| X-1 |
|
Bell |
1 Reaction Motors XLR11 |
1 |
XS-1 |
| X-1A |
|
Bell |
1 Reaction Motors XLR11 |
1 |
|
| X-1B |
|
Bell |
1 Reaction Motors XLR11-RM-6 |
1 |
|
| X-1C |
|
Bell |
none selected |
1 |
cancelled |
| X-1D |
|
Bell |
1 Reaction Motors XLR11 |
1 |
|
| X-1E |
|
Bell |
1 Reaction Motors LR8-RM-5 |
1 |
|
| X-2 |
|
Bell |
1 Curtiss-Wright LR25-CW-1 |
1 |
XS-2 |
| X-3 |
Stiletto |
Douglas |
2 Westinghouse J34 |
1 |
XS-3 |
| X-4 |
Bantam |
Northrop |
2 Westinghouse J30 |
1 |
XS-4 |
| X-5 |
|
Bell |
1 Allison J35-A-17 |
1 |
XS-5 |
| X-6 |
|
Convair |
4 General Electric J53 |
|
cancelled |
| X-7 |
|
Lockheed |
1 Allegany Ballistics Lab X202-C3 and 1 ramjet |
0 |
PTV-A-1, X-7A |
| X-7A |
|
Lockheed |
1 Allegany Ballistics Lab X202-C3 and 1 ramjet or 2 Thiokol XM45 and 1 ramjet |
0 |
PTV-A-1, X-7 |
| X-7B |
|
Lockheed |
|
0 |
|
| X-8 |
Aerobee |
Aerojet General |
|
0 |
RTV-A-1 |
| X-8A |
Aerobee |
Aerojet General |
1 Aerojet General X103C10 and 1 Aerojet General AJ10-25 |
0 |
RTV-A-1a |
| X-8B |
Aerobee |
Aerojet General |
|
0 |
RTV-A-1b |
| X-8C |
Aerobee |
Aerojet General |
1 Aerojet General AJ10-25 |
0 |
RTV-A-1c |
| X-8D |
Aerobee |
Aerojet General |
|
0 |
RTV-A-1d |
| X-9 |
Shrike |
Bell |
1 Bell XLR65-BA-1 |
0 |
RTV-A-4 |
| X-10 |
|
North American |
2 Westinghouse J40-WE-1 |
0 |
RTV-A-5 |
| X-11 |
Atlas A |
Convair |
1 North American LR43 |
0 |
|
| X-12 |
Atlas B |
Convair |
3 North American LR43 |
0 |
|
| X-13 |
Vertijet |
Ryan |
1 Rolls-Royce J54 Avon |
1 |
X-13A |
| X-13A |
Vertijet |
Ryan |
1 Rolls-Royce J54 Avon |
1 |
X-13 |
| X-14 |
|
Bell |
2 Armstrong Siddley ASV8J Viper |
1 |
|
| X-14A |
|
Bell |
2 General Electric J85-GE-5/19 |
1 |
|
| X-14B |
|
Bell |
2 General Electric J85-GE-5/19 |
1 |
|
| X-15 |
|
North American |
1 Reaction Motors LR99 |
1 |
X-15A |
| X-15A |
|
North American |
1 Reaction Motors LR99 |
1 |
X-15 |
| X-16 |
|
Bell |
2 Pratt & Whitney J57 |
|
|
| X-17 |
|
Lockheed |
1 Thiokol XM20 Sergeant and 3 Thiokol XM19 Recruit, and 1 Thiokol XM19E1 Recruit |
0 |
|
| X-18 |
|
Hiller |
2 Allison T40-A-14 and 1 Westinghouse J34 |
2 |
|
| X-19A |
|
Curtiss-Wright |
2 Lycoming T55-L-7 |
2 |
|
| X-20 |
Dynasoar |
Boeing |
none |
|
X-20A |
| X-20A |
Dynasoar |
Boeing |
none |
|
X-20 |
| X-21 |
|
Northrop |
2 General Electric J79-GE-13 |
5 |
X-21A |
| X-21A |
|
Northrop |
2 General Electric J79-GE-13 |
5 |
X-21 |
| X-22A |
|
Bell |
4 General Electric T58-GE-8D |
2 |
|
| X-23A |
|
Martin Marietta |
none |
0 |
|
| X-24A |
|
Martin Marietta |
1 Reaction Motors XLR11-RM-13 |
1 |
|
| X-24B |
|
Martin Marietta |
1 Reaction Motors XLR11-RM-13 |
1 |
|
| X-25 |
|
Bensen |
1 McCulloch 4318E |
0 |
|
| X-25A |
|
Bensen |
1 McCulloch 4318E |
1 |
|
| X-25B |
|
Bensen |
1 McCulloch 4318E |
1 |
|
| X-26A |
Frigate |
Schweizer |
