DRAFT

SYSTEM REQUIREMENTS

FOR A

MILITARY SPACEPLANE

MILITARY SPACEPLANE TECHNOLOGY PROGRAM

AT THE

PHILLIPS LABORATORY

SPACE TECHNOLOGY DIRECTORATE

IN SUPPORT OF

AFSPC AND AFMC

Maj Ken Verderame

Maj Andrew Dobrot

VERSION: 1.0

DATE: 24 April 1997

Preface

Comments and questions on this draft SRD should be forwarded to Maj Ken Verderame, PL/VT-X, DSN 246-8927 ext. 150 or (505) 846-8927 ext. 150, or Maj Andy Dobrot, HQ AFSPC/DRSV, DSN 692-2567 or (719)554-2567.

Contents

1. INTRODUCTION 11.1 BACKGROUND 11.2 SCOPE 11.3 REQUIREMENTS RATIONALE 11.4 USE OF THIS SRD 21.5 CONTROL OF THIS SRD 21.6 BASIS OF THIS SRD 21.7 TERMS 22.0 MILITARY SPACEPLANE SYSTEM REQUIREMENTS 32.1 MILITARY SPACEPLANE SYSTEM 32.1.1 GENERAL MISSION CAPABILITIES 32.1.1.1 DESIGN REFERENCE MISSIONS AND MISSION SETS 42.1.1.2 DESIGN REFERENCE MISSIONS AND MISSION SETS 42.1.2 SYSTEM DEFINITION 42.1.3 OPERATIONAL SITES 42.1.4 FERRY CAPABILITY 52.1.5 SYSTEM OPERATIONS 52.1.5.1 OPERATIONS AT THE MOB 52.1.5.2 OPERATIONS AT DOLs 52.1.5.3 SORTIE RATES 62.1.5.4 HOLD AND ALERT GENERATION 62.1.6 OPERATIONAL ENVIRONMENTS 62.1.6.2 FLIGHT ENVIRONMENTS 72.1.6.3 SPACE ENVIRONMENTS 72.1.7 FLIGHT SAFETY 72.1.8 SYSTEM OPERABILITY 72.1.9 SYSTEM SUPPORTABILITY AND MAINTAINABILITY 72.1.10 SYSTEM AFFORDABILITY 82.1.11 SYSTEM INSPECTABILITY AND TESTABILITY 82.1.12 FLIGHT APPROVAL AND TESTING 82.1.13 TRAINING 82.1.14 HUMAN SYSTEMS 92.1.15 ENGINEERING PRINCIPLES AND PRACTICES 92.1.16 ENVIRONMENTAL CONSIDERATIONS 92.2 FLIGHT SEGMENT 92.2.1 REUSABILITY 92.2.2 CONFIGURATION 92.2.3 FLIGHT SEGMENT OPERATIONAL REQUIREMENTS 102.2.3.1 STANDARD MISSION PERFORMANCE REQUIREMENTS 102.2.3.2 STANDARD MISSION PROFILES 102.2.3.2.1 SUB-ORBITAL "POP-UP" PROFILES 102.2.3.2.2 ORBITAL 102.2.3.2.2 FERRY 102.2.3.3 MISSION CAPABILITIES 112.2.3.3.1 CROSS RANGE 112.2.3.3.2 "POP-UP" RANGE 112.2.3.3.3 ON-ORBIT MANEUVERING 112.2.3.3.4 POINTING ACCURACY 112.2.3.3.5 RENDEZVOUS, CO-ORBIT AND DOCKING 112.2.3.3.6 MISSION DURATION 122.2.3.3.7 ORBITAL IMPACT 122.2.4 FLIGHT SEGMENT DESIGN REQUIREMENTS 122.2.4.1 FLIGHT SEGMENT INTEGRITY 122.2.4.2 DESIGN LIFE 132.2.4.3 CRITICAL FAILURE CONDITION RATE 132.2.4.4 MASS AND BALANCE 142.2.4.5 FLIGHT PERFORMANCE RESERVE 142.2.4.6 FAILURE TOLERANCE AND DETECTION 142.2.4.7 FLIGHT ABORT 152.2.4.8 TAKEOFF AND LANDING 152.2.4.9 PROPULSION SYSTEM 162.2.4.9.1 ENGINE FAIL/OPERATIONAL CAPABILITY 162.2.4.9.2 PROPELLANTS 162.2.4.10 PAYLOAD SYSTEMS 162.2.4.10.1 PAYLOAD OPERATIONS CONCEPT 162.2.4.10.2 PAYLOAD CONTAINER 162.2.4.10.3 PAYLOAD CONTAINER CHANGE-OUT DURATION 172.2.4.10.4 PAYLOAD BAY 172.2.4.10.5 PAYLOAD BAY AND PAYLOAD CONTAINER ACCESS 172.2.4.11 CREW SYSTEMS 172.2.4.11.1 CREW COMPLEMENT 172.2.4.11.2 CREW STATION 172.2.4.11.2.1 CREW STATION ENVIRONMENT 182.2.4.11.2.2 CREW VISIBILITY 182.2.4.11.2.3 EMERGENCY INGRESS AND EGRESS 182.2.4.11.3 CREW ESCAPE DURING ASCENT AND DESCENT 182.2.4.12 TOWING 192.2.4.13 INTEROPERABILITY 192.2.4.13.1 COMMUNICATION SYSTEMS 192.2.4.13.2 NAVIGATION SYSTEMS 192.2.4.14 AUTOMATED TEST AND CHECKOUT 192.2.5 FLIGHT SEGMENT MISSION CAPABLE RATE 192.3 COMMAND AND CONTROL SEGMENT REQUIREMENTS 192.3.1 HUMAN-IN-THE-LOOP CONTROL 192.3.2 AUTONOMOUS CONTROL 192.4 SUPPORT SEGMENT REQUIREMENTS 202.4.1 MAINTENANCE, SUPPORT, AND UPGRADES 202.4.2 FERRY 20APPENDIX A: DESIGN REFERENCE MISSIONS 21APPENDIX B: MAXIMUM PERFORMANCE MISSION SETS 22APPENDIX C: REQUIREMENTS MATRIX 24

1. INTRODUCTION

1.1 BACKGROUND

The Air Force Space Command and the Air Force Materiel Command are evaluating the potential benefits of military spaceplanes for conducting a variety of on-orbit and transatmospheric military missions. This evaluation is being undertaken by the AFSPC-AFMC Military Spaceplane Integrated Concept Team (ICT) directed by the AFSPC and AFMC commanders.

Air Force interest in military spaceplanes 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 Aerospaceplane 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 airbreathing 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 spaceplane.

With the increasing importance and criticality of military space operations to Global Engagement capabilities of the Air Force, it is recognized that achieving safe, reliable, affordable, and routine access to, through, and from space will increasingly be important to national security. Current military space launch capabilities, largely based upon upgraded ballistic missiles, are not able to support the increased military operations in space to be necessary in the near future. What is desired is to rebuild space access with new forms of transportation that embody the "aircraft-like" characteristics of safety, reliability, operability, supportability, producibility, testability, and affordability. Many of the studies previously undertaken, and highlighted above, indicate that reusable military spaceplanes are expected to achieve these objectives.

1.2 SCOPE

This System Requirements Document (SRD) establishes system requirements for a Military Spaceplane. These requirements represent top-level performance and functional goals or objectives that have been defined by the AFSPC-AFMC Military Spaceplane ICT to assist in the definition of military spaceplane concepts and to evaluate technology development needs.

1.3 REQUIREMENTS RATIONALE

Rationale for selected requirements are stated herein to assist in understanding why the requirement has been instituted.

1.4 USE OF THIS SRD

This SRD shall be used:

a. To support the conceptual design of military spaceplanes for use in mission solution analyses undertaken in support of the Military Spaceplane ICT;

b. To define key performance and functional requirements to support the evaluation of Technology Needs and to define appropriate science and technology (S&T) programs;

c. To provide a starting point for the evolutionary development of the Military Spaceplane requirements and associated system verification methods;

d. To support the definition of a military spaceplane acquisition strategy;

e. To baseline Air Force requirements for use in comparisons with existing and future commercial launch capabilities;

f. To provide a starting point for the conduct of trade studies, analyses, tests, and demonstrations of the proposed Military Spaceplane System that will establish and refine performance requirements acceptable to the user organizations;

g. To provide potential users with an improved understanding of the performance and functional capabilities of this new flight system; and

h. To support the development of Mission Need Statements and Operational Requirements Documents.

1.5 CONTROL OF THIS SRD

This SRD and any changes to it shall be approved by the AFSPC-AFMC Military Spaceplane ICT. Minor changes between revisions shall be identified by change bars in the left margin.

1.6 BASIS OF THIS SRD

This SRD is based upon the Technical Requirements Document for a military TAV developed as part of the BMDO SSRT program and the subsequent S&T programs executed through the Air Force Phillips Lab PL/VT-X organization.

1.7 TERMS

a. Herein the term "including" shall be interpreted as "including but not limited to."

b. Herein the term "TBD" refers to design parameters or information to be completed by the contractor.

2.0 MILITARY SPACEPLANE SYSTEM REQUIREMENTS

The Military Spaceplane System shall provide a safe, reliable, operable, supportable, producible, testable, and affordable suborbital and Earth-to-Orbit-and-Return flight system. The Military Spaceplane System may be configured as a single-stage-to-orbit (SSTO) Spaceplane or a configuration incorporating multiple flight vehicles, stages and/ or take-off assist systems. Initial Mark I Demonstrator efforts will concentrate on developing SSTO technologies and operational concepts using a suborbital configuration. Technology maturity during Mark I testing will help make the SSTO versus TSTO or multi-stage decision at a later time.

2.1 MILITARY SPACEPLANE SYSTEM

2.1.1 GENERAL MISSION CAPABILITIES

a. The Military Spaceplane System shall be capable of supporting a wide range of military air and space superiority, global attack, precision engagement, and information superiority missions requiring flight operations in, through, and from space and the transatmosphere.

b. The Military Spaceplane System shall be capable of ascending to, operating in, and descending from designated orbits. The Military Spaceplane System shall be capable of suborbital flight including exoatmospheric flight.

c. The Military Spaceplane System shall be capable of carrying a payload and deploying or otherwise utilizing the payload to execute the military missions in orbit, while ascending to orbit, while descending from orbit, or during suborbital flight.

d. The Military Spaceplane System shall be capable of executing these missions alone or in conjunction with other Military Spaceplane Systems, other civil or commercial space transportation systems, or other orbiting, endoatmospheric, marine, and/ or ground military, civil, or commercial systems.

e. The Military Spaceplane System shall be capable of supporting four levels of employment: peacetime, military operations other than war (MOOTW), major regional conflict (MRC), and global conflict.

f. The Military Spaceplane System shall be capable of executing the following missions assigned to the Air Force Space Command: Force Support, Force Enhancement, Force Application, and Space Control.

g. The Military Spaceplane System shall be capable of crewed, virtually-commanded, or autonomous operations as required by specific mission needs and system requirements.

2.1.1.1 DESIGN REFERENCE MISSIONS AND MISSION SETS

a. Military Spaceplane System Design Reference Missions (DRMs) are defined in Appendix A. The requirements of these DRMs augment the performance and functional requirements stated herein.

b. Maximum Performance Mission Sets are defined in Appendix B. These mission sets identify specific performance capabilities or trade studies to be assessed during concept formulation. The four point solutions derived from these trade studies will assist the Air Force in understanding the military spaceplane performance trade space and utility.

2.1.1.2 DESIGN REFERENCE MISSIONS AND MISSION SETS

To the extent practical, the incorporation of commercial requirements is highly encouraged but shall not interfere with military requirements. The Military Spaceplane system shall be designed to support deployment of small military satellites and if possible, commercial payloads (i.e., Iridium, Teledesic, etc.). The contractor is encouraged to work with the commercial sector and/or potential operating companies to develop and market a commercial spin-off capability. To augment military capabilities in crisis, consideration shall be given to operating these commercial systems as part of a dual-use Civil Reserve Air Fleet (CRAF).

2.1.2 SYSTEM DEFINITION

The Military Spaceplane System shall be comprised of three major elements-the Flight Segment, the Command and Control Segment, and the Support Segment.

a. The Flight Segment consists of the spaceplane (a flight vehicle capable of achieving orbit), flight hardware, payloads carried by the spaceplane, and any non-orbital flight vehicles, such as a carrier aircraft first stage.

b. The Command and Control Segment consists of the flight control and ground control necessary for operators to control the total Military Spaceplane System.

c. The Support Segment supports the execution of the spaceplane missions. This includes meteorological control, planning and scheduling, maintenance, logistical support, training, and payload processing. The Support Segment may include ground systems, transportable systems, and other aircraft.

2.1.3 OPERATIONAL SITES

a. For the purpose of undertaking performance, safety, operability, and supportability analyses, a Main Operating Base (MOB) at Holloman AFB NM is designated. (This designation does not represent a selection of a MOB by the Air Force but is needed to provide for consistent performance estimates.)

b. For the purpose of undertaking performance, safety, operability, and supportability analyses, designated Dispersed Operating Locations (DOLs) are located at (in alphabetical order) Edwards AFB CA, Falcon AFB CO, Patrick AFB (Cape Canaveral) FL, Vandenberg AFB CA, White Sands NM, and (TBD).

2.1.4 FERRY CAPABILITY

The Military Spaceplane System shall be capable of ferrying the Spaceplane with its maximum payload between the production and depot facilities, MOB, DOLs, commercial airports, and military bases worldwide.

2.1.5 SYSTEM OPERATIONS

2.1.5.1 OPERATIONS AT THE MOB

a. For peacetime operations from the MOB, the Military Spaceplane System shall be capable of fully preparing the Flight Segment for mission execution within two (2) days, with an objective of one (1) calendar day, of its landing from a previous mission. This may exclude scheduled inspections and maintenance and major repairs. The Military Spaceplane System shall be capable of maintaining this peacetime rate of flight operations indefinitely. The stated times include the time required to ferry the elements of the Flight Segment to the MOB.

b. For other than peacetime operations from the MOB, the Military Spaceplane System shall be capable of the following:

(1) For a minimum of 30 days, fully preparing a Flight Segment for flight within 18 hours, with an objective of 12 hours of its landing. This may exclude all but safety-of-flight and mission-critical system inspections and maintenance. The stated times include, as an objective, the time required to ferry the elements of the Flight Segment to the MOB.

(2) For a minimum of seven (7) days, fully preparing a Flight Segment for flight within 12 hours, with an objective of 8 hours of its landing. This may exclude all but safety-of-flight and mission-critical system inspections and maintenance. The stated times include, as an objective, the time required to ferry the elements of the Flight Segment to the MOB.

(3) Under emergency war or peace conditions, fully preparing the Flight Segment for flight within eight (8) hours, with an objective of two (2) hours of its landing at the MOB. This may exclude all but safety-of-flight and mission-critical system inspections and maintenance.

2.1.5.2 OPERATIONS AT DOLs

a. For peacetime operations at a DOL, the Military Spaceplane System shall be capable of fully preparing the Flight Segment for mission execution within three (3) days, with an objective of one (1) calendar days, of its landing at the DOL from a previous mission. This may exclude scheduled inspections, maintenance, and major repairs.

b. For other than peacetime operations at a DOL, the Military Spaceplane System shall be capable of fully of the following:

(1) For a minimum of 30 days, preparing a Flight Segment for flight within 24 hours, with an objective of 12 hours of its landing at the DOL. This may exclude all but safety-of-flight and mission-critical system inspections and maintenance.

(2) For a minimum of seven (7) days, preparing a Flight Segment for flight within 18 hours, with an objective of 8 hours of its landing at the DOL. This may exclude all but safety-of-flight and mission-critical system inspections and maintenance.

2.1.5.3 SORTIE RATES

a. The Flight Segment shall be capable of an average peacetime sortie rate per Spaceplane of at least one (1) sortie every ten (10) days, with an objective of one (1) sortie every five (5) days.

b. The Flight Segment shall be capable of an average war and exercise sustained sortie rate per Spaceplane of at least one (1) sortie every three (3) days, with an objective of one (1) sortie every two (2) days.

c. The Flight Segment shall be capable of an average war and exercise surge sortie rate per Spaceplane of at least one (1) sortie every two (2) days, with an objective of one (1) sortie every day.

2.1.5.4 HOLD AND ALERT GENERATION

a. A mission-capable Flight Segment (no outstanding maintenance actions) shall remain mission capable without further maintenance action for 15 days (threshold), 30 days (objective).

b. A mission-capable Flight Segment shall be capable of generating to an Alert two (2) hour (launch within two (2) hours of notification) status within four (4) hours (threshold), with an objective of two (2) hours. The Flight Segment shall be able to maintain Alert two (2) hour status for three (3) days (threshold), seven (7) days (objective).

c. A Flight Segment shall be capable of generating from Alert two (2) hour status to Alert 15 minute (launch within 15 minutes of notification) status within one (1) hour 45 minutes (threshold), 30 minutes (objective). The Flight Segment shall be capable of maintaining Alert 15 Minute status for 12 hours (threshold), 24 hours (objective). A Flight Segment on Alert 15 Minutes shall be capable of launching within 15 minutes (threshold), five (5) minutes (objective).

2.1.6 OPERATIONAL ENVIRONMENTS

The Military Spaceplane System shall, as an objective, have an all weather capability.

2.1.6.1 GROUND ENVIRONMENTS

The Military Spaceplane System shall be capable of conducting ground operations in the following conditions:

CONDITION THRESHOLD OBJECTIVE

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

Wind 40 knots 50 knots

Absolute Humidity 30 gms/m3 45 gms/m3

Precipitation Light Moderate

2.1.6.2 FLIGHT ENVIRONMENTS

The Military Spaceplane System shall be capable of conducting atmospheric flight operations (including take-off, landing and ferry operations) in the following conditions:

CONDITION THRESHOLD OBJECTIVE

Visibility 0 ft 0 ft

Ceiling 0 ft 0 ft

Crosswind component 25 knots 35 knots

Total wind 40 knots 50 knots

Upper level winds 95th percentile shear all shear conditions

Icing light rime icing moderate rime icing

Absolute humidity 30 gms/m3 45 gms/m3

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

Precipitation Light Moderate

2.1.6.3 SPACE ENVIRONMENTS

The Military Spaceplane System shall be capable of conducting space operations in the following conditions:

CONDITION THRESHOLD OBJECTIVE

Radiation level TBD TBD

2.1.7 FLIGHT SAFETY

a. The Military Spaceplane System shall be able to operate from the MOB and DOLs with a risk of loss of the flight vehicles due to system failure of less than once per 2000 sorties (0.9995), with an objective of less than once per 5000 sorties (0.9998).

b. Risk to friendly populations shall be less than 1 x 10-6 (threshold), 1 x 10-7 (objective), per sortie.

2.1.8 SYSTEM OPERABILITY

The Military Spaceplane System shall be designed such that the processes used to operate the system are analogous to the processes used to operate military aircraft.

2.1.9 SYSTEM SUPPORTABILITY AND MAINTAINABILITY

The Military Spaceplane System shall be designed such that the processes used to support and maintain the system are analogous to the processes used to support and maintain military aircraft. This includes standard aircraft support and maintenance processes of procuring and storing war ready reserves.

2.1.10 SYSTEM AFFORDABILITY

a. The Military Spaceplane System shall be designed to be produced and sustained such that the cost of ownership throughout the total life cycle of the system is minimized while complying with the performance and functional requirements herein.

b. Demonstrated advanced industrial practices shall be incorporated into the management of the total system program to minimize the cost of doing business with the government. This shall include a comprehensive review of all business and policy stipulations for the elimination of unnecessary requirements.

c. Commercial business and validated commercial engineering and production practices shall be used where consistent with achieving the performance and functional requirements herein.

2.1.11 SYSTEM INSPECTABILITY AND TESTABILITY

The Military Spaceplane System shall be designed such that compliance with the performance and functional requirements herein can be validated through appropriate inspections, tests, and demonstrations in a manner similar to that undertaken for military or commercial aircraft. (For example, an envelope expansion flight test program is used to verify the proper functioning of the flight hardware and software and is used measure actual loads, for comparison with predicted loads, prior to approval for unlimited flight release.)

2.1.12 FLIGHT APPROVAL AND TESTING

The Military Spaceplane System shall be approved for flight and tested in a manner analogous to Air Force aircraft. The goal shall be to field military spaceplanes able to routinely and reliably over-fly populated areas in a manner analogous to aircraft today. The design, development, operation, testing, and support of the Military Spaceplane System shall be undertaken such that this approval may be achieved.

An integral part of this approval and testing process shall be the ability to perform gradual flight envelope expansion tests. Military Spaceplanes, including demonstrators, shall support extensive subsonic to supersonic flight testing over a government range followed by hypersonic flight testing between government ranges. This gradual flight envelope expansion will be part of a robust risk reduction program.

2.1.13 TRAINING

The training of flight and ground support crews for the Military Spaceplane System shall be undertaken in a manner similar to that undertaken for the training of Air Force flight and ground crews for military aircraft. The design, development, operation, and support of the Military Spaceplane System shall be undertaken in a manner that supports this training.

2.1.14 HUMAN SYSTEMS

a. The design of the Military Spaceplane System shall ensure full integration of the human into the system. Consideration shall be given to Human Systems Integration elements in the design, mission concepts, and maintenance activities associated with the Military Spaceplane System. The Military Spaceplane System should accommodate male and female crew members of no less than 100 pounds and no more than 240 pounds and a height of no less than 60 inches and no more than 76 inches.

b. Human Systems Integration shall consider the burden the design imposes on: manpower, personnel, and training; human factors engineering; survivability; and health hazards.

c. Human factors engineering requirements shall be established to: develop effective human-machine interfaces and to minimize or eliminate system characteristics that require extensive cognitive, physical, or sensory skills; require excessive training or workload for intensive tasks; or result in frequent or critical errors or safety/health hazards. MIL-STD-1776, Aircrew Systems, provides guidance.

2.1.15 ENGINEERING PRINCIPLES AND PRACTICES

The design, analysis, development, testing, demonstration, fabrication, operation, maintenance, and support of the Military Spaceplane System shall be based upon engineering principles and practices defined specifically for this system. These principles and practices shall be based upon the concept of engineering precedence and validation of change through test. These principles and practices shall be derived from appropriate military and commercial principles and practices. Modifications to existing precedence required to accommodate unique aspects of the Military Spaceplane System shall be validated through appropriate testing and demonstration undertaken in each stage of the system design and development.

2.1.16 ENVIRONMENTAL CONSIDERATIONS

The Military Spaceplane System shall comply with all federal, state, and local environmental laws and regulations appropriate to the intended use of this system.

2.2 FLIGHT SEGMENT

2.2.1 REUSABILITY

The Flight Segment shall, as an objective, be fully reusable. As used in this context, fully reusable allows for the replacement of items subject to normal wear and tear, such as tires and brakes, provided such replacement can be undertaken while meeting the requirements defined herein.

2.2.2 CONFIGURATION

The portion of the Flight Segment that achieves orbit shall be referred to as a Spaceplane.

2.2.3 FLIGHT SEGMENT OPERATIONAL REQUIREMENTS

2.2.3.1 STANDARD MISSION PERFORMANCE REQUIREMENTS

a. The Military Spaceplane System shall be capable of achieving design reference missions I through IV contained in Appendix A with capabilities as defined in Appendix B.

b. The payload mass includes the standard payload container/interface (see paragraph 2.2.4.10.2).

c. The payload mass includes the mass of the crew and all crew accommodations that would be removed for autonomous and/or uncrewed operations.

2.2.3.2 STANDARD MISSION PROFILES

The Flight Segment shall capable of the following mission profiles:

2.2.3.2.1 SUB-ORBITAL "POP-UP" PROFILES

a. The Military Spaceplane System shall be capable of executing an "unrestricted" sub-orbital "pop up" (i.e. ballistic) exoatmospheric trajectory. The Spaceplane shall be capable of deploying the payload during the exoatmospheric portion of the ballistic flight trajectory and, then, reentering and landing downrange. The deployed payload is boosted by an upper stage to its intended target or orbit.

b. The Military Spaceplane System shall be capable of executing a "restricted" suborbital "pop up" exoatmospheric tajectory with the take-off and landing sites located within CONUS. The spaceplane shall be capable of deploying the payload during the exoatmosphrc portion of the ballistic flight trajectory. The deployed payload is then boosted by an upper stage to its intended target or orbit.

c. The maximum "pop-up" payload mass shall be as defined in Appendices A and B.

d. The Flight Segment shall be capable of safely landing in the event that the "pop-up" payload is retained.

2.2.3.2.2 ORBITAL

a. The Spaceplane flies directly into an orbital trajectory. The payload is then used onboard, deployed directly into orbit or is boosted to mission destination via an upper stage.

b. The Spaceplane shall be capable of a "once-around" orbit and landing at its takeoff base.

2.2.3.2.2 FERRY

The Miliary Spaceplane System shall be able to ferry the Flight Segment from one location to another, with or without payload onboard the Spaceplane (the payload is not deployed or used). The minimum ferry range shall be 2000 NM without landing and with a global range as an objective. All ferry profiles include carrying maximum payload.

2.2.3.3 MISSION CAPABILITIES

2.2.3.3.1 CROSS RANGE

a. The Spaceplane shall have a minimum cross range for an unrestricted "pop-up" profile of 600 NM (threshold), 1200 NM (objective).

b. The Spaceplane shall have a minimum cross range for a CONUS "pop-up" profile of 400 NM (threshold), 600 NM (objective).

c. The Spaceplane shall have a minimum cross range for an orbital profile of is 1200 NM (threshold), 2400 NM (objective).

2.2.3.3.2 "POP-UP" RANGE

For a CONUS only, restricted profile, the Spaceplane shall be able to take-off and land within 1600 NM (threshold), 1200 NM (objective).

2.2.3.3.3 ON-ORBIT MANEUVERING

a. The Spaceplane shall be capable of on-orbit maneuvering with full six degree-of-freedom (DOF) translation and rotation.

b. The Spaceplane propellant tankage shall be sized to carry sufficient on-board propellant to provide an excess (over that required to orbit and deorbit the spaceplane) on-orbit maneuvering velocity change (V) of 300 feet per second (fps), with an objective of 600 fps.. This maneuvering capability shall be accomplished with the maximum easterly payload installed. Propellant mass required to achieve the maneuvering capability shall be chargeable to the payload.

2.2.3.3.4 POINTING ACCURACY

a. The Spaceplane shall be able to control the on-orbit payload bay attitude (pointing requirement) to within 15 milliradians, with an objective of 10 milliradians, simultaneously in all three axes. This pointing requirement shall be with or without the payload bay doors being open and with or without the payload extended from the bay.

b. The Spaceplane shall be capable of maintaining this pointing requirement in support of appropriate DRMs.

2.2.3.3.5 RENDEZVOUS, CO-ORBIT AND DOCKING

a. The Spaceplane shall be able to rendezvous and co-orbit (station keep) with orbital systems including other spaceplanes and satellites. This capability shall be achieved with standard mission equipment.

b. The Spaceplane, with an appropriately configured payload container/payload, shall be able to dock with orbital systems including other spaceplanes and satellites.

2.2.3.3.6 MISSION DURATION

a. The Spaceplane shall be capable of powered on-orbit operations for a minimum of 24 hours, with an objective of 72 hours.

b. Under emergency conditions, the Spaceplane shall be capable of extending the period of on-orbit operations by 12 hours, with an objective of 24 hours.

c. For all missions, the Spaceplane shall possess sufficient reserves to support a maximum duration descent from orbit, landing, and post-landing operations following a maximum duration on-orbit stay.

2.2.3.3.7 ORBITAL IMPACT

The Flight Segment shall be able to safely reenter and land after an impact from debris of 1-cm diameter (mass and velocity TBD) threshold, 1-cm diameter (mass and velocity TBD) objective.

2.2.4 FLIGHT SEGMENT DESIGN REQUIREMENTS

2.2.4.1 FLIGHT SEGMENT INTEGRITY

a. The Flight Segment shall incorporate the essential characteristics in subsystems and equipment that allow the specified performance, safety, reliability, operability, supportability, inspections, and testing to be achieved under the specified operational conditions over the defined service lifetime. These subsystems and equipment shall include, but not be limited to, the structure, propulsion subsystems, mechanical subsystems, avionics/electronics, and software. These essential characteristics may be achieved by evaluating and prudently applying standards from Air Force aircraft integrity programs and from test requirements for space vehicles. The following may be used for general guidance: MIL-STD-1530, Aircraft Structural Integrity Program (ASIP); MIL-STD-1783, Engine Structural Integrity Program (ENSIP); MIL-STD-1798, Mechanical Equipment and Subsystem Integrity Program (MECSIP); MIL-STD-1796, Avionics/Electronics Integrity Program (AVIP); MIL-STD-1803, Software Development Integrity Program (SDIP); and MIL- STD-1540, Test Requirements for Space Vehicle. (The guidance contained in these military standards represent the systems engineering processes that enable the achievement of the "aircraft-like" characteristics required herein. Many of these system engineering processes begin during the conceptual design phase and, as such, are appropriate for consideration at this time.

b. The Flight Segment shall be designed, analyzed, produced, operated, supported, inspected, demonstrated, and tested using engineering principles and practices that are specifically selected for this application. These unique engineering principles and practices shall be incorporated throughout the life-cycle of the system beginning with conceptual design. The concept of engineering precedence and validation of change through test shall be applied.

c. The Flight Segment shall have sufficient strength, stiffness, durability, and damage tolerance to achieve the performance and functional requirements defined herein.

d. The Flight Segment shall be designed to minimize damage and the risk of loss of the flight vehicles due to battle damage, foreign object damage, and atmospheric and space natural environments.

2.2.4.2 DESIGN LIFE

a. For the Spaceplane, the primary structure, including the thermal protection subsystem and the propellant tanks, shall be designed for a minimum life of 250 sorties, with an objective of 500 sorties, over a design life of 20 years.

b. For the Spaceplane, the primary structure, including the thermal protection subsystem and the propellant tanks, shall be capable of a minimum of 100 sorties with an objective of 250 sorties between major inspections and overhauls.

c. For the Spaceplane, the main engines shall be designed for a minimum life of 100 sorties with an objective of 250 sorties. The main engines shall be designed to be removed and replaced within eight (8) hours with an objective of less than four (4) hours.

d. For the Spaceplane, the propulsion subsystem and propellant transfer subsystem shall be capable of a minimum of 50 sorties with an objective of 100 sorties between major inspections and overhauls.

e. For the Spaceplane, all other subsystems and components shall be capable of a minimum life of 100 sorties with an objective of 250 sorties.

f. For the Spaceplane, all other subsystems and components shall be capable of a minimum of 100 sorties with an objective of 250 sorties between major inspections and overhauls.

g. For other aircraft or flight vehicles, the design life and inspection and overhaul intervals shall be comparable to military or commercial cargo and transport aircraft.

2.2.4.3 CRITICAL FAILURE CONDITION RATE

a. For the purposes of allocating Spaceplane subsystem and component reliability's while conducting failure modes and effects analysis (FMEA), the probability of loss of the Spaceplane shall be less than once per 2000 sorties, with an objective of less than once per 5000 sorties.

b. For other aircraft or flight vehicles, critical failure rates shall be consistent with those for large commercial aircraft.

2.2.4.4 MASS AND BALANCE

a. Starting with the conceptual design, the Flight Segment's performance shall be based upon the empty and fueled system mass estimates, including center of gravity and mass moments of inertia, derived from estimated, calculated, and/ or measured masses of the subsystems, components, and parts.

b. Estimated and calculated masses shall specifically incorporate mass allocations to accommodate the requirements for safety, reliability, supportability, operability, producibility, inspectability, affordability, and test capabilities.

c. Estimated and calculated masses shall account for margins and uncertainties specified elsewhere in this SRD.

d. Estimated and calculated masses shall be for a complete configuration as best known at the time the estimate is made.

e. Estimated and calculated masses shall be consistently used in related analyses including performance, cost, structural analyses, etc. The accuracy (number of significant figures) of the estimated and calculated masses shall be consistent with the accuracy of related analyses.

2.2.4.5 FLIGHT PERFORMANCE RESERVE

a. The flight performance reserve of the Military Spaceplane System shall be based on 3 sigma stochastic combination of uncontrollable variables (e.g., weather, atmosphere density, propellant temperatures, propellant loading accuracy, residual unusable propellants, prediction uncertainties and hardware uncertainties) which affect this performance estimate.

b. Analytical predictions of system performance shall include performance margins commensurate with the uncertainties in the predictive methods used.

2.2.4.6 FAILURE TOLERANCE AND DETECTION

a. Flight-critical and mission-critical subsystems shall be designed to be fail-safe, as a minimum, and shall, as an objective, be fail-operational/fail-safe. Fail-operational means that the Flight Segment shall be capable of continuing with the mission following the failure of a critical system. Fail-safe means that the Flight Segment shall be capable of achieving a safe mode of operation following the failure of a critical subsystem. During ascent and under fail-safe conditions, the Flight Segment shall be capable of either landing or continuing with insertion of the Spaceplane into a safe orbit. During descent and under fail-safe conditions, the Spaceplane shall be capable of safely landing. On-orbit and under fail-safe conditions, the Spaceplane shall be capable of remaining in a safe orbit and conducting a safe emergency entry and landing.

b. Flight-critical subsystems required for a safe return from orbit shall be fail-safe, as a minimum, at the beginning of the descent. The proper functioning of these subsystems shall be determined prior to the commitment to de-orbit, re-enter, and land.

c. Combined failure rates of flight-critical subsystems shall be determined stochastically.

d. Flight-critical subsystem failure shall be detectable to allow reconfiguration of the flight system and to prevent loss of control of the flight vehicles or subsequent catastrophic failure.

2.2.4.7 FLIGHT ABORT

a. The Flight Segment shall be capable of a safe shut down following engine start, but prior to takeoff, without damage to the Flight Segment or support system, or risk to personnel.

b. At any time after takeoff and under emergency conditions, the Flight Segment shall be capable of either returning to a safe landing or continuing the ascent of the Spaceplane to an emergency orbit. Specially prepared and supported down range abort sites shall not be necessary. Emergency conditions involve the failure of any flight-critical subsystem that does not lead to immediate catastrophic loss and is not fail-operational.

c. The flight vehicles shall be capable of landing at alternate bases during abort.

d. Flight under fail-safe emergency conditions shall not exceed the design limits of the flight vehicles.

