When Apollo planning was underway in 1960, NASA was looking for a simulator to profile the descent to the Moon's surface. Three concepts surfaced: an electronic simulator, a tethered device, and the ambitious Dryden contribution, a free-flying vehicle. All three became serious projects, but eventually the NASA Flight Research Center’s (FRC) Lunar Landing Research Vehicle (LLRV) became the most significant one. After conceptual planning and meetings with engineers from Bell Aerosystems Company, Buffalo, N.Y., NASA FRC issued a $3.6 million production contract awarded in 1963, for delivery of the first of two vehicles for flight studies.

Built of tubular aluminum alloy like a giant four-legged bedstead, the vehicle was to simulate a lunar landing profile from around 1500 feet to the Moon’s surface. The LLRV had a turbofan engine mounted vertically in a gimbal, with 4200 pounds of thrust. The engine, lifted the vehicle up to the test altitude and was then throttled back to support five-sixths of the vehicle's weight, thus simulating the reduced gravity of the Moon. Two lift rockets with thrust that could be varied from 100 to 500 pounds handled the LLRV's rate of descent and horizontal translations. Sixteen smaller rockets, mounted in pairs, gave the pilot control in pitch, yaw, and roll. The pilot’s platform extended forward between two legs while an electronics platform, similarly located, extended rearward. The pilot had a zero-zero ejection seat that would then lift him away to safety.

The two LLRVs were shipped from Bell to the FRC in April 1964, with program emphasis on vehicle No. 1. The first flight, Oct. 30, 1964, NASA research pilot Joe Walker flew it three times for a total of just under 60 seconds, to a peak altitude of approximately 10 feet. By mid-1966 the NASA Flight Research Center had accumulated enough data from the LLRV flight program to give Bell a contract to deliver three Lunar Landing Training Vehicles (LLTVs) at a cost of $2.5 million each. 1966 ended with the phasing out of the Flight Research Center’s portion of the LLRV program. The LLRV #1 had flown 198 flights, with flight times reaching 9-1/2 minutes and altitudes of around 750 feet. In December 1966 vehicle No. 1 was shipped to NASA Manned Spacecraft Center, followed by No. 2 in mid January 1967 with a total of six flights. The two LLRV’s were soon joined by the three LLTV’s. All five vehicles were relied on for simulation and training of Moon landings.

The LRV-2 (Low Reynolds Vehicle No. 2), seen here on the ramp at NASA's Dryden Flight Research Center, Edwards, California, was a remotely piloted research vehicle (RPRV) developed to conduct aerodynamic and auto-pilot systems experiments on ultra-light aircraft. The aircraft made its maiden voyage October 20, 1982. The LRV-2 had a 32 ft. wingspan with a 1.5 lb per square foot wing loading. The aluminum tube structure was covered with a lightweight dacron fabric and was powered by a ten horsepower two-stroke engine.

The LRV-2 was equipped with a lightweight RPRV system comprised of a radio-control uplink, a nose-mounted television system, a radar transponder for precise tracking and a telemetry system for research data.

Wing tip extensions, with experimental wing airfoil sections, were installed and instrumented for surface pressures and wake drag measurements. The very low flying speed of the LRV-2 allowed Reynolds numbers matching those of current and future high altitude lightweight RPRVs. The Reynolds number is a measurement roughly equivalent to "viscosity" as measured in liquids.

The LRV-2 was flown by one of two "radio-control" pilots. The vehicle could be flown by a "visual pilot" sitting in the back of a "chase" pickup truck, or by an "IFR" pilot watching a television screen and a radar plot board. Landings and take-offs were conducted by either pilot, however, research maneuvers were performed by the IFR pilot having attitude information from the forward looking TV and other data from the telemetry system down-linked from the aircraft.

The LRV-2 was flown to 20,000 ft altitude to provide Reynolds number variations and altitude effects on the onboard experiments.

NASA Ames Research Center Aeronautical Engineer Robert T. Jones conceived the idea of an oblique wing. His wind tunnel studies at Ames (Moffett Field, CA) indicated that an oblique wing design on a supersonic transport might achieve twice the fuel economy of an aircraft with conventional wings. The oblique wing on the AD-1 pivoted about the fuselage, remaining perpendicular to it during slow flight and rotating to angles of up to 60 degrees as aircraft speed increased. Analytical and wind tunnel studies that Jones conducted at Ames indicated that a transport-sized oblique-wing aircraft flying at speeds of up to Mach 1.4 (1.4 times the speed of sound) would have substantially better aerodynamic performance than aircraft with conventional wings.

