Military Space Plane

Air Force interest in military space planes stretches back nearly 40 years. This has taken the form of science and technology development, design and mission studies, and engineering development programs. Examples of these activities include: the first Aerospace plane program and Dyna-Soar/X-20 program (late 1950s-early 1960s); X-15 hypersonic and X-24 lifting body flight test programs (late 1950s through early 1970s); Advanced Military Space Flight Capability (AMSC), Transatmospheric Vehicle (TAV), and Military Aerospace Vehicle (MAV) concept and mission studies (early 1980s); the Copper Canyon air breathing single-stage-to-orbit (SSTO) feasibility assessment and the National Aerospace Plane (NASP) program (1984-1992); SCIENCE DAWN, SCIENCE REALM, and HAVE REGION rocket-powered SSTO feasibility assessments and technology demonstration programs (late 1980s); and, most recently, the Ballistic Missile Defense Organization's Single-Stage Rocket Technology program that built the Delta Clipper-Experimental (DC-X) experimental reusable space plane.

Industry sources are being sought to develop critical technologies for future military spaceplanes using ground based advanced technology demonstrations. The first step is envisioned to include a streamlined acquisition that develops, integrates and tests these technologies in an Integrated Technology Testbed (ITT). Due to constrained budgets, the Air Force is seeking innovative, "out of the box", industry feedback and guidance to: 1) develop and demonstrate key military spaceplane technologies, 2) ensure competitive industry military spaceplane concepts are supported via critical technology demonstrations, and 3) ensure a viable, competitive military spaceplane industrial base is retained now and in the future.

The primary objective of the ITT is to develop the MSP Mark I concept design and hardware with direct scaleability: directly scaleable weights, margins, loads, design, fabrication methods and testing approaches; and traceability: technology and general design similarity, to a full-scale Mark II-IV system. The ITT is intended to demonstrate the technologies necessary to achieve systems integration within the mass fraction constraints of Single Stage to Orbit (SSTO) vehicles. In addition, the ITT will meet the military operational requirements outlined in the MSP SRD. The ITT is an unmanned ground demonstration. The Mark I demonstrator is also envisioned to be unmanned.

The Military Space plane (MSP) ITT ground demonstration consists of an effort to develop a computer testbed model. It may also include options for multiple technology, component and subsystem hardware demonstrations to support and enable the acquisition and deployment of MSP systems early in the next century. Although the ITT is not a flight demonstrator, it is anticipated that critical ground Advanced Technology Demonstrator (ATD) components and subsystems shall be designed, fabricated and tested with a total systems and flight focus to demonstrate the potential for military "aircraft like" operations and support functions. The latter point refers to eventual systems that 1) can be recovered and turned around for another mission in several hours or less on a routine basis, 2) require minimal ground and flight crew to conduct routine operations and maintenance , 3) are durable enough to sustain a mission design life of hundreds of missions, 4) are designed for ease of maintenance and repair based on military aircraft reliability, maintainability, supportability and availability (RMS&A) standards including the use of line replaceable units to the maximum extent possible, and 5) can be operated and maintained by military personnel receiving normal levels of technical training. The ITT effort is envisioned to culminate with a vigorous integrated test program that demonstrates how specific components and subsystems are directly traceable and scaleable to MSP system requirements and meet or exceed these operational standards.

The testbed itself shall be a computer sizing model of the Military Spaceplane. Input parameters include mission requirements and all of the critical component, subsystem and system technical criteria. Output are the critical design features, size, physical layout, and performance of the resulting vehicle. The computer model shall be capable of modeling the technology componenta, subsystems and systems demonstrated characteristics and the resulting effect(s) on the Military Spaceplane vehicle concept design. Although the ITT is required to show analytical component and subsystem scaleability to SSTO, the contractor may also show scaleability and traceability to alternative MSP configurations. Those alternatives may include two stage to orbit (TSTO) configurations. The ITT is using SSTO as a technology stretch goal in the initial ground demonstrations. However, a future Military Spaceplane can use either single or multiple stages.

The contract structure for ITT is anticipated to be Cost Reimbursement type contracts with possible multiple options and a total funding of approximately $125-150M. Due to initial funding limitations, the minimum effort for the contract is anticipated to consist of a broad conceptual military spaceplane design supported by a computer testbed model. However, should funding become available, additional effort may be initiated prior to the conclusion of the testbed model design. Offerors will be requested to submit a series of alternatives for delivery of major technology components and subsystems as well as an alternative for subsystem/system integration and test.

Upon direction of the Government through exercise of the option(s) the contractor shall design, fabricate, analyze, and test Ground Test Articles (GTAs), and provide a risk reduction program for all critical technology components, subsystems and subsystems assembly. The contractor will prepare options for an ITT GTA designs which satisfy the technical objectives of this SOO, including both scaleability and traceability to the Mark I and Mark II-IV vehicles. These design shall be presented to the Government at a System Requirements Review (SRR). The contractor shall use available technologies and innovative concepts in the designs, manufacturing processes, assembly and integration process, and ground test. Designs shall focus on operational simplicity and minimizing vehicle processing requirements. The contractor shall provide the detailed layout and systems engineering analysis required to demonstrate the feasibility and performance of the Mark I vehicle as well as scaleability and traceability to the Mark II-IV vehicles. The low cost reusable upper stage (i.e., mini-spaceplane) is envisioned to be an integral part of an overall operational MSP system.

The contractor shall use the ITT to implement the initial risk reduction program that mitigates risks critical to developing both the Mark I and Mark II-IV MSP configurations. The ITT shall mitigate risks critical to engineering, operability, technology, reliability, safety, or schedule and any subsequent risk reduction program deemed necessary. The program may include early component fabrication, detailed vehicle integration planning or prudent factory and ground/flight testing to reduce risks. The Technology levels will be frozen at three points in the Military Spaceplane Program (MSP): At the ITT contract award for the Ground Demonstrator, at contract award for any future Flight Demonstrator, and at contract award for an orbital system EMD.

Since the ITT is not a propulsion demonstration/integration effort there are two parallel propulsion efforts. One in NASA for the X-33 aerospike, and one in the AF for the Integrated Powerhead Demonstration ( IPD). It is anticipated that the Mark I demonstrator would use an existing engine. Propulsion modifications and integration will be addressed in the offerors concept design but limited funding probably precludes any new engine development. The contractor should evaluate the use of the Integrated Powerhead Demonstration (IPD) XLR-13X engine as a risk reduction step being done in parallel and as a baseline engine for MSP. LOX/LH2 offers an excellent propellant combination for future Military Spaceplanes. Nearer term demonstrators, however, may be asked to use alternative propellants with superior operability characteristics.


Maximum Performance Missions Sets are system defining and encompass the four missions and the Design Reference Missions. Instead of giving a threshold and objective for each mission requirement, missions sets are defined. Each mission set will define a point solution and provide visibility into the sensitivities of the requirements from the thresholds (Mark I) to the objective (Mark IV). If takeoff and landing bases are constrained to the U.S. (including Alaska and Hawaii), this will reduce stated pop-up payloads by at least half.

Mark I (Demonstrator or ACTD non-orbital vehicle that can only pop up)

  • Pop-up profile: Approximately Mach 16 at 300 kft at payload separation
  • Pop up and deliver 1 to 3 klbs of mission assets (does not include boost stage, aeroshell, guidance or propellant) to any terrestrial destination
  • Pop up and deliver 3 to 5 klbs of orbital assets (does not include upperstage) due east to a 100 x 100 NM orbit
  • Payload bay size 10' x 5' x 5', weight capacity 10 klbs


Mark II (Orbit capable vehicle)

  • Pop up and deliver 7 to 9 klbs of mission assets (does not include boost stage, aeroshell, guidance or propellant) to any terrestrial destination
  • Pop up and deliver 15 klbs of orbital assets (does not include upperstage) due east to a 100 x 100 NM orbit
  • Launch due east, carrying 4-klb payload, orbit at 100 x 100 NM
  • Payload bay size 25' x 12' x 12', weight capacity 20 klbs


Mark III

  • Pop up and deliver 14 to 18 klbs of mission assets (does not include boost stage, aeroshell, guidance or propellant) to any terrestrial destination
  • Pop up and deliver 25 klbs of orbital assets (does not include upperstage) due east to a 100 x 100 NM orbit
  • Launch due east, carrying a 6-klb payload, orbit at 100 x 100 NM and return to base
  • Launch polar, carrying 1-klb payload and return to base
  • Payload bay size 25' x 12' x 12', weight capacity 40 klbs


Mark IV

  • Pop up and deliver 20 to 30 klbs of mission assets (does not include boost stage, aeroshell, guidance or propellant) to any terrestrial destination
  • Pop up and deliver 45 klbs of orbital assets (does not include upperstage) due east to a 100 x 100 NM orbit
  • Launch due east, carrying a 20-klb payload, orbit at 100 x 100 NM and return to base
  • Launch polar, carrying 5-klb payload and return to base
  • Payload bay size 45' x 15' x 15', weight capacity 60 klbs



      Ref Mission          Mark I       Mark II        Mark III         Mark IV     

Payload Bay Data         10' x 5' x   25' x 12' x     25' x 12' x     45' x 15' x   
                             5'           12'             12'             15'       
                          10 klbs       20 klbs         40 klbs         60 klbs     

DRM 1 (Pop up and         1-3 klb      7 to 9 klb    14 to 18 klb    20 to 30 klb   
deliver mission                                                                     

DRM 2 (Pop up and         3-5 klb        15 klb         25 klb          45 klb      
deliver orbit assets                                                                
due east 100 x 100 NM)                                                              

DRM 3 (Co-Orbit)            N/A        4 klb due    6 klb due east    20 klb due    
                                       east 100 x    100 x 100 NM   east 100 x 100  
                                         100 NM                           NM        

DRM 4 (Recover)             N/A           TBD             TBD             TBD       

DRM 5 (Polar Once           N/A           N/A            1 klb           5 klb      


Mission asset weight is a core weight and does not include a boost stage, aeroshell, guidance or propellant.

Orbital asset weight does not include an upperstage.

                  Requirements Matrix for Mark II, III and IV                   
                             (Desired for Mark I)                               

             Requirement                   Threshold             Objective        

Sortie Utilization Rates                                                          

Peacetime sustained                     0.10 sortie/day       0.20 sortie/day     

War/exercise sustained (30 days)        0.33 sortie/day       0.50 sortie/day     

War/exercise surge (7 days)             0.50 sortie/day       1.00 sortie/day     

Turn Times                                                                        

Emergency war or peace                      8 hours               2 hours         

MOB peacetime sustained                      2 days                1 day          

MOB war/exercise sustained (30 days)        18 hours              12 hours        

MOB war/exercise surge (7 days)             12 hours              8 hours         

DOL peacetime sustained                      3 days                1 day          

DOL war/exercise sustained (30 days)        24 hours              12 hours        

DOL war/exercise surge (7 days)             18 hours              8 hours         

System Availability                                                               

Mission capable rate                       80 percent            95 percent       

Flight and Ground Environments                                                    

Visibility                                    0 ft                  0 ft          

Ceiling                                       0 ft                  0 ft          

Crosswind component                         25 knots              35 knots        

Total wind                                  40 knots              50 knots        

Icing                                   light rime icing    moderate rime icing   

Absolute humidity                          30 gms/m3             45 gms/m3        

Upper level winds                       95th percentile     all shear conditions  

Outside temperature                       -20 to 100F           -45 to 120F       

Precipitation                                light                moderate        

Space Environment                                                                 

Radiation level                               TBD                   TBD           

Flight Safety                                                                     

Risk to friendly population                < 1 x 10-6            < 1 x 10-7       

Flight Segment loss                      < 1 loss /2000    < 1 loss/5000 sorties  

Reliability                                  0.9995                0.9998         

Cross Range                                                                       

Unrestricted pop-up cross range              600 NM               1200 NM         

CONUS pop-up cross range                     400 NM                600 NM         

Orbital cross range                         1200 NM               2400 NM         

"Pop-up" Range                                                                    

CONUS pop-up range                          1600 NM               1200 NM         

Ferry range minimum                         2000 NM              worldwide        

On-orbit Maneuver                                                                 

Excess V (at expense of payload)            300 fps               600 fps         

Pointing accuracy                       15 milliradians       10 milliradians     

Mission Duration                                                                  

On-orbit time                               24 hours              72 hours        

Emergency extension on-orbit                12 hours              24 hours        

Orbital Impact                                                                    

Survival impact object size             0.1-cm diameter        1-cm diameter      

Survival impact object mass                   TBD                   TBD           

Survival impact velocity                      TBD                   TBD           

Alert Hold                                                                        

Hold Mission Capable                        15 days               30 days         

Mission Capable to Alert 2-hour             4 hours               2 hours         

Hold Alert 2-hour Status                     3 days                7 days         

Alert 2-hour to Alert 15-minute        1 hour 45 minutes         30 minutes       

Hold Alert 15-minute Status                 12 hours              24 hours        

Alert 15 Minute to Launch                  15 minutes            5 minutes        

Design Life                                                                      

Primary Structure                         250 sorties           500 sorties      

Time between major overhauls              100 sorties           250 sorties      

Engine life                               100 sorties           250 sorties      

Time between engine overhauls              50 sorties           100 sorties      

Subsystem life                            100 sorties           250 sorties      

Take-off and Landing                                                             

Runway size                            10,000 ft x 150 ft    8000 ft x 150 ft    

Runway load bearing                           S65                   S45          

Vertical landing accuracy                    50 ft                 25 ft         

Payload Container                                                                

Container change-out                         1 hour             30 minutes       

Crew Station Environment (if rqd)                                                

Life support duration                       24 hours             72 hours        

Emergency extension on-orbit                12 hours              24 hours        

Crew Escape (if rqd)                                                             

Escape capability                           subsonic           full envelope     

Maintenance and Support                                                          

Maintenance work hours/sortie              100 hours             50 hours        

R&R engine                                  8 hours               4 hours        

X-40 Space Manoeuvre Vehicle (SMV)

The Air Force Research Laboratory's Space Manoeuvre Vehicle (SMV) is a small, powered space vehicle technology demonstrator. An eventual operational version could function as the second stage-to-orbit vehicle as well as a reusable satellite with a variety of available payloads. SMV could perform missions such as:
  • Tactical reconnaissance
  • Filling gaps in satellite constellations
  • Rapid deployment of Space Manoeuvre Vehicle constellations
  • Identification and surveillance of space objects
  • Space asset escorting


An SMV is envisioned to dwell on-orbit for up to one year. Its small size and ability to shift orbital inclination and altitude would allow repositioning for tactical advantage or geographic sensor coverage. Interchangeable SMV payloads would permit a wide variety of missions. SMV would use low-risk subsystem components and technology for aircraft-like operability and reliability.


An operational SMV might include:
  • Up to 1,200 pounds of sensors/payload
  • 72-hours or less turnaround time between missions
  • Up to 12 month on-orbit mission duration
  • Rapid recall from orbit
  • Up to 10,000 feet per second on-orbit velocity change for manoeuvring


The Space Manoeuvre Vehicle Program is directed by the Air Force Research Laboratory's Military Space plane Technology Office at Kirtland Air Force Base, New Mexico. A three phase program is planned to provide affordable technology and operations demonstrations. The program is presently funded through Phase I. The schedule for Phases II and III depends on additional Air Force funding.


The program is currently conducting ground and flight tests of a 22-foot-long, 2,500-pound, graphite-epoxy and aluminium vehicle. The cost of this vehicle is approximately $1 million for fabrication and construction. In addition, the government has contributed approximately $5 million to the project. The partnership with the Air Force Research Laboratory's Air Vehicles Directorate and has already accomplished:
  • A helicopter release of a 90-percent-scale of the SMV to demonstrate autonomous control and landing capability.
  • The design and construction of a full-scale SMV center fuselage and wing carry-through box that successfully passed its structural tests.


The Space Manoeuvre Vehicle completed a successful autonomous approach and landing on its first flight test on 11 August 1998. The unmanned vehicle was dropped from an Army UH-60 Black Hawk helicopter at an altitude of 9,000 feet above the ground, performed a controlled approach and landed successfully on the runway. The total flight time was 1-1/2 minutes. During the initial portion of the its free fall, the manoeuvre vehicle was stabilized by a parachute. After it is released from the parachute, the vehicle accelerated and perform a controlled glide. This glide simulated the final approach and landing phases of such a vehicle returning from orbit. The vehicle, which landed under its own power, used an integrated Navstar Global Positioning Satellite and inertial guidance system to touch down on a hard surface runway. The 90 percent-scale vehicle was built by Boeing Phantom Works, Seal Beach CA, under a partnership between Air Force Research Laboratory Space Vehicles Directorate at Kirtland Air Force Base NM and the Air Vehicles Directorate at Wright-Patterson Air Force Base OH

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