Can airships and UAVs bridge the satellite gap?
High-altitude airships could be surrogate geostationary satellites
- By David Perera
- Apr 21, 2008
With mounting pressure for high-bandwidth connectivity for forces in the field, and concern about available satellite communications, a number of programs are seeking to revive an old technology — airships.
Lighter-than-air vehicles might be a viable alternative or supplement to satellites, some defense analysts say – especially as such programs as the Transformational Satellite System (TSAT) fail each year to materialize by their timelines.
TSAT has been the projected backbone for military high-bandwidth global communications needs, but the latest round of budget cuts means TSAT won’t launch until 2016, at the earliest. Network-centric military programs such as the Army’s Future Combat Systems face a major question: “Who’s going to pick up all that bandwidth that TSAT was promising to support?” said Isaac Porche III, a Rand senior analyst. “It’s conceivable, especially if TSAT keeps getting pushed out, that high-altitude airships could be right in the sweet spot.”
Charlie Lambert, a retired Air Force colonel, remembers being skeptical about airships a decade ago, when a general gave the North American Aerospace Defense Command (NORAD) a proposal to launch airships as high-footprint surveillance platforms.
“We patted him on the back and we said, ‘OK, General, don’t call us, we’ll call you,’ ” Lambert recalled. “It seemed kind of far out.”
But Lambert now counts himself as a stalwart supporter of military airships and advises Air Force Research Laboratory (AFRL) contractors who are working on a hybrid unmanned aerial vehicle and airship project called the High Altitude Return Vehicle (HARV).
Depending on their design, high-altitude airships could be surrogate geostationary satellites that cost less than ones in space. And with new technologies, such as light-weight thermal-resistant fabric and solar-powered battery propulsion systems, now is the time for a blimp revival, Lambert said.
Lambert and others envision airships that fly at 60,000 feet and above, where line-of-sight radius to the horizon is more than 300 miles, and can remain airborne from days to months.
THE HIGH-ALTITUDE HOLY GRAIL
There are different ways for an airship to get to 60,000 feet and stay there, and design would dictate whether the aircraft takes on a strategic satellite-like role or has more of a tactical gap-filler function.
For example, HARV’s designers envision a readily deployable device that carries a payload of about 30 pounds. It could be launched when partially inflated by two warfighters in the field whenever local bandwidth needs outstrip satellite availability.
On the other end of the spectrum is the High Altitude Airship (HAA), a prototype project that until recently was sponsored by the Missile Defense Agency (MDA), which would launch fully inflated from a hangar — probably in the continental United States — and carry payloads that weigh thousands of pounds to a fixed position in the stratosphere and remain there for as long as a year without refueling. The Army Space and Missile Defense Command (SMDC) assumed control over the program April 9.
“The giant high-altitude airship, that’s the holy grail,” Porche said.
The HAA project has been the centerpiece of current military airship development efforts since it gained approval in 2003. And the project has been highly successful – at least in capturing the imagination of pundits. For example, in a November article, Lexington Institute defense commentator Loren Thompson railed against “proponents of less cost-effective solutions who might try to use the airship money for other purposes.”
However, HAA was not well-loved by MDA or Congress. Its shaky status suggests that despite recent enthusiasm from a select crowd, airships’ future could be earthbound. Speaking on background, an MDA official said the agency is reluctant to grant interviews about HAA, suspecting an attempt by HAA-contractor Lockheed Martin to drum up publicity for the beleaguered program. In December 2005, MDA awarded a $149.2 million contract to the company to develop an HAA prototype capable of staying at 61,000 feet with a 500-pound payload for several weeks.
Since then, government support for the project has waned. David Kier, a Lockheed Martin vice president of program management, reportedly lamented during a press call earlier this year that the company is “having difficulty finding a sponsor and keeping it alive.”
Congress has reduced HAA funding twice, and in fiscal 2008, MDA requested no annual appropriations for the project.
“You’ve got to pick the critical stuff,” said Rick Schwarz, who managed HAA for MDA. “You go the movies or buy food for your kids.” Still, MDA officials could offer no clarification on why HAA was classified internally as a low priority. “I would be speculating,” Schwarz said.
Congress appropriated enough money that year to keep HAA on life support by injecting $2.5 million through a budget line of the Army SMDC, but the project’s future remains uncertain. To save the program by transferring it to SMDC, Lockheed Martin enlisted the help of Akron, Ohio, congressman Tim Ryan, who declared himself ready to “do everything I can in Congress to ensure its success.”