2.2.4.8 TAKEOFF AND LANDING

a. For horizontal take-off and/or landing vehicles, they shall be capable of using conventional runways designed for large military and commercial transports, of less than 10,000 ft x 150 ft, and, as an objective, less than 8,000 ft x 150 ft.

b. For vertical landing vehicles, they shall be able to land within a 50 ft radius on conventional concrete runway surfaces, and as a goal within a 25 ft radius.

c.. The Flight Segment shall be able to operate from runways with an equivalent load bearing capacity of 65,000 lbs (threshold) for single wheel type landing gear (S65) with an objective of S45.

d. For vertical takeoff Flight Segments, a maximum ground area of (TBD) shall be required.

e. Takeoff and landing from a conventional runway shall not cause damage to the runway such that the runway would be put out of commission until repairs are made.

f. For vehicles that utilize runways, the Runway Condition Reading is defined in (TBD).

2.2.4.9 PROPULSION SYSTEM

2.2.4.9.1 ENGINE FAIL/OPERATIONAL CAPABILITY

The Flight Segment shall be capable of safely continuing controlled flight, either to orbit or a landing after failure of a critical propulsion component.

2.2.4.9.2 PROPELLANTS

The flight vehicle shall not use hypergolic or toxic propellants.

2.2.4.10 PAYLOAD SYSTEMS

2.2.4.10.1 PAYLOAD OPERATIONS CONCEPT

a. To facilitate ground processing and minimize turnaround times, an off-line payload processing and containerization system shall be required.

b. The Flight Segment shall have a standard interface to a stand-alone payload container that can be installed in and removed from the payload bay of the Spaceplane without modification to or reconfiguration of the Spaceplane.

c. Special non-standard services or requirements needed to support specific mission assets shall be accommodated by the installation of appropriate Airborne Support Equipment (ASE) in the Payload Container. Integration of the payload container, ASE, and payload shall be controlled by the payload program office.

d. The Support System shall be capable of easily and quickly removing or installing a payload container from the flight vehicle when landing at the MOB or DOL.

2.2.4.10.2 PAYLOAD CONTAINER

a. The payload container shall provide standardized structural, mechanical, electrical, communications, and other interfaces between the payload and the Spaceplane.

b. The standardized payload container shall have the internal dimensions indicated in Appendix B, or similarly functional dimensions with adequate volume able to support the DRMs. The loaded payload container shall be air, truck and rail transportable.

c. The payload deployment and safety status shall be capable of being monitored by the Military Spaceplane System.

d. The payload container shall be able to carry additional on-orbit propellant for the Spaceplane.

2.2.4.10.3 PAYLOAD CONTAINER CHANGE-OUT DURATION

The maximum time required for payload container/change-out (removal of one payload container and the replacement of it with another) shall be less than one (1) hour, with an objective of less than 30 minutes.

2.2.4.10.4 PAYLOAD BAY

a. The Spaceplane shall have a payload bay capable of housing a standardized payload container as defined above.

b. The payload bay and container mounting provisions shall be capable of structurally supporting the loads associated with the design payloads, including the payload container mass, during all phases of flight including emergency flight.

c. The Spaceplane shall provide the environmental and physical interfaces to the container as defined in (TBD).

d. The payload bay shall include the equipment and mechanisms necessary to safely jettison the payload and payload container while in exoatmospheric flight.

e. The Spaceplane shall be designed to fly through all nominal and abort conditions with or without the container/payload installed.

2.2.4.10.5 PAYLOAD BAY AND PAYLOAD CONTAINER ACCESS

If required to perform a DRM, access between the payload bay/container and the crew station during crewed missions shall be provided.

2.2.4.11 CREW SYSTEMS

Crew systems, as defined in the following requirements, shall be incorporated into the Spaceplane only when the need for human presence is required to meet the requirements stated herein.

2.2.4.11.1 CREW COMPLEMENT

a. The crew station shall accommodate two crew members.

b. The design of the Spaceplane crew station shall, as an objective, allow for the addition of one more crew member.

2.2.4.11.2 CREW STATION

a. Each Spaceplane shall be capable of accommodating a crew if it is determined that crewed operations are required. The crew station may be removable and located in the payload bay provided this does not unacceptable diminish the performance of the DRMs or affect crew health, safety, and comfort.

b. The crew station shall be designed to accommodate flight crews wearing pressurized suits. Avionics and controls shall be fully integrated with the human and be anthropometrically designed. Display symbology will be standardized with current Air Force systems.

2.2.4.11.2.1 CREW STATION ENVIRONMENT

a. The crew station shall be operable during and following exposure to space.

b. The crew station shall contain a life support system capable of supporting two crew members for a minimum of 24 hours, with an objective of 72 hours.

c. The crew station shall contain an emergency life support system capable of minimally supporting two crew members for an additional 12 hours, with an objective of 24 hours.

d. The operating pressures and gas combinations of the cabin pressurization systems and the crew pressure suits shall be designed to permit rapid crew egress with little or no preoxygenation.

2.2.4.11.2.2 CREW VISIBILITY

a. The crew station shall have a window(s) or suitable alternatives for direct outside visibility as required for the execution of the DRMs.

b. The crew shall have sufficient visibility (either directly or via video) of the payload container and payload during payload operations to verify the status of the payload and payload container as required for mission execution and vehicle safety.

2.2.4.11.2.3 EMERGENCY INGRESS AND EGRESS

a. While on the ground, the Flight Segment shall have provisions for unassisted emergency crew egress.

b. While on-orbit, the Spaceplane shall have provision for ingress and egress to enable crew rescue.

c. Spaceplane emergency access hatches, doors, or airlocks shall be capable of being manually opened, closed, and secured so as to not hinder safe reentry and landing. These hatches, doors, or airlocks shall be accessible and usable by crew members in pressure suits or by external rescue crews.

