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home > April 21, 2008 issue > article
High bandwidth
By David Perera
Special to Defense Systems
Can airships and UAVs bridge the satellite gap?
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.
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