After a two-year absence, the Perseus B remotely piloted aircraft is due to return to Dryden within the next couple of weeks for resumption of developmental flight tests.

Project officials in the Environmental Research Aircraft and Sensor Technology (ERAST) program report that the Perseus B is scheduled to be shipped from Aurora Flight Sciences in Manassas, Va., April 9 and should arrive at Dryden by April 13. After a Flight Readiness Review at Aurora this week, the Perseus B will be the focus of an Airworthiness and Flight Safety Review Board at Dryden April 7. Flights tests should begin in late April.

Perseus B, one of several technology demonstrators being developed within the ERAST umbrella, has undergone extensive modifications and upgrades at Aurora. Among the upgrades outlined by project manager Gary Cosentino are a stronger wing, which is slightly longer than the original, and the installation of a three-stage turbocharger to provide increased airflow to its four-cylinder Rotax engine. This will enable the craft to reach higher altitudes. The strengthened wing recently passed a loads test at 3Gs, or three times the aircraft's weight.

The original Perseus prototype was test-flown at Dryden in 1991. Dryden also has flow two other variations of the aircraft - Perseus A and B.

Perseus B is designed to operate at a sustained altitude of 65,000 feet for up to four days, although the goal of the next series of flights at Dryden will be to maintain flight at 60,000 feet for at least six hours. The upcoming flight research will be focused on evaluation of its propulsion system, lightweight structures, integration of science payloads and its fault-tolerant flight control system. Dryden will provide hangar space for the aircraft and the Aurora team, as well as range communications and safety services during the flight evaluations.

One or more experiments developed by scientists at NASA's Jet Propulsion Laboratory in Pasadena may be flown aboard Dryden's Pathfinder-Plus aircraft this summer in Hawaii, following discussions between JPL and officials in the Environmental Research Aircraft and Sensor Technology (ERAST) program at Dryden.

John Del Frate, Pathfinder project manager at Dryden, met with JPL scientists in mid-March to outline the attributes of the Pathfinder-Plus. The hybrid craft incorporates portions of the original Pathfinder vehicle with a center wing section, motors and propellers from the follow-on Centurion.

He said the JPL scientists expressed interest in the ability of the solar-powered flying wing to loiter at intermediate altitudes in the 50,000-foot range.

Del Frate said the ERAST program has invited the JPL group to propose experiments that could be flown on Pathfinder-Plus, noting that one fairly lightweight JPL instrument, which is targeted for that altitude, may be ready in time for this summer's planned series of flights from the Pacific Missile Range Facility on Kauai.

JPL is a major contributor of experiments that are flown on the ER-2 and DC-8 platform aircraft in the Airborne Science Program at Dryden.

LASRE test scheduled for in-flight ignition test

On April 9, the Linear Aerospike SR-71 Experiment (LASRE) will move one step closer to an in-flight hot fire, when it is scheduled to undergo an in-flight ignition test.

During the test, the aircraft will carry liquid oxygen and the igniter fluid -- tri-ethyl-aluminum/ tri-ethyl-borane on board, which will burn during the flight. The aircraft will not carry hydrogen, however.

During a hot fire flight, which may occur as early as May, the LASRE pod will contain both oxygen and hydrogen. The oxygen and hydrogen will ignite and burn for about three seconds during the flight.

Three hot fires currently are planned for the program -- at.9 Mach, 1.2 Mach and 1.5 Mach.

Linear Aerospike rocket engines are going to power the X-33 Advanced Technology Demonstrator, scheduled to fly in 1999.

LASRE is designed to gather data on the aerospike's exhaust plume as it travels through the transonic region of flight. Linear aerospike rocket engines have been laboratory and ground tested many times over the past thirty years, but have never flown until now.

' RESTORE '-ing the X-36

Work on software and hardware changes to develop a reconfigurable control system for the X-36 research aircraft is now under way, following initiation of a task order change on the contract between Boeing's Phantom Works and the Air Force Research Laboratory for the "RESTORE" program.

Project officials say the revised plan calls for developmental and ground testing to be performed by Boeing this fiscal year, with flight tests of the new damage-tolerant control system at Dryden in Fiscal Year 1999. The flight research missions are planned to be conducted in three phases, the first of which will involve about 15 flights. Dryden will provide range and safety support for the flight research, as well as hangar space.

The objective of the RESTORE program, which is primarily funded by the Air Force, the Navy and Dryden, is the development of neural network-based flight control laws that have the ability to compensate for damaged or inoperable flight-control surfaces by use of alternate surfaces.

X-36 photos

Research Update

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Responsible NASA Official: John Childress For questions, contact: Dryden Web Group Page Curator: Marty Curry Modified: April 8, 1998