Northrop HL-10
Encyclopedia
The Northrop
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. It was a NASA design and was built to evaluate "inverted airfoil" lifting body and delta planform. It currently is on display at the entrance to the Dryden Flight Research Center, Edwards Air Force Base, California.
, 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, Virginia
. Main gear was a modified T-38
system retracted manually, and lowered by nitrogen pressure. Nose gear was modified T-39
unit, retracted manually and lowered with nitrogen pressure. Pilot Ejection System was a modified F-106
system. Silver zinc batteries provided electrical power for control system, flight instruments, radios, cockpit heat, and stability augmentation system. To assist in pre-landing flare, four throttleable hydrogen peroxide rockets provided up to 400 lbf (1.8 kN) of thrust.
After delivery to NASA in January 1966, the HL-10 made its first flight on December 22, 1966, with research pilot Bruce Peterson
in the cockpit. Although the XLR-11 rocket engine (same type used in the Bell X-1
) was installed, the first 11 drops from the B-52
launch aircraft were unpowered 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 February 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 90030 feet (27,441.1 m), which became the highest altitude reached in the program.
During a typical lifting body flight, the B-52—with the research vehicle attached to the pylon mount on the right wing between the fuselage and inboard engine pod—flew to a height of about 45000 feet (13,716 m) and a launch speed of about 450 mi/h.
Moments after being dropped, the XLR-11 was lit by the pilot. Speed and altitude increased until the engine was shut down by choice or fuel exhaustion, depending upon the individual mission profile. The lifting bodies normally carried enough fuel for about 100 seconds of powered flight and routinely reached from 50000 feet (15,240 m) to 80000 feet (24,384 m) and speeds above Mach 1.
Following engine shutdown, the pilot maneuvered the vehicle through a simulated return-from-space corridor into a pre-planned approach for a landing on one of the lakebed runways on Rogers Dry Lake
at Edwards. A circular approach was used to lose altitude during the landing phase. On the final approach leg, the pilot increased his rate of descent to build up energy. At about 100 feet (30.5 m) altitude, a "flare out" maneuver dropped air speed to about 200 mi/h for the landing.
Unusual and valuable lessons were learned through the successful flight testing of the HL-10. During the early phases of the Space Shuttle
development program, lifting bodies patterned on the HL-10 shape were one of three major types of proposals. These were later rejected as it proved difficult to fit cylindrical fuel tanks into the always-curving fuselage, and from then on most designs focused on more conventional delta wing
craft.
His plan was to heavily modify the HL-10 at the Flight Research Center with the addition of an ablative heat shield, reaction controls, and other additional subsystems needed for manned spaceflight. The now space-rated vehicle would have then flown on the Apollo-Saturn V launch vehicle in the same space which originally held the Lunar Module
.
Once in Earth orbit, it was planned that a robotic extraction arm would remove the vehicle from the rocket's third stage and place it adjacent to the manned Apollo CSM spacecraft. One of the astronauts, who would be trained to fly the vehicle, would then spacewalk from the Apollo and board the lifting body to perform a pre-reentry check on its systems.
It was planned that there would be two flights in this program. In the first, the lifting body pilot would return to the Apollo and send the HL-10 back to earth unmanned. If this flight was successful, on the next launch, he would then pilot the HL-10 back to earth for a planned landing at Edwards AFB.
Reportedly, Wernher von Braun
thought it a wonderful idea and offered to prepare two Saturn Vs and Apollo Command Service Modules for the mission. Flight Research Center director Paul Bickle said no, stating that this was beyond his expertise or area of interest.
entitled "The Deadly Replay", the HL-10 is identified as the aircraft flown by Col. Steve Austin
when he crashed, leading to his transformation into a bionic man, and the HL-10 is also featured in this episode. Other episodes and Martin Caidin
's original novel, Cyborg
, contradict this, however, by identifying Austin's aircraft as a fictional cousin of the HL-10, the M3-F5. Further confusion is added by the fact that both the HL-10 and the M2-F2 are featured in the opening credits of the TV show.
