As 2004 drew to a close, NASA's Dryden Flight Research Center at Edwards Air Force Base looked back on a year of challenge and accomplishment in its role of NASA's lead center for atmospheric flight research.

A few of the highlights included:

• X-43A / Hyper-X -- On March 27, four decades of supersonic-combustion ramjet propulsion research culminated in a successful flight of the X-43A hypersonic technology demonstrator, the first time a scramjet-powered aircraft had flown freely. After being launched by Dryden's venerable B-52B mothership off the coast of Southern California, a modified first-stage Pegasus booster rocketed the X-43A to 95,000 feet before the X-43A separated and flew under its own scramjet power at an airspeed of Mach 6.8, or about 5,000 mph, for about 11 seconds. On Nov. 16, another identical scramjet-powered X-43A did it again, this time reaching hypersonic speeds above Mach 9.6, or about 6,800 mph, in the final flight of the X-43A project.
  Both flights set world airspeed records for an aircraft powered by an air-breathing engine, and proved that scramjet propulsion is a viable technology for powering future space-access vehicles and hypersonic aircraft.

• Access 5 -- In May, Access 5, the joint government-industry program to enable use of the national airspace by remotely operated unmanned aircraft was kicked off. Primarily funded by NASA through the High-Altitude, Long-Endurance Remotely Operated Aircraft in the National Airspace project within the Vehicle Systems Program, Access 5 brings NASA, the Federal Aviation Administration, the Department of Defense and six major industry members together to plan the safe, orderly and efficient integration of unmanned aircraft into civil airspace over the next five years. The focus is not only on development of procedures and standards, but also on technologies such as command and control, detection and avoidance.
• Airborne Science -- Advanced technology was used to improve our understanding of biological and cultural resources and their sustainable development. The Central and South America AirSAR 2004 mission used an Airborne Synthetic Aperture Radar aboard NASA's DC-8 flying laboratory. The mission took place during the several weeks in March over Costa Rica, Chile, Patagonia and the Antarctic Peninsula.
  Other major Earth science missions during the year involving the converted jetliner included the INTEX global air pollution surveys and an AirSAR mission that captured 3-D images of seven active Alaskan volcanoes to evaluate volcanic hazards and to improve the understanding of the eruption process and frequency. NASA Dryden's
  ER-2 high-altitude science aircraft also was kept busy during 2004 on a variety of atmospheric sampling and imaging missions.
• Active Aeroelastic Wing -- After a lengthy hiatus, Dryden's Active Aeroelastic Wing F/A-18 returned to the skies in mid-December to begin its second phase of research flights. Following completion of the first phase that evaluated the flight characteristics of a more flexible wing, NASA Dryden and Boeing Phantom Works engineers developed control laws over the past 18 months to enable active control of wing flexibility for primary maneuvering control. About 35 flights at both subsonic and supersonic speeds are planned in Phase II of the AAW project before it concludes next spring. Initial data from the first four research flights indicate that AAW control law roll rates were higher than predicted. Active Aeroelastic Wing employs conventional control surfaces such as ailerons and leading-edge flaps to aerodynamically induce twist. From flight test and simulation data, the program will develop structural modeling techniques and tools to help design lighter, more flexible high aspect-ratio wings for future high-performance aircraft, which could enable more economical operation or greater payload capability.

• B-52B "Mothership" Retirement -- After almost 50 years of serving as a test and research aircraft, NASA's venerable Boeing B-52B air-launch "mothership" was retired from service on December 17. With no future programs needing its capability envisioned in the foreseeable future and maintainability becoming increasingly difficult for the one-of-a-kind aircraft, the decision was made to retire the eight-engine converted bomber to a place of honor on display at the Edwards Air Force Base north gate. First flown in June 1955, the B-52B air-launched a variety of exotic research aircraft ranging from the X-15 rocket plane of the 1960s to the X-43A scramjet of 2004 during its storied career.

In 2005, NASA Dryden will be supporting both the Vision for Space Exploration and Space Shuttle Return-to-Flight with several engineering and flight research tasks.

• Exploration Systems -- NASA's Exploration Systems Mission Directorate selected Dryden to participate in two research and technology development activities. Dryden has been tasked with leading the Aero Assisted Mars Transfer Vehicle Study, with other NASA centers and universities supporting the effort. For the second, the Ceramic Aft Heat Shield Hot Structures Test, Dryden would provide the necessary thermal and load testing of a candidate aft heat shield design for the planned Crew Exploration Vehicle. Additionally, the directorate has tasked Dryden to provide increased support to a number of engineering disciplines that support the overall exploration vision via integrated product and design teams.
• Space Shuttle Return to Flight -- NASA Dryden will support Space Shuttle Return-to-Flight engineering efforts with a series of flights by the center's F-15B Research Testbed aircraft in early 2005. The flights will obtain data on the shuttle's external fuel tank insulating foam debris or "divot" trajectories for computer code validation. Among several objectives, the flights will help engineers quantify divot trajectories using high-speed videography and provide flight verification of debris tracking systems to be used for the next shuttle launch.

FMI: www.nasa.gov/centers/dryden