X-15 Flight 91
| Mission type | Test flight |
|---|---|
| Operator | US Air Force/NASA |
| Mission duration | 11 minutes, 8.6 seconds |
| Distance travelled | 543.4 kilometers (337.7 mi) |
| Apogee | 107.96 kilometers (67.08 mi) |
| Spacecraft properties | |
| Spacecraft | X-15 |
| Manufacturer | North American |
| Launch mass | 15,195 kilograms (33,499 lb) |
| Landing mass | 6,260 kilograms (13,800 lb) |
| Dry mass | 6,577 kilograms (14,500 lb) |
| Crew | |
| Crew size | 1 |
| Members | Joseph A. Walker |
| Start of mission | |
| Launch date | August 22, 1963, 18:05:57 UTC |
| Launch site |
NB-52A #52-003, Edwards Dropped over Smith Ranch Dry Lake 39°20′N 117°29′W / 39.333°N 117.483°W |
| End of mission | |
| Landing date | August 22, 1963, 18:17:05 UTC |
| Landing site | Rogers Dry Lake, Edwards |
 Joe Walker | |
X-15 Flight 91 was a 1963 American human spaceflight mission, and the second and final flight in the program to achieve sub-orbital spaceflight—a flight over 100 km in altitude—which was previously achieved during Flight 90 a month earlier. It was the highest flight of the X-15 program. It was the first flight of a reused spacecraft, as plane number three flew the previous sub-orbital flight on July 19. This mission was piloted by Joseph A. Walker on August 22, 1963, with the air-launch occurring from a modified Boeing B-52 Stratofortress support plane over Smith Ranch Dry Lake, Nevada, United States. Walker piloted the X-15 to an altitude of 107.96 km and remained weightless for approximately five minutes. The altitude was the highest manned flight by a spaceplane to that time and remained the record until the 1981 flight of Space Shuttle Columbia. Walker landed the X-15 about 12 minutes after it was launched, at Rogers Dry Lake, Edwards Airforce Base, in California. This was Walker's final X-15 flight.
Crew
| Position | Astronaut | |
|---|---|---|
| Pilot | Joseph A. Walker Second spaceflight | |
Mission parameters
- Mass: 15,195 kg fueled; 6,577 kg burnout; 6,260 kg landed
- Maximum Altitude: 107.96 km
- Range: 543.4 km
- Burn time: 85.8 seconds
- Mach: 5.58
- Launch vehicle: NB-52A Bomber #003
Mission highlights
On this flight, Joe Walker became the first person to enter space twice. He had a maximum speed of 3,794 MPH and a maximum altitude of 354,200 feet. Second and final X-15 flight over 67 miles.[1] Unofficial altitude record set for class. Highest altitude achieved by X-15.[1] Last flight for Walker in X-15 program. Number 1 left RCS nozzle froze up. First flight with altitude predictor instrument (needed calibration).
The mission was flown by X-15 #3, serial 56-6672 on its 22nd flight.[1]
Launched by: NB-52A #003, Pilots Bement & Lewis. Takeoff: 17:09 UTC. Landing: 18:56 UTC.
Chase pilots: Wood, Dana, Gordon and Rogers.
The X-15 engine burned about 85 seconds. Near the end of the burn, acceleration built up to about 4 G (39 m/s²). Weightlessness lasted for 3 to 5 minutes. Re-entry heating warmed the exterior of the X-15 to 650°C in places. During pull-up after re-entry, acceleration built up to 5 G (49 m/s²) for 20 seconds. The entire flight was about 12 minutes from launch to landing.
Notes
References
- Goodwin, Robert (2000). X-15: the NASA mission reports, incorporating files from the USAF. Burlington, Ontario: Apogee Books. ISBN 1-896522-65-3.
- Jenkins, Dennis R. (2000), Hypersonics Before the Shuttle: A Concise History of the X-15 Research Airplane, NASA Technical Reports, NASA, hdl:2060/20000068530; Document ID: 20000068530
- Price, A. B. (1968), Thermal protection system X-15A-2 Design Report, NASA Technical Reports, NASA, hdl:2060/19680016245; Document ID: 19680016245
- Stillwell, W. H. (1965), X-15 research results with a selected bibliography, NASA Technical Reports, NASA, hdl:2060/19650010561; Document ID: 19650010561
- Watts, Joe D. (1968), Flight experience with shock impingement and interference heating on the X-15-2 research airplane, NASA Technical Reports, NASA, hdl:2060/19920075739; Document ID: 19920075739