Airships are a unique form of transportation—giant, balloon-like, lighter-than-air vehicles which can stay aloft for extended periods of time. Their design makes them useful for commercial purposes, such as carrying materials or observations from low to relatively high altitudes. We are familiar with ones like the Goodyear blimp, but now NASA wants to take more advantage of this technology, which could be used for everything from astronomy to monitoring climate change.
The space agency is considering issuing a challenge to various interested communities to design a new airship which could fly at high altitudes and also stay aloft for record periods of time. A request for information has been issued by NASA for the proposed “20-20-20 Airship Challenge.” The total prize purse awarded would be from $1 to $1.5 million dollars, with the competition taking place over the next 3 to 4 years.
“We are seeking to take astronomy and Earth science to new heights by enabling a long-duration, suborbital platform for these kinds of research,” said Jason Rhodes, an astrophysicist at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. Rhodes is heading the effort for this challenge.
The original goals of the study were to:
- Inform scientists of the capabilities of airship vehicles as instrumental platforms, as well as discuss how this technology could be expanded and improved to better accommodate science instrumentation requirements.
- Identify science observational/experimental projects that are uniquely addressed by airship vehicles, as well as science which can be supported by airships at a significantly lower cost than other platforms (i.e., satellites).
- Construct science concepts for viable airship platforms.
The proposed competition is divided into two tiers. The first would require getting an airship with a 44-pound (20-kilogram) payload to stay at an altitude of 65,000 feet (20 kilometers) for 20 hours.
As Rhodes explained: “The 65,000-foot mark is the sweet spot where the airship would get as high as possible while still having enough air to propel against, because it needs propulsion to stay in the same spot. It’s also a good altitude in terms of average wind speed.”
In the second tier, the airship would still be at the 65,000-foot (20-kilometre) altitude, but would carry a 440-pound (200-kilogram) payload for 200 hours. This will be challenging, since so far no airship has been able to remain at that altitude for more than eight hours. Some balloons can, but they are not powered the way that airships are, and are more susceptible to wind and other weather conditions.
There are various ways that NASA could use such airships, two of them being astronomy and monitoring climate change. At that altitude, with less atmosphere to interfere, telescopes attached to the ends of the airship could take excellent astronomical images. It is also an ideal vantage point to observe changes in climate and weather over extended periods of time. Another advantage to airships is they can remain in one spot, which improves downlink capabilities.
As Rhodes noted: “You would be able to follow weather patterns, even get above a hurricane. A satellite can’t do that because its orbit can’t be changed.”
As outlined in the study report from the Keck Institute for Space Studies:
Airships would provide a unique and more flexible alternative to other more mature technologies already being used, such as ground measurements, static towers, ships, balloons, aircraft, and satellites.
“An airship provides persistent, high-resolution measurements that fill an observational scale gap in Earth and atmospheric science between ‘anecdotal’ ground-based or aircraft measurements and coarse-resolution satellite measurements. In addition, in situ and remote sensing views of our dynamic and evolving atmosphere, Earth ecosystems, coastal processes, atmospheric plume chemistry, extreme weather, upper troposphere and lower stratosphere processes like convection and exchange across the tropopause could all be made possible using airships. Airships also open up the parameter space of long-duration, high spatio-temporal resolution observations of ‘Urban Dome’ air quality associated with large cities. For instance in astrophysics, a 1-2 meter optical telescope placed at about 65 kft 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.”
Astronomical uses could even include observations of protoplanetary disks around young stars, since there is less water vapor in the atmosphere at those altitudes to interfere with the telescopes. Other possibilities include commercial applications, such as providing wireless internet services to remote locations.
“We’re only limited by our imagination,” Rhodes said. As to whether the airship would be crewed, Rhodes added, “We’re not looking at any manned capability at the moment but that doesn’t preclude that in the future.”
The study concluded with three follow-on recommendations:
- Build a roadmap to stratospheric airship observatories: Establish a “Challenge/Prize” for the development of a maneuverable, station-keeping, stratospheric airship, which can stay aloft at an altitude above 65 kft (20 km) for at least a full diurnal cycle (>20 hours) while carrying a science payload of at least 20 kg in mass.
- Take advantage of existing low and mid altitude airships: Develop a consortium led by atmospheric and Earth science users to make immediate use of existing low altitude airships for a wide variety of science programs.
- Pursue technical development of stratospheric tethered platforms: Construct and fly one or more LTA stratospheric vehicles tethered to the ground, a sea vessel, or even a secondary lower altitude aerial vehicle, to test their use as science platforms.
In terms of Earth studies, such airships could be used for observing:
- The extent and chemistry of the ozone hole
- The transport of air pollution between countries and continents
- The rates of glacial and sea ice retreat
- Changes in land cover and use due to both human and natural causes
- Changing weather patterns due to pollution and land conversion
- The complex interactions between earthquake faults
- The global-scale effects of El Niño and La Niña on weather and the ocean’s state and productivity
- The development and tracking of hurricanes, typhoons, and other severe storms
- Assessing damage from natural disasters and targeting relief
There is also the possibility of using tethered aerostats/airships, which would be less expensive to maintain. Variations of these could include:
- The conventional single stratospheric balloon tethered to the ground.
- Multi-balloon architectures that use lower altitude balloons to carry some of the tether weight and thereby reduce the size and mass of the stratospheric platform and potentially of the overall system.
- Tethering the balloon(s) to a ship at sea both as an aid to initial deployment, where the ship can move with the winds and help reduce the aerodynamic drag loads, and to provide mobility for the system to avoid bad weather or to observe from a different location.
- In contrast to the conventional deployment approach of having the tether always connected to the ground and the aerostat, use the alternative of having the aerostat drop the tether to the ground once at altitude. This requires a separate vehicle (ship, truck) to collect the tether once it reaches the ground and anchor it.
- Tethered multi-balloon concepts that are not connected to the ground but are connected to each other. This concept relies on drag modulation capability on each balloon and different winds at different altitudes to provide station-keeping without the need for propulsion.
- Tethering a high-altitude, stratospheric airship or balloon to a lower altitude, tropospheric “tug” vehicle (Fesen and Brown, in prep.) making use of the east/west wind shear between the stratosphere and upper troposphere to keep the upper platform on station and carrying a science payload (see Figure 5.2).
- Adding lift modulation (wings) to any of the above concepts to help carry tether weight via aerodynamic lift instead of buoyancy.
The challenge also extends to potential competitors who would be interested in building the airship, as well as non-profit organizations to run the challenge or partnering on building payloads. NASA is seeking competitors from a wide range of sources, including small businesses, industry, and academia.
As Sam Ortega, Centennial Challenges program manager, explained, “Formulating a challenge that focuses on the technology of airships is an exciting new sector for Centennial Challenges to explore for a possible prize competition.”
If it goes ahead, the airship competition and construction will significantly increase NASA’s capabilities for both Earth sciences and astronomy in ways not previously achieved. Submissions for the competition will be accepted until Dec. 1. More information is available here; see also the detailed study report from the Keck Institute for Space Studies entitled Airships: A New Horizon for Science.