The Off-Key Bard
History

This Day in History — Joe Walker Takes the X-15 Into Space

On this day in 1963

On August 22, 1963, Joe Walker flew an airplane to space for the second time — and waited 42 years, posthumously, for anyone to officially call him an astronaut.

The Off-Key Bard watches an aircraft climb until the blue sky fades to black, reaching a place where the distinction between pilot and astronaut begins to disappear…

"Most astronauts reached space sitting atop massive vertical rockets. Joe Walker flew an airplane there."

On this day in 1963, NASA civilian test pilot Joseph Albert Walker dropped away from the wing of a modified NB-52A carrier aircraft over Smith Ranch Dry Lake, Nevada, at approximately 45,000 feet and Mach 0.82. Seconds later he ignited the XLR-99 rocket engine of X-15 number 3 and pulled into a steep ballistic climb. It was his 25th and final flight in the X-15 program. It was also the highest any human being had ever flown in a winged vehicle — a record that would stand for 41 years.

Flight 91 was the culmination of a program that had been pushing the edges of the possible since 1959. The X-15 was not a conventional aircraft in any meaningful sense. It was a black rocket ship with stubby wings, air-launched because no conventional runway takeoff could get it to the speeds and altitudes it was built to reach. Its XLR-99 engine burned anhydrous ammonia and liquid oxygen for 85.8 seconds at full thrust — enough to accelerate the aircraft to Mach 5.58 as the propellant ran out at approximately 176,000 feet. Then the engine stopped, and Walker and the X-15 continued upward on momentum alone for nearly two more minutes.

The Ascent: The XLR-99 built acceleration to roughly 4 Gs during its burn. At engine cutoff, X-15 number 3 was already above the altitude where most aircraft have ever flown. The aircraft coasted another 178,200 feet — more than 33 miles — purely on the energy the engine had already put into it before shutting down.

The Peak: At 354,200 feet — 67.08 miles, or 107.96 kilometers — Walker reached the top of his arc. He was above 99.9 percent of Earth's atmosphere. The sky above him was black. He experienced between three and five minutes of weightlessness. The Kármán line — the 100-kilometer boundary internationally recognized as the edge of space — lay nearly eight kilometers below him. He had crossed it for the second time.

The Reaction Controls: Above approximately 100,000 feet on the way up, the aerodynamic control surfaces lost effectiveness in air too thin to bite. Walker steered using hydrogen peroxide reaction control thrusters mounted on the nose and wings — the same principle used by orbital spacecraft. At peak altitude he was flying a spacecraft, not an airplane.

The Reentry: Pitching the nose down to the correct angle for atmospheric reentry, Walker rode the X-15 back into denser air. As the vehicle decelerated, it experienced up to 7 Gs of force. The Inconel X alloy skin of the aircraft heated to over 1,200°F on the leading edges. The aerodynamic surfaces regained authority at approximately 95,000 feet. Eleven minutes and 8.6 seconds after launch, Walker glided the unpowered aircraft to a deadstick landing on Rogers Dry Lake at Edwards Air Force Base.

A Record and a Footnote

Flight 91 set the absolute altitude record for the entire X-15 program — a record that stood until October 2004, when Scaled Composites' SpaceShipOne reached 112 kilometers during the Ansari X Prize competition. Walker's flight also made him the first person in history to reach space twice, and the first civilian — as a NASA employee rather than a military pilot — to enter space at all.

Then he went largely unrecognized for it.

The U.S. Air Force had its own definition of space: 50 miles (80.5 kilometers). By that standard, Walker and several other X-15 pilots had crossed it multiple times. But the internationally recognized Kármán line sat at 100 kilometers, and only Walker's flights on July 19 and August 22, 1963 cleared that threshold. NASA awarded him neither astronaut wings nor formal recognition of his spaceflights during his lifetime.

Joseph Walker died on June 8, 1966, when his F-104 Starfighter collided with the XB-70 Valkyrie he was flying chase for during an Air Force formation flight over the Mojave Desert. He was 45 years old. The flights that had made him the first person to reach space twice were not counted in any official record at the time.

On August 23, 2005 — 42 years and one day after Flight 91 — NASA held a ceremony at the Dryden Flight Research Center and posthumously awarded Joe Walker his astronaut wings.

"The engine burned, the blue turned black,
Then gravity called the pilot back…
No capsule fell through ocean spray,
He flew to space — and flew away."

History reminds us: the road to orbit wasn't built exclusively with capsules and splashdowns. Sometimes the fastest path to space began on a dry lake bed runway — and sometimes the people who got there first had to wait decades for the rest of the world to catch up.

Sources

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