The AD-1 structure allowed the project to complete all of its technical objectives. The type of low-speed, low-cost vehicle - as expected - exhibited aeroelastic and pitch-roll-coupling effects that contributed to poor handling at sweep angles above 45 degrees. The fiberglass structure limited the wing stiffness that would have improved the handling qualities. Thus, after completion of the AD-1 project, there was still a need for a transonic oblique-wing research aircraft to assess the effects of compressibility, evaluate a more representative structure, and analyze flight performance at transonic speeds (those on either side of the speed of sound).

The aircraft was delivered to the Dryden Flight Research Center, Edwards, CA, in March 1979 and its first flight was on December 21, 1979. Piloting the aircraft on that flight, as well as on its last flight on August 7, 1982, was NASA Research Pilot Thomas C. McMurtry. The AD-1 flew a total of 79 times during the research program. The aircraft was constructed by the Ames Industrial Co., Bohemia, NY, under a $240,000 fixed-price contract. NASA specified the design based on a geometric configuration provided by the Boeing company. The Rutan Aircraft Factory, Mojave, CA, provided the detailed design and loads analysis for the vehicle.

The aircraft was 38.8 feet long and 6.75 feet high with a wing span of 32.3 feet, unswept. It was constructed of plastic reinforced with fiberglass and weighed 1,450 pounds,empty. The vehicle was powered by two small turbojet engines, each producing 220 pounds of thrust at sea level. Due to safety concerns, the aircraft was limited to speeds of 170 mph.

The Altair is designed to carry an 700-lb. payload of scientific instruments and imaging equipment for as long as 32 hours at up to 52,000 feet altitude. Eleven-foot extensions on each wing give the Altair an overall wingspan of 86 feet with an aspect ratio of 23. It is powered by a 700-hp. rear-mounted TPE-331-10 turboprop engine, driving a three-blade propeller. Following successful completion of basic airworthiness flight tests in 2003, Altair is scheduled to be acquired by NASA for evaluation of over-the-horizon control, collision-avoidance and other technologies required to enable UAVs to operate safely and routinely with other aircraft in the national airspace.

The remotely-piloted, semi-autonomous Apex combined a modified ASC sailplane fuselage with a new wing designed at the Massachusetts Institute of Technology. The wing had a special airfoil designed for high subsonic speeds at extreme altitudes.

A device extending behind the right wing was a "wake rake," which was to measure aerodynamic drag behind a test section of the wing, while a rocket pack mounted beneath the fuselage was to have assisted the Apex in transitioning to horizontal flight. Research flights were expected to begin in mid-1998, but a series of technical problems delayed them. In the spring of 1999, Apex entered mothball status. This continued for a year, and in the spring of 2000 NASA selected Apex as part of phase 1 of the Revolutionary Concepts effort. Subsequently, the effort was again cancelled, ending the program.

The early 1970s showed a growing interest in continuing atmospheric research. The B-57B was at the NASA Flight Research Center for a joint program with NASA Langley Research Center, Hampton, Virginia and was having a special set of instrumentation installed. Delays in completing the instruments provided an opportunity to support the NASA space program. The B-57B was used in proof-of-concept testing of the Viking Mars landers. The deceleration drop testing part of the program took place at the Joint Parachute Test Facility, El Centro, California.

With completion of the Viking parachute tests, the B-57B was flown for measuring and analysis of atmospheric turbulence research in 1974-75 as part of a joint NASA program between the Flight Research Center and Langley Research Center. Additional atmospheric testing provided samples of aerosols for the University of Wyoming and clear-air turbulence data for the Department of Transportation.

The aircraft was tested over a span of many years at Edwards Air Force Base by various NASA centers for other types of research. Earlier, in the 1960s, the aircraft was flown at the Flight Research Center by the Lewis Research Center (now the John Glenn Research Center) in support of the newly established NASA Electronics Center in Boston, Massachusetts. Later, in 1982, the B-57B aircraft returned to the (then) Ames-Dryden Flight Research Facility for more Langley-sponsored turbulence testing.

The atmospheric research conducted using the B-57B Canberra provided information on mountain waves, jet streams, convective turbulence, and clear-air turbulence.

