X-15 Flight 91

X-15 Flight 91
Mission statistics
Mission name	X-15 Flight 91
Spacecraft name	X-15 #3
Spacecraft mass	15,195 kg fueled; 6,577 kg burnout; 6,260 kg landed
Crew size	1
Call sign	X-15
Launch pad	NB-52A flying near Smith Ranch Dry Lake, NV 39°20′N 117°29′W
Launch date	August 22, 1963 18:05:57 UTC
Landing	August 22, 1963 18:17:05.6 UTC Rogers Dry Lake, Edwards AFB, CA
Mission duration	00:11:08.6
Number of orbits	0 (sub-orbital)
Apogee	107.96 km
Distance traveled	543.4 km
Crew photo
Joe Walker
Related missions
Previous mission Subsequent mission X-15 Flight 90 X-15 Flight 92

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 100km in altitude. 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 107.96km and remained weightless for approximately five-minutes. The altitude was the highest sub-orbital flight by a spaceplane to that time, and remained the record altitude until the 2004 flight of SpaceShipOne. Walker landed the X-15 about 12 minutes after it was launched, at Rogers Dry Lake, Edwards Airforce Base, in California. The successful flight marked the X-15 as the world's first reusable spacecraft, and it also turned out to be Walker's final flight in one.

Crew

The X-15 was piloted by Joseph A. Walker on his second flight.

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

Unofficial world altitude record from 1963 to 2004. On this flight, Joe Walker became the first person to enter space twice. Maximum Speed - 6106 km/h. Maximum Altitude - 107,960 m. Second and final X-15 flight over 100 km. Unofficial altitude record set for class. Highest altitude achieved by X-15. 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.

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 burns about 85 seconds. Near the end of the burn, acceleration builds up to about 4 G (39 m/s²). Weightlessness lasts for 3 to 5 minutes. Re-entry heating warms the exterior of the X-15 to 650°C in places. During pull-up after re-entry acceleration builds up to 5 G (49 m/s²) for 20 seconds. The entire flight is about 12 minutes from launch to landing.

1st 100 km Flight: X-15 Flight 90

X-15 Program

2nd 100 km Flight: X-15 Flight 91

References

• Goodwin, Robert (2000). X-15: the NASA mission reports, incorporating files from the USAF. Burlington, Ontario: Apogee Books. ISBN 1896522653. 
• Jenkins, Dennis R. (2000), "Hypersonics Before the Shuttle: A Concise History of the X-15 Research Airplane", NASA Technical Reports, NASA, Document ID: 20000068530, http://hdl.handle.net/2060/20000068530 
• Price, A. B. (1968), "Thermal protection system X-15A-2 Design Report", NASA Technical Reports, NASA, Document ID: 19680016245, http://hdl.handle.net/2060/19680016245 
• Stillwell, W. H. (1965), "X-15 research results with a selected bibliography", NASA Technical Reports, NASA, Document ID: 19650010561, http://hdl.handle.net/2060/19650010561 
• Watts, Joe D. (1968), "Flight experience with shock impingement and interference heating on the X-15-2 research airplane", NASA Technical Reports, NASA, Document ID: 19920075739, http://hdl.handle.net/2060/19920075739