Comparable aircraft:
Northrop Corporation
Northrop Corporation was a leading United States aircraft manufacturer from its formation in 1939 until its merger with Grumman to form Northrop Grumman in 1994. The company is known for its development of the flying wing design, although only a few of these have entered service.-History:Jack...
HL-10 was one of five heavyweight lifting body
Lifting body
A lifting body is a fixed-wing aircraft configuration in which the body itself produces lift. In contrast to a flying wing, which is a wing with minimal or no conventional fuselage, a lifting body can be thought of as a fuselage with little or no conventional wing...
designs flown at NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
's Flight Research Center (FRC—later Dryden Flight Research Center
Dryden Flight Research Center
The Dryden Flight Research Center , located inside Edwards Air Force Base, is an aeronautical research center operated by NASA. On March 26, 1976 it was named in honor of the late Hugh L. Dryden, a prominent aeronautical engineer who at the time of his death in 1965 was NASA's deputy administrator...
), Edwards, California
Edwards, California
Edwards is an unincorporated community in Kern County, California.It is located east-southeast of Mojave, at an elevation of 2356 feet ....
, from July 1966
1966 in aviation
This is a list of aviation-related events from 1966:-January:* The United States Armys helicopter assault-oriented 1st Cavalry Division begins Operation Matador to destroy North Vietnamese Army forces in Pleiku and Kon Tum Province, South Vietnam....
to November 1975
1975 in aviation
This is a list of aviation-related events from 1975:-January:* A specially modified McDonnell Douglas F-15 Eagle sets eight time to climb records, including one of 3 minutes 27 seconds from standstill on the runway to a height of 30,000 metres ....
to study and validate the concept of safely maneuvering and landing a low lift-over-drag
Lift-to-drag ratio
In aerodynamics, the lift-to-drag ratio, or L/D ratio, is the amount of lift generated by a wing or vehicle, divided by the drag it creates by moving through the air...
vehicle designed for reentry from space. It was a NASA design and was built to evaluate "inverted airfoil" lifting body and delta planform. It currently is on display at the entrance to the Dryden Flight Research Center, Edwards Air Force Base, California.
Development
Northrop Corporation built the HL-10 and Northrop M2-F2Northrop M2-F2
|-See also:-External links:***** of Peterson's crash...
, 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
Langley Research Center
Langley Research Center is the oldest of NASA's field centers, located in Hampton, Virginia, United States. It directly borders Poquoson, Virginia and Langley Air Force Base...
, Hampton, Virginia
Hampton, Virginia
Hampton is an independent city that is not part of any county in Southeast Virginia. Its population is 137,436. As one of the seven major cities that compose the Hampton Roads metropolitan area, it is on the southeastern end of the Virginia Peninsula. Located on the Hampton Roads Beltway, it hosts...
. Main gear was a modified T-38
T-38 Talon
The Northrop T-38 Talon is a twin-engine supersonic jet trainer. It was the world's first supersonic trainer and is also the most produced. The T-38 remains in service as of 2011 in air forces throughout the world....
system retracted manually, and lowered by nitrogen pressure. Nose gear was modified T-39
T-39 Sabreliner
The North American Sabreliner is a mid-sized business jet developed by North American Aviation. It was offered to the U.S. Air Force in response to their Utility Trainer Experimental program...
unit, retracted manually and lowered with nitrogen pressure. Pilot Ejection System was a modified F-106
F-106 Delta Dart
The Convair F-106 Delta Dart was the primary all-weather interceptor aircraft for the United States Air Force from the 1960s through the 1980s. Designed as the so-called "Ultimate Interceptor", it has proven to be the last dedicated interceptor in USAF service to date...
system. Silver zinc batteries provided electrical power for control system, flight instruments, radios, cockpit heat, and stability augmentation system. To assist in pre-landing flare, four throttleable hydrogen peroxide rockets provided up to 400 lbf (1.8 kN) of thrust.
Operational history
Bruce Peterson
Bruce Peterson was a test pilot for NASA.A native of Washburn, North Dakota, he attended the University of California at Los Angeles, and California Polytechnic State University...
in the cockpit. Although the XLR-11 rocket engine (same type used in the Bell X-1
Bell X-1
The Bell X-1, originally designated XS-1, was a joint NACA-U.S. Army/US Air Force supersonic research project built by Bell Aircraft. Conceived in 1944 and designed and built over 1945, it eventually reached nearly 1,000 mph in 1948...
) was installed, the first 11 drops from the B-52
B-52 Stratofortress
The Boeing B-52 Stratofortress is a long-range, subsonic, jet-powered strategic bomber operated by the United States Air Force since the 1950s. The B-52 was designed and built by Boeing, who have continued to provide maintainence and upgrades to the aircraft in service...
launch aircraft were unpowered 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
Lifting body
A lifting body is a fixed-wing aircraft configuration in which the body itself produces lift. In contrast to a flying wing, which is a wing with minimal or no conventional fuselage, a lifting body can be thought of as a fuselage with little or no conventional wing...
program. On February 18, 1970, Air Force test pilot Peter Hoag piloted the HL-10 to Mach
Mach number
Mach number is the speed of an object moving through air, or any other fluid substance, divided by the speed of sound as it is in that substance for its particular physical conditions, including those of temperature and pressure...
1.86 (1,228 mph). Nine days later, NASA pilot Bill Dana
William H. Dana
-Career:Dana was born in Pasadena, California, November 3, 1930, received his Bachelor of Science degree from the U.S. Military Academy in 1952 and served four years as a pilot in the U.S. Air Force...
flew the vehicle to 90030 feet (27,441.1 m), which became the highest altitude reached in the program.
During a typical lifting body flight, the B-52—with the research vehicle attached to the pylon mount on the right wing between the fuselage and inboard engine pod—flew to a height of about 45000 feet (13,716 m) and a launch speed of about 450 mi/h.
Moments after being dropped, the XLR-11 was lit by the pilot. Speed and altitude increased until the engine was shut down by choice or fuel exhaustion, depending upon the individual mission profile. The lifting bodies normally carried enough fuel for about 100 seconds of powered flight and routinely reached from 50000 feet (15,240 m) to 80000 feet (24,384 m) and speeds above Mach 1.
Following engine shutdown, the pilot maneuvered the vehicle through a simulated return-from-space corridor into a pre-planned approach for a landing on one of the lakebed runways on Rogers Dry Lake
Rogers Dry Lake
Rogers Dry Lake is an endorheic desert salt pan in the Mojave Desert of Kern County, California. The lake derives its name from the Anglicization from the Spanish name, Rodriguez Dry Lake. It is the central part of Edwards Air Force Base as its hard surface provides a natural extension to the...
at Edwards. A circular approach was used to lose altitude during the landing phase. On the final approach leg, the pilot increased his rate of descent to build up energy. At about 100 feet (30.5 m) altitude, a "flare out" maneuver dropped air speed to about 200 mi/h for the landing.
Unusual and valuable lessons were learned through the successful flight testing of the HL-10. During the early phases of the Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
development program, lifting bodies patterned on the HL-10 shape were one of three major types of proposals. These were later rejected as it proved difficult to fit cylindrical fuel tanks into the always-curving fuselage, and from then on most designs focused on more conventional delta wing
Delta wing
The delta wing is a wing planform in the form of a triangle. It is named for its similarity in shape to the Greek uppercase letter delta .-Delta-shaped stabilizers:...
craft.
- HL-10 pilots
- John A. Manke - 10 flights, 7 powered flights
- William H. DanaWilliam H. Dana-Career:Dana was born in Pasadena, California, November 3, 1930, received his Bachelor of Science degree from the U.S. Military Academy in 1952 and served four years as a pilot in the U.S. Air Force...
- 9 flights, 8 powered flights - Jerauld R. GentryJerauld R. GentryJerauld Richard "Jerry" Gentry was a United States Air Force test pilot and Vietnam combat veteran. As chief USAF pilot of the Lifting Body Research Program, he helped validate the concept of flying a wingless vehicle back to Earth from space and landing it like an aircraft—an approach used...
