This scenario assumes that a small-medium reusable launcher will be developed that can be successfully upgraded for passenger transportation, and a destination facility will be put in place later. An approach that illustrates this is the Kistler Co. rocket that is expected to begin tests next year. Planned upgrades to this system include a reusable two-stage system building on the initial surface low-Earth orbit ( LEO) vehicle. Also, some of the X-Prize Foundation candidate concepts under development appear to fit this scenario.

1. Enablers. There is a growing market for small LEO launchers because of the growth of interest in using LEO communications satellite constellations by the communications industry. A reusable vehicle could have a significant market advantage and force the development of similar type vehicles for other markets, including upgrades for passenger carrying.

2. Barriers. The expansion of the satellite communications market is already in progress, so there is concern as to whether a new small LEO vehicle may be acquired too late to capture the bulk of the initial market. If a higher production rate of expendable launch vehicles is attained, it will lower their cost and thus perhaps become a barrier to a new reusable vehicle development. Upgrades of a new or existing system for passengers may find Government-sponsored competitors that will try to deter their access to space through market barriers and regulatory and policy entanglements. Basically, anything that can carry people to/from space at a lower cost than the Shuttle or Soyuz could be viewed by some as a threat to those multibillion-dollar Government programs.

3. Strengths. The fact that this scenario depends on no Government investment is considered a major strength. As illustrated by the Kistler concept, several X-Prize Foundation candidates, and others, the vehicle development would be driven by market considerations instead of Government missions. This in itself makes the development and operations of the small LEO vehicle more cost efficient, and permits quick response to market demands for passenger transports.

4. Weaknesses. The development of a small LEO vehicle system would be expensive and complex-perhaps more so than their developers appreciate-as illustrated by the problems encountered by the X-33 and X-34 program Government and industry partners. It may also be difficult for the developer to find sufficient private financial backing to construct a system that can be upgraded to meet the needs of multiple markets, while capturing enough initial market to justify the investment needed.

This scenario assumes that a small reusable suborbital vehicle is designed to provide fast express package delivery services around the world for military and/or commercial purposes. It would likely be upgraded to a human suborbital vehicle for executive travel and tourism. The DOD is now studying the use and character of military space planes. This, in turn, would lead to the development of orbital capabilities for cargo and human transportation and, eventually, the development of destination facilities.

1. Enablers. Aerospace technology development for small, highly reusable vehicles is a key enabler for this market since fast turnaround and a high trip rate is required. There should be early market acceptance of this service inasmuch as there is already an established package delivery service worldwide. Regulatory clearance for initial operations should be similar to those used for today's commercial aircraft and could take advantage of the X­33 regulatory issues being addressed now. Growth to a passenger point-to-point transportation system would enable services to be provided for general PST and tourism, and the addition of small stages for LEO insertion of payloads would address the market growth expected for small LEO communications satellite constellations.

2. Barriers. The fact that space package delivery services are a totally new concept to the aerospace industry is an early barrier in itself. Also, new kind of transports may find Government-sponsored competitors that would see them as a threat to the traditional launch systems now in use.

3. Strengths. The potential for very high trip rates-higher than any now in existence-is very attractive. Also, the fact that the market is an entirely commercial market that does not require Govern- ment support in meeting it adds to the strength of this approach.

4. Weaknesses. The primary weaknesses in this scenario could be the upgrade to a passenger system if the initial vehicle is designed as an automated system without a pilot. Such an upgrade would require justification in pursuit of other markets in addition to the package delivery service one. Also, this market does not require an orbital vehicle. So, again, other markets will be required to prompt upgrading the vehicle to provide LEO delivery capabilities.

This scenario assumes that an investor service has access to great wealth to finance a tourist- class space transportation system (STS) service upfront without any need for incremental vehicle devel- opments. A good example of this can be seen, conceptually, through some of the proposals put forward in Japan. Also, some of the X-Prize Foundation participants fit this category because their vehicles are designed for human space flight with plans for direct upgrade to passenger-carrying if their endeavors are successful.

1. Enablers. The enablers in this scenario could result from market surveys that many believe show sufficient justification for the large upfront investments required. Also, the availability of invest- ment funds from interested parties with the prospect of high returns from the market or, in the case of the X-Prize, some payback in the prize itself along with a lot of prestige for the winning party may also enable this development path.

2. Barriers. Concern about the technology base, regulatory circumstances, and operating experience are seen as primary barriers to the large investor approach. There are still many technologies that need further development to achieve the high operability needed to bring the cost per trip down and to ensure acceptably safe, reliable, and comfortable operations. Also, many of the regulatory issues for general PST and tourism have yet to be addressed, which could result in costly delays to the first opera- tional flights if all the safety concerns are not worked out properly. Also, a great deal of operating experience is required to build up credibility and confidence.

3. Strengths. The strengths of this scenario are that it is purely commercial, very focused, does not need incremental developments, and uses nontraditional approaches-a committed, large "leap of faith" investment would support the vehicle development. With enough money, this could be the fastest way to create a large-scale general PST and tourism business; and once one company proves the market, others will follow.

4. Weaknesses. The major weakness to this approach is that it is hard to justify such a large investment with the apparent lack of a convincingly large market in this area. Large investors usually look for more secure markets for such substantial investments, ones where the return on investment is to be associated with a proven track record.

This scenario starts with a ground-based hotel and theme park where visitors enjoy space simulations. As an added commercial draw, the market for use of the hotel and theme park would then grow through the use of parabolic flights in aircraft that provide some 20 sec of zero gravity, as is done now in the training of astronauts and the development of zero-gravity equipment. As interest in this adventure vacation experience grows, investments would be made to develop suborbital vehicles for short sightseeing rides to space. Orbital vehicles and space theme-park destinations would follow as the market grows.

1. Enablers. Hotels and resorts with the appropriate space theme ties would be the primary enablers for this market. These could include space camps, Disney's Epcot, and the entertainment business theme parks that include space adventure rides and simulators. These space-related theme parks could have sufficient draws to create package deals that could finance the operations and provide the entertainment and training needed.

2. Barriers. This approach is heavily dependent on the development of a market large enough to justify the vehicle investments. Several steps are required before reaching the orbital vehicle goal, which means this approach may prove to be very slow in development.

3. Strengths. If the adventure ride into space is sufficiently tied to the ground-based theme park experience, then the investment for the initial suborbital vehicle does not have to be justified as a stand-alone business. The ride itself becomes a draw to all the other attractions, products, and services that in turn finance the entire operation. Users of the suborbital vehicle would also provide revenue for food, lodging, and other services at the hotel/theme park. The terrestrial destination might also avoid the need for an orbital destination in early years if the total experience is sufficiently entertaining, even though the space ride itself is very short. Also, since this approach follows through a full range of parabolic and suborbital rides first, there will be greater opportunity to build an experience base for space tourist operations, so the orbital adventure will be a more assured and successful investment.

4. Weaknesses. This approach is also a weakness in that there are multiple steps and upgrades along the way to the development of an orbital vehicle. This highly synergistic approach would require multiple justifications for the developer to go through to reach the next step.

Note: It must be appreciated that incidents causing serious injury or death could shut down the market indefinitely through increased regulation or faltering customer trust. This fundamental consider- ation applies to all of the scenarios.

The actual path taken to realize the servicing of a general PST and tourism market could easily encompass any or all of the five scenarios described above. One approach cannot be selected today above another, around which to develop a primary strategy. Much more careful analysis and imaginative thinking will have to be done in the private sector over the next few years to narrow down the opportunities.

Given the range of development scenarios that could occur, the key issues associated with the development of transportation and destination facilities for general PST and tourism were identified. These issues are grouped into four areas technical, market, regulatory and legal, and venture or organizational management.

The STS must achieve high safety and reliability, reasonable comfort, and low price. It is commonly assumed that this will happen by bootstrapping onto the developments from industry/Government technology programs such as the X­33. Unfortunately, high safety for Government programs may involve doing only a little better than current safety factors for the Shuttle and the expendable vehicles now in operation, which are not nearly as high as the aircraft level of safety needed for the general public. Also, the cost reductions targeted for the X­33 are good enough for Government programs, but are still a long way from allowing trip prices that approach those charged for airline tickets and tours. Commercial alternatives or appropriate modifications of the Government programs are needed to develop the right propulsion and vehicle technologies and to address all the design issues and complex systems engineering tasks related to high safety and low price.

The ISS development is the state of the art in destination facilities development. That technology will likely provide a basis for the initial on-orbit facility infrastructure. Technical issues not being addressed include the need for large volume facilities that would require on-orbit construction, and variable gravity facilities, and eventually 1-G (Earth gravity) facilities. The cost for the initial destination experience will be high, and the size of ISS accommodations may not be sufficient. Technologies for a hotel specifically optimized for tourism must also be considered. These technologies would be quite different than those required for the ISS. As an example, the tourism-optimized design may call for modifications to more traditional technologies such as partial-G toilets, showers, washers, dryers, food preparation devices, and emergency medical care (see app. A).

A combination of both the vehicle and accommodations into one system could be an approach that would eliminate the need for early development of destination facilities. However, this approach would be constrained by the volume.

Detailed market analysis will lay the basis for the type and size of initial services to be provided. Although there were several market surveys cited during the workshop, there was a consensus that more detailed market surveys were needed before major investors would be willing to advance the large sums. Also, there needs to be a way to validate or test the market before commitment to a large system. This is where the features of the parabolic and suborbital ventures look attractive for initial transportation systems, as is the use of the Shuttle fleet. Initial destination facilities utilizing existing space assets or constructed from existing ISS technologies were cited as a first step toward testing the destination facility market.

In most cases, regulatory and legal issues can be resolved by using a common sense application of existing codes and regulations that are now in use in analogous surface businesses. This will likely be the approach taken initially, with specific regulations put in place as needed. There is a concern that too much regulation initially may stifle the development of this novel business, whereas too little could hinder investment because of the uncertainty of the regulatory environment.

Physical/medical screening will be somewhat dependent on the vehicle system. If it is operated as an airliner, then the physical requirements will be minimal. However, if the launch environment is more strenuous, and the time for emergency return is not flexible, then physicals and liability waivers will be required to protect the passengers, crew, and investors.

Liability and indemnification will be similar to other activities of similar risk. Regulations will be needed to define the limits of liability for the operators.

Regulations that govern the operating "rules of the road" will be needed and are currently being explored through the X­33 and X-34 development programs and other private sector programs. The Federal Aviation Administration (FAA), Department of Transportation (DOT), Department of State, Department of Commerce (DOC), DOD, and NASA all have concerns about vehicles passing through the atmosphere, into space, and over international territories.

Current Government control of human access to space is also an issue. Any new system will need to consider the general public, specifically. When the general public thinks about space today, they think about NASA. A human system including NASA, or having NASA's blessing, would be viewed positively by the public. On the other hand, any commercial system may be viewed as a competitor to the Shuttle system and might be viewed as a threat to a very large and well-established Government and Government-contractor infrastructure. These issues must be worked out as public space trip systems-services come closer to fruition.

Standards, codes, and certification need to be modeled after existing Earth- and space-based facilities and transportation systems. In general, these are not Government-driven, but are recognized business standards that have been promoted by the private sector as a means to promote safety and provide bases for arriving at acceptable insurance liability. A similar approach needs to be taken for the establishment of safety codes for space transportation and destination facilities. For transportation, the aviation industry may serve as the initial model, but for destination facilities, surface building codes would be applicable, as well as the codes that govern the development of passenger ships at sea. For example, any space vessel should have a captain with the same authority as a sea captain. It is debatable as to whether escape provisions for large space structures should be the same as for sea vessels where there is life boat capacity for every person, or whether it should be like building construction where there is a safe haven or fire wall that divides the facility up internally to provide for safety. These issues are being explored in the ISS program.

The venture or organizational management structures will likely be as varied as the scenarios described earlier. They will develop funding sources and venture paths that inevitably look to minimum cost and risk wherever possible, including the use of Government assets, tax incentives, and anchor tenancy from the Government or a large private investor. The establishment of a firm fixed price for the use of Government assets, the establishment of broad tax incentives, and the imaginative use of the large Government civil and defense space transportation markets were identified as major contributions that the Government could make to the establishment of a general PST and tourism business.

The credibility of the management and technical team will also be key to the success of the space venture. Do they have credible space technology and management experience? Are they using proven space technology? Do they have operating experience? A positive response to these questions will help provide reassurance to the investors and the respective insurance backers.

Opportunities to eliminate the barriers to the PST and tourism business were identified.

In the space transportation area it was noted that NASA's and our space industry's current emphasis on the development of new propulsion systems, new engines, prototypes, demonstrations, and X-vehicles, with focus on integrated systems engineering approaches, provides a major opportunity to eliminate barriers to general PST and tourism. More emphasis is needed on general public space transportation issues to focus Government and private technology developments into areas of high economic leverage.

In the destination facilities area, the completion of the ISS provides a major opportunity to eliminate perceived barriers to space construction and habitation. Further expansion of this effort is needed to develop and demonstrate low-cost technology and to focus systems engineering on hygene issues, closed-loop life support systems, power, safety, and emergency medical care, as well as large-volume and low-gravity facilities.

Simulations of space travel at the space centers, space camps, theme parks, and in the entertainment industry have already gone a long way towards eliminating some of the barriers to space development. This momentum needs to be continued but is not enough to open the in-space market. Obtaining better market data, and then validating the data, would be major steps towards helping to eliminate barriers to general PST and tourism.

The Government needs to take a proactive position to promote general PST and tourism. This can be achieved through proper policy and regulatory actions. A change to the administration's space policy that would identify general PST and tourism as a national goal would go a long way toward eliminating barriers. In addition, providing public access to Government-controlled technology, systems, and facilities for market validation (STS/Mir/ ISS) is needed. The establishment of initial suborbital flight regulations and the establishment of the rules of the road, standards, and regulations that industry needs to follow, are also required.

Continuing with this need for a proactive Government position, financial incentives for the venture investors need to be established. This could include tax incentives, use of independent research and development funds, and encouragement to form company consortia with investments from the financial community.

Specific recommendations for future actions by Government and/or industry are as follows.

Space Transportation:

• Explore the near-term development of more robust, reusable rocket engines for Government and commercial use.
• Support the long-term Integrated High Payoff Propulsion Technology program to develop the next generation robust propulsion systems to meet Government and commercial space transportation needs.

Destination Facilities:

• Explore the use of ISS capabilities and its technology for public use.
• Develop technologies for low-cost, large-volume, artificial-gravity habitat systems.
• Organize a workshop to focus on the definition of relationships, systems engineering, and integration between ISS and early destination facilities for general PST and tourism.

• Develop high-fidelity market data as tools and aids to understanding the market potential and the risks in development of a general PST and tourism business.
• Conduct more indepth analyses of potential space travel markets, especially those of particular interest to the investment community.
• Initiate a nationwide public awareness campaign on the potential for PST and tourism.
• Use the Shuttle fleet and the ISS to explore and stimulate the space tourism market.

• Develop policies for private use of Government space transportation and destination systems; i.e., the Shuttle and the United States (U.S.) portion of the ISS, to allow testing of the market.
• Form a Washington, DC-based coalition "Interest Group" to promote general PST and tourist interests.
• Work with Congress and the Administration to form policies which encourage and permit proactive support from all Government agencies for the development of a large, general PST and tourism business.
• Work for regulatory, tax, and legislative policies which will encourage this new business by better defining the playing field for commercial investments.

• Promote legislation to provide tax incentives for commercial investments to stimulate a large general PST and tourism business.
• Better define accounting and tax implications for all space systems/services.
• Form partnerships to conduct systems engineering studies to define space transportation vehicles and destination facilities concepts that will serve to guide technology, marketing, and financial planning for the commercial investors.

This is an accumulation of ideas that express the general requirements and characteristics of general PST and tourism systems and services. These ideas relate to quasi-"ultimate" large-scale, surface LEO trips rather than to early niche market adventure trips.

Several characteristics of STS's are driven by the particular needs of general PST and tourism. Too, the development of the market is heavily influenced by these characteristics. These characteristics include price, safety, reliability, comfort of the provided services, and schedule availability.

Initial space trips have been suggested purely for sightseeing purposes, where passengers do not disembark from the vehicle, and the vehicle provides all of their sustenance for the duration of the adventure. Terrestrial analogies to this include sightseeing flights which travel to and transit Antarctica and the North Pole, as well as sightseeing flights over natural wonders, such as the Grand Canyon. Discussions of the viability of these flights and their related STS/services are driven by the perception that the market for such flights is a limited one, compared to the travel to a destination for a stay of some days or weeks. A terrestrial analogy is that of a hypothetical market for a sightseeing flight from San Francisco to the Hawaiian islands that would circle the islands from the air and return to San Francisco, versus the market for a flight to these islands with hands-on sightseeing and a stay in a resort there. Obviously, the market for a destination resort is more substantial if the costs are roughly equivalent. Thus, the obvious conclusion that the market for space transportation services is closely tied to the destination for the tourist.

However, there is also a sidelight to the market. There is a substantial terrestrial market in "cruises," where the vehicle/transportation system are the destination itself. Here the vehicle acts as a mobile resort, including substantial amenities for the passengers. In the cruise transportation trade the vehicle itself must position itself as a luxury resort, and the passenger must see the vehicle itself as equivalent to the destination resort. For STS services, this may be a more difficult situation to accommodate, because of the conflicting requirements of low-price transportation and sophisticated tourist services. The dollars and technical capability required to provide a trip which offers low-price transportation and resort level accommodations will be difficult to achieve. Such a space trip eventually might become more feasible using in-space transportation where less rigorous constraints of system mass fraction and a simpler in-space operating environment might be encountered.

Ground infrastructure requirements depend greatly on the vehicle design and operational requirements. For instance, the ideal vehicle might be much like an aircraft that is single stage to orbit ( SSTO), with horizontal launch and horizontal landing profiles. This type of vehicle could be integrated into the world-wide network of existing airports and would therefore require only modification of some existing facilities and operational procedures to absorb the new vehicle fleet. If the vehicle is designed to be launched vertically, then new or modified existing ground facilities will be required. The implications that a space transportation vehicle design can impose on the ground infrastructure follow.

1. Access. First- and second-generation passenger-carrying STS's would probably build upon existing launch-recovery sites associated with orbital destinations. There are about a dozen sites in the world today that could accommodate orbital trips without undue worries about overflight of populated areas. If, as expected, fully reusable systems are the STS's of the future, and a suitable safety and reliability database is established, then these sites may be expanded greatly. However, there would be some restrictions upon the development of these sites, driven by both economic and physical constraints. The first of these is access both to markets from which the passengers will come and to any orbital destination desired. Access to the site should be moderately simple and low cost and should not involve major inconveniences or hardships for a passenger or cargo to reach the space trip site. This will be important both for attractiveness to the passenger and for logistics operations. As an example, the Orlando, FL area can be seen as an attractive location given its proximity to both terrestrial attractions and destinations and its ability to draw upon other major transportation hubs. In comparison, a site located on an atoll in the mid-Pacific would be more difficult to reach, offer fewer amenities for passengers in transit, and be more difficult to stage supplies through, both for the transportation system and the orbital resort destination.

   Similarly, it is desirable that the launch site be located at a latitude lower than that of the orbital destination because of orbital mechanics considerations; i.e., because of launch energy requirements, it is more difficult for a space transportation vehicle to rendezvous with a destination whose orbital inclination is more or less than the latitude of the launch site. Similarly, the location of the trip sites would be influenced by the orbital destination, the duration of stay there, and the transportation system cross range required. If a vehicle has only a very small cross range capability, then it may have to wait on orbit for some period of time until it can reach a recovery site. This calculation is dependent upon the specific geographic distribution of sites, the cross range capability of the vehicle, and the inclination and altitude of the orbital destination. Given a reasonable global distribution of flight departure and landing sites and a moderate cross range of a thousand miles or so, assured access to a landing site can be achieved in a short duration orbital flight.

2. Ground Support Systems. If you look at a modern airport or cruise ship terminal facility, there is a substantial amount of ground infrastructure which supports the transportation system. This is one of the primary reasons why space transportation vehicles that could be integrated into air transportation sites are desirable. The ground support infrastructure could include the following:
   • Passenger transit facilities, such as lobbies, waiting rooms, amenities, lodging, parking, transit facilities, intermodal transportation facilities, and lounges
   • Cargo/luggage collection, sorting, handling, packaging (into cargo containers), on-site transportation, shipping/receiving, distribution, and disbursement facilities
   • Office/sales activities, including ticketing, reception, sales, reservations, and communications
   • Vehicle processing, including on-site transportation (tow bar vehicles and tugs), positioning, repair and maintenance shops and facilities
   • Vehicle servicing, including cosmetic maintenance (window washing, deicing, etc.), fueling, cleaning, and amenities/catering/servicing (lavatory/waste water servicing, food and drink catering, rubbish removal, etc.)
   • Passenger embarkation/disembarkation, including passenger marshaling and disbursement, and gangway/flight way access
   • Site logistics and facilities, including propellant storage and distribution systems, warehouses, hangers, utilities' distribution (water, power, sewage, gas, etc.), and transportation.

   Many of these support systems are "behind the scenes" for routine ocean cruise or air transportation operations to the point that it is a sign of a well-run and efficient operation if the passengers are not aware of these operations and considerations. Such ground support operations and facilities will also be needed for routine and efficient space travel operations. They can be provided at virtually any site, but at a price. As a point of departure, new major terrestrial airports can easily cost several billions of dollars. The new Chek Lap Kok airport in Hong Kong is projected to cost $9 billion by the time that it opens in 1998,1 and the new Denver International Airport is carrying $3.7 billion in debt from its acquisition.[2] If such a facility is needed for space passenger service, then the cost of this facility must be recovered against the commercial traffic through the facility, and the costs of operating the facility recovered as well. For commercial aircraft this is done through landing and transit fees. The ability to share facilities with other transportation nodes, or to build off of existing facilities, may drive such space trip facilities to co-locate with other transportation nodes as part of a global transportation infrastructure.

3. Noise. Among other environmental considerations, noise is one consideration for transportation node selection. Terrestrial airport operations may be constrained by local noise ordinances and in the U.S. by FAA noise-abatement regulations. STS's capable of orbital flight are expected to expend substantial energies in a short duration of time, which typically produces high noise levels. For rockets, the rocket exhaust produces a very high characteristic noise level, and for high-speed flight in departure or return, the impact of supersonic shock waves must be considered. Routine general PST and tourism operations from a trip site which may involve frequent departures, potentially at a higher than daily frequency, must deal with these noise considerations. This may mean increasing the clearance zone around such a flight landing site, and controlling departure and return corridors to minimize the impact of noise upon the environment. Some analysis indicates that a 15-km zone around such facilities[3] should be sufficient, but further study is necessary. Other more configuration-dependent and technically driven considerations include shaping the vehicle ascent or descent trajectory to minimize impact upon specific areas, or operating in some form of mixed mode to minimize such impacts. For example, using turbofans to lift the vehicle off the ground and cruise to an orbital ascent location over a remote area may allow space transportation vehicle operations to operate much closer to populated regions without major noise impacts.

4. Propulsion/Propellants Safety. Transportation systems for general PST and tourism will, by their nature, carry a concentrated load of propellants, potentially including volatile hazardous materials. If a high level of reliability and safety in the use of these systems is established, then current standards may be relaxed. But until enough of an operational database is established that is adequate to provide confidence in safe operations, STS's must comply with current space vehicle launch regulations.

   Explosions, caused by the uncontrolled combustion of propellants, may produce a blast wave with the potential of causing damage by crushing forces and winds. Debris, made up of vehicle fragments that may land upon structures or populated areas, and fires, where the uncontrolled combustion of the propellants results in heat, or thermal radiation, must be controlled. Toxic vapors can be eliminated through eliminating specific hazardous materials from the propellant systems of the vehicle (such as toxic hypergolic propellants). But, in the aftermath of an accident where a vehicle's composite structure or its cargo may be consumed by fire, a toxic vapor hazard may still occur.

   Current operating procedures require specified trajectory clearances away from inhabited areas. This includes consideration of the potential blast wave, and the quantity/distance of debris from a potential problem. This safety zone from the launch/recovery site to inhabited areas, such as passenger terminals, may be as much as 13,000 ft or more, depending upon the specific design of the vehicle and the results of detailed technical hazard analyses. However, it should be noted that a typical commercial jetport has a runway of about 10,000 ft. So locating the site at the opposite end of the runway from the terminal may provide sufficient clearance for routine operation, if a sufficient cleared area exists there. Flight paths to/from the site should also be designed to minimize the impact of any potential problems, at least until enough experience is gained to demonstrate high levels of reliability.

   Similar considerations should be employed for the storage and transport of propellants. There are existing commercial standards for STS's. A comparison between a typical jet port and a space trip site is informative. If the jet port accommodates 300 flights per day of MD-80's or Boeing 737's, with each plane potentially carrying 60,000 lb of fuel, the jetport may have to accommodate 18 million lb of fuel per day. A 2-day storage would be equivalent to 36 million lb of fuel, or about 654,000 ft3 of storage volume. If a space trip site accommodates 1 daily trip of a liquid oxygen/liquid hydrogen (lox/ LH2) system, each carrying 1.8 million lb of propellant (typical for an SSTO-type vehicle), then a 2-day storage capability would be equivalent to 43,400 ft3 of lox and about 115,600 ft3 of LH2. While these are cryogenic fuels with their attendant issues of boil-off and insulation, an advanced trip site capable of over 300 trips per year would not require substantially larger propellant storage acreage than is already provided by commercial airports.

5. Traffic Control. With the increase in space trip traffic, space traffic control issues must also be resolved. This includes establishing clearance for travel to or from orbit, assuring clear orbital paths from collision with other space objects, warning of space debris, and scheduling vehicles out of/into a general PST and tourism facility.

On-orbit infrastructure requirements include the orbital requirements for the Earth-to/from-orbit transportation vehicle, the destination facility(s), be it a space station-laboratory, hotel, or space business park, and an in-space orbital transfer vehicle to transport cargo and personnel between destination points in orbit.

1. Space Transportation Vehicle On-Orbit Requirements. The basic requirements should include a transportation system to/from LEO destinations at high inclination to include access to the ISS and the Mir. This does not necessarily mean the vehicle has to go to the ISS orbit. That would be a preferred capability, but for initial tourism needs a destination facility at a lower inclination may be more economical with an orbital transfer vehicle added later to complete the transportation system to all possible destinations. Once on orbit, the vehicle will require orbital maneuvering and docking capabilities comparable to the Space Shuttle and the Soyuz vehicles.

   Space transportation vehicle on-orbit requirements will also depend on the basic vehicle design and destination trajectory. If the launch to the destination timeframe is only a few hours, then minimum commercial aircraft type accommodations can be provided. However, if the designed trajectory requires a day or more to reach the orbital inclination, passenger accommodations will tend to become more like private compartments on overnight passenger railway systems. These two comparisons represent the lower and upper range of demand for passenger accommodations.

   The transportation cost will probably be the most expensive part of the entire price to a passenger (including costs for their in-flight amenities, as well as themselves), which suggests the need for a quick trip to an on-orbit destination with minimum facilities in the vehicle for passengers, and more plush facilities on-orbit at the destination facility.

