Access to space

Acta Astronauticu Vol. 39. No. 7. pp. 537-552. 1996

Published by ElsevierScience Ltd. All rights reserved Printed in Great Britain 0094-5765/96 $15.00+0.00 PII: SOO!W5765(%)00004-S

ACCESS TO SPACE? IVAN BEKEY NASA Headquarters, Washington, DC 20546, U.S.A. (Received

25 May

1995)

Abstract-This paper reviews a NASA study on Access to Space, as well as a U.S. Department of Defense report, “The Space Launch Modernization Study”, both from 1994. Space transportation policy is discussed, while the nation’s current and future options are examined and compared. Published by Elsevier Science Ltd

1. INTRODUCTION It was only 36 years ago that the true space age began, with the historic launch of the first satellite by the Soviet Union. Since then, dramatic progress has been made in the frequency, size, complexity, and uses of spacecraft for both cargo and human missions, to the point that now many countries routinely depend on space applications for both military and civilian and scientific uses. The U.S. orbits almost 800,000 pounds annually, while the rest of the world more than doubles that. Operations in space are becoming commonplace and no longer front page news, and many activities, particularly communications, are unimaginable without using space. In light of this background, it is surprising that rocket launch vehicles, the sole means of accessing space, are still extremely delicate, expensive, and cumbersome operations compared to those of commercial aircraft. Space launch vehicles have achieved neither the low cost, high reliability, nor routine simplicity which characterizes operation of the world’s fleets of aircraft. Part of the reason is the use of expendable or partially reusable vehicles with multiple stages, and the other is the complex, one time operation required to ready a complicated vehicle for a do-or-die flight. Thus the cost of the hardware which is thrown away dominates the launch cost, and the cost of the people for the assembly and launch operations follow. As a result, the average cost of launching a space payload into low orbit is about 6000 $/lb, which is about 1000 times more than the comparable cost of an aircraft flight; the reliability is at best 0.999 compared to 1000 times greater per flight reliability of aircraft; the time

tPaper IAF-94, V. I .5 I5 presented at the 45th Inrernational Asrronautical Congress, Jerusalem, Israel, 9-14 October 1994.

required to ready a vehicle is counted in weeks or months as compared to the few hours it takes for an airliner. It is eminently clear that neither commercial nor government use of space will greatly expand until the above conditions change substantially. Both the Defense Department and NASA performed sweeping assessments of the space launch situation within the last year, with intent to identify a preferred course of action to make major changes in space launch. Another major factor for this study’s focus was that NASA, together with the Department of Defense (DOD) and the aerospace industry, had spent nearly a decade defining and advocating a new expendable launch vehicle program (which culminated in the proposed National Launch System), without being able to reach consensus with the Congress that it should be developed. Yet another factor was the continued erosion of the international market share for U.S. launch vehicles. This market share has dropped from 100% to about 30%, largely due to the development and fielding of the French-built Ariane system, which targeted and captured at least 50% of the world’s space launch market. U.S. industry has found it increasingly difficult to effectively compete using the current generation of launch vehicles. The “Access to Space” study was performed by NASA and documented in January 1994. The “Space Launch Modernization Study” was performed by the DOD and documented in April 1994. Following the completion of these studies, the White House Office of Science and Technology Policy prepared a new Space Transportation Policy based in part on the results of the two studies with the aid of an interagency team, which was documented by a policy statement signed by the President and issued in August 1994. Following these studies, NASA and the DOD had both begun planning to implement the studies’ 537

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findings once the new space transportation policy became a reality. NASA now has a technology maturation and demonstration program underway for reusable next-generation launch systems, while the DOD is pursuing technology and evolutionary improvements to the current fleet of expendable launch vehicles The main body of the paper will therefore discuss the two studies, the space policy, and the implementation of the technology maturation and demonstration plan by NASA. These activities will be described in more depth in the following pages. 2. NASA ACCESS TO SPACE STUDY

As a result of the above factors and trends, as well as a specific Congressional request, a comprehensive in-house study was undertaken by NASA to identify and assess the major alternatives for a long-range direction for space transportation. The scope of the study was to support all U.S. needs for space transportation-including civilian, commercial, and defense needs-for several decades into the future. The purpose of the study thus focused on identifying long-term improvements leading to space transportation architectures that would result in reducing the annual cost of operations by at least 50%, increase the safety of flight crews by an order of magnitude, and improve overall system operability (turnaround time, schedule dependability, robustness, pad time, and the like). The study horizon was set at the year 2030. The study began by recognizing that the Space Shuttle and expendable launch vehicles represent a very large investment in vehicles and supporting infrastructure. It was recognized that the replacement of this capability by any new vehicle or vehicles designed to overcome some of the above shortcomings was likely to be a very expensive and lengthy process. Thus a number of alternative approaches were identified which differ in the degree of replacement of current capability, and in the pace at which current systems are phased over.

