The Naval Air Engineering Station in Lakehurst New jersey must be one of the most famous airfields in the world. If you’ve ever watched the extraordinary footage of the German passenger airship Hindenburg catching fire as it attempted to moor, you’ll have seen Lakehurst. That’s where the disaster took place.
Despite its notorious past, Lakehurst is still a centre of airship engineering and technology. In 2012, it was home to the Long Endurance Multi-Intelligence Vehicle, an airship designed and built for the US military to use for surveillance purposes over Afghanistan.
The vehicle is colossal–91 metres long, 34 metres wide and 26 metres high, about the size of a 30 story office block on its side. And it is designed to fly uncrewed at about 10 kilometres for up to three weeks at a time. But last year, the program was cancelled and the airship sold back to the British contractor that built it, which now intends to fly it commercially.
And therein lies the problem. Despite huge promise, airships have never reached their potential.
Today, Sarah Miller and few pals have prepared a report for the Keck Institute of Space Studies in Pasadena suggesting that scientists have unnecessarily ignored the advantages of airships and that the time is right for a new era of science based on this capability.
While scientists have invested hugely in orbiting observatories, Earth observing satellites and numerous ground-based experiments, there has been little interest in airships as platforms for scientific experiments.
That’s partly because of the lack of development of these vehicles, perhaps because of disasters such as the one that befell the Hindenburg.
Nevertheless, airships have huge potential. “Our study found considerable scientific value in both low altitude and high altitude airships across a wide spectrum of space, atmospheric, and Earth science programs,” say Miller and co.
At altitudes of up to 20 km, they can survey wide areas of the planet for long periods of time, monitoring pollution, earthquakes or providing telecommunications support.
At this altitude, they are also above most of the atmosphere and all of the atmospheric water. This makes them the perfect platform for telescopes. “In astrophysics, a 1-2 meter optical telescope placed at about [20 km] with state-of-the-art pointing stability would have superior resolving power to any optical ground-based telescope, providing exceptional image quality night after night above the weather,” say Miller and co.
What’s more, airships would be fantastically cheap compared to satellites. A typical orbiting observatory or Earth-observing mission costs in the region of $1 billion for a single use instrument with a relatively limited life. Even the airborne infrared telescope, SOFIA, which is carried aboard a modified Boeing 747, cost well over $1 billion and per hour of observation is almost as costly as the Hubble Space Telescope.
By contrast, an airship-based mission would cost perhaps tens of millions and be reusable many times over.
The problem, of course, is that airships capable of these missions have not yet been built. Most of the well funded development has come from the military for long duration surveillance missions. But with the end of the wars in Iraq and Afghanistan and the downsizing of the US military machine, this funding has dried up.
But Miller and co have a suggestion. They say that innovation in this area could be stimulated by setting up a prize for the development of a next-generation airship, just as the X-Prize stimulated interest in reusable rocket flights. The goal, they say, should be to build a manoeuvrable, stationed-keeping airship that can stay aloft at an altitude of more than 20 km from least 20 hours while carrying a science payload of a least 20 kg.
That’s a significant challenge. One problem will be carrying or generating the power required to propel the airship. This increases with the cube of its airspeed and so will be the biggest drain on the vehicle’s resources.
Another challenge is to handle the thermal loads at this altitude, where temperatures can vary by as much as 50°C and where there is little air to carry heat away.
But none of these problems look like showstoppers. Given the right kind of incentives, it should be possible to put one of these things in the air in the very near future, perhaps based on the technology developed for vehicles like the Long Endurance Multi-Intelligence Vehicle.
All that’s needed is a sponsor willing to cough up a few million dollars for a prize. Anybody with a few bucks to spare?
Ref: arxiv.org/abs/1402.6706 : AIRSHIPS : A New Horizon for Science
Visit site: