Chapter Five Intro

Military strategy for space follows from the four distinct aerospace roles and missions: force support, force enhancement, force application, and aerospace control. Space strategy includes coordination of these missions in pursuit of national objectives and as directed by policy.(1) Countries usually employ military forces consistently with basic doctrine. The 1992 version of AFM 1-1, Basic Aerospace Doctrine of the United States Air Force, implies that space forces are most effective when integrated with air forces.

The aerospace environment can be most fully exploited when considered as an indivisible whole. . . . Aerospace consists of the entire expanse above the earth's surface. . . . Its lower limit is the earth's surface . . . and its upper limit reaches toward infinity.(2)

The function space forces are to perform drives their deployment. The USAF usually deploys communications satellites in geosynchronous orbits and weather satellites in Sun-synchronous orbits. Likewise, the Air Force usually deploys missile warning satellites in geostationary orbits and reconnaissance satellites in orbits optimizing resolution or collection time. Thus since two of the above space missions (force application and aerospace control) are constant regarding assets employed, it follows that we need only to discuss space missions: force support and force enhancement, in the context of space strategy as currently pursued by the US Air Force.

Space Force Support

The space segment begins at an altitude where the principles of orbital mechanics replace the principles of aerodynamic lift. Space forces, like electronic warfare forces and mobility forces, support war fighters on land, on the sea, and in the air through all levels of conflict: low, mid, and high intensity. In addition, like air forces, space forces cannot be characterized as being solely strategic or tactical. Rather, space forces support multiple users and can simultaneously support strategic and tactical objectives. A good example of such support was the use of Defense Support Program satellites to provide theater/tactical warning during Operation Desert Storm while the satellites were also performing their strategic mission: attack assessment/warning of intercontinental ballistic missiles and submarine-launched ballistic missiles.

The first mission priority of Air Force space strategy, consistent with basic aerospace doctrine, is aerospace control. AFM 1-1 states that

aerospace control normally should be the first priority of aerospace forces. Aerospace control permits aerospace and surface forces to operate more effectively and denies these advantages to the enemy. As the degree of control increases, all aerospace and surface efforts gain effectiveness. Conversely, any reduction in control threatens every mission, campaign, and type of force. Control is an enabling means rather than an end in itself. . . .

Absolute control of the environment is the ideal aim of aerospace control operations. Airmen must be particularly aware that aerospace control is generally a matter of degree. Absolute control of the air (air supremacy) or of space [space supremacy] is not possible as long as the enemy possesses any aerospace forces capable of effective interference.(3)

Controlling the space environment involves ensuring access to space, defense of friendly space forces, and offensive actions to deny the enemy's use of its space forces. Forces can achieve space supremacy by conducting offensive counterspace operations or defensive counterspace operations. The objective of offensive counterspace operations is to disrupt, disable, or destroy the enemy's access and ability to operate in space. Forces can attain these objectives through such hard-kill means as the employment of an antisatellite interceptor or ground-based laser and also by employing such nontraditional means as jamming, blinding, or spoofing. The objectives of defensive counterspace operations include active defense of friendly satellites and passive defense measures, such as frequency hopping, hardening, and maneuvering that reduce vulnerability and increase survivability.

US space supremacy was the key to the tactical deception operations carried out during Operation Desert Storm. Iraq's lack of space reconnaissance and surveillance capability allowed allied terrestrial forces to maneuver undetected and achieve surprise, thus saving lives and accelerating the termination of hostilities. The US cannot achieve the same level of success against an enemy possessing space forces without first achieving and maintaining space supremacy.

After achieving space supremacy, space forces can enhance ground forces. The force enhancement value space forces contribute to terrestrial operations in peacetime and during conflict is difficult to measure. However, Operation Desert Storm demonstrated that space forces are essential to overall US force posturing. Desert Storm was the first major combat operation where space was integrated into operations.