   Passenger accommodations should include an open cabin with individual recliner-type seating similar to a commercial aircraft, but it should be adjustable to a more erect position for better body support during ascent and descent accelerations, and on-orbit zero-gravity body posture. The passenger cabin should include side and/or overhead view ports and individual video monitors for communications and entertainment. Personal safety and hygiene requirements may include a half-mask respirator combination bag for all passengers to wear early in the trip until it can be confirmed that space sickness medi- cations have been effective. A body tether may also be needed for attachment to an overhead rail for zero-gravity movement about the cabin and to/from public toilet facilities. Early flights with small passenger loads will determine if these features are really required, as well as to uncover other unfore- seen problems.

   Crew requirements for the space transportation vehicle on-orbit would be similar to those of a commercial passenger airline. Even though the vehicle will probably be nearly autonomous, it will be necessary to have a pilot and copilot who can provide a leadership role, communicate vehicle performance to the passengers, provide an understanding of the vehicle systems and anomalies, perform manual orbital maneuvering and landing when needed, and communicate with the surface and any orbital destination. Flight attendants would likewise serve the passengers as on a commercial aircraft.

2. On-Orbit Transfer Vehicle Requirements. Passenger safety and flexibility in transportation operations must be assured as the on-orbit infrastructure matures. A vehicle system designed to service the tourist market would include a passenger module capable of making passenger transfers between all human destinations in space. Initially this would mean the ability to transfer humans and cargo between the on-orbit tourist facility, the Mir, and the ISS. Such a vehicle transfer system has broad market appeal today. Possible services could include astronaut, passenger, and supply transfers between stations; satellite servicing and satellite orbital transfer; space rescue operations; orbital debris collection; and space station reboost operations.

   Passenger transfer vehicle accommodations would vary according to the length of time required for the orbital transfer. If the transfer vehicle makes only short trips between the vehicles and several destinations in close proximity to each other, then minimum accommodations would be sufficient as described above for the space transportation vehicle. If the transfer vehicle is used to make transfers from low inclination orbits to high inclination orbits that take a day or more, then more spacious cabin-type accommodations would be required. Since the transfer vehicle is maintained on orbit, this option may prove more economical than including cabin-type accommodations in the surface-space vehicle.

1. Cost/Price. One of the most important drivers in the general PST and tourism market is the cost of space transportation. This directly drives the ticket price per passenger and secondarily drives the cost of installing any orbital destination facility and supporting the passenger with food, drink, air, and amenities.

   Several prior studies4­7 have directly linked the price of space transportation to expected demand for space tourism. Typically, the challenge has been to provide a ticket for space transportation at a very low price to a potential customer, while still ensuring sufficient revenue stream to justify the development of the advanced STS that would allow this lower cost. In this consideration, the price/demand elasticity between the ticket price and service demand is of great importance. But, as of this time, the price-demand elasticity for this new market is not known with sufficient confidence (see app. A in Vol. 1).

   It is important to note also that the prices charged for space tourism trips are by necessity higher than just the recurring cost of the transportation. A transportation system operator or developer must recover sufficient returns from the operation of their system to pay back their creditors, sustain recurring operations (including the replacement of vehicles), and earn a profit for their investors. Since the market demand for general PST and tourism is not well established as yet, this also has an effect upon the viability of STS's developed to service this new market. High risk requires high returns in a business investment and, therefore, the required returns for a significant investment may impose additional investment risks and initially force up the required price for the use of the system to obtain these returns. This is a "chicken or the egg" problem. If this market is to be realized, additional emphasis must be placed on conducting detailed market surveys and in-space market-related studies which address the types of services that are actually expected to be made available and the price that passengers/tourists are willing to pay.

2. Safety and Reliability. Besides a low price, a transportation system for space tourism must also provide a relatively safe service on a reasonably consistent schedule. To achieve this, it must demonstrate operations that are at least two orders of magnitude safer and more reliable than current systems. In analogy, aircraft transportation systems have demonstrated a sustained growth in safety over the past 70+ yr of commercial passenger operations. This safety record has been the result of a persistent focus upon identifying problem areas in airline safety, applying well thought out, technically, operationally, and economically sound design approaches, and establishing a regulatory and operations process to control these characteristics.

   The aircraft business has developed an extensive database on how to maintain safe, reliable, and efficient operations. In 1960, major U.S. airlines carried 58 million passengers on board 3.8 million flights and suffered 67 accidents, 12 with fatalities. In 1995, they carried 550 million passengers on 8.2 million flights, suffering 33 accidents, two of them with fatalities. That is, over 35 yr, we have seen the market grow by an order of magnitude, while the probability of a fatal accident has dropped from one in 300,000 departures to one in a million.8 Commercial space transportation operations have a long way to go in order to approach those of airline operations of 35 yr ago. Current space operations run about 35 trips per year, and lose one vehicle in every 20­30. Our passenger-carrying vehicle, the Shuttle, does much better. It is now approaching one fatal accident in 100 trips, but this is lower than commercial airline operations by four orders of magnitude.

   Passenger-carrying STS's should be designed and tested to high reliability. Approaching the same safety levels as commercial aircraft may be difficult until an equivalent database has been developed for sustained safe operations, but, initially, at least two orders of magnitude increase over current levels should be pursued. Establishing a much higher operational trip rate for space systems would aid in this effort.

3. Services. Current STS's are not designed to provide general PST and tourism services. The process to integrate and carry a payload on a space vehicle typically takes from 12­18 mo or more and may involve unique consideration of the interactions of the payload with the vehicle.

   General PST and tourism will require a totally different approach to accommodate passengers as paying customers. There will have to be a standard set of services available, with the capability of a mixed payload of passengers and cargo (luggage and/or supplies). Unique interfaces between the payload and the vehicle will be replaced by standard interfaces. Also, to accommodate people, the STS must be able to provide an appropriate Environmental Control and Life Support System (ECLSS), as well as appropriate access and habitability considerations. This can perhaps be accommodated through a modular passenger module, which would provide aircraft-like services and stand-alone ECLSS capabilities. But the interface between the passenger module and the vehicle must provide appropriate access and suitable services for the passengers.

4. Schedule/Availability. An STS for general PST and tourism should also provide scheduled services. There are two paths to follow for tourism-driven vehicle operations. The first is similar to charter aircraft operations and is similar to existing launch system operations: trips are not launched on predetermined schedules, but only when a sufficient cargo has been accumulated. Services for passen- gers, as well as the flight departure and return times, may be more catered to meet individual needs. Early trips may follow this model until sufficient traffic builds up to allow scheduled services.

   Scheduled services are the long-term goal for the general PST and tourism market. Then, a transportation system is expected to provide a standard set of services with departures and returns on an established schedule. However, this service paradigm assumes the services provided are highly standardized, that the space transportation service "route" (including to and from a destination) is standardized, and there is enough traffic along this route to allow the system to operate economically.

1. Windows. Obviously, one the biggest draws for a passenger on a space liner will be the ability to look out the window. Most conceptualizations of space passenger-carrying vehicles include windows at least similar to those of current commercial passenger aircraft. However, structural considerations during ascent and reentry may preclude having large banks of windows along the sides of the vehicle. This has been an ongoing issue between the designers of spacecraft and their passengers, and resolution of this issue will probably not take place until plans for the first routine passenger operations are formalized in detail.

   However, there are valid psychological and market needs which drive the system to provide some form of external view to each passenger. Some passenger aircraft are currently experimenting with the delivery of video from the cockpit, and it may be found that such a direct video link to each seat from an external camera may be a sufficient substitute for a window. Similarly, windows in a passenger module contained in a vehicle may be covered until on orbit, thereby avoiding the issues of having to design windows capable of accommodating the harsher environments of ascent and/or reentry.

2. Volume. The immediate physical environment around the passengers should be conducive to their psychological and physical well being, as well as to establishing the proper environment for a quality trip experience. This includes the design and location of seats, walls, floors, and the selection of materials, colors and textures as is done for commercial aircraft. Based upon the experience of U.S. and Russian astronauts on Skylab, Mir, and the Shuttle, some persons may be very uncomfortable without a local vertical reference, and subtle clues could be maintained in the passenger accommodations areas to ease this physiological circumstance.

   A passenger vehicle may be cramped, particularly if the vehicle is just acting as a transport to/from an orbital destination. Anyone who has flown across country in coach class on a modern jet is aware of the tight volume constraints. However, some volume should be utilized to allow the passengers to experience weightlessness and to play with small objects in the new environment. Certainly, if this is not planned for, then passengers will play with whatever is at hand pens, glasses, watches, etc., to see them "float." As this may also involve playing with food or liquids, care must be taken to ensure that they do not interfere with the vehicle's safe operations or the health and safety of other passengers. To capture and control small objects located near the passengers during flight, some personal stowage space near each passenger must be provided.

3. Lighting and ECLSS. Some lighting and ECLSS should also be associated with each passenger's volume. Lighting for each passenger should be controlled at each individual seat, and area lighting made available throughout the passenger area. Local airflow should be conditioned, with some ability of different passengers to adjust the level for personal comfort. Furthermore, the air flow should be designed to move floating debris and objects out of the way. This will aid in continuously minimizing debris and capturing small objects which have not been properly stowed.

4. Ingress/Egress. Depending upon the specific design of the passenger vehicle, the passengers should have simple, nonphysically demanding access to their positions for the trip. This may be done as on commercial airliners with aisles and doors, but the consideration of when and how the passengers are loaded for vertical takeoff may impose some different access problems.

   Once in space the full volume of the vehicle will be available, but access to and from the seats should be maintained to allow services and attendants to reach the passengers, or to allow the passengers to move about to reach the lavatory or other facilities. The design of the passenger volume should include appropriate handholds and rails. Wherever possible, the design should avoid sharp protrusions so as to minimize the possibility of bruises or painful collisions between a passenger and the vehicle's internal structure.

   Consideration of passenger ingress and egress should include dealing with emergency situations where the passengers may have to exit the vehicle rapidly. Similar criteria as required by the FAA for airliner passenger egress may be required. This means emergency doors, slides, or other capabilities may be needed.

5. Entertainment and Communications. It is reasonable to expect services similar to those available in commercial airline operations including music, video, and communications devices. With modern aircraft-like systems, it is possible to provide data communications, giving the trip status of the vehicle with its position in orbit, camera views from around the craft during the trip, and space-surface communications links for individual passengers.

6. Timetable. The duration of time the passenger spends on board the vehicle should be considered. Current Shuttle operations have the crew entering the vehicle some hours before liftoff, but such delays should be minimized for general public passenger-carrying vehicles. The specific timeline between start of passenger loading and launch may be dependent upon specific considerations for vehicle processing and preparation, as well as safety considerations (loading time for cryogenic propellants), but experience and proper design should minimize this concern. Similarly, the habitability volume per passenger should be greater for longer trips.

7. Training/Guidance. The amount of specialized training required for passengers should be minimized. However, some familiarization and training probably will be needed. At a minimum, as with commercial airlines, some familiarization and guidance in emergency procedures should be provided.

8. Galley Services. The whole issue of food and drink in space is worthy of an extensive document. However, for an orbital trip with a duration of more than an hour or so, some type of galley services to provide liquids and solid food refreshments to passengers should be provided. While exten- sive meal services would be difficult to provide and the potential inexperience of passengers with the techniques of zero-gravity eating may make meals a particularly difficult matter there are methods of providing refreshment and sustenance to passengers during flight, and, of course, this service in itself will provide some entertainment.

9. Lavatory Services. Comfortable facilities for the elimination of bodily wastes in orbit must also be considered. Current Shuttle and proposed ISS systems are nonintuitive to persons used to being in a gravity field during the conduct of this common bodily function.

1. Crew On-Orbit Requirements. The on-orbit facility has to be piloted and will have orbital maneuvering and reboost capabilities to maintain on orbit. Crew capabilities must be designed to service the facility and the tourist population. A surface cruise ship is a good analogy to consider. The numerous systems on board the facility will have to be monitored and controlled by a capable captain and an engineering staff. Stewards will serve the passengers in the same way as on a ship at sea. Quarters for the crew with passenger-restricted access to the control of all vehicle systems is preferable. Complete crew rotations should occur every few months at first, with longer crew duration permitted as experience permits. It should be noted here that the zero-gravity environment will provide unique employment opportunities for many people with physical disabilities that are inhibited by the 1-G environment on Earth; some may actually prefer a permanent residence in space.

2. Passenger On-Orbit Requirements. The first space tourism facility will probably be the transportation vehicle itself. Like the Shuttle now, the accommodations will be limited to an open cabin area, windows, simple personal experiment activities, public-available lavatory, and a sleeping bag on the wall or bunk-sized locker. Tourists will expect better accommodations as the on-orbit time increases and dedicated permanent facilities become available.

The first permanent on-orbit facilities will probably be similar to those planned for the ISS. The ISS provides a good baseline design for safety and reliability and should help establish a precedent that the insurance industry can base risk estimates upon. Production and installed cost can also be derived from ISS experience, but operating costs are not as well defined at this time. Certainly, they must become much less costly.

Another approach for an early tourism facility could be a rotating hotel designed to provide a partial gravity environment. This would permit the use of existing terrestrial equipment and systems (e.g., toilet facilities, food preparation equipment, mechanical and plumbing systems, etc.) with proven terrestrial safety and reliability. ISS habitation experience should be carefully analyzed and the partial-gravity approach experimented with in order to understand the performance, estimate the cost, and help to focus upon the preferred technology and systems development.

By analogy to cruise vessels, medical facilities would include a staff physician or nurse with emergency medical equipment and a quick-return vehicle capability similar to those to be provided on the ISS. Medical facilities would expand as the facility expands. A side-line benefit to this is that some treatments such as those for severe burns and certain orthopedic procedures could benefit from a zero-gravity environment.9 This type of activity could be expected to expand the demand for on-orbit medical research facilities.

A second-generation hotel could provide cruise ship-like accommodations. More experience will be needed with on-orbit construction methods and large vehicle operations in the space environment. A need that is not being addressed by the ISS or Mir programs is the on-orbit construction of large pressurized volumes and low-gravity facilities. Three near-term options appear to be viable for the construction of large, low-cost, habitable volumes on orbit: (a) The conversion of Shuttle external tanks on orbit to habitable facilities, (2) the launch of a converted or partially converted external tank for habitation, and (3) the development of new rigid and/or inflatable structures that can be made habitable on orbit. Such a facility could be multipurpose-it could be used to accommodate televised sports events, tourist recreation, and film production.10

The need for a continuing dialogue between Government and travel and tourism interests must be emphasized as plans are developed for providing an STS-service for the general public. The promise of this capability has been recognized since humans first went to space in the 1960's, but it has not been realized, in part, because of the lack of critical technologies and the lack of proper Government policy. The initial critical technologies are within reach, and a proactive Government policy initiative for general PST and tourism can open up this new business opportunity. The recommendations listed in section F of this chapter (Recommendations for Future Actions) express these needs more concisely and should be implemented as soon as possible.

1. Aviation Week and Space Technology, p. 38, Sept. 30, 1996.
2. Aviation Week and Space Technology, p. 39, Jan. 6, 1997.
3. Nagatomo, Hanada, Naruo, and Collins, 1995, "Study on Airport Services for Space Tourism", AAS 95-603
4. J P Penn and C A Lindley, Jan 26-30 1997, " Space Tourism Optimized Reusable Spaceplane Design", STAIF-97 Conference, Albuquerque, NM
5. "Commercial Space Transportation Study Final Report", performed as a cooperative effort by Boeing, General Dynamics, Lockheed, Martin Marietta, McDonnell Douglas, and Rockwell International, with the coordination of NASA Langley Research Center, Hampton,VA, May 1994.
6. P Collins, R Stockmans and M Maita, 1995, "Demand for Space Tourism in America and Japan, and Its Implications for Future Space Activities" AAS 95-605
7. P Collins, Y Iwasaski, H Kanayama and M Ohnuki, "Commercial Implications of Market Research On Space Tourism". Space Energy and Transportation, Vol. 1, No. 1.
8. Aviation Week and Space Technology, p. 46, Nov. 4, 1996.
9. 'Commercial Space Transportation Study Final Report', May 1994, previous cite. Section 3.7.3 "Space Medical Facilities"
10. 'Commercial Space Transportation Study Final Report', May 1994, previous cite. Section 3.6 "Entertainment"