The JetStar was later used as a testbed to investigate acoustic characteristics of a series of subscale advanced design propellors which featured blades that curved rearward. The aircraft was also used as a support vehicle during the Space Shuttle Approach and Landing Tests at Dryden in 1977, and for a variety of general purpose airborne simulation studies related to general aviation aircraft.

These unique aircraft were designed and constructed by a group of students, professors, and alumni of the Massachusetts Institute of Technology within the context of the Daedalus project. The construction of the Light Eagle and Daedalus aircraft was funded primarily by the Anheuser Busch and United Technologies Corporations, respectively, with additional support from the Smithsonian Air and Space Museum, MIT, and a number of other sponsors.

To celebrate the Greek myth of Daedalus, the man who constructed wings of wax and feathers to escape King Minos, the Daedalus project began with the goal of designing, building and testing a human-powered aircraft that could fly the mythical distance, 115 km. To achieve this goal, three aircraft were constructed. The Light Eagle was the prototype aircraft, weighing 92 pounds. On January 22, 1987, it set a closed course distance record of 59 km, which still stands. Also in January of 1987, the Light Eagle was powered by Lois McCallin to set the straight distance, the distance around a closed circuit, and the duration world records for the female division in human powered vehicles.

Following this success, two more aircraft were built, the Daedalus 87 and Daedalus 88. Each aircraft weighed approximately 69 pounds. The Daedalus 88 aircraft was the ship that flew the 199 km from the Iraklion Air Force Base on Crete in the Mediterranean Sea, to the island of Santorini in 3 hours, 54 minutes. In the process, the aircraft set new records in distance and endurance for a human powered aircraft.

The specific areas of flight research conducted at Dryden included characterizing the rigid body and flexible dynamics of the Light Eagle, investigating sensors for an autopilot that could be used on high altitude or human powered aircraft, and determining the power required to fly the Daedalus aircraft.

The research flights began in late December 1987 with a shake-down of the Light Eagle instrumentation and data transfer links. The first flight of the Daedalus 87 also occurred during this time. On February 7, 1988, the Daedalus 87 aircraft crashed on Rogers Dry Lakebed. The Daedalus 88, which later set the world record, was then shipped from MIT to replace the 87's research flights, and for general checkout procedures. Due to the accident, flight testing was extended four weeks and thus ended in mid-March 1988 after having achieved the major goals of the program; exploring the dynamics of low Reynolds number aircraft, and investigating the aeroelastic behavior of lightweight aircraft. The information obtained from this program had direct applications to the later design of many high-altitude, long endurance aircraft.

The Dryden Flight Research Center, NASA's premier installation for aeronautical flight research, celebrated its 50th anniversary in 1996. Dryden is the "Center of Excellence" for atmospheric flight operations. The Center's charter is to research, develop, verify, and transfer advanced aeronautics, space, and related technologies. It is located at Edwards, Calif., on the western edge of the Mojave Desert, 80 miles north of Los Angeles.

Dryden's history dates back to the early fall of 1946, when a group of five aeronautical engineers arrived at what is now Edwards from the NACA's Langley Memorial Aeronautical Laboratory, Hampton, Va. Their goal was to prepare for the X-l supersonic research flights in a joint NACA-U.S. Army Air Forces-Bell Aircraft Corp. program. NACA--the National Advisory Committee for Aeronautics--was the predecessor of today’s NASA.

Since the days of the X-l, the first aircraft to fly faster than the speed of sound, the installation has grown in size and significance and is associated with many important developments in aviation -- supersonic and hypersonic flight, wingless lifting bodies, digital fly-by-wire, supercritical and forward-swept wings, and the space shuttles. Its name has changed many times over the years. From 14 November 1949 to 1 July 1954 it bore the name NACA High-Speed Flight Research Station. From 1 July 1954 until 1 October 1958 it was called the NACA High-Speed Flight Station, with Research removed from its name but not its mission.

The first flight of a solar-powered aircraft took place on November 4, 1974, when the remotely controlled Sunrise II, designed by Robert J. Boucher of AstroFlight, Inc., flew following a launch from a catapult.

Following this event, AeroVironment, Inc. (founded in 1971 by the ultra-light airplane innovator--Dr. Paul MacCready) took on a more ambitious project to design a human-piloted, solar-powered aircraft. The firm initially took the human-powered Gossamer Albatross II and scaled it down to three-quarters of its previous size for solar-powered flight with a human pilot controlling it. This was more easily done because in early 1980 the Gossamer Albatross had participated in a flight research program at NASA Dryden in a program conducted jointly by the Langley and Dryden research centers. Some of the flights were conducted using a small electric motor for power.

Gossamer Penguin

The scaled-down aircraft was designated the Gossamer Penguin. It had a 71-foot wingspan compared with the 96-foot span of the Gossamer Albatross. Weighing only 68 pounds without a pilot, it had a low power requirement and thus was an excellent test bed for solar power.

AstroFlight, Inc., of Venice, Calif., provided the power plant for the Gossamer Penguin, an Astro-40 electric motor. Robert Boucher, designer of the Sunrise II, served as a key consultant for both this aircraft and the Solar Challenger. The power source for the initial flights of the Gossamer Penguin consisted of 28 nickel-cadmium batteries, replaced for the solar-powered flights by a panel of 3,920 solar cells capable of producing 541 Watts of power.

The battery-powered flights took place at Shafter Airport near Bakersfield, Calif. Dr. Paul MacCready’s son Marshall, who was 13 years old and weighed roughly 80 pounds, served as the initial pilot for these flights to determine the power required to fly the airplane, optimize the airframe/propulsion system, and train the pilot. He made the first flights on April 7, 1980, and made a brief solar-powered flight on May 18.

The official project pilot was Janice Brown, a Bakersfield school teacher who weighed in at slightly under 100 pounds and was a charter pilot with commercial, instrument, and glider ratings. She checked out in the plane at Shafter and made about 40 flights under battery and solar power there. Wind direction, turbulence, convection, temperature and radiation at Shafter in mid-summer proved to be less than ideal for Gossamer Penguin because takeoffs required no crosswind and increases in temperature reduced the power output from the solar cells.

Consequently, the project moved to Dryden in late July, although conditions there also were not ideal. Nevertheless, Janice finished the testing, and on August 7, 1980, she flew a public demonstration of the aircraft at Dryden in which it went roughly 1.95 miles in 14 minutes and 21 seconds.

This was significant as the first sustained flight of an aircraft relying solely on direct solar power rather than batteries. It provided the designers with practical experience for developing a more advanced, solar-powered aircraft, since the Gossamer Penguin was fragile and had limited controllability. This necessitated its flying early in the day when there were minimal wind and turbulence levels, but the angle of the sun was also low, requiring a panel for the solar cells that could be tilted toward the sun.

Using the specific conclusions derived from their experience with Gossamer Penguin, the AeroVironment engineers designed Solar Challenger, a piloted, solar-powered aircraft strong enough to handle both long and high flights when encountering normal turbulence.

Among the difficulties facing the Apollo program in the 1960s and early 1970s was how to move large rocket stages from the contractor facilities where they were built to the launch pads in Florida. In 1961, John M. Conroy of Aero Spacelines, Inc., proposed modifying a Boeing Stratocruiser airliner with a bulging fuselage. Despite the ungainly appearance of the "Pregnant Guppy" as it came to be called and despite Conroy's nearly running out of cash and credit during the conversion, the project was successful.

In September 1963, the Pregnant Guppy flew the S-IV stage for the fifth Saturn I launch from California to Florida. The aircraft has also carried Gemini launch vehicles, Apollo command and service modules, Pegasus meteoroid detection equipment, F-1 engines for the Saturn V, an instrument unit for the Saturn I, and other large NASA cargo.

The HL-10 was one of five heavyweight lifting-body designs flown at NASA's Flight Research Center (FRC--later Dryden Flight Research Center), Edwards, California, from July 1966 to November 1975 to study and validate the concept of safely maneuvering and landing a low lift-over-drag vehicle designed for reentry from space.

Northrop Corporation built the HL-10 and M2-F2, the first two of the fleet of "heavy" lifting bodies flown by the NASA Flight Research Center. The contract for construction of the HL-10 and the M2-F2 was $1.8 million. "HL" stands for horizontal landing, and "10" refers to the tenth design studied by engineers at NASA's Langley Research Center, Hampton, Va.

After delivery to NASA in January 1966, the HL-10 made its first flight on Dec. 22, 1966, with research pilot Bruce Peterson in the cockpit. Although an XLR-11 rocket engine was installed in the vehicle, the first 11 drop flights from the B-52 launch aircraft were powerless glide flights to assess handling qualities, stability, and control. In the end, the HL-10 was judged to be the best handling of the three original heavy-weight lifting bodies (M2-F2/F3, HL-10, X-24A).

The HL-10 was flown 37 times during the lifting body research program and logged the highest altitude and fastest speed in the Lifting Body program. On Feb. 18, 1970, Air Force test pilot Peter Hoag piloted the HL-10 to Mach 1.86 (1,228 mph). Nine days later, NASA pilot Bill Dana flew the vehicle to 90,030 feet, which became the highest altitude reached in the program.

Some new and different lessons were learned through the successful flight testing of the HL-10. These lessons, when combined with information from it's sister ship, the M2-F2/F3, provided an excellent starting point for designers of future entry vehicles, including the Space Shuttle.

Today's takeoff sets the stage for a two-day Helios endurance flight in the stratosphere planned for mid-July. The Helios wing, spanning 247 feet and weighing about 2,400 pounds, is giving NASA and industry engineers confidence that remotely piloted aircraft will be able to stay aloft for weeks at a time, providing environmental monitoring capabilities and telecommunications relay services.

Helios is an all-electric airplane. In addition to being non-polluting, Helios can fly above storms, and use the power of the sun to stay aloft during daylight. Key to the success of this type of aircraft is the ability to fly in darkness, using fuel cells when sunlight cannot furnish energy.

The flights of Helios this summer are from the Navy’s Pacific Missile Range Facility, where favorable sun exposure and test ranges closed to other air traffic will benefit the NASA research effort.

The Helios Prototype is the latest and largest example of a slow-flying ultralight flying wing designed for high-altitude, long-duration Earth science or telecommunications relay missions. A follow-on to the Pathfinder and Pathfinder-Plus solar aircraft, the Helios Prototype soared to 96,863 feet altitude in August 2001, setting a new world record for sustained altitude by winged aircraft, powered only by energy from the sun.

Developed by AeroVironment, Inc., of Monrovia, Calif., under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project, the unique craft was designed to demonstrate two key missions: the ability to reach and sustain horizontal flight near 100,000 feet altitude on a single-day flight, and to maintain flight above 50,000 feet altitude for almost two days, the latter mission with the aid of an experimental fuel cell-based supplemental electrical system now in development.

The Helios Prototype is an enlarged version of the Centurion flying wing that flew a series of test flights at Dryden in late 1998. The craft has a wingspan of 247 feet, 41 feet greater than the Centurion, 2 1/2 times that of the Pathfinder flying wing, and longer than the wingspans of either the Boeing 747 jetliner or Lockheed C-5 transport aircraft.

The remotely piloted Helios Prototype first flew during a series of low-altitude checkout and development flights on battery power in late 1999 over Rogers Dry Lake adjacent to NASA's Dryden Flight Research Center in the Southern California desert.

In upgrading the Centurion to the Helios Prototype configuration, AeroVironment added a sixth wing section, a fifth landing gear pod and a differential Global Positioning Satellite (GPS) system to improve navigation, among other improvements. The additional wingspan increased the area available for installation of solar cells and improved aerodynamic efficiency, allowing the Helios Prototype to fly higher, longer and with a larger payload than the smaller craft.

During 2000, more than 62,000 bi-facial silicon solar cells were mounted on the upper surface of Helios' wing. Produced by SunPower, Inc., these solar arrays convert about 19 percent of the solar energy they receive into electrical current and can produce up to 35 kw at high noon on a summer day.

The second milestone established by NASA for its development Ð a long-endurance demonstration flight of almost two days and nights Ð required development of a supplemental electrical power system to provide power at night when the solar arrays are unable to produce electricity. AeroVironment developed an experimental fuel cell-based electrical energy system combining advanced automotive fuel cell components with proprietary control technology designed for the harsh environment above 50,000 feet altitude.

The first version of this system combines gaseous hydrogen from two pressurized tanks mounted on Helios' outboard wing sections with compressed oxygen from the atmosphere via a series of proton-exchange membrane fuel cell "stacks" mounted in the central landing gear pod. The system produces more than 15 kW of direct-current electricity to power Helios' motors and operating systems, with the only by-product being water vapor and heat. The system will increase the Helios Prototype's flight weight by about 800 lb to about 2,400 lb.