Communication, navigation, weather, and space-based surveillance and warning satellites all supported theater forces and were directly responsible for the high degree of success achieved in combat. The lack of a communications infrastructure in Saudi Arabia forced ground commanders to use space-based communication assets (normally used for long-haul, intertheater communications) for intratheater communications. "Over 90 percent of all communication in theater was carried on satellite communications."(4)

Exaggerating the importance that the Global Positioning System (GPS) played in Desert Shield and Desert Storm is inconceivable. GPS, a space-based navigation system, provided ground forces, tactical air forces, and naval forces three-dimensional positional accuracy within 16 meters, velocity accuracy within 0.1 meters per second, and time accuracy to within 0.1 microsecond. In addition, GPS receivers are passive and do not emit a targetable signature like traditional navigation systems. Aircraft equipped with GPS receivers achieved great success finding targets and had greater bomb-on-target accuracies than platforms without GPS receivers. Ground forces were equipped with the GPS hand-held receiver. These receivers, small enough to fit in a trouser pocket, provided soldiers with an all-weather, day/night capability to find their way in terrain characterized by few landmarks. The hand-held receiver proved so versatile and indispensable that many were duct-tape mounted in vehicle panels and helicopter cockpits. At the conclusion of Desert Storm, in excess of ten thousand hand-held GPS receivers were in the theater. (See classified annex A for more information on GPS's role in Desert Storm.)

The Defense Meteorological Satellite Program (DMSP) also contributed significantly to combat operations during Desert Storm (see annex A). DMSP satellites and land- and sea-based transportable tactical ground terminals provided near-real-time infrared and high-resolution visual weather imagery of the area of operations. By providing current data on cloud cover and such atmospheric disturbances as dust storms, DMSP directly influenced target and weapon selection for interdiction sorties. In addition, the Army and Navy used DMSP data for planning aerial assaults and to warn ground and naval forces to "button up" during storms. The availability of DMSP prevented aborted sorties due to weather and saved lives and equipment.

Space Force Enhancement

While force support is concerned with what is to be done, how it is done, and where it needs to be done, force enhancement is concerned with the resources for multiplying combat effectiveness.(5) In the book, Making Strategy, Col Dennis Drew and Dr Donald Snow identified the need for strategists to achieve balance between technology and mass when developing forces. Drew and Snow offered several reasons underlying the problems associated with achieving balance:

First, it is difficult, if not impossible, to calculate what degree of technological sophistication (quality) offsets what amount of mass (quantity). . . . Second, technology changes rapidly and the military advantages it offers are almost always temporary. Third, new technology is not battle tested before one is forced to rely on it. Fourth, possession of superior technology is no guarantee that the technology will be employed effectively or, in fact, that it will be employed at all. . . . Finally, clever operational strategy can offset an advantage whether that advantage is in quality or quantity.(6)

The Commander in Chief United States Space Command (USCINCSPACE) Gen Donald J. Kutyna, in testimony before the Senate Armed Services Committee on 23 April 1991, identified several high-priority space systems needed to implement the current military space strategy. First, to achieve space supremacy, General Kutyna identified the need to develop an antisatellite system. "The need for an antisatellite capability is simple: deny the enemy use of space systems integral to warfighting capability."(7) The USCINCSPACE requirement to employ space forces for offensive counterspace activities is established in doctrine and supported by national space policy.

Second, existing tactical warning and attack assessment systems require improvements. As an increasing number of third world nations are acquiring tactical ballistic missile technology, the need for reliable and unambiguous warning is essential.(8) In addition, the USAF needs to continue upgrading command center processing and display systems and survivable integrated communications and to replace the Cheyenne Mountain Air Force Base Communications System Segment.(9)

Third, spacelift infrastructure, including lift vehicles and supporting facilities, requires upgrading. As the cornerstone of US space force enhancement capability (note that spacelift is defined as a force enhancement mission in AFM 1-1), existing spacelift capability is degraded by

capacity constraints at the lift operations support elements: limited resiliency for recovery from catastrophic failures; lack of flexibility caused by lift schedules driven primarily by hardware availability and long payload preparation timeliness; and today's high lift and integration costs.(10)

Fourth, the US needs the deployment of the Milstar communications system. As the major element of US war-fighting communications architecture, Milstar will provide antijam, interoperable communications and flexibility to adjust capacity in response to most operational requirements.(11)

Evolving Systems

This section provides an overview of satellite systems and launch vehicles to which General Kutyna referred. A few of the high-priority space systems needed in support of US military space strategy include space-based wide area surveillance (SBWAS) to provide warning information on global air and maritime threats; multispectral imagery to provide broad area change detection, terrain analysis, mapping support, and concealment information; Milstar to provide survivable communications for strategic and theater users; tactical satellites to augment existing space force structure quickly in crises or war; and the National Launch System to provide a robust capability to access space.(12) These emerging space systems will enhance strategic and tactical warfare.