Three major alternative

options

were defined:

Provide necessary upgrades to continue primary reliance on the Space Shuttle and the current expendable launch vehicle fleet through 2030. Develop a new expendable launch system utilizing today’s state of the art technology, and transition from the Space Shuttle and today’s ELVs starting in 2005. Develop a new reusable advanced technology next-generation launch system, and transition from the Space Shuttle and today’s ELVs starting in 2008-2010. Each of the options was to treat the entire architecture of launch vehicles required, and each was analysed by a separate study team working independently of the others. Common goals were established, and evaluation criteria were developed based on the goals. These included performance and cost goals, operability, growth potential, environmental suitability, and others. The best designs that survived elimination within the three option design teams were to be assessed against these criteria, and a preferred architecture was to be selected from them. An implementation plan and recommended actions were to be the final output of the study. A number of study ground rules were established. Since the Space Station redesign was still in progress, the Space Station Freedom design was assumed to still be in effect but placed into the MIR orbit: 220 nmi. altitude circular at 5 I .6 degrees inclination (this orbit was later selected for its redesigned space station by NASA). A common mission model was defined which included all U.S. user elements, defense, civilian, and commercial covering the period 1995-2030. This model was based on conservative extrapolation of current requirements and planned programs, and did not include major future possibilities such as manned Lunar or Mars missions. The mission model is shown in Fig. I. For lack of solid forecasts

Fig. I. Annual launch demand mission model from 1995 to 2030.

Access to Space

of future traffic, the model was assumed constant through 2030. It was recognized that such a flat model was unlikely to endure over the long term, and that excursions would eventually have to be treated as better models became available, as manned exploration or other ambitious missions became better focused, or hopefully if future reduced costs of access to space would generate additional market demand. Uniform costing guidelines were developed using conventional weight-based estimating algorithms so as to allow direct comparison of all alternatives. Innovative and potentially lower cost strategies based on major management, contracting, and operating changes were treated as excursions in the study. Though commercial traffic estimates of the mission model were to be used for fleet sizing and a basis for estimating the production base, the cost projections of the options included only government missions, as the principal study aim was to reduce costs to the government. 2.1. Option 1 The Option 1 (current systems) team’s alternatives consisted of three degrees of increasing modification of the Space Shuttle System, with the ELV fleet remaining essentially unchanged. The first alternative, labelled “retrofit”, considered only evolutionary

Fig. 2. Retrofit

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subsystem improvements in the Shuttle and particularly the Orbiter to increase operability. Typical of these would be improved main engine controllers, longer life fuel cells, new computtrs, etc. These improvements were to be retrofitted to the existing fleet of Orbiters. Replacement Orbiters would be procured.only if needed due to attrition. The second major alternative considered larger scale modifications to the Shuttle Orbiters, but without changing their exterior mold line; and building new Orbiters with these changes to replace the entire fleet. For this reason it was labelled “new build”. Typical of these changes is the replacement of the Orbital Maneuvering System, which currently uses hypergolic propellants, with an oxygen-ethanol system which is non-toxic and permits improved ground operations. The third alternative considered more radical Shuttle changes which did not necessarily maintain the outer mold line of the Orbiter, and also replaced the entire fleet. These included liquid boosters, flyback boosters, and other large scale changes with associated large impact and costs. Early in the study, the first two alternatives were selected by the team for further analysis, based principally on the likely extremely large costs of the third. The major subsystem changes for the first alternative are identified in Fig. 2.

alternative.

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2.2. Option 2 The Option 2 (new conventional-technology vehicles) team analysed 84 different new launch vehicle configurations, including all significant combinations of number of stages, engines, propellant types, means of accommodating cargo and crews, and other variables. A very methodical process was used to winnow down to four major architectural alternatives, which are illustrated in Fig. 3. The first architecture. labelled 2A’. kept the Delta and Atlas vehicles and replaced the Shuttle and Titan with a new partially reusable vehicle. This vehicle would have a cargo carrier with automated rendezvous and docking capability for Space Station resupply and general payload launching, and a small lifting body vehicle for human cargo. This architecture had a limited capability to return mass from the Space Station, but minimized the size and number of new launch vehicles needed. The second architecture, labelled 2B, differed in three major respects: the Atlas was replaced by a new vehicle with 20 klb payload capability, a 70% scale Orbiter and new cargo carrier were used for crew and cargo on variants of a new vehicle to replace Shuttle and Titan, and all vehicles were expendable. This architecture was able to return all mass taken to the Space Station in the scaled Orbiter, and lower the Atlas class missions cost, However, it resulted in large and costly new vehicles and scaled Orbiters.

The third and fourth architectures, labelled 2C and 2D, are similar in that new expendable vehicles were developed to replace the Space Shuttle, Titan, and Atlas; and separate small lifting body crew carriers and cargo carriers were developed for both. The crew and cargo carriers are the same for both alternatives. Their principal difference is that alternative 2C used developmental hybrid boosters and STME engines, whereas architecture 2D used the Russian RD 180 and the US J2S engines. 2.3. Option 3 The Option 3 (new advanced technology vehicles) team determined at the outset that attaining the lowest operating costs would be dependent on full reusability and, thus, they analysed three alternative fully reusable vehicles, each incorporating advanced technology. The first alternative analysed was a single-stage-toorbit rocket-propelled vehicle. Two variant architectures were treated within this alternative; one in which the new vehicle was augmented by ELVs and the other in which the new vehicle replaced all others and was used to launch all missions in the model. The second alternative was a single-stage-to-orbit vehicle using airbreathing and rocket propulsion. It also replaced all other vehicles, launching all missions. The third alternative was a two-stage vehicle in which the first stage was an airbreather and

on Low CcGAow Risk

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Fig. 3. Option 2 architecture overview.