But money to build the prototype might never materialize, said Mike Lee, an SMDC space technology division general engineer. MDA estimated that building and launching the HAA prototype by summer 2009 would cost less than $30 million.
The bulk of that money would be required for manufacturing the prototype, with the design issues surrounding the fabric, battery power and solar cells having all been solved, Schwarz said. “We’ve got things to a point where things can be picked back up when the funding allows,” he said.
“MDA kind of lost confidence in the program,” Lambert said. Technological challenges proved more daunting and expensive than initially expected. The project is a victim of its own size and ambition, he said. “It was an exquisite design, but it ended up being quite expensive, and that ended up putting the whole program into jeopardy.”
COMING DOWN TO EARTH
Lost in the tussle over HAA prototype funding is a sense of whether even a successful prototype launch would clear a path for deployable high-altitude airships.
Scientists often refer to the part of the atmosphere where any high-altitude blimp would operate as the “ignorosphere.” It’s an area of the Earth where humans have little experience in operating aircraft for prolonged periods.
And even proponents say that conditions at 60,000 feet could be less than ideal. “You can’t design the thing to cope with any weather condition,” said Tim Tozer, a United Kingdom University of York senior lecturer in electronics and co-author of several papers on high-altitude communications platforms. “Well, you could, but it would be very expensive.” Airships could also potentially be vulnerable to long-range missiles, he said.
Lockheed Martin brushed away those uncertainties. “There’s a lot of conjecture about system vulnerability, both man-made and natural,” said Ron Browning, the company’s director of business development for surveillance systems. “If you look at the vulnerability of any aircraft, is HAA any better or any worse?”
However, that uncertainty is precisely an argument that defense thinkers who haven’t committed themselves to airships tend to bring up. “No one can guarantee that it might not take as much time to develop these airships” as it would be to launch more satellite coverage, Porche said.
Airship proponents might do better to focus on less expensive designs, Lambert said, albeit ones with shorter station times and lighter payloads, and therefore be focused more on tactical rather than strategic use.
HARV designers say they could launch an airship as high as 60,000 feet from the field, with each unit costing about $60,000. Their system consists essentially of a UAV dangling from an airship – either a free-floating balloon that can’t maneuver, or an inexpensive airship with a basic propulsion system on board.
The idea behind the hanging UAV is that it houses the expensive payload – the communications routers or surveillance equipment – and flies back home under its own power, letting the relatively inexpensive airship piece of the platform fall to the earth once it goes out of range.
OFF-THE-SHELF TO IN THE AIR
HARV designers made it a point to use only commercial technology, so “it’s vastly, vastly less expensive” than HAA, said an official at AFRL’s Space Vehicles Directorate (AFRL/RV) working with the HARV project, who requested anonymity for security reasons. The project has conducted 14 tests, five of which sent platforms to 65,000 feet.
However, even more than HAA, the HARV program has lacked funding. “We want to emphasize that we’ve gone to 65,000 feet on a shoestring budget,” said the AFRL/RV official. AFRL has enough money to fund another test and validation phase, but whether anything more comes after that is a question that makes program officials nervous. “We need requirements and a sponsor,” he said.
SMDC also has an airship project, called HiSentinel. Like HARV, this project is launched when only partially inflated, meaning that it doesn’t require a hangar and could be deployed tactically from the field. Like HAA, it would have a propulsion system capable of keeping it in one place for prolonged periods.
SMDC and the Southwest Research Institute launched a 146- foot-long prototype with a 60-pound payload in November 2005, and plan on floating another airship this spring. The goal is to get a 200-pound payload to that attitude, but “we don’t have a funded program, and we don’t know what we’re going to get” in terms of money, said Mike Lee, the SMDC general engineer.
Meanwhile, one group is absolutely sure how the military can fill its bandwidth needs: commercial satellite providers. In an analysis posted online shortly after the military announced a probable $4 billion funding reduction for TSAT, telecommunications market analyst firm Northern Sky Research predicted that “delays and perhaps a reduction in TSAT’s capabilities should once again boost the commercial satellite industry, perhaps even until 2020.”
Said NSR analyst Jose del Rosario, “Something has to augment [the military’s] current capacities, and this is where the commercial satellite industry comes into play.” The military spends about $1 billion annually on commercial satellite services.