Space-Based Wide Area Surveillance

Space-based wide area surveillance is a proposed space-based, near-real-time, all-weather global surveillance, target acquisition, and tracking system for Air Force, Navy, and Army war fighters. General Kutyna told the Senate Armed Services Committee that an effective space-based wide area surveillance system has the potential to revolutionize tactics and to deny an adversary the element of surprise.(13)

SBWAS would employ one or both of two basic sensor phenomenologies--radar or infrared (IR). The radar concept would use an array antenna; the IR system would have either a staring or scanning sensor.

The phased array radar concept uses radio-frequency energy radiated through an array of transmit/receive (T/R) modules distributed across the face of a planar antenna.(14) These modules allow phased arrays to instantaneously point the radar beam anywhere in its field of view. The drawbacks with a phased array system are the power requirements and the large number of electronic components required for a single antenna. Array integration and the number of T/R modules required pose significant challenges in cost and construction of a space-based system.

Infrared sensor concepts are promising because of their passive nature. The advantage of an IR sensor is its ability to provide better resolution through the use of small instantaneous fields of view. The primary disadvantage of IR is its susceptibility to degradation by weather.(15)

Regardless of the technology chosen for SBWAS, it has the potential to serve both strategic and tactical users. Strategic users of SBWAS data would be found at the level of data fusion centers, commanders in chief headquarters, carrier battle groups, and national decision makers. Tactical users of SBWAS data could be squadrons, wings, and battalions.

SBWAS data would include information on aircraft, ship, and ground target locations. The system would provide forward users longitude, latitude, azimuth, elevation, speed, direction, and classification type (i.e., aircraft, ship).(16) The SBWAS system is intended to allow users to task the satellite constellation, assure timely distribution of detection and track data, and provide survivable surveillance support during conflict. Multiple-user communication paths and ground site transportability will provide enhanced survivability against ground attacks.

Track data would be disseminated in near real time to decision nodes and data fusion centers. The timeliness and quality of this data are critical to operational commanders because such data maximizes warning time and increases options in military response.

Multispectral Imagery

Multispectral imagery (MSI) is not a new technology; the civilian community uses it to study the Earth's landmass and oceans. MSI systems collect multiple, discrete bands of digital electro-optical imagery in the visible and reflected/emitted infrared regions of the spectrum.(17) Current civil applications include estimate of nutrient content, identification of geologic structures, estimates of crop yields, location of transportation infrastructures, identification of pollution, and support of water management.

MSI data can provide terrain analysis, indicate surface conditions that can affect mobility, and provide tactically useful broad area surveillance as well as detailed image maps and charts useful to sustained ground campaigns. Combining MSI data with terrain elevation data allows aircrews to simulate flying a mission profile visually and choose optimum target approaches. Comparing MSI data of the same scene over time allows automated detection of changes in an area of interest. Combinations of visible and infrared imagery can make man-made efforts to conceal personnel and equipment stand out from the background.(18) MSI data was used extensively during the Gulf conflict, but future MSI systems will need to be enhanced to meet the Department of Defense's tactical requirements. (Classified annex A provides more information on the role of MSI during Desert Storm.)

Primarily, DOD uses two space sensors for MSI data, Landsat and Satellite pour L'Observation de la Terre (SPOT). The original Landsat was a civil satellite system managed by NASA, then by the Department of Commerce. The current Landsat program is an integrated NASA/DOD program. SPOT is a French civil MSI program that sells imagery data. The US used SPOT imagery extensively for tactical planning, map updates, and terrain analysis during the Gulf crisis because SPOT features finer resolution than Landsat. However, neither of these systems meet timeliness, accuracy, resolution, wide-area coverage, or responsiveness criteria for current US tactical requirements.(19)

Requirements to make MSI a more productive system for future air, land, and sea campaigns are improved spectral and spatial resolution, stereo imaging, and wide-area coverage.(20) If these requirements are met, MSI could play a major role in tactical decision making.

