Small unmanned aircraft systems (UAS) provide valuable
intelligence, surveillance and reconnaissance (ISR) capabilities
for units at the infantry company level and below, allowing
over-the-next-hill imagery or short-term monitoring of convoys
as an example. State-of-the-art battery power for these small
UASs, however, has limited the duration of missions to about two
hours. “A small unmanned aircraft system with long-endurance
capability could give the military the ability to do with a
small craft what has previously been doable only with larger
airframes. This has potential for tremendous cost savings – we
can maintain and even improve on our UAS capabilities with a
much smaller footprint and lower operating cost,” said Brian
Holloway, DARPA program manager for this effort. DARPA’s
Tactical Advanced Power (TAP) program has addressed the power
limitation by developing a compact solid oxide fuel cell (SOFC)
fueled by propane, a very high energy-density hydrocarbon fuel.
DARPA researchers have also developed th