The problem is getting them to stay in the harsh environment.
Image: Keck Institute for Space Studies
Until recently, blimps were good for little more than taking pictures of football games and helping to sell tires. But new technological advances have changed blimps and other airships from a punchline into a platform that could be used, in many instances, to replace satellites.
Last year, researchers from NASA, Caltech, Lockheed Martin, and Northrop Grumman met to discuss the future of airships, and many of them believe that the future of surveillance, environmental monitoring, and even astronomy lies in airships that hover somewhere in the stratosphere, between 8 and 50 miles above the Earth’s surface. From those altitudes, airships can perform many of the functions that satellites already do, such as monitoring climate, imaging the Earth’s surface, and even hosting cell phone networks. Researchers even think that airship-tethered telescopes would have capabilities that rival the Hubbel Space Telescope and far surpass anything we have stationed on Earth.
Last month, the Keck Institute for Space Studies released a report based on the researchers’ meeting about the future of airships and, if we’re able to figure out some geopolitical and technological concerns, it’s looking like they could be a disruptive force.
In a way, an airship could function as a surrogate satellite but offer much shorter transmission distances and ranges and thus higher resolution for connectivity of ground transmitters and receivers … A stratospheric astronomy airship could provide space-like observing conditions across a broad range of wavelength regimes and be launched quickly, affordably, and repeatedly. Even a modest telescope at stratospheric altitudes would provide image quality that could compete with space-based telescopes.
Airships are gigantic, slow, and kind of difficult to move around, but actually, that’s perfect. The researchers envision “airborne science stations” that are solar powered and can persistently sit in one spot, which is what you want when you’re trying to monitor the environment (or spy on something), and it also makes powering them easier. Many of the best ideas for keeping these things afloat involve solar panels, and it’s easier to predict exactly how much energy they’ll provide if you know the environment they’re going to be in isn’t going to change.
A quick note on airships versus blimps: All blimps are airships, but not all airships are blimps. The ones we're talking about will probably have a rigid interior skeleton, whereas blimps do not.
Airships have several advantages over satellites. For one, it’s very expensive to send a satellite into space—it’s not uncommon for a commercial launch to cost more than a billion dollars once everything is said and done. A cheap airship, on the other hand, can cost just a couple million dollars, and researchers hope that, one day, stratospheric ones that can stay in the sky for weeks at a time will cost on the order of about a hundred million dollars. That’s not chump change, but, once developed, payloads can easily be swapped in and out of airships, something that’s difficult and makes no practical sense to do on a satellite. Satellites will still have a huge range advantage, but “unlike satellites, airships do not typically require persistent and costly global-scale control, tracking, and communications. They can operate more typically on a local scale.”
"Tug" aircraft could be used to put an airship in place. Image: Keck
The problem is, we’re not quite there yet. People have been waiting on a new golden era of airships for years now, and not much has come to fruition, especially in the ultra-high-altitude space. Eight years ago, DARPA sunk $15.5 million into the initial development of a stratospheric airship called the Integrated Sensor is Structure. Since then, the United States Air Force has spent roughly $400 million on the project, and it’s still not ready.
Besides making sure the science is there (“the [stratospheric] environment more closely resembles outer space than sea level,” the report notes), there are also some political reasons why airships aren’t yet ready to become the new satellites. Not every government is enthused about allowing foreign countries’ airships float over their airspace, especially when they can easily be outfitted with surveillance equipment (and in many cases, they’re designed for specifically that reason). At lower altitudes, we’ve had some better success. The Raytheon-developed JLENS aerostat is ready to start surveilling much of the Eastern seaboard, although that one hovers just 10,000 feet above Earth.
To turn these things into reality, the Keck report suggests that we might need something similar to the X Prize in order to spur innovation in the sector. The researchers propose that, in order for stratospheric airships to make any sense, they have to be able to be able to float statically at 12 miles above the Earth’s surface for at least 20 hours at a time and be able to hold a scientific payload of at least 20 kilograms. That’s just a starting point: If airships are ever going to replace satellites, they’re going to have to be able to stay in the air for weeks at a time and be able to carry a lot more than just 20 kilograms.
We’re already working on solving it, with some pretty wacky ideas. With a tether to the Earth, airships can stay afloat longer and can potentially reach altitudes of 22 miles, the researchers in the Keck Report suggest. They even propose that a “tug aircraft” could fly below an airship to move an airship quicker and conserve fuel.
There’s still a long way to go, but it’s looking more and more like giant balloons are going to someday do much of what satellites do, for much cheaper.