- 9 flights, 2 powered flights - Peter C. Hoag - 8 flights, 7 powered flights
- Bruce PetersonBruce PetersonBruce Peterson was a test pilot for NASA.A native of Washburn, North Dakota, he attended the University of California at Los Angeles, and California Polytechnic State University...
- 1 flight, 0 powered flights
Unrealized space flight
According to the book "Wingless Flight", by project engineer R. Dale Reed, if he had had his way, the HL-10 would have flown in space in the early to mid-1970s. Following the cancellation of the Apollo moon project, Reed realized that there would be substantial Apollo hardware left over, including several flight-rated command modules and Saturn V rockets.His plan was to heavily modify the HL-10 at the Flight Research Center with the addition of an ablative heat shield, reaction controls, and other additional subsystems needed for manned spaceflight. The now space-rated vehicle would have then flown on the Apollo-Saturn V launch vehicle in the same space which originally held the Lunar Module
Apollo Lunar Module
The Apollo Lunar Module was the lander portion of the Apollo spacecraft built for the US Apollo program by Grumman to carry a crew of two from lunar orbit to the surface and back...
.
Once in Earth orbit, it was planned that a robotic extraction arm would remove the vehicle from the rocket's third stage and place it adjacent to the manned Apollo CSM spacecraft. One of the astronauts, who would be trained to fly the vehicle, would then spacewalk from the Apollo and board the lifting body to perform a pre-reentry check on its systems.
It was planned that there would be two flights in this program. In the first, the lifting body pilot would return to the Apollo and send the HL-10 back to earth unmanned. If this flight was successful, on the next launch, he would then pilot the HL-10 back to earth for a planned landing at Edwards AFB.
Reportedly, Wernher von Braun
Wernher von Braun
Wernher Magnus Maximilian, Freiherr von Braun was a German rocket scientist, aerospace engineer, space architect, and one of the leading figures in the development of rocket technology in Nazi Germany during World War II and in the United States after that.A former member of the Nazi party,...
thought it a wonderful idea and offered to prepare two Saturn Vs and Apollo Command Service Modules for the mission. Flight Research Center director Paul Bickle said no, stating that this was beyond his expertise or area of interest.
HL-10 flights
| Vehicle Flight # |
Date | Pilot | Mach | Velocity /km/h | Altitude /m | Duration | Comments |
|---|---|---|---|---|---|---|---|
| HL-10 #1 | December 22, 1966 | Peterson | 0.693 | 735 | 13,716 | 00:03:07 | First HL-10 Flight Unpowered glide |
| HL-10 #2 | March 15, 1968 | Gentry | 0.609 | 684 | 13,716 | 00:04:03 | Unpowered glide |
| HL-10 #3 | April 3, 1968 | Gentry | 0.690 | 732 | 13,716 | 00:04:02 | Unpowered glide |
| HL-10 #4 | April 25, 1968 | Gentry | 0.697 | 739 | 13,716 | 00:04:18 | Unpowered glide |
| HL-10 #5 | May 3, 1968 | Gentry | 0.688 | 731 | 13,716 | 00:04:05 | Unpowered glide |
| HL-10 #6 | May 16, 1968 | Gentry | 0.678 | 719 | 13,716 | 00:04:25 | Unpowered glide |
| HL-10 #7 | May 28, 1968 | Manke | 0.657 | 698 | 13,716 | 00:04:05 | Unpowered glide |
| HL-10 #8 | June 11, 1968 | Manke | 0.635 | 697 | 13,716 | 00:04:06 | Unpowered glide |