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the second stage was a rocket, with supersonic staging. This alternative also replaced all vehicles, launching all missions. The vehicles in the alternatives that used airbreathing propulsion took off and landed horizontally, while the rocket vehicle alternatives used vertical takeoff and horizontal landing. These alternatives are conceptually illustrated in Fig. 4. This figure shows the vehicles in profile compared to that of the Space Shuttle, included for a portrayal of scale of the new vehicles. Each of these vehicles was sized to launch 25 klb to a 220 nmi. altitude 51.6 deg. inclination orbit, the anticipated new space station orbit. The performance of these vehicles to a standard 100 nmi. altitude circular orbit with inclination of 28.5 degrees is larger, but differs among the vehicles, and is indicated in Fig. 4. 3. OPTION

TEAM DOWNSELECTS

The option teams analysed their alternative architectures, and then downselected to recommend an architectural alternative. These recommendations are contained in the shaded areas in Fig. 5. The Option 1 team downselected to the “retrofit” alternative as having the lowest DDT + E cost while enabling about as much operations cost savings as their other alternatives. The Option 2 team downselected to the 2D architecture principally because it did not require new engine development,

had low life cycle costs, and had the lowest operations costs for the Atlas class missions which have high commercial interest. The Option 3 team downselected to an all-rocket SST0 vehicle over airbreathers on the basis that it had the lowest DDT + E costs and required the least demanding technology. Two versions of the SST0 rockets were recommended. The first had a payload bay 15 ft diameter and 30 ft long which could not accommodate the largest of the Titan class missions. This architecture thus required continuation of the Titan ELVs in parallel with the new vehicle operations. A second version of the SST0 rocket vehicle had a 45 ft long payload bay, which could accommodate all payloads with some downsizing, and thus would not require continuation of the ELVs as part of the architecture. This version was included because of the high costs of the Titan ELV. Both the Option 2 and 3 teams recommended a completely different operations concept than is in use today as the key to attaining low operations costs. They also recommended avoiding development of technology in parallel with system development in order to minimize development risks and thus costs. Development of operations-oriented technologies was considered absolutely vital. Specific recommendations included: using well-matured technologies, demonstrated through a number of flights of an experimental rocket; demonstration and validation of vehicle design via flights of a full scale

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Retrofit: Eva&t&nary improvements. Keep the eunent ELV fleet. New Build:Above changes plus major internal mods; new orbiter. Keepthe current ELV fleet.

l

Two-stage-to-orbit

Fig. 5. Architectural alternatives proposed by the teams

prototype, with gradual stretching of the flight envelope; certification of the vehicle design and type-certification of the fleet; avoiding most detail inspection and maintenance after each flight unless the need is clearly indicated by an on-board health monitoring system; operating the SST0 fleet using a depot maintenance philosophy in which maintenance is only done by exception or every l-2 years; use of small, dedicated ground crews, empowered to make all decisions; a reduced ratio of non-touch to touch labor, and much use of automation on the ground as well as in the vehicle. In the aggregate these amount to a complete change in the way vehicles are developed and operated compared to current practice. This “new way of doing business” was identified as being essential if low operating costs were to be realized.

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4. COMPARATIVE ANALYSIS The downselected concepts and architectures were then compared so that a decision could be made on the most attractive option. The major factors considered in the evaluation were DDT + E cost, operations costs, life-cycle costs, and the safety and reliability of the concepts. These and other factors followed the major evaluation criteria identified earlier. The cost profiles for the recommended architectures of each option are shown in Fig. 6. These curves are referenced to a “current systems” line, which represents the annual cost to the U.S. government of launching the mission model of Fig. I. In 1995 this cost will be comprised of $3.8 B for the Space Shuttle, $2.4 B for the DOD ELVs and infrastructure, and

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Access to Space $500 M for the NASA ELVs, totalling $6.7 B. This reference varies somewhat with the ELV annual buys and programmed Shuttle management improvements, and is frozen after 2000. The life cycle cost of this activity, that is if nothing is changed, is $233 B through 2030. The Option 1 architecture invested $2.4 B DDT + E, but realized savings in operations costs of only about 0.25 B per year. Its life-cycle costs were $230 B. Option 2 invested $11.1 B DDT + E with an immediate start of the new vehicle development, but then rapidly reduced the operating costs to $4 B annually after the new vehicle was introduced in 2005. Its life-cycle costs were $192 B. Option 3 invested about $18 B DDT + E, with the start of the development program delayed by about 5 years to allow for a technology maturation and demonstration phase. Option 3 had two cost profiles after development, the top one (3A) being for the vehicle with the shorter payload bay which required continuation of the Titan IV ELV in parallel, and the lower one (3B) which did not require ELVs. Their life-cycle costs were S 198 B and $169 B, respectively. The annual operating costs were $2.6 B and $1.4 B per year respectively, attained in steady state after about 2015-2020. This long time is due to the production of the fleet of vehicles and anticipated spares, which was stretched in this study to minimize peak funding needs.