2.2.4.11.3 CREW ESCAPE DURING ASCENT AND DESCENT

An endoatmospheric, subsonic crew escape capability shall be provided. A crew escape capability throughout the flight envelope is an objective. An on-orbit crew escape and survival capability is an objective.

2.2.4.12 TOWING

The unfueled Flight Segment shall be capable of being towed intact (i.e., without vehicle disassembly or Spaceplane demating) on prepared surfaces with the maximum payload onboard.

2.2.4.13 INTEROPERABILITY

2.2.4.13.1 COMMUNICATION SYSTEMS

Each Flight Segment shall be capable of interfacing with the United States C4ISRT (Command, control, communications, computers, intelligence, surveillance, recconisense and targeting) systems required to accomplish the DRMs and maintain safe, controlled flight.

2.2.4.13.2 NAVIGATION SYSTEMS

Each Flight Vehicle shall be capable of utilizing the NAVSTAR/GPS (Global Positioning System) navigation aid in addition to a normal complement of aircraft navigation capabilities.

2.2.4.14 AUTOMATED TEST AND CHECKOUT

Each Flight Segment shall be capable of automated test and checkout of the flight- and mission-critical subsystems and the payload. Such test and checkout shall be capable of being performed while on the ground and during all phases of mission execution.

2.2.5 FLIGHT SEGMENT MISSION CAPABLE RATE

An individual Flight Segment shall have a mission capable rate of 80 percent, with an objective of 95 percent. System availability shall be determined in the same manner as is done for Air Force aircraft.

2.3 COMMAND AND CONTROL SEGMENT REQUIREMENTS

The Command and Control Segment shall plan, supervise, and execute all aspects of the command and control of the Military Spaceplane System. The Command and Control Segment shall interface with the command, control, communications, and computer systems utilized by the Air Force and Department of Defense necessary for execution of the military missions assigned to the Military Spaceplane System.

2.3.1 HUMAN-IN-THE-LOOP CONTROL

The flight crew shall be able to direct the Spaceplane either from onboard the Spaceplane or from the ground or support vehicles via a virtual crew interface. This capability shall be provided with or without a crew onboard.

2.3.2 AUTONOMOUS CONTROL

The Spaceplane portion of the Flight Segment shall be capable of autonomous execution of preprogrammed missions with or without a crew onboard. Autonomous operation shall not degrade flight safety or mission execution.

2.4 SUPPORT SEGMENT REQUIREMENTS

The Support Segment shall maintain, support, operate, and train the Military Spaceplane System. The Support Segment shall maintain, support, and operate the payload container off-line ground processing. The Support Segment shall provide for operations at the MOB as well as at DOLs. The Support Segment shall provide for its own maintenance and support.

2.4.1 MAINTENANCE, SUPPORT, AND UPGRADES

a. The Support Segment shall be able to turn a Flight Segment around for flight with no more than 100 work-hours, with an objective of 50 work-hours, of on-vehicle maintenance and servicing.

b. The main engines shall be designed to be removed and replaced within eight (8) hours, with an objective of less than four (4) hours.

c. "Aircraft like" depot or factory maintenance at regularly scheduled intervals shall be utilized as a basis for the Military Spaceplane Support Segment.

d. Modifications and system upgrades shall be undertaken in the same manner as accomplished for military aircraft.

2.4.2 FERRY

a. The Support Segment shall be capable of undertaking the required ferry of the Flight Segment as well as the transportation of any Support Segment elements required to support this ferry capability.

b. All on-board subsystems required to ferry the Spaceplane shall be field repairable/ replaceable to the extent necessary to perform a ferry mission.

c. All ground equipment required to repair and ferry the Spaceplane shall be transportable to unprepared landing sites via existing transport aircraft.

d. If specialized support air vehicles are required, they must carry all necessary equipment.

APPENDIX A: DESIGN REFERENCE MISSIONS

  1. The Military Spaceplane System shall be able to accurately deliver, using a pop-up maneuver, mission assets to any location on earth from any azimuth within 90 minutes from takeoff.
  2. The Military Spaceplane System shall be able to deliver using a pop-up maneuver mission assets to orbit.
  3. The Military Spaceplane System shall be able to co-orbit and/or dock with a satellite or other orbiting object, deploy or use on-board mission assets and return to base
  4. The Military Spaceplane System shall be able to co-orbit with a satellite or other orbiting object, recover that object and return to base
  5. The Military Spaceplane System shall be able to launch into any azimuth and use or deploy mission assets, while in a once around orbit and return to base.

Possible Future Design Reference Missions

  1. The Military Spaceplane System shall be able to perform rescue missions of stranded astronauts in orbit.
  2. The Military Spaceplane System shall be able to co-orbit with a satellite or other orbiting object and reposition that object and return to base
  3. The Military Spaceplane System shall be able to co-orbit with a satellite or other orbiting object, deploy or use its onboard mission assets and allow manned extra-vehicular activities to that object and return to base
  4. The Military Spaceplane System shall be able to retrieve mission assets from anywhere on earth and return to the United States (U.S.) without refueling.
  5. The Military Spaceplane System shall be able to deliver mission assets and personnel to anywhere on earth and return to the U.S. without refueling.

APPENDIX B: MAXIMUM PERFORMANCE MISSION SETS

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)

Mark II (Orbit capable vehicle)

Mark III

Mark IV

REFERENCE MISSIONS TO MISSION SETS MATRIX


      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                                                                     
assets)                                                                             

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      
Around)                                                                             



NOTES:

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.

APPENDIX C: REQUIREMENTS MATRIX


                  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  
                                             shear                                

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  
                                            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         
Status                                                                            

Hold Alert 2-hour Status                     3 days                7 days         

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

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