| HL-10 #9 | June 21, 1968 | Gentry | 0.637 | 700 | 13,716 | 00:04:31 | Unpowered glide |
| HL-10 #10 | September 24, 1968 | Gentry | 0.682 | 723 | 13,716 | 00:04:05 | Unpowered glide XLR-11 installed |
| HL-10 #11 | October 3, 1968 | Manke | 0.714 | 758 | 13,716 | 00:04:03 | Unpowered glide |
| HL-10 #12 | October 23, 1968 | Gentry | 0.666 | 723 | 12,101 | 00:03:09 | 1st powered flight engine malfunction landed Rosamond |
| HL-10 #13 | November 13, 1968 | Manke | 0.840 | 843 | 13,000 | 00:06:25 | 3 tries to light engine |
| HL-10 #14 | December 9, 1968 | Gentry | 0.870 | 872 | 14,454 | 00:06:34 | - |
| HL-10 #15 | April 17, 1969 | Manke | 0.994 | 974 | 16,075 | 00:06:40 | - |
| HL-10 #16 | April 25, 1969 | Dana | 0.701 | 744 | 13,716 | 00:04:12 | Unpowered glide |
| HL-10 #17 | May 9, 1969 | Manke | 1.127 | 1,197 | 16,246 | 00:06:50 | 1st lifting body supersonic flight |
| HL-10 #18 | May 20, 1969 | Dana | 0.904 | 959 | 14,966 | 00:06:54 | - |
| HL-10 #19 | May 28, 1969 | Manke | 1.236 | 1,312 | 18,959 | 00:06:38 | - |
| HL-10 #20 | June 6, 1969 | Hoag | 0.665 | 727 | 13,716 | 00:03:51 | Unpowered glide |
| HL-10 #21 | June 19, 1969 | Manke | 1.398 | 1,484 | 19,538 | 00:06:18 | - |
| HL-10 #22 | July 23, 1969 | Dana | 1.444 | 1,350 | 19,446 | 00:06:13 | - |
| HL-10 #23 | August 6, 1969 | Manke | 1.540 | 1,656 | 23,195 | 00:06:12 | 1st four chambered flight |
| HL-10 #24 | September 3, 1969 | Dana | 1.446 | 1,542 | 23,762 | 00:06:54 | - |
| HL-10 #25 | September 18, 1969 | Manke | 1.256 | 1,341 | 24,137 | 00:07:06 | - |
| HL-10 #26 | September 30, 1969 | Hoag | 0.924 | 980 | 16,383 | 00:07:16 | - |
| HL-10 #27 | October 27, 1969 | Dana | 1.577 | 1,675 | 18,474 | 00:06:57 | - |
| HL-10 #28 | November 3, 1969 | Hoag | 1.396 | 1,482 | 19,544 | 00:07:19 | - |
| HL-10 #29 | November 17, 1969 | Dana | 1.594 | 1,693 | 19,687 | 00:06:48 | - |
| HL-10 #30 | November 21, 1969 | Hoag | 1.432 | 1,532 | 24,165 | 00:06:18 | - |
| HL-10 #31 | December 12, 1969 | Dana | 1.310 | 1,402 | 24,372 | 00:07:08 | - |
| HL-10 #32 | January 19, 1970 | Hoag | 1.310 | 1,399 | 26,414 | 00:06:50 | - |
| HL-10 #33 | January 26, 1970 | Dana | 1.351 | 1,444 | 26,726 | 00:06:51 | - |
| HL-10 #34 | February 18, 1970 | Hoag | 1.861 | 1,976 | 20,516 | 00:06:20 | Fastest lifting body flight |
| HL-10 #35 | February 27, 1970 | Dana | 1.314 | 1,400 | 27,524 | 00:06:56 | Highest lifting body flight |
| HL-10 #36 | June 11, 1970 | Hoag | 0.744 | 810 | 13,716 | 00:03:22 | Lift/Drag powered approach |
| HL-10 #37 | July 17, 1970 | Hoag | 0.733 | 803 | 13,716 | 00:04:12 | Last flight |
Specifications (Northrop HL-10)
General characteristics
- Crew: one pilot
- Length: 21 ft 2 in (6.45 m)
- Wingspan: 13 ft 7 in (4.15 m)
- Height: 9 ft 7 in (2.92 m)
- Wing area: 160 ft² (14.9 m²)
- Empty: 5,285 lb (2,397 kg)
- Loaded: 6,000 lb (2,721 kg)
- Maximum takeoff: 10,009 lb (4,540 kg) (propellant wt 3,536 lb - 1,604 kg)
- Powerplant: 1 x Reaction Motors XLR-11Reaction Motors XLR-11The XLR11 was the first liquid-fuel rocket engine developed in the United States for use in aircraft. It was designed and built by Reaction Motors Inc., and used ethyl alcohol and liquid oxygen as propellants to generate a maximum thrust of . Each of the four combustion chambers produced of thrust...
