Transfer of solar aircraft technology to the commercial
market has moved a step closer with the recent signing of an
agreement between NASA’s Dryden Flight Research Center and
AeroViroment, Inc., to jointly sponsor further development of
AeroVironment’s Helios Prototype and Pathfinder Plus solar-electric
flying wings.

The Joint Sponsored Research Agreement (JSRA) was signed
recently by Kevin Petersen, director of NASA Dryden, and Timothy
Conver, president and chief executive officer of AeroVironment, on
the occasion of the final flight in a three-mission series of
high-altitude telecommunications relay demonstrations by the
Pathfinder Plus from the U.S. Navy’s Pacific Missile Range Facility
(PMRF) on the Hawaiian Island of Kauai.

At the same time, the two entities revealed that a second
supplemental energy system is being perfected by AeroVironment that
will give the Helios the ability to fly multi-week missions at high

“Not only does this agreement help focus the ongoing
NASA-sponsored development efforts, it also forms the framework for
enabling the commercialization of the solar-electric platforms to
support various commercial, government, and university needs,” said

“This NASA-AeroVironment collaboration offers a huge
advantage to the nation of accelerating access to the revolutionary
low-cost benefits of communication and remote sensing from the
stratosphere to both the government and private sectors,” added

Commercialization of high-altitude remotely piloted or
autonomously operated unmanned aerial vehicles (UAVs) has been a high
priority for partners of the Environmental Research Aircraft and
Sensor Technology (ERAST) alliance since its inception in late 1993.
The new agreement builds upon a similar JSRA pact between NASA and
several small high-technology firms that forms the basis for the
ERAST project.

“This new arrangement streamlines existing efforts-both
commercially and federally sponsored-by AeroVironment and NASA’s
ERAST project to merge solar powered UAV development into a single
solar/electric platform program aimed at developing multiple
aircraft,” said John Del Frate, project manager for solar powered
aircraft at NASA Dryden. “The agreement also sets forth a framework
for future partnering in commercial activities related to the Helios
solar-electric family of aircraft.”

As part of the agreement, AeroVironment will provide program
management personnel; expertise in energy storage systems, fuel cell
propulsion and solar-electric airframes; design and flight teams; and
facilities, such as their UAV Development Center, Fuel Cell Lab, and
Mobile Test Facility.

The agreement calls for NASA Dryden to maintain safety
oversight for flight and ground testing for all solar aircraft as
well as for energy storage and power systems, stationary and mobile
ground support systems. Dryden will also provide support for flight
demonstrations, including provision of the Pathfinder Plus and Helios
Prototype aircraft and their flight kits, support for technology
development for next-generation Helios aircraft and components, and
facilities and equipment such as PMRF, environmental test, simulator
facilities and range equipment.

AeroVironment and NASA Dryden Flight Research Center have
been collaborating on development of solar-powered UAVs since 1993.
These efforts were initiated with the Pathfinder, which set a series
of altitude records as it underwent extensive modifications and
upgrades over the next five years. In its latest form, the Pathfinder
Plus, it is capable of altitudes up to 80,000 feet.

Also being worked as a collaborative effort is the
development of the Pathfinder’s follow-on, the Helios Prototype.
Originally named the Centurion, Helios first flew in 1998 and
currently holds a world altitude record for its flight to 96,863 feet
in August 2001, also flown out of PMRF.

Initially, AeroVironment and NASA are commercializing two
versions of the Helios solar/electric extreme-endurance UAV. One
version will be able to fly at lower latitudes for up to six months
without landing by employing a regenerative fuel cell-based energy
storage system to provide power at night. The regenerative system
uses excess power from the solar arrays during the daytime to power
an electrolyzer that breaks down water into its component gases,
hydrogen and oxygen, which are then stored in pressurized tanks. At
night, the process is reversed, with fuel cell stacks recombining the
gases into water, producing electricity as a byproduct to power the

The other version will use a similar fuel cell-based energy
system without the regenerative feature to power the aircraft at
night. Designed to allow Helios to fly for one to two weeks at all
latitudes any time of the year, this system combines stored hydrogen
with oxygen collected from the atmosphere. Initiated by AeroVironment
and now a joint effort by NASA and the Monrovia, Calif., -based firm,
development of the non-regenerative system has accelerated rapidly
over the past nine months. AeroVironment is currently operating
developmental versions of both fuel cell-based energy systems at its
California development facility.

The Helios Prototype is currently being modified in
preparation for a series of experimental long-endurance demonstration
flights late next summer, which will use the primary non-regenerative
system to provide power for night operations.

“The measured performance of both our primary and
regenerative fuel cell systems is very good, and indicates that years
of hard work on these complex and often under-estimated systems is
paying off,” said Robert Curtin, vice-president and director of
AeroVironment’s UAV Design Development Center in Simi Valley, Calif.
“The integration of these systems with our proven stratospheric solar
aircraft will enable a global, low-cost, extreme-endurance UAV

Both the Pathfinder Plus and the Helios Prototype have been
developed as platform aircraft to test unique technologies and
demonstrate a variety of potential applications. Among proposed uses
are earth monitoring for climate, environmental changes and natural
disasters; “last mile” connectivity for systems such as TV, cell
phone systems and the Internet; and surveillance applications for
border patrol, port and pipeline security and the military.

“Fundamentally, affordability is why we’re building the
Helios,” Curtin added. “Cost is very important to potential military
and commercial users. The extreme endurance of Helios will result in
a short logistics “tail,” a very small operational infrastructure and
low operational costs. The bottom line is much lower operational
costs than any conventional UAV.”