Milstar

The military, strategic, and tactical relay satellite (Milstar) is the next generation military satellite communications system designed to serve the nation's strategic and tactical forces. The system will provide a worldwide, highly jam-resistant, survivable, and enduring satellite communications capability. Its design meets the minimum essential command and control communications requirements of the national command authorities and armed forces well into the next century. Use of extremely high frequency (EHF) and other advanced techniques will enable the system to achieve a high degree of survivability under both electronic warfare and physical attack. Unlike systems dependent on lower frequencies, EHF satellite communications recover quickly from the scintillation caused by a high-altitude nuclear detonation.(21)

The Milstar system will serve the strategic needs of US nuclear-capable forces and the priority needs of mobile tactical forces.(22) Milstar has been specifically designed to overcome the shortfall characteristics of existing satellite communications systems. Concepts for survivability in a hostile space environment have shaped the design of this military communication system. Milstar will be the first major space-based communications effort using EHF technology (30 - 300 gigahertz) to overcome crowding and interference in other frequencies.(23)

The system will use a variety of new technologies, onboard signal processing, adaptive antennas, uplink nulling, steerable downlinks, and cross-links to provide satellite-to-satellite interconnectivity.(24) Milstar will be capable of both EHF and ultra high frequency (UHF) transmissions to take advantage of existing air- and ground-based terminals. The use of higher frequencies offers a number of advantages--assurance of reliable communications in a nuclear environment, minimal susceptibility to enemy jamming and eavesdropping, and the ability to achieve smaller secure beams with modest-sized antennas.(25) Milstar will be the first defense communication satellite system to use frequency hopping on the uplink to frustrate enemy eavesdropping and jamming. Additional protection against jammers will be obtained by using a phased-array antenna on the satellite that can minimize sensitivity in the direction of a jamming signal.(26)

The Milstar space segment will consist of a constellation of six satellites in a mixture of low- and high-inclination orbits. A low-inclination orbit would place the satellites in positions to cover the Atlantic, Pacific, and Indian Ocean areas and North and South America. Satellites in the high-inclination orbit would cover the polar regions, Europe, Africa, and western Asia.(27) Satellite-to-satellite cross-link capability will assure global coverage. The cross-link network will route the appropriate communication traffic from terminals in view of one satellite to another terminal located at other parts of the world not covered by that satellite's field of view.(28) The cross-link capability will provide near-real-time connectivity without extensive relay and circuit patching.

The Milstar space segment will serve priority users in all the services through a variety of ground terminals. Although each service manages a program to develop terminals suited to its unique operational needs, channelization and standardized signal formats will ensure system integrity and control.(29) Two requirements for these terminals are mobility and compatibility. Rapid movement of communication terminals to the operational area, rapid setup, and quick circuit configuration are essential for timely support of the initial stages of deployment.(30)

Ultra High Frequency Follow-On

The Ultra High Frequency Follow-on (UFO) Satellite Program will provide communications for airborne, ship, submarine, and ground forces. The UFO constellation will replace the current Fleet Satellite Communications System (FLTSATCOM) constellation and will consist of eight satellites and one on-orbit spare. The ground terminal segment will consist of equipment and resident personnel at existing satellite communication stations.(31)

Its UHF satellites will primarily serve tactical users. UFO will provide almost twice as many channels as FLTSATCOM and has about 10 percent more power per channel.(32) The EHF package on satellites four through nine will have an Earth coverage beam and a steerable five-degree spot beam that enhances its tactical use. The EHF capability also allows the UFO network to connect to the strategic Milstar system.

First launch of the UFO is scheduled for the near future, with constellation completion dependent on replacement needs for the aging FLTSATCOM constellation. The Atlas II is the current launch vehicle of choice; however, space shuttle compatibility will exist. The UFO bus and payload will weigh 2,300 pounds. The solar array spans 60.5 feet and will produce 2,500 watts at the end of the planned 14-year lifetime.

Tactical Satellites

Tactical satellites (tacsat) are an initiative to provide responsive and dedicated space-based, space combat support to the combatant commander. Concerns about availability of existing satellite to tactical commanders in an emergency and the ability to reconstitute satellite services in a conflict drive this concept. Tacsats would be a family of satellite systems designed to provide essential surveillance, warning, reconnaissance, communications, environment, and airspace control information.(33)

The tacsats are intended to provide an alternative to complex multimission space systems. Current plans include design features that would use standard interfaces to provide mission flexibility, responsive launch, simplified support, common training, and lower cost. The system would either launch on schedule or demand, using responsive vehicles or prepositioned assets in orbit.(34) Built for simplicity, tacsats do not carry the redundant systems necessary to keep conventional satellites operational.(35) They do not need these redundancies because less is expected of them in terms of mission and lifespan.

