# X-15

> 1959 experimental aircraft model by North American Aviation and NASA

**Wikidata**: [Q221269](https://www.wikidata.org/wiki/Q221269)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/North_American_X-15)  
**Source**: https://4ort.xyz/entity/x-15

## Summary
The X-15 is a 1959 experimental aircraft model developed by North American Aviation and NASA. It was a sub-orbital spaceplane, meaning it flew high enough to reach space but did not achieve orbital velocity. The X-15 holds the record for the highest speed ever achieved by a piloted aircraft and was instrumental in advancing aerospace research.

## Key Facts
- **Class**: Sub-orbital spaceplane (does not reach orbit)
- **Developed by**: North American Aviation
- **Operated by**: United States Air Force and NASA
- **First flight**: June 8, 1959
- **Service entry**: September 17, 1959
- **Service retirement**: December 1968
- **Total produced**: 4 aircraft
- **Country of origin**: United States
- **Notable crew members**: Neil Armstrong, Michael Adams, and Albert Scott Crossfield
- **Key achievement**: Highest speed for a piloted aircraft (4,520 mph / 7,274 km/h)
- **Subclass**: Experimental aircraft

## FAQs
### Q: What was the X-15 used for?
A: The X-15 was used to test high-speed flight, aerodynamics, and human factors in spaceflight. It helped NASA and the Air Force gather critical data for future space missions.

### Q: How many X-15 aircraft were built?
A: Only four X-15 aircraft were produced.

### Q: Who were the most famous pilots of the X-15?
A: Neil Armstrong, Michael Adams, and Albert Scott Crossfield were among the most notable pilots, with Armstrong later becoming the first person to walk on the Moon.

### Q: What was the X-15's top speed?
A: The X-15 reached a maximum speed of 4,520 mph (7,274 km/h), the fastest speed ever achieved by a piloted aircraft.

### Q: When was the X-15 retired?
A: The X-15 was retired in December 1968 after completing its research missions.

## Why It Matters
The X-15 was a groundbreaking experimental aircraft that pushed the boundaries of atmospheric flight and human spaceflight capabilities. It provided critical data on high-speed aerodynamics, thermal protection, and human performance in extreme conditions. The X-15’s achievements laid the foundation for NASA’s Mercury, Gemini, and Apollo programs, as well as modern spacecraft design. Its legacy includes setting records for altitude, speed, and flight duration, influencing aerospace engineering for decades. The X-15 also demonstrated the feasibility of reusable spacecraft, a concept later adopted in NASA’s Space Shuttle program.

## Notable For
- **Highest speed for a piloted aircraft**: 4,520 mph (7,274 km/h)
- **First to exceed Mach 6.72**: Critical for understanding hypersonic flight
- **Tested thermal protection**: Data used in designing heat shields for space vehicles
- **Pioneered reusable spacecraft concepts**: Influenced NASA’s Space Shuttle
- **Trained future astronauts**: Many X-15 pilots later flew in NASA’s Mercury and Apollo programs

## Body
### Development and Design
The X-15 was developed by North American Aviation under contract with NASA and the U.S. Air Force. It was designed as a rocket-powered research aircraft to study high-speed flight, aerodynamics, and human factors in spaceflight. The program aimed to gather data on hypersonic flight, thermal protection, and spacecraft re-entry.

### Operational History
- **First flight**: June 8, 1959
- **Service entry**: September 17, 1959
- **Service retirement**: December 1968
- **Total flights**: 199, with 12 flights reaching altitudes above 50 miles (80 km), qualifying as spaceflight.

### Key Achievements
- **Altitude record**: 354,200 feet (107.96 km) by William J. Knight
- **Speed record**: 4,520 mph (7,274 km/h) by William J. Knight
- **Thermal testing**: Data used to develop heat shields for the Apollo program

### Crew and Legacy
The X-15’s crew included future astronauts like Neil Armstrong, Michael Adams, and Albert Scott Crossfield. The program’s success paved the way for NASA’s human spaceflight programs and influenced modern spacecraft design.

### Media and Documentation
- **Image**: [X-15 aircraft](https://commons.wikimedia.org/wiki/Special:FilePath/North_American_X-15.jpg)
- **Video**: [X-15 in flight](https://commons.wikimedia.org/wiki/Special:FilePath/1959-06-11_X-15_Aloft.ogv)
- **Documentation**: Detailed records available from NASA and the National Archives

## References

1. [Source](https://github.com/JohnMarkOckerbloom/ftl/blob/master/data/wikimap)
2. Freebase Data Dumps. 2013
3. National Library of Israel