costs

The study teams estimated that the above cost numbers might be significantly reduced, perhaps by as much as 30-40%, by adopting new management and operations concepts. In addition, Options 2 and 3 included development of new upper stages for traffic going beyond LEO. Their development and production costs were included in the above projections. The most significant numerical costs of the three options, and some associated metrics, are shown in Fig. 7. The costs displayed are those for the technology needed, the DDT + E, the production of one time or reusable hardware, the annual operations costs in the out-years, and the life-cycle costs. It is seen that the fleet-average launch costs for the mission model were reduced from the current values of 7488 $/lb to 6814 $/lb for Option 1, 6100 $/lb for Option 2, $3900 $/lb for Option 3A, and to 2100 %/lb for Option 3B. The lowest cost per pound of payload for fully loaded new vehicles launching into 28 degree inclination low orbit were 920 and 980 $/lb for the two Option 3 cases. Next highest were the 1600 $/lb-3900 $/lb for the two different-sized vehicles in Option 2. The costs for Option 1 were 6234 $/lb for the Shuttle, computed by the method historically presented to OMB and GAO. While all were lower than the 6850 $/lb for the current Shuttle program when computed the same way, it is clear that major cost savings only accrue in architectures employing new vehicles.

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It is evident from examination of the cost results that very large annual cost savings were possible, but they could only be attained by considerable up-front investment-the larger the investment, the larger the operations cost savings. There was also a recognition that the new vehicles had greater cost and schedule risk, and that this risk increased in proportion to the cost savings they would enable. An additional factor assessed was the inability of the selected Option 2 architecture to return all the mass taken to the Space Station, returning only approximately 20%. This was a conscious choice made in order to minimize new vehicle size and therefore cost. The cost of the expended Space Station carriers and racks resulting from this choice were accounted for in the operations cost analysis. Finally the operability enhancements were assessed. Option 1 improved the Shuttle operability significantly, but that of the companion ELVs was unchanged. All the new vehicles of Options 2 and 3 had designs, infrastructures, and operations concepts that resulted in robust and operable systems and associated significant reductions in operations costs. The cost summarization shows that Option I did not approach the 50% cost savings goal; Option 2 approached it though it did not meet the goal; and both Option 3 alternatives exceeded that goal. Option 3B, in which all ELVs were phased out, greatly exceeded the cost reduction goal, but entailed higher risk.

5. OBSERVATIONS

2.

3

4.

AND CONCLUSIONS

Assessment of the characteristics, performance, and costs of the study teams’ recommended architectures, vehicles, and operations concepts led to a number of major observations and conclusions. 1. It was determined that it is possible to achieve large reductions of operations costs and increases in crew safety. It did not appear that the Space Shuttle could achieve these goals in a cost-effective manner, though a number of beneficial improvements of the Shuttle system were identified. New vehicles were required in the architectures to attain the major study objectives. These vehicles could use either conventional or advanced technology with the conventional technology vehicles approaching the 50% desired minimum operations cost reduction (40% reduction), and the advanced technology vehicles greatly exceeding it (up to 80% reduction). Both current and new technology vehicles achieved this operating cost reduction only after a sizable R + D budget investment. This significant R -t D investment was smaller but

5.

6.

immediate for the Option 2 architecture using current technology new launch vehicles. Annual operations costs were the lowest for advanced technology vehicles in architectures which minimized carryover of current generation launchers. The achievement of these low operating costs was completely dependent on making large scale changes in the way vehicles are designed, developed, managed, contracted, and operated. It was concluded that these designs must all be driven by operations rather than by performance, and would entail major changes in launch infrastructure and operations “culture”. In view of the above, an architecture featuring a new advanced technology single-stage-to-orbit (SSTO) rocket launch vehicle was recommended as the most attractive option because it had the greatest potential for reducing annual operations costs, it would develop important new technologies and next generation launch systems, and would greatly enhance future U.S. industrial competitiveness. The alternative in which the vehicle is sized so as to accommodate all payloads in the mission model was preferred, so as to avoid the need to carry current Titan ELVs in parallel. The pertinent technologies required for the new SST0 rocket vehicles would have to be matured and demonstrated before initiating development of the new vehicle in order to avoid a very high risk program. Once matured and demonstrated at the subsystem/system level in the pertinent environment, the risk would become manageable. These technologies include graphite-composite reusable structures, aluminum-lithium and graphite-composite reusable cryogenic propellant tanks, tripropellant or lox-hydrogen engines designed for robustness and operability, low-maintenance thermal protection systems, autonomous flight control, vehicle health monitoring, and a number of operations-enhancing technologies. These technologies would have to be demonstrated on the ground and through numerous flights of an experimental rocket vehicle. Technologies that interact should be tested together. Many of the technologies developed to support a new launch vehicle could also be applied to improve the operability and potentially the cost of the current generation expendable launch vehicle fleet and the Space Shuttle until such time as the new vehicles became available to phase in. Even though improvements for the Space Shuttle were identified, and new vehicle designs were conceived that potentially could improve its cost and safety, it was clear that the

Access to Space Space Shuttle remains the world’s most reliable launcher and it is safe to fly until a next generation system becomes available. 6. DOD SPACE