four-chamber rocket engine. 8,000 lbf (35.7 kN) thrust
Performance
- Maximum speed: 1,228 mph (1,976 km/h)
- Range: 45 miles (72 km)
- Service ceiling: 90,303 ft (27,524 m)
- Rate of climb: ft/min ( m/min)
- Wing loading: 62.5 lb/ft² (304.7 kg/m²)
- Thrust-to-weight: 1:0.99
Fictional references
In an episode of The Six Million Dollar ManThe Six Million Dollar Man
The Six Million Dollar Man is an American television series about a former astronaut with bionic implants working for the OSI...
entitled "The Deadly Replay", the HL-10 is identified as the aircraft flown by Col. Steve Austin
Steve Austin (fictional character)
Steve Austin is a fictional character created by Martin Caidin for his 1972 novel, Cyborg, who later became a 1970s television icon as portrayed by Lee Majors in the 1974-1978 series The Six Million Dollar Man.-Background:...
when he crashed, leading to his transformation into a bionic man, and the HL-10 is also featured in this episode. Other episodes and Martin Caidin
Martin Caidin
Martin Caidin was an American author and an authority on aeronautics and aviation.Caidin wrote more than 50 books, including Samurai!, Black Thursday, Thunderbolt!, Fork-Tailed Devil: The P-38, Zero!, The Ragged, Rugged Warriors, A Torch to the Enemy and many other works of military history...
's original novel, Cyborg
Cyborg (novel)
Cyborg is the title of a science fiction/secret agent novel by Martin Caidin which was first published in 1972. The novel also included elements of speculative fiction, and was adapted as the television series The Six Million Dollar Man and also inspired its spin-off, The Bionic Woman.-Plot...
, contradict this, however, by identifying Austin's aircraft as a fictional cousin of the HL-10, the M3-F5. Further confusion is added by the fact that both the HL-10 and the M2-F2 are featured in the opening credits of the TV show.
See also
- X-planeX-planeThe X-planes are a series of experimental United States airplanes and helicopters used for the testing and evaluation of new technologies and aerodynamic concepts...
- List of experimental aircraft
- HL-20 Personnel Launch SystemHL-20 Personnel Launch SystemThe HL-20 Personnel Launch System was a circa 1990 NASA spaceplane concept for manned orbital missions studied by NASA's Langley Research Center in Hampton, Virginia. HL-20 was envisaged as a lifting body re-entry vehicle based on the Soviet BOR-4 spaceplane design featuring low operational costs,...
Comparable aircraft:
- X-24
- M2-F1NASA M2-F1The NASA M2-F1 was a lightweight, unpowered prototype aircraft, developed to flight test the wingless lifting body concept. It looked like a "flying bathtub," and was designated the M2-F1, the "M" referring to "manned" and "F" referring to "flight" version. In 1962, NASA Dryden management approved...
- M2-F2Northrop M2-F2|-See also:-External links:***** of Peterson's crash...
- M2-F3Northrop M2-F3The Northrop M2-F3 was a heavyweight lifting body rebuilt from the Northrop M2-F2 after it crashed at the Dryden Flight Research Center in 1967. It was modified with an additional third vertical fin - centered between the tip fins - to improve control characteristics...
- X-38 Crew Return VehicleX-38 Crew Return Vehicle|- Trivia :* The Oakland-based, Space-themed punk/rockabilly band, The Phenomenauts, released a song called "Where is the X-38?" openly criticizing the cancellation of the X-38 project. The song was released on their second album, Re-Entry, in 2004....