Mercury · Gemini · Apollo · Shuttle
The legacy of the X-15
The X-15 never went into orbit, but a great deal of what spaceflight relies on was tested on it first. NASA says the results contributed to Mercury, Gemini, Apollo and the Space Shuttle, and that program data supported more than 765 research reports.
Twenty-five accomplishments
Langley researcher John Becker listed 25 specific accomplishments of the program. Among them:
- The first reusable superalloy structure able to withstand hypersonic re-entry temperatures.
- The first use of reaction controls for attitude control in space.
- The first practical full pressure suit for pilot protection.
- The first application of energy-management techniques for landing, later used on the Space Shuttle.
What the flights measured
Hypersonic boundary-layer flow turned out to be turbulent rather than laminar. Turbulent heating rates and skin friction were lower than theory predicted. The program carried 28 experiments, from astronomy to micrometeorite collection, and its work on horizon definition and thermal protection fed into navigation equipment and insulation used on the Apollo-era Saturn launch vehicles.
From the X-15 to orbit
Neil Armstrong flew seven X-15 flights before he flew Gemini and later commanded Apollo 11. Joe Engle, who flew the X-15 above 50 miles three times, later flew the Space Shuttle. The people who learned to manage energy and attitude at the edge of the atmosphere carried that experience into the next programs. Meet all twelve pilots.
Where to see an X-15
- X-15-1: National Air and Space Museum, Milestones of Flight gallery, Washington, D.C.
- X-15A-2: National Museum of the United States Air Force.
- NB-52B "Balls 8": outside the north gate of Edwards Air Force Base.
- NB-52A "The High and Mighty One": Pima Air and Space Museum, Tucson.
- Painted displays: Edwards Air Force Base and Evergreen Aviation & Space Museum, among others.
Fly the legacy
Project X-15 puts you through the same decisions the pilots faced, from the drop to the dry-lake landing. Take the controls or read the full timeline.