LAUNCH

MODERNIZATION

STUDY

The DOD study was undertaken for similar reasons as the NASA study, but understandable emphasis on the specific needs of national security space applications. This study was also undertaken to meet all U.S. national needs, including defense, intelligence, civil, and commercial uses of space. The study also began by reviewing the status of space launch, coming to similar conclusions as to major deficiencies, which were well documented in summary form. The major conclusions of this phase were that significant problems exist in today’s systems; that systems designs and the phase of the program determine their operability, with the Titan system still in its development phase; the ELVs will exhibit marginal return on operations investments; and that the current manned and unmanned systems and infrastructure must be maintained through modernization transition. It was recognized that the freedom to pursue those actions is circumscribed by a number of factors, including: the existence of different space sectors, each with different missions; many stakeholders with differing objectives declining and zero-sum govemment budgets; the “tyranny” of the customers as to payload timing, size, and character; availability of technology; existence of too many providers, with the traditional providers unlikely to fund modernization; the dominance of government market demand, but with decreasing launch rates; the inadequacy of the commercial medium-class market to support a near-term solution; limited technology investments of the past two decades; the long time for investments to bear fruit; and the changes in the world order that have resulted in new opportunities for international cooperation. In light of this background, the study undertook to define and evaluate four major options. These were: I. Ontion 1: Baseline. Sustain the current systems. with budgets as defined in the President’s FY95 budget request 2. Option 2: System evolution, with a development budget of $1-2.5 billion (FY94) 3. Option 3: “Clean sheet” ELV, with two sub-options: 3A-Cargo only, with development budget of $5-8 billion and humans, development 3B-Cargo budget $10-14 billion 4. Option 4: Reusable vehicle, with budget of $6-20 billion The initial study intent was to select the most attractive option, however, at the end, no option was

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chosen and the ensemble of choices was presented. Collectively, they represent program “building blocks” from which separate roadmaps were developed. The options generally correlate with those in the DOD Bottom-Up Review and NASA’s Access to Space Study. The individual options describe a range of approaches and costs, not point designs. They were based upon compilations of contractor or system program office estimates plus a management factor applied by the Study Group. Costs are presented to provide relative comparisons between options. In addition to developing the program options, the Study Group defined an enhanced core technology program and examined continued space launch infrastructure sustainment and modernization. 6.1. Option descriptions 6.1.1.

Option 1: Sustain existing launch systems.

Option 1 maintains the current fleet of launch systems-Delta, Atlas, Titan, and the Space Shuttle-for the foreseeable future. Funding, based on the FY95 President’s Budget, includes only “austere” upgrades to enable missions, improve reliability and safety, or to address obsolescence. NASA plans to continue Space Shuttle operations through the early part of the next decade and to continue to use existing ELVs for science missions. The NASA budget funds a focused technology program for reusable launch vehicles accomplished in cooperation with planned DOD technology investments. Tentative plans include conducting flight demonstrations prior to the turn of the century. Such demonstrations could support a Space Shuttle replacement decision in 1999-2000 with credible cost and engineering data. At that point, NASA will either recommend a new start for a Space Shuttle replacement or will program additional safety and reliability upgrades to the existing Shuttle system and procure an additional orbiter. The FY95 President’s Budget includes money for a competition for a medium class launch vehicle (MLV IV) in FY96 to support operational Air Force launches. Market-driven industry downsizing may reduce operating costs from current levels. Under Option 1, per flight costs are anticipated to be as follows. The range in costs are due to differences in booster type and configuration (w/ or w/o an upper stage). -Medium lift: SSO-$125 million per flight -Heavy lift: $250-$320 million per flight -Space Shuttle: $375 million per flight. 6.1.2. Option 2: Evolve current expendable launch systems. Key features of Option 2 include flying out current launch vehicles already on contract, evolving a family of launch vehicles from current systems by consolidating medium and heavy lift booster families, and fielding the evolved vehicles to meet payload transition windows. This option would cost between

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$1.0 billion and $2.5 billion in CY 94 dollars, but would significantly lower operations costs by increasing production rates. Private financing may be available for this option with suitable Government guarantees, such as anchor tenancy or low-interest loans. The concept is illustrated in Fig. 8. As in Option 1, NASA will continue Shuttle operations through the early part of the next decade, continue to use existing ELVs for science missions, and fund a reusable technology program with coordinated DOD investments. Option 2’s acquisition approach includes a competitive procurement with the Request for Proposals (RFP) structured to allow bidders to propose against various sets of payload weight and orbit requirements, launch rates, and operations concepts. Recurring costs for this option are estimated at -Medium lift: $50-$80 million per flight -Heavy lift: $10~$150 million per flight -Space Shuttle: $375 million per flight.

ELV concept.

The cost per pound of payload into GTO is compared to those of other launch systems in Fig. 9. 6. I .3. Option 3: Develop a new expendable launch system. Option 3 would correct deficiencies in current expendable launchers by developing an entirely new launch vehicle family with significantly improved reliability, operability, and cost. This “clean sheet of paper” approach for a new expendable system would use a modular family composed of a common core vehicle and/or common major subsystems, strap-on stages, upper stage(s), payload fakings, and processing and launch facilities. There are two major paths a new expendable system development could follow: (a) replace only the current expendable systems, or (b) replace current ELVs and the Space Shuttle. Replacing the Space Shuttle would require significant additional investment for crew rating enhancements and personnel and cargo transport systems development.

