GiGi checked the manifest twice — the payload bay is still empty.
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Fueling up…
The machine behind the mission
A robotic spaceplane that rides a rocket to orbit, stays up for years at a time, then flies itself home and lands on a runway — including the old Shuttle runway at Kennedy.
Where dry lakebeds make runways miles long, America built aircraft to answer dangerous unknowns. The X-1 broke the sound barrier; the X-15 hit Mach 6.7, glowing from friction heat.
Experimental flight is “what if?” asked at 700 mph and graded in telemetry. Our X-Planes collection is built for that mindset: fly the hypothesis.
Drawn three years before it flew. Design speed Mach 6; Pete Knight took it to 6.7.
X-15 three-view, 1956 design
Above about 100,000 feet the air is too thin for the tail; hydrogen peroxide thrusters take over.
Control regions
Built to work at Mach 4 and 120,000 feet. In 199 flights, nobody ever pulled the handle.
Ejection seat
Before anyone rode a rocket, they strapped one to an airplane and dropped it from a bomber over the Mojave. These are the flights that found the edge of the air - and the pilots who flew past it.
The airplane as it was drawn in October 1956, three years before it flew. The numbers on the three-view are the design targets: 6,600 feet per second and 250,000 feet. The real airplane beat both. Fifty feet long, a 22-foot wing, and a tail so thick it was a wedge, because at Mach 6 a thin fin stops working.
Source: NACA Research-Airplane-Committee Report on Conference on the Progress of the X-15 Project, Langley Field, 25-26 October 1956 (declassified).
The X-15 flew so high that eight of its pilots earned astronaut wings — without ever riding a rocket off a launchpad.
At Mach 6.7, friction heated the X-15's nickel-alloy skin past 1,200°F — hot enough to glow cherry red in flight.
The X-15 never took off on its own. They were carried to 45,000 feet under a mothership's wing and dropped like a dart.
Pilot in front, then the equipment bay, then the tanks: liquid oxygen ahead of anhydrous ammonia, with the engine at the back. The fuselage is the tankage; the side fairings carry the plumbing. Peroxide drove the turbopump and the auxiliary power units, and small peroxide rockets in the nose and wings steered where the air ran out.
Source: NACA Research-Airplane-Committee Report on Conference on the Progress of the X-15 Project, Langley Field, 25-26 October 1956 (declassified).
Twelve research flights, each one a number nobody had reached before.
| Aircraft | Date | Pilot | Mach / Alt | Event |
|---|---|---|---|---|
| Bell X-1 | 14 Oct 1947 | Charles E. Yeager, USAF | Mach 1.06 | First supersonic flight. Dropped from a B-29 over Muroc; Yeager flew it with two broken ribs |
| D-558-1 Skystreak | 25 Aug 1947 | Marion Carl, USMC | 650.8 mph | World speed record, flown from a runway - the straight-wing jet |
| D-558-2 Skyrocket | 20 Nov 1953 | A. Scott Crossfield, NACA | Mach 2.005 | First to twice the speed of sound |
| Bell X-2 | 27 Sep 1956 | Milburn Apt, USAF | Mach 3.2 | First past Mach 3 - and lost on the same flight when the aircraft tumbled |
| X-15 No. 1 | 8 Jun 1959 | A. Scott Crossfield | Glide | First X-15 flight, unpowered, from the B-52 |
| X-15 | 22 Aug 1963 | Joseph A. Walker, NASA | 354,200 ft | The highest - 67 miles. A record for a winged aircraft until SpaceShipOne in 2004 |
| X-15A-2 | 3 Oct 1967 | William J. Knight, USAF | Mach 6.72 | The fastest - 4,520 mph. The ablative coating burned and the ventral fin nearly melted off |
| X-15 | 15 Nov 1967 | Michael J. Adams, USAF | 266,000 ft | The only fatal X-15 flight - the aircraft broke up in a hypersonic spin |
| XB-70 Valkyrie | 1964 - 1969 | NASA / USAF crews | Mach 3.1 | Six-engine bomber turned research plane; studied the sonic boom for the SST |
| HL-10 | 27 Feb 1970 | Peter Hoag, USAF | 90,303 ft | Highest lifting body - a wingless shape that proved a Shuttle could land |
| X-24B | 5 Aug 1975 | John Manke, NASA | Runway | First lifting body to land on a concrete runway - the case for the Shuttle landing unpowered |
| X-43A | 16 Nov 2004 | Unpiloted | Mach 9.6 | Fastest air-breathing aircraft; a scramjet, dropped from the same NB-52B that carried the X-15 |
The X-15 flew 199 times between 1959 and 1968. Thirteen flights went above 50 miles; eight pilots earned astronaut wings for them.
Three tanks, one engine, and a mother ship. The X-15 was topped off from the carrier aircraft all the way to launch because the oxygen boiled away. The 1956 plan says B-36; the airplane actually flew from under the wing of a B-52, dropped at 45,000 feet and Mach 0.8 over the Nevada desert.
Source: NACA Research-Airplane-Committee Report on Conference on the Progress of the X-15 Project, Langley Field, 25-26 October 1956 (declassified).
The first full pressure suit that was practical to fly in, made by the David Clark Company for the X-15 and the direct ancestor of the Gemini suit. It inflated only if the cabin failed. Above 60,000 feet, without it, a pilot's blood would boil at body temperature.
Source: NACA Research-Airplane-Committee Report on Conference on the Progress of the X-15 Project, Langley Field, 25-26 October 1956 (declassified).
Typical flight - drop from the NB-52 mothership
Tick through a flight. Every X-15 mission began under the wing of a B-52 at 45,000 feet, 200 miles from the lakebed.
Tap a box to check it off
Built to work at Mach 4 and 120,000 feet, which no seat had done. Fins and telescoping booms popped out to keep it pointed into the wind, the pilot was clamped at four points, and the seat let go of him on its own on the way down. In 199 flights it was never used.
Source: NACA Research-Airplane-Committee Report on Conference on the Progress of the X-15 Project, Langley Field, 25-26 October 1956 (declassified).
The chart that explains why the X-15 had two sets of controls. Below the shaded band the air is thick enough for the tail and ailerons. Above it, around 100,000 feet, the dynamic pressure is under 10 pounds per square foot and the surfaces do nothing, so the pilot switched to hydrogen peroxide jets. In the band he used both. This is how astronauts learned to fly before there were astronauts.
Source: NACA Research-Airplane-Committee Report on Conference on the Progress of the X-15 Project, Langley Field, 25-26 October 1956 (declassified).
Negative. Not in the flight cards.
