NASA Dryden News Releases


April 6, 1998

Release: 98-17

A unique experiment that will probe previously unexplored areas of atmospheric flight has passed a major milestone at NASA's Dryden Flight Research Center, Edwards, Calif.

The Apex High-Altitude Flight Experiment was the subject of an extensive Critical Design Review (CDR) at Dryden in late March. "The design review was very successful," said Seunghee Lee, Dryden's Apex project manager. "There were no roadblocks that we identified and we met the objectives of the CDR."

According to Lee, the Apex design is essentially "locked in" as a result of the successful CDR and fabrication of the unique research aircraft can begin as soon as two major tests currently in progress are completed. Those tests include altitude chamber testing of the thermal management system, which must protect the Apex instrumentation and other systems from extreme temperatures of (minus 100 degrees to 160 degrees Fahrenheit) and structural loads testing of a wing section. The Apex wing will include an outer skin fabricated from a tough, lightweight boron composite fiber.

The Apex project, part of NASA's Environmental Research Aircraft and Sensor Technology (ERAST) program, is intended to help give researchers a better understanding of the aerodynamics of flight at controlled subsonic speed and at altitudes of 70,000 to 100,000 feet. Among the project 's goals are the validation of a new airfoil design for that flight regime and the collection of aerodynamic data to qualify the design of airfoils and propellers for other high-altitude aircraft being developed under ERAST. The project also is attempting to reduce the technical risks associated with developing avionics, structures, science payloads, solar cells and heat exchangers for piston engines that must operate at extreme altitudes.

To accomplish its objectives, the Apex project is developing a remotely piloted unpowered sailplane design to be a testbed for the evaluation of airfoils, structures and the various systems that must function in the extremely thin air and bitter cold l6 to 20 miles above the Earth. ERAST Alliance partner Advanced Soaring Concepts of Camarillo, Calif., will build the Apex research aircraft.

Six flights are planned at Dryden over a six-month period in the first phase of flight research. The flight plan calls for Apex to be towed aloft tail-first by a large high-altitude balloon provided by the National Science Balloon Facility, Palestine, Texas, and then released nose-down after a two and one-half hour ascent. During its first flight, the Apex will be released between 90,000 and 95,000 feet altitude and on subsequent flights near 108,000 feet altitude.

A pack of four small rockets mounted underneath the fuselage just ahead of the center of gravity will help the Apex transition to horizontal flight within 5,000 feet of launch altitude. From that point, the Apex will fly a series of test maneuvers to collect aerodynamic data down to about 70,000 feet. Each flight is expected to take only 30 minutes to an hour from release to landing.


Note to Editors: Photos are available from the Dryden Public Affairs Office to support this release. Among those available are EC98-44487-9, Apex wing structural loads tests, and ED97-44119-2, a computer-generated image of the Apex aircraft design. For photo prints, please call (805) 258-3449. Photos also are available on the Internet under NASA Dryden Research Aircraft Photo Archive, Dryden News and Feature Photos, URL:

/centers/dfrc/Gallery/Photo/index.html Additional information about the Apex project can be obtained from Dryden's Apex project home page on the World Wide Web. The page includes a summary of the project and separate pages detailing the Apex aircraft and answers to frequently asked questions. The website address is:


NASA Dryden news releases also are available on Dryden's website at: