NASA Facts

National Aeronautics and 

Space Administration 

Dryden Flight Research Center 

P.O. Box 273

Edwards, California 93523 

Voice 661-276-3449 

FAX 661-276-3566 

pao@dfrc.nasa.gov FS-1998-05-011-DFRC 

The Lifting Bodies

Three of the five heavyweights--X-24A (L), M2-F3 (C), & HL-10 (R) E21115 

A fleet of lifting bodies flown at the NASA Flight Research Center (FRC), Edwards, Calif., from 1963 to l975 

demonstrated the ability of pilots to maneuver (in the atmosphere) and safely land a wingless vehicle. These lifting 

bodies were basically designed so they could fly back to Earth from space and be landed like an aircraft at a predetermined site. (In 1976 NASA renamed the FRC as the NASA Dryden Flight Research Center in honor of Hugh 

L. Dryden.)

These unique research vehicles, with their unconventional aerodynamic shapes, were the M2-F1, M2-F2, M2-F3, 

HL-10, X-24A, and the X-24B. The information the lifting body program generated contributed to the data base 

that led to development of today’s space shuttle program as well as the X-33 and X-38 technology demonstrators. 

Lockheed Martin’s X-33 features a lifting-body design, while the X-38 vehicles get their configuration from the 

X-24A. 

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Aerodynamic lift—essential to flight in the atmosphere— 

was obtained from the shape of the vehicles rather than 

from wings on a normal aircraft. The addition of fins and 

control surfaces allowed the pilots to stabilize and control the vehicles and regulate their flight paths. 

All but the M2-F1 were powered by the same type of 

XLR-11 rocket engine used in the famed Bell 

X-1—first aircraft to fly faster than the speed of sound. 

The M2-F1, a lightweight prototype, was unpowered. 

Background 

The original idea of lifting bodies was conceived about 

1957 by Dr. Alfred J. Eggers Jr., then the assistant 

director for Research and Development Analysis and 

Planning at what later became the NASA Ames Research 

Center, Moffett Field, Calif. (then called the Ames 

Aeronautical Laboratory). 

NASA had earlier been investigating the problems associated with reentry of missile nose cones. H. Julian 

Allen, another Ames engineer, determined that a blunt 

nose cone was a desirable shape to survive the aerodynamic heating associated with reentry from space. Eggers 

found that by slightly modifying a symmetrical nose 

Orbital entry footprints (lateral and longitudial maneuverability) of lifting bodies and spacecraft. (Note the very small area 

for the Mercury, Gemini, and Apollo capsules as compared 

with the lifting bodies and the Space Shuttle.) 

cone shape, aerodynamic lift could be produced. This lift 

would enable the modified shape to fly back from space 

rather than plunge to earth in a ballistic trajectory. 

These studies by Eggers, Allen, and their associates led 

to the design known as the M-2, a modified half-cone, 

rounded on the bottom and flat on top, with a blunt, 

rounded nose and twin tail-fins. This configuration and 

those of the later lifting bodies allowed them to be 

maneuvered both in a lateral and a longitudinal direction 

so they could be landed on a runway rather than simply 

parachuting into the ocean as did the contemporary 

ballistic capsules used in the Mercury, Gemini, and 

Apollo programs.

 The Pioneering M2-F1 

In 1962, FRC Director Paul Bikle approved a program 

to build a lightweight, unpowered lifting body as a 

prototype to flight test the wingless concept. It would 

look like a “flying bathtub,” and was designated the M2-

F1. It featured a plywood shell, built by Gus Briegleb, a 

sailplane builder from El Mirage, Calif., placed over a 

tubular steel frame crafted at the FRC. Construction was 

completed in 1963. 

The first flight tests 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 

2
 E 10962 M2-F1 towed aloft by C-47 

tests produced enough flight data about the M2-F1 to 

proceed with flights behind a NASA R4D tow plane at 

greater altitudes. The R4D (Navy version of the C-47) 

took the craft to an altitude of 12,000 ft. where free flights 

back to Rogers Dry Lake began. NASA research pilot 

Milt Thompson flew the M2-F1 during the first series

 of tests. 

Typical glide flights with the M2-F1 lasted several 

minutes and reached speeds of 110 to l20 mph. 

More than 400 ground tows and 77 aircraft tow flights 

were carried out with the M2-F1 before it was retired and 

gave way to more advanced versions of lifting bodies. A 

historical artifact belonging to the Smithsonian’s National Air and Space Museum, the M2-F1 is located at 

Dryden where it has been restored to a flight-like condition.

 The Heavyweights 

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. The “M” refers 

to “manned” and “F” refers to “flight” version. “HL” 

comes from “horizontal landing” and “10” is for the tenth 

lifting body model to be investigated by Langley. 

The Air Force later became interested in lifting body 

research and had a third design concept, the X-24A, built 

by the Martin Company. It was later modified into the X24B and both configurations were flown in the joint 

NASA-Air Force lifting body program located

 at Dryden. 

M2-F2 

The first flight of the M2-F2—which looked much like 

the M2-F1—occurred on July 12, 1966. 

Thompson was the pilot. By then, the same B-52 used to 

air launch the famed X-15 rocket research aircraft had 

been modified to also carry the lifting bodies into the air 

and Thompson was dropped from the B-52’s wing pylon 

mount at an altitude of 45,000 feet on that maiden glide 

flight. 

The M2-F2 weighed 4,620 pounds without ballast, was 

ECN 1567 M2-F2 and F-104 chase aircraft. 

roughly 22 feet long, and had a width of about 10 feet. 

On May 10, 1967, during the sixteenth glide flight 

leading up to powered flight, a landing accident severely 

damaged the vehicle and seriously injured the NASA 

pilot, Bruce Peterson. 

M2-F3 

NASA pilots said the M2-F2 had lateral control 

problems, even though it had a stability augmentation 

control system. When the M2-F2 was rebuilt at Dryden 

and redesignated the M2-F3, it was modified with an 

additional third vertical fin—centered between the tip 

fins—to improve control characteristics. 

The first flight of the M2-F3, with NASA pilot Bill Dana 

at the controls, was on June 2, 1970. It was a glide flight 

to evaluate changes in the vehicle’s performance due to 

the modifications. The modified vehicle exhibited much

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better lateral stability and control characteristics than 

had the M2-F2. 

Over the next 26 missions, the M2-F3 reached a top 

speed of l,064 mph (Mach 1.6). Bill Dana was the pilot, 

and the high-speed flight took place on Dec. 13, 1972. 

The highest altitude reached by the vehicle was 71,500 

feet on Dec. 20, 1972, the date of its last flight, with 

NASA pilot John Manke at the controls. 

A reaction jet control system, similar to thrusters used on 

orbiting spacecraft, was also installed to obtain research 

data about their effectiveness for vehicle control. As the 

M2-F3’s portion of the lifting body program neared an 

end, it evaluated a rate command augmentation control 

system, and a side-arm control stick similar to side-arm 

controllers now used on many modern aircraft. 

The M2-F3 is now on display in the National Air and 

Space Museum, Washington, D. C. 

HL-10 

The HL-10 was delivered to the FRC by Northrop in 

January 1966. Its first flight was on Dec. 22 of the same 

year. The pilot was Bruce Peterson, before he was injured 

in the M2-F2 accident. 

The HL-10 was flown 37 times and it set several program 

records. On Feb. 18, 1970, Air Force test pilot Maj. Peter 

Hoag flew it to 1,228 mph (Mach 1.86), fastest speed of any 

of the lifting bodies. Nine days later, NASA’s Bill Dana 

flew the HL-10 to 90,303 feet, the highest altitude reached 

by any of the lifting body vehicles. The HL-10 was also the 

first lifting body to fly supersonically—on May 9, 1969, 

with Manke at the controls. 

The HL-10 featured a flat bottom and rounded top —much 

like an airfoil—and it had a delta planform. In its final 

configuration, three vertical fins, two of them canted outwards from the body and a tall center fin, gave the craft 

directional control. A flush canopy blended into the smooth 

rounded nose. 

It was about 21 feet long, with a span of 13.6 feet. Its glideflight weight was 6,473 lbs. and its maximum gross weight 

was over 10,000 lbs.

 Flights with the HL-10 contributed substantially to the 

decision to design the space shuttles without air-breathing 

engines that would have been used for landings. Its final 

flight was on July 17, 1970. 

The HL-10 is now on public display at Dryden.

 X-24A 

Built for the Air Force by Martin, the X-24A was a bulbous 

vehicle shaped like a teardrop, with three vertical fins at the 

rear for directional control. It weighed 6,270 pounds without propellants, was just over 24 feet long, and had a width 

of nearly 14 feet. 

The first unpowered glide flight of the X-24A was on April 

17, 1969. The pilot was Air Force Maj. Jerauld Gentry. 

Gentry also piloted the vehicle on its first powered flight 

Mar. 19, 1970. 

It was flown 28 times in a program which, like that of the 

HL-10, helped validate the concept that a space shuttle 

vehicle could be landed unpowered. Subsequently, the X38 program managers elected to use the X-24A design to 

save money, since the existing X-24A aerodynamic database was complete. This limited the number of wind tunnel 

tests that would have been required for a totally new design. 

Fastest speed in the X-24A was 1,036 mph (Mach 1.6). The 

Graph showing 

cross-range distances in miles the vehicles could fly perpendicular to the re-entry path plotted against hypersonic lift over drag for 

several vehicles returning from orbit. Notice that the sleeker 

vehicles such as the X-24B and Hyper III have the greatest crossrange capability—around 2,500 miles, whereas the more bluntnosed lifting bodies has cross-range capabilities more comparable 

to that of the Space Shuttle. 

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Launch and flight sequence for a powered lifting body, showing 

the X-24B as an illustration of a general pattern. 

pilot was John Manke, who also reached the highest altitude 

in the vehicle, 71,400 feet. He was the pilot on its final flight 

June 4, 1971. 

X-24B 

ECN 4643 X-24B on an approach to a lakebed landing. 

The X-24B’s design evolved from a family of potential 

reentry shapes, each with higher lift-to-drag ratios, proposed by the Air Force Flight Dynamics Laboratory. 

To reduce the costs of constructing a research vehicle, 

the Air Force returned the X-24A to Martin for modifications that converted its bulbous shape into one resembling a “flying flatiron”—rounded top, flat bottom, and 

a double delta planform that ended in a pointed nose. 

First to fly the X-24B was Manke, a glide flight on Aug. 

1, 1973. He was also the pilot on the first powered 

mission Nov. 15, 1973. 

Among the final flights with the X-24B were two precise 

landings on the main concrete runway at Edwards, which 

showed that accurate unpowered reentry vehicle landings were operationally feasible. These missions were 

flown by Manke and Air Force Maj. Mike Love and 

represented the final milestone in a program that helped 

write the flight plan for today’s space shuttle program. 

After launch from the B-52 “mothership” at an altitude of 

about 45,000 feet, the XLR-11 rocket engine was ignited 

and the vehicle accelerated to speeds of more than 1,100 

mph and to altitudes of 60,000 to 70,000 feet. After the 

rocket engine was shut down, the pilots began steep 

glides towards the Edwards runway. As the pilots 

entered the final approach leg, they increased their rate of 

descent to build up speed and used this energy to perform 

a “flare out” maneuver and slow their landing speed to 

about 200 mph—the same basic approach pattern and 

landing speed of today’s space shuttles. 

The final powered flight with the X-24B was on Sept. 23, 

l975. The pilot was Bill Dana, and it was also the last 

rocket-powered flight flown at Dryden. It was Dana who 

also flew the last X-15 mission about seven years earlier. 

Top speed reached with the X-24B was 1,164 mph 

(Mach 1.75) by Love on October 25, 1974. The highest 

altitude reached was 74,100 feet, by Manke on May 22, 

1975. 

The X-24B is on public display at the Air Force Museum, 

Wright-Patterson AFB, Ohio. 

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