In 1995 the first phase of the JRS Space Tourism Study Program was completed with the publication of the design of the " Kankoh-maru" reference vehicle designed to carry 50 fare-paying passengers on scheduled flights to low Earth orbit (3). Members of the Transportation Research Committee included staff from Kawasaki Heavy Industries, Mitsubishi Heavy Industries, Fuji Heavy Industries, Ishikawajima Harima Heavy Industries, Nissan Motor Company, All Nippon Airways, Teisan, Japan Aircraft Development Corporation and the Institute for Space and Astronautical Science. Since then the Transportation Research Committee has completed a second phase of activity, revising many details of the design of Kankoh-maru, estimating the time and budget required for its development and flight-testing, and estimating its manufacturing costs based on a nominal production scenario of 52 vehicles over 7 years (4).

Changes made in the design of Kankoh-maru during the second phase of the Committee's work included more detailed analysis of all the different sub-systems, including the vehicle structure, the propulsion system and the propellant tanks. It also included re-evaluation of all the on-board electric power requirements. As a result the budget was reduced from 38kW to 15.3kW as shown in Table 1.

Table 1 Initial and Revised Kankoh-maru Electric Power Budgets

In addition to the technical details of the specification of Kankoh-maru, its manufacturing costs are also strongly influenced by the planned development and production schedule. As shown in Table 2, the reference scenario assumes a 4-year development phase. This is followed by the initial production of 4 vehicles which perform 1200 test-flights over a 3-year period in order to obtain certification for passenger carrying. After this the production phase begins with a rate of production of 4 Kankoh-maru vehicles/year for two years, followed by production of 8 vehicles per year for 5 years. The 4 test vehicles are refurbished for passenger carrying in the first year of production and operation.

Table 2 Development, Test-Flight and Production Schedule of Kankoh-maru

The analysis of the development cost of Kankoh-maru involved breaking the vehicle design down to a more detailed level than had been done in the first phase of the JRS Study Program, analysing the various components and their specifications, and estimating the amount of development work which is required. For components not currently available in Japan, an alternative to domestic development is to purchase from abroad. Several different factors enter into such a decision, including the relative cost of imports and of domestically developed components, the expected market potential of different components, and the scale of foreign participation in the project, including in its financing. The overall development cost estimate is shown in Table 3.

Table 3 Summary of Kankoh-maru Development and Manufacturing Cost Estimate

It should be noted that the Kankoh-maru cost estimate is based to a large extent on the development cost of the H2 rocket, of which the development was successfully completed by NASDA in 1994. The development of the H2-A rocket, based on the H2, is currently under way, and its manufacturing cost is planned to be less than 50% of that of the H2 which it will replace. This