Tacsats would be smaller than conventional satellites by design (500 to 1,500 pounds in weight and only 38 inches in diameter). The smaller, simplified systems would cost less and could be readily produced. With few exceptions, the long development cycle time between requirement identification and launch date for advanced systems limits US ability to react quickly to fast-changing or newly emerging threat situations. Small, less complex space vehicles produced at lower costs would allow the US the ability to deploy quickly against specific threats.

The Air Force currently tailors constellations of large space vehicles for coverage of selected geographic areas based upon historical requirements. Thus, a change in coverage is at the expense of other geographic areas. Tacsats could fill geographic gaps for selected theaters of operation or other areas of interest. Using tacsats could not only provide dedicated battlefield support in wartime but also could help to reduce tasking conflicts for larger assets required for higher priority actions.

The current force structure emphasizes large multipurpose satellites which serve many users. Tacsats could give users who require dedicated support a space asset totally responsive to their needs. The use of these small satellites strategically planned in advance could also offer additional surge capability in time of war.

A benefit of tacsats is the relative ease with which boosters can place them in orbit. For example, Pegasus (an air-launched vehicle that can be strapped onto a B-52 or other aircraft and can boost approximately 400-700 pounds to low-Earth orbit(36)) could launch the lighter tactical satellite. This launch tool would give the theater or component commander the flexibility and responsiveness needed in a low-intensity conflict. The air-launched booster also offers more survivable access to space.

Tacsats could also augment the Defense Satellite Communications System and the future Milstar system. Desert Storm is a prime example of a situation in which tactical communications satellites could serve a significant role as a force multiplier.

The US Defense Advanced Research Projects Agency (DARPA) is the lead organization for tacsat experimentation. DARPA hopes to demonstrate a quick-reaction space capability for operational forces, learn about operational constraints and utility of small satellites, and establish baseline parameters for future small satellite systems.(37) Tacsats would provide a capability to reconstitute and augment space systems during a period of high attrition and crisis situations. A tacsat system would give payload control to component commanders, allowing them to allocate system capability commensurate with the tactical situation.

National Launch System

In April 1991 the president's National Space Council (NSpC) directed a joint DOD/NASA program to develop and procure a family of launch vehicles and supporting infrastructure to meet civil, commercial, and national security needs. The national launch system (NLS) effort is aimed at providing NASA and DOD with a capability to deliver a wide range of payloads to low-Earth orbit at a low cost and with improved reliability.

Gen John L. Piotrowski, commander in chief United States Space Command, described the US military launch infrastructure as lacking characteristics key to other military forces: combat readiness, sustainability, and force structure.(38) In recent years, a series of unfortunate events highlighted the fragile nature of the US launch infrastructure (the Challenger tragedy and the explosion at a solid motor propellant plant that destroyed more than half the nation's space and tactical missile propellant production capability).(39) As a result of these problems, the NSpC outlined a national recovery plan. This plan rejects sole dependence on the shuttle for access to space and places emphasis on basic technology by calling for designing and building a new booster to meet the needs of US launch activities. This new booster will have to be cost-effective and efficient for peacetime launch, as well as survivable and responsive to the needs of combat forces.

The NLS is aimed at achieving a reliability of 98 percent or higher with a launch-on-schedule probability of at least 95 percent, vehicle availability of 90 percent or better, a 30 day or less launch response time, and a surge capability that will accommodate seven payloads within a five-day period.(40) The NLS family of launch vehicles is based upon a set of common building blocks that can combine into different vehicles. The Air Force is currently reviewing three vehicle specifications (fig. 11). Designing common modules and using existing launch system elements will minimize NLS costs. The modules will be usable on different vehicles in the family without changing subsystems or redoing major qualification tests. This feature lowers production and operation costs. High-value avionics, control subsystems, and the main engines are integrated into a propulsion module that represents the large majority of the launch vehicle's total cost. This module also allows recovery and reuse of the high-cost hardware.