Two other versions of the system are contemplated: One, employing liquid hydrogen, would enable the Helios to fly for up to two weeks in the stratosphere anywhere around the Earth, not limited to temperate or equatorial latitudes. Another version, a closed or "regenerative" system, uses water, a fuel cell, and an electrolyzer to form a system similar in function to a rechargeable or "secondary" battery, but with much greater efficiency than the best rechargeable battery systems.

A production version of the Helios with the regenerative fuel cell system is of interest to NASA for environmental science, the military and AeroVironment for various roles, primarily as a stratospheric telecommunications relay platform. With other system reliability improvements, production versions of the Helios are expected to fly missions lasting months at a time, becoming true "atmospheric satellites."

About one-half the size of a standard manned fighter and powered by a small jet engine, the HiMAT vehicles were launched from NASA's B-52 carrier aircraft at an altitude of about 45,000 feet. They were flown remotely by a NASA research pilot from a ground station with the aid of a television camera mounted in the HiMAT cockpits.

Technologies tested on the HiMAT vehicles appearing later on other aircraft include the extensive use of composites common now on military and commercial aircraft; rear-mounted wing and forward canard configuration used very successfully on the X-29 research aircraft flown at Dryden; and winglets, now used on many private and commercial aircraft to lessen wingtip drag and enhance fuel savings.

The Hyper III as originally conceived was a stiletto-shaped lifting body that had resulted from a study at NASA’s Langley Research Center in Hampton, Virginia. It was one of a number of hypersonic, cross-range reentry vehicles studied at Langley. (Hypersonic means Mach 5--five times the speed of sound--or faster; cross-range means able to fly a considerable distance to the left or right of the initial reentry path.) The FRC added a small, deployable, skewed wing to compensate for the shape’s extremely low glide ratio. Shop personnel built the 32-foot-long Hyper III and covered its tubular frame with dacron, aluminum, and fiberglass, for about $6,500.

Hyper III employed the same "8-ball" attitude indicator developed for control-room use when flying the X-15, two model-airplane receivers to command the vehicle’s hydraulic controls, and a telemetry system (surplus from the X-15 program) to transmit 12 channels of data to the ground not only for display and control but for data analysis. Dropped from a helicopter at 10,000 feet, Hyper III flew under the control of research pilot Milt Thompson to a near landing using instruments for control. When the vehicle was close to the ground, he handed the vehicle off to experienced model pilot Dick Fischer for a visual landing using standard controls. The flight demonstrated the feasibility of remotely piloting research vehicles and, among other things, that control of the vehicle in roll was much better than predicted and that the vehicle had a much lower lift-to-drag ratio than predicted (a maximum of 4.0 rather than 5.0).

Pilot Milt Thompson exhibited some suprising reactions during the Hyper III flight; he behaved as if he were in the cockpit of an actual research aircraft.

"I was really stimulated emotionally and physically in exactly the same manner that I have been during actual first flights." "Flying the Hyper III from a ground cockpit was just as dramatic as an actual flight in any of the other vehicles....responsibility rather than fear of personal safety is the real emotional driver. I have never come out of a simulator emotionally and physically tired as is often the case after a test flight in a research aircraft. I was emotionally and physically tired after a 3-minute flight of the Hyper III."

The first flight tests of the M2-F1 were over Rogers Dry Lake at the end of a tow rope attached to a hopped-up Pontiac convertible driven at speeds up to about 120 mph. These initial tests produced enough flight data about the M2-F1 to proceed with flights behind a NASA C-47 tow plane at greater altitudes. The C-47 took the craft to an altitude of 12,000 where free flights back to Rogers Dry Lake began. Pilot for the first series of flights of the M2-F1 was NASA research pilot Milt Thompson. Typical glide flights with the M2-F1 lasted about two minutes and reached speeds of 110 to 120 mph.

More than 400 ground tows and 77 aircraft tow flights were carried out with the M2-F1. The success of Dryden's M2-F1 program led to NASA's development and construction of two heavyweight lifting bodies based on studies at NASA's Ames and Langley research centers--the M2-F2 and the HL-10, both built by the Northrop Corporation, and the U.S. Air Force's X-24 program. The Lifting Body program also heavily influenced the Space Shuttle program.

The M2-F1 program demonstrated the feasibility of the lifting-body concept for horizontal landings of atmospheric entry vehicles. It also demonstrated a procurement and management concept for prototype flight research vehicles that produced rapid results at very low cost (approximately $50,000, excluding salaries of government employees assigned to the project).