodes, a cosmologist at NASA JPL and also one of the workshop study's co-leads, thinks an airship should be able to operate at a fraction of a cost of a dedicated space mission and at some 20,000 ft higher than the highest flying commercial aircraft.
'About 60,000 ft in the stratosphere is the sweet spot for these craft,' said Rhodes. 'That's about as high as you can go and still have enough of an atmosphere to propulse against.'
Yet researchers say the atmospheric turbulence at that altitude is still low enough to get what is known as telescopic diffraction-limited seeing at optical wavelengths. That means the telescope's resolution of distant objects is only limited only by the size of the telescope's mirror and not by the blurring effects of the atmosphere.
And at such altitudes, astronomers would expect to do much better in the ultraviolet and the sub-millimeter and millimeter ranges.
The Hubble Space Telescope (HST) is currently the only space telescope operating in that ultraviolet wavelength range, says Rhodes, and it will reach the end of its lifetime in 5 to 10 years. Thus, he says in the next decade, even a one-meter aperture stratospheric telescope could 'really complement' NASA's space missions.
However, as Rhodes notes, at 65,000 feet, the airship will still encounter some telescopic jitter from stratospheric winds. It's a problem that Rhodes says HAA designers are still trying to work through.
In principle, a one-meter airship telescope could be up for many weeks or months at a time and do station-keeping which would allow for line of sight communications with a ground station. Likely powered by lightweight propulsive propellers, such an airship's instruments and propulsion system would be run by energy gleaned from solar photovoltaic arrays within or on the airship's surface.
But to date, as Rhodes notes, no one has even demonstrated an airship that could fly for 24 hours at a time at such altitudes. Even so, if there's enough interest in such an airship for astronomy, Rhodes says NASA will run an X Prize-styled challenge over the next couple of years.
Rhodes says NASA has not yet committed itself to running the challenge, but sometime this Fall he and colleagues will initiate a Request for Information (ROI) from potential challenge participants.
'It would be a two-tiered challenge,' said Rhodes. 'The first would be to fly an airship for 20 hours with a small 20 kg payload at an altitude of 20 km for a $1 million prize. A second would be a 200 kg payload at 20 km for 200 hours for a $2 to $4 million prize.'
Entities 0 Name: Rhodes Count: 6 1 Name: NASA Count: 3 2 Name: Miller Count: 2 3 Name: Hubble Space Telescope Count: 1 4 Name: University of California Count: 1 5 Name: Sarah Miller Count: 1 6 Name: Keck Institute for Space Studies Count: 1 7 Name: Jason Rhodes Count: 1 8 Name: HAA Count: 1 9 Name: Irvine Count: 1 10 Name: NASA JPL Count: 1 11 Name: Boeing Count: 1 12 Name: Earth Count: 1 Related 0 Url: http://ift.tt/1u8KvY7 Title: More Eyes on the Skies Description: The future, it is often said, belongs to those who plan for it. And astronomers have been busy working the proverbial smoke-filled rooms (or whatever passes for them today) where the destiny of big science is often shaped and crisscrossing one another in airports on fund-raising trips.
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