none |
1 |
|
| X-26B |
Frigate |
Schweizer/Lockheed |
1 Continental O-200A |
2 |
|
| X-27A |
Lancer |
Lockheed |
1 Pratt & Whitney TF30-PW-100 |
1 |
cancelled |
| X-28A |
Osprey |
Pereira |
1 Continental C90-12 |
1 |
|
| X-29A |
|
Grumman |
1 General Electric F404-GE-400 |
1 |
|
| X-30A |
National Aerospace Plane |
|
none selected |
2 |
cancelled |
| X-31A |
|
Rockwell/MBB |
1 General Electric F404-GE-400 |
1 |
|
| X-32A |
|
Boeing |
1 Pratt & Whitney F119-SE-614 |
1 |
|
| X-32B |
|
Boeing |
1 Pratt & Whitney F119-SE-614 |
1 |
|
| X-32C |
|
Boeing |
1 Pratt & Whitney F119-SE-614 |
1 |
|
| X-33A |
|
Lockheed Martin |
2 Rocketdyne XRS-2200 |
0 |
cancelled |
| X-34A |
|
Orbital Sciences/Rockwell |
1 Marshall Spaceflight Center MC-1 Fastrac |
0 |
cancelled |
| X-34B |
|
Orbital Sciences/Rockwell |
|
0 |
cancelled |
| X-35A |
|
Lockheed Martin |
1 Pratt & Whitney F119-SE-611 |
1 |
|
| X-35B |
|
Lockheed Martin |
1 Pratt & Whitney F119-SE-611 |
1 |
|
| X-35C |
|
Lockheed Martin |
1 Pratt & Whitney F119-SE-611 |
1 |
|
| X-36A |
|
McDonnell Douglas |
1 Williams Research F112-WR-100 |
0 |
|
| X-37A |
Future-X |
Boeing |
1 Rocketdyne AR2-3 |
|
|
| X-37B |
Future-X |
Boeing |
|
|
|
| X-38A |
|
Scaled Composites |
none |
|
|
| X-40A |
Space Maneuver Vehicle |
Boeing |
none |
0 |
|
| X-40B |
Space Maneuver Vehicle |
Boeing |
none |
0 |
|
| X-41A |
|
|
|
|
|
| X-42A |
|
|
|
|
|
| X-43A |
Hyper-X |
MicroCraft/Boeing |
1 General Applied Science Laboratory (GASL) scramjet |
0 |
|
| X-43B |
Hyper-X |
|
1 Marshall Spaceflight Center ISTAR engine |
0 |
cancelled |
| X-43C |
Hyper-X |
Allied Aerospace Industries |
1 Pratt & Whitney HyTECH engine |
0 |
cancelled |
| X-43D |
Hyper-X |
|
|
0 |
|
| X-44A |
|
Lockheed Martin/Pratt & Whitney |
|
|
|
| X-45A |
|
Boeing |
1 Garrett F124-GA-100 |
0 |
|
| X-45B |
|
Boeing |
1 General Electric F404-GE-102D |
0 |
cancelled |
| X-45C |
|
Boeing |
1 General Electric F404-GE-102D |
0 |
|
| X-46A |
|
Boeing |
|
0 |
|
| X-47A |
Pegasus |
Northrop Grumman |
1 Pratt & Whitney Canada JT15D-5C |
0 |
|
| X-47B |
Pegasus |
Northrop Grumman |
1 Pratt & Whitney F100-PW-220E |
0 |
|
| X-48A |
|
NASA Langley Research Center/Boeing |
3 Williams International WJ24-8 |
0 |
|
| X-48B |
|
Boeing/Cranfield University |
3 JetCat P200 |
0 |
|
| X-48C |
|
Boeing/Cranfield University |
2 JetCat P200 |
0 |
|
| X-49A |
|
Sikorsky/Piasecki |
2 General Electric T700-GE-401C |
|
|
| X-50A |
Dragonfly |
Boeing |
1 Williams F112 |
0 |
|
| X-51A |
Waverider |
Boeing/Pratt & Whitney |
1 rocket and 1 Pratt & Whitney Rocketdyne SJY-61-1 |
0 |
|
| X-53A |
|
Boeing |
2 General Electric F404-GE-400 |
1 |
|
| X-54A |
|
Gulfstream Aerospace |
2 Rolls-Royce Tay 651 |
|
|
| X-55A |
Advanced Composite Cargo Aircraft |
Lockheed Martin |
2 |
|
|