To achieve NLS cost, operational flexibility, responsiveness, and reliability goals, contractors are looking closely at both the technology and process involved in launch vehicles.(41) Area contractors are reviewing on-site assembly of vehicles, launchpads (repairs and numbers), automation of vehicle/payload integration, adaptive guidance and control systems, and ground flow operations and analysis.(42)

On-site assembly of vehicles before they are positioned on a launchpad would reduce pad time, enable a multiprocessing capability, and facilitate the exploitation of built-in autonomous testing and processing.(43) Months of final assembly and payload integration, all done on pad, inhibit rapid response to operational requirements.

Prelaunch preparation and postlaunch refurbishment time requirements dictate a large number of pads. Adding flexibility to launch scheduling and allowing faster launch responsiveness in a crisis requires more launchpads and simplified launch structures. Pad redundancy would alleviate the risk of being denied access to space for certain payload/booster combinations and cover a launch catastrophe that could disable a pad for months.

Launch vehicle processing has historically employed large numbers of analysts for data monitoring, diagnostic interpretation, maintenance repair, mission planning, and real-time problem solving. The entire process of booster and payload testing, processing, and launch is lengthy, manpower intensive, and inflexible. An automated monitoring and testing system that can calibrate, process, store, and notify the user of which subsystem has failed and needs replacement could reduce the lengthy integration process time considerably.

Building in more software sophistication for launch guidance and control systems would enable a vehicle to adapt to changes it senses in flight without human intervention. In addition, design of a redundant, multistring guidance and control package using lower cost components would reduce the expense associated with the current single string guidance package, which requires tightly screened electronic components.(44)

Low-cost ground operations require an automated system to document and manage ground operations, monitor health status, and perform fault isolation down to the lowest repairable unit. A set of automated test hardware embedded within the vehicle would be needed. The goal would be to develop systems that allow subsystem monitoring and diagnostics on a continuous basis and subsequent unit replacement with minimal time lost.

The long-term goal as seen by military leaders is to develop a launch system designed to function under an operational commander and responsive to operational requirements. Assured access to space has become an essential element of national security. Access to space through all levels of conflict is a must as it will contribute directly to US ability to deter war and to provide its forces with the support they need to resolve armed conflict on favorable terms.

National Aerospace Plane

The objective of the national aerospace plane (NASP), or X-30 program, is to develop and demonstrate the technology for hypersonic-to-orbital flight vehicles that have technical, cost, and operational advantages over existing military and commercial aircraft and space launch systems.(45) Development of hypersonic-to-orbital velocity test equipment, new materials and fabrication methods, and advanced combustion technology is a major technological challenge.(46)

Five prime contractors, represented by a national program office and the government-led USAF/NASA/Navy joint program offices at Wright-Patterson AFB, Ohio, are leading the NASP effort. Designers plan for the X-30 to demonstrate sustained hypersonic cruise at velocities of Mach 5 to 14 at altitudes between 80,000 and 150,000 feet.(47) It also is to demonstrate single stage to orbit speeds of Mach 25. Designers expect propulsion for the vehicle to be provided by three to five supersonic combustion ramjet (scramjet) engines and by a single 50,000- to 70,000-pound thrust rocket integrated into the airframe.(48) Early reports depict four different types of engines working together to get the plane rolling and up to hypersonic-orbital velocity. The craft will rely on turbojets, which use a spinning turbine to draw air into a combustion chamber and compress it, to reach Mach 2. At that speed, air is rushing into the engine so fast that it compresses itself, and the turbine's blades become a hindrance. The turbojets will shut down, and ramjets kick in. Ramjets work like turbojets except they have no blades. The front of the ramjet simply gulps in air, and the high speed of the plane helps squeeze a maximum amount of air into the combustion chamber, compensating for the lower oxygen levels found at higher altitudes. The ramjets will operate until the plane reaches between Mach 6 and 8 when scramjets take over. The scramjets will carry the plane to Mach 20 and lift it to the edge of space. At that nearly airless altitude, hydrogen-fueled rocket engines will push the plane to Mach 25 and send it into orbit.(49)

More innovative than the space plane's engine scheme will be its skin. With the space plane, temperatures will rise not only when the plane is coming down but also when it is going up. The heating is due to the plane's speed and the trajectory it will follow during its climb. The NASP program has been a catalyst for significant advances in metal and metal-matrix technologies. The objective of the materials work by the NASP contractors is to reduce the X-30's weight as much as possible to cut the amount of fuel and thrust required by the engines in addition to solving the heat management problems.

