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Perseus A, which incorporated a closed-cycle combustion system that mixed oxygen carried aboard the aircraft with engine exhaust to compensate for the thin air at high altitudes. Perseus A Home Page
Four different vehicles have flown for the Perseus program. The first, a proof-of-concept vehicle to test basic design concepts, flew beginning in 1991. The Perseus A then made its maiden voyage Dec. 21, 1993. Two Perseus A aircraft were flown; AU002 and AU003. AUOO3 later suffered irrepairable damage in a crash November of 1994.
The Perseus A had a very unique method of propulsion, known as a closed-loop engine system. This system operated by recycling the exhaust back through the engine after adding more fuel and oxygen from onboard tanks, thereby creating enough pressure to operate. The aircraft, designed to reach altitudes of up to 80,000 feet, didn't need to extract air from the thin upper-atmosphere like most aircraft to operate since it carried its own oxygen.
The Perseus A also had a unique method of takeoff and landing. To make the aircraft as aerodynamic and lightweight as possible, designers gave it only two very small centerline wheels for landing. These wheels were very close to the fuselage, and therefore produced very little drag. However, since the fuselage sat so close to the ground, it was necessary to keep the large propeller at the rear of the aircraft locked in a horizontal position during takeoff. The aircraft was towed into the air, where the propellor was then released and the aircraft began flying under its own power.
After the crash of AU003 in November of 1994, the second Perseus A went into storage and the B model, AU004, began research flights.
The Perseus B, designed for slightly lower altitude flight, and built with a different, relatively more conventional engine and landing gear system, first flew October 7, 1994.
Perseus B was a propulsion and performance testbed for the ERAST program. The aircraft was designed to operate in the 65,000-foot (20 kilometer) region and had a duration goal of 8 hours at that altitude. Perseus B's engine, which was double-turbocharged to offset the thin atmosphere, "breathed" air surrounding the vehicle. The aircraft also featured tricycle-shaped landing gear, which allowed the aircraft to sit higher off the ground than its predecessors.
Perseus B tested engine concepts, lightweight structures, science payload integration and a fault-tolerant flight-control system. Perseus B's maiden flight occurred on Oct. 7, 1994.