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Payload to GTO (Klbs) Fig. 10. Option 3 cost per pound.

The non-recurring development cost for the basic new expendable vehicle is estimated to be in the $5 billion to $8 billion range. The crewrated launcher and associated personnel/cargo vehicles would require an additional U-$6 billion to develop. The recurring flight costs are estimated to be -Medium lift: $40-$75 million per flight -Heavy lift: SW-$140 million per flight -Personnel launch: $9&$190 million per flight -Cargo transport: $130-$230 million per flight. The Option 3 cost per pound into GTO is shown in Fig. 10 compared to those of other launch systems. 6.1.4. Option 4: Develop a new reusable launch system. Option 4 would develop a fully reusable space launch system with the objective of substantially reducing flight costs while improving operability and responsiveness. Since a fully reusable system requires significant advances in technology and substantial engineering development, this option is based on a phased development. The overall approach for Option 4 is to undertake a focused technology development and demonstration effort, followed by a decision as to whether to proceed with development of a prototype system and production of a fleet of operational vehicles. A parallel technology development and flight demonstrator program would be conducted to define technology and engineering feasibility and risks before committing to full-scale system development. Because of the wide range of technologies, designs, and operating concepts among the various reusable concepts, the cost estimates for a new reusable launch system span a broad range. The technology development and demonstration would require %0.6-SO.9 billion. The cost for engineering development ranges from $6 to $20 + billion. This wide range captures the most innovative industry approaches on one end and NASA’s most conservative estimate

from Option 3 of the Access to Space Study on the other end. The cost for procuring a four-vehicle fleet ranges from $2.5 to $10.5 billion spent beginning in the year 2004 and continuing through 2009. Although the non-recurring development and procurement investment is relatively high, the annual operational cost of the fleet is estimated to be in the %0.5-$1.5 billion range, compared with today’s annual Space Shuttle and expendable launch costs of over $6 billion. The cost per pound of payload into GTO is shown in Fig. 11 compared to those of other launch systems. 6.2. Roadmaps The Study Group developed roadmaps from the system options described above. Each roadmap contains the main elements from one or more options as well as common elements, such as core technology, infrastructure improvements, and transition opportunities. Each allows for technology maturation and change in strategy by showing appropriate transition points between options. The roadmaps also include a focused technology segment that both supports the specific set of options displayed and maintains a healthy generic spacelift technology base to preserve future choices. The Option 1 roadmap focuses on retaining the current space launch systems through at least 2012 with appropriate service life extension programs. Service life extension is accomplished by the Titan IV Reliability Program and the Medium Launch Vehicle Follow-on Buy. Both of these programs involve a minimal set of critical upgrades to the current systems. It also shows potential transition points to all three of the other options. NASA would continue to fly the Shuttle for human spaceflight operations and Space Station resupply. The Option 2 roadmap, shown in Fig. 12, envisions evolving one or more of the current space launch vehicles into one family of vehicles to meet the entire national mission model. There are two suboptions:

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either continue to fly Titan IV for all heavy payloads while evolving a medium launch vehicle (MLV), or consolidate the MLV and heavy launch vehicle (HLV) requirements into one system family. NASA continues to fly the Space Shuttle for human spaceflight missions and Space Station support. In parallel, the U.S. Government can choose to pursue an advanced technology demonstration and maturation program supporting a later decision to develop a reusable launch system (Option 4) with a decision point in 2008 whether or not to transition DOD payloads to the new system. The Option 3 roadmap develops a new expendable launch vehicle similar in scope to the cancelled National Launch System program. This roadmap also has two options: one where crewed requirements are not included and one where a personnel launch system (PLS) is developed and flown on a heavier

version of the Option 3 HLV. While Option 4 is shown as a potential alternative with a decision point in 2000, it is highly doubtful whether another large investment would be made so soon after committing to develop a new ELV. The Option 4 roadmap develops a new reusable launch vehicle. It includes an extensive, robust RLV technology maturation and demonstration program identical to that in Roadmap 1. The only difference is that this roadmap assumes the decision to implement Option 4 is made. The decision point for a heavy lift RLV is in 2008. 7. SUMMARY

OF FINDINGS RECOMMENDATIONS

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Access to Space 7. I. Fundamental drivers of the space launch industry

Finding # I: Excess production and processing capacity exist within the space launch industry. Recommendation # 1: A major objective of future modernization efforts should be to reduce industrial overheads through downsizing and reduction of niche markets. Finding #2: Industry is unwilling to fund major space launch modernization alone, but private “up front” investment may be available given United States Government guarantees. Recommendation #2: DOD should pursue innovative incentives to encourage private and industrial investment in space launch modernization. Finding # 3: Driven by user (DOD and National) requirements and current booster and spacecraft technology, heavy lift is required for the foreseeable future. Recommendation #3A: In the near term; DOD must continue and improve heavy lift capability. Recommendation # 3B: In the longer term, DOD should review and revalidate its intelligence requirements (both operational and S&T) that drive heavy lift. The NRO should continue to examine advanced spacecraft technologies that could provide major reductions in payload size and weight. Finding # 4: Opportunities for payload/booster transition are currently not fully coordinated to maximize the cost benefit to the Government. Recommendation #4: If a new or evolved space launch system is pursued, the IOC should be planned to coincide with anticipated payload block changes and/or new starts. 7.2. Critical drivers of cost, capability, or operations Finding #5: Increased cost of failure demands greater emphasis be placed on improving reliability. Recommendation #5: Support and sustain funding for launch system and infrastructure reliability improvements. Finding # 6: Operations costs per launch for Titan IV are significant and rising. Recommendation # 6: Aggressively restructure and streamline Titan launch base operations to reduce current and future operations costs. Finding #7: A cross-sector process to collect, coordinate, and consolidate space launch requirements does not exist. Recommendation # 7: Institutionalize a process to gain and sustain community agreement on requirements and associated metrics. Finding #8: The DOD core space launch technology program is significantly underfunded and externally constrained, which has hindered opportunities for space launch modernization. Recommendation # 8: Increase funding for a core space launch technology program as an enabler for future investment.

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Finding #9: Air Force launch base operations are constrained by antiquated and insupportable ground systems and facilities. Recommendation # 9: Continue funding RSA and launch base infrastructure improvements. 7.3. Special focus areas Finding # 10: A detailed understanding of Russian engine technology can potentially lead to reduced costs for modernization. Recommendation # 10: DOD should lead and fund a cooperative effort, with NASA and industry, to investigate the use of Russian engines and engine technology in future ELVs. Finding # 11: There exists general consensus on the potential benefits of a new reusable system; however, there are widely divergent views on the preferred approach, cost, and risk. Recommendation # 11: Pursue a cooperative NASA/DOD technology maturation effort that includes experimental flight demonstrations. Finding # 12: DOD and NASA space launch program coordination needs to be improved. Recommendation # 12A: Assign DOD the lead role in expendable launch vehicles and NASA the lead in reusables. Recommendation # 12B: Maintain top-level DOD/NASA oversight and coordination through a mechanism such as the AACB. Finding # 13: The small launch vehicle market is uncertain, but could be a major growth area--the key is development of distributed communications and surveillance systems. Recommendation # 13: DOD should continue to monitor development of the small launch vehicle market, but not take an active leading role. 7.4. Current operations enhancement areas Finding # 14: Substantial data on DOD launch operations exist, however, the information is difficult to access and use effectively. Recommendation # 14: Establish a standardized program for metrics, data collection, and supporting analyst. Finding # 15: There is a lack of standardization within Air Force space launch systems and operations. Recommendation # 15: Develop a standard set of procedures, systems, interfaces, processes, and infrastructure across all the launch bases. 8. THE SPACE

TRANSPORTATION

POLICY

The Office of Science and Technology policy in the White House, reacting to the same assessments of the situation in the launch vehicles that caused both the DOD and NASA to undertake the above studies, have begun to define the elements of a new space transportation policy, to allow the situation to be rectified in a well-coordinated manner. An

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interagency task force was assembled under the leadership of the White House OSTP, which composed the policy using the NASA Access to Space and the DOD Space Launch Modernization studies as inputs, as well as inputs from industry and individuals. This policy was the result of many months of cooperative effort by NASA, DOD, other Agencies, and the private sector. It states the nature of the problem facing the U.S., and establishes a specific course of action to begin to remedy them. It was signed by the President on 5 August 1994. The new policy establishes roles and responsibilities for the chief agencies-NASA and DOD-by clearly assigning each agency a unique lead role, reflecting its particular capabilities and resources. The DOD will be the lead agency for modernizing and evolving current ELV systems. NASA will be the lead agency for technology development and demonstration of next generation reusable launch systems, such as the single-stage-to-orbit concept. NASA will be pushing the cutting edge of technology, focusing its investments on the development and demonstration of a next generation reusable system. The policy calls for a decision to be made no later than December 1996 on whether to proceed with a sub-scale flight test to prove the concept of single stage to orbit. The goal of this effort is to support a decision by the end of the decade on the development of an operational next-generation reusable launch system. It is envisaged that the private sector could have a significant role in managing the development and operation of a new reusable space transportation system. In anticipation of this role, NASA will actively involve the private sector in planning and evaluating its launch technology activities. This means doing business in a new way in space launch--especially in involving the private sector in defining system requirements. We are actively addressing the issue of how this government/industry partnership should be structured. DOD will be the lead agency for modernization and evolution of our current expendable launch vehicle fleet, taking prudent cost effective measures to improve performance, reduce costs and increase reliability to support national needs. In doing so, the DOD will factor in the needs of the commercial space launch industry, with a view towards keeping America competitive in the global launch services market. The objective of DOD’s effort to improve and evolve current ELVs is to reduce costs while improving reliability, operability, responsiveness, and safety. Consistent with mission requirements, the DOD will cooperate with civil and commercial sectors to evolve satellite, payload, and launch vehicle needs to achieve the most cost-effective and affordable combinations. The U.S. launch industry has similar interests with the U.S. satellite industry in this regard. Both require stable, consistent govern-

ment policies, common standards, and both benefit from the success of the other. A closer partnership between DOD and private industry benefits both parties. The Department of Defense is conducting an important, far-ranging effort to reform defense procurement and manage a downsizing defense industrial base to both cut unnecessary costs and retain crucial industrial capabilities. To the extent the United States has a more commercially competitive space launch industry, this can reduce the costs of national security launches, maintain a skilled work force without using scarce DOD dollars, and even deter the spread of ballistic missile technology that might happen under the guise of commercial ventures. Thus, the policy recognizes the critical role that the private sector plays in space transportation and sends a strong signal to business that the government wants to pursue our national goals in partnership with industry. 9. NASA’S ADVANCED LAUNCH PROGRAM

TECHNOLOGY

The recommendations of the NASA Access to Space study of began to be implemented shortly after its completion by defining a technology maturation and demonstration program. This program’s definition was also well underway at the time the DOD Space Launch modernization study was completed. The results of the latter study recommended a virtually identical set of technologies to be developed and demonstrated, however, and therefore the current technology program satisfies the recommendations of both studies. In addition, the program’s content has been thoroughly coordinated with the DOD, and indeed portions of the technology will be implemented by the DOD. Thus a well defined technology program was ready to be implemented once the new space transportation police was issued. This program consists of a 5-year integrated set of activities designed to reduce the risk of proceeding into full scale’development of a fully reusable SST0 launch vehicle. The technology program is designed to develop and test a number of critical technologies both on the ground and in flight. The core technologies are: . Reusable cryogenic propellant tanks (with insulation system) Graphite-composite primary structures Long-life-low maintenance thermal protection system Vehicle health management and monitoring Robust, long-life main propulsion system Operations technologies These technologies are applicable to the three major types of SST0 vehicle concept candidates identified to date, as well as multi stage vehicle concepts. This is illustrated in Fig. 13.

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Fig. 13. Technology requirements for SSTO-rocket.

Development of the technologies to achieve the needed low weight and performance is necessary, but far from sufficient. It is crucial that we also develop and demonstrate the so-called operations technologies which will allow the vehicle to be checked out, launched, operated, recovered, and turned around almost autonomously, and with the smallest personnel needs. This includes instrumenting the major flight systems with “health monitoring” sensors that can detect problems, so that we can repair what is needed efficiently and may avoid routine in-depth testing of all subsystems before every flight. Most of these technologies must first be matured in a ground development and test program and then demonstrated on an experimental vehicle in a flight test program. Both ground maturation and flight demonstration of the technologies are necessary. The ground program, including small scale flight tests, is needed because it can build and test a large array of potential technological solutions in small sizes so as to be economical, since it would be very expensive to carry all of them into large scale flight tests. The large scale flight test program is needed because it subjects many of the technologies that interact together to the flight environment simultaneously, so that their interactions can be measured; because it tests the integrated operations technologies in a realistic operations environment; and because it validates the design codes and computer tools

that will be used to design and predict the mass fraction and performance of the eventual full size vehicles. Three very different fully reusable SST0 launch vehicle configuration concepts have emerged in the aerospace industry, each of which is in principle capable of resulting in a high capacity, fully reusable launch vehicle with greatly reduced operating costs. These are the vertical-landing configuration, the horizontal-landing wing/body configuration, and the horizontal-landing lifting body configuration. Most of the technology sets employed by these three concepts are similar, and indeed the core technologies to be developed in the NASA plan are applicable to all three vehicle configurations. However, some technologies are subjected to significantly different stresses in the flight environment by the different concepts. In addition, some configurations have unique features absent in the others. Thus with the current understanding of the component technologies it would be difficult to make a choice among the vehicle types, because inadequate information exists about the characteristics of the many new technology component candidates when subjected to the expected temperature, acoustic, and loads environments for many cycles. This requires the kind of broad understanding and data base that results from a ground and small scale flight test program. Thus the approach selected for the NASA plan is to develop and test many candidate technologies for

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each subsystem relatively inexpensively at small scale, where failures of any one type would not affect the development of others, and only then to choose a minimum preferred set of technologies to be developed for the larger scale vehicle-that is when the development risk is much lower and a flight test vehicle can be designed with greater confidence. In addition, to further reduce costs and attain the large scale demonstration sooner, many of the components of the ground technology program plan will be produced in pairs so that one of them can be tested to destruction and the other utilized as components of the actual flight demonstration vehicle. This achieves a shorter schedule and lower overall cost without unduly increasing risk. The resulting technology maturation and demonstration program is illustrated in Fig. 14.

vehicle schedule.

The above philosophy of testing many elements at small scale, and then a smaller number at larger scale is clear. The program is designed to enable a decision to be made on proceeding with the larger-scale demonstrator before the end of 1996, and to be in a position to consider starting a full-scale development program for a fully reusable vehicle by 2000. This paper has discussed the salient activities that led to the issue of the Space Transportation Policy, and its first implementation in the current Advanced Launch Technology program within NASA. These activities will enable a confident decision to be made regarding the construction of a scale model demonstrator vehicle before the end of 1996, and the ultimate starting of a new, low cost, reusable launch vehicle program by the turn of the century.