In October 1990 the NASP program selected the lifting body design because it provides propulsion advantages over a winged aircraft. The directionally stable lifting body incorporates short wings, dual stabilizers, and a two-man, dorsal crew compartment.(50) The plane will probably be 150 to 200 feet long and have a wingspan of about 50 feet.(51) The formal teaming of the contractors and selection of a single design will allow program resources to be concentrated and technical problems and solutions to be more sharply defined.

The focus of the program is to get to orbit using a single-stage vehicle and to stretch the limits of air-breathing propulsion technology. NASP is a stimulus to new technology and can provide space launch flexibility and cheaper access to space. The fundamental barrier to reducing the costs of space launch with rockets is technical--the need to carry both fuel and oxygen. Development of NASP can lighten this inescapable weight burden and associated cost per pound.

Single Stage to Orbit

The single stage to orbit (SSTO) program basically has the same objectives as the NASP program--to develop a cheap and reliable spacecraft that will have widespread military, commercial, and scientific applications. SSTO differs from NASP in that it is a vertical takeoff and landing orbiter. The benefits of SSTO also mirror that of NASP: recoverable, reusable, low cost, and flexible as to its launch capability.

Many technologies critical to the development of this single stage vehicle (known as the Delta Clipper) have been derived from the related national aerospace plane and the national launch system programs. Research and development of lightweight composite aeroshell structures, fabrication of modular reusable engines, and manufacturing knowledge for graphite-epoxy composite cryogenic fuel tanks are available for use on the Delta Clipper project.(52)

Designed to meet the requirements of a broad set of commercial and military missions, the Delta Clipper offers a path to vastly improved space transportation where rocket performance combines with routine airline safety and reliability. The ship has the capability for vertical takeoff and landing, for which operational feasibility has already been demonstrated both on Earth and the Moon.(53) It would launch like an everyday expendable launch vehicle and land like a lunar module. Navigation and guidance would be accomplished via global positioning satellites.

The vehicle would be able to operate independently of complex launch ranges and mission controls, as it can launch on demand from any base and in any direction. Vehicle and ground servicing techniques are derived from those used for commercial aircraft. Automated ground flight operations would reduce the number of support personnel needed and associated costs.

The planned versatility of the spacecraft is impressive. The spacecraft could operate with or without a crew. It will launch with an acceleration of 1.3g, far less than the 3g force astronauts experience on the shuttle.(54) The Delta Clipper could remain in orbit for missions lasting seven to 14 days and with on-orbit fueling could serve as a transfer vehicle to geostationary orbit. The craft reenters the atmosphere nose first, then rotates for a vertical landing (fig. 12). In powered descent, half the engines operate at 20 percent power, while the others remain in reserve for contingencies.(55)

Congress has approved funding for a one-third scale model flight demonstration scheduled in 1993. A full-scale Delta Clipper is scheduled to make a first orbital flight by the late summer of 1996. The full-scale spacecraft will be 127 feet high, have a gross weight of just over one million pounds, and a payload capacity of 10,000 pounds.(56)

Global Protection against Limited Strikes

The Strategic Defense Initiative Organization is acquiring and managing the global protection against limited strikes (GPALS) system. GPALS consists of multilayered ground and space-based sensors and weapons that will provide the capabilities for global surveillance and destruction of ballistic missiles.

GPALS is comprised of three segments: theater missile defense, national missile defense, and global missile defense. These segments and the GPALS architecture are discussed in chapter 3. In operation, GPALS will give the US and allied nations high-confidence protection against limited ballistic missile attacks, including accidental or unauthorized launches from any source.

The role of space in future conflicts will be limited only by failures to develop new technologies and enhancements to current space systems and to provide access to war fighters. Space and launch systems of tomorrow must focus on requirements to provide improved tactical warning and attack assessment. Upgrades to the ground- and space- based surveillance assets, improved launch capacity, support needs, flexibility, and responsiveness of space systems are a necessity to ensure continued support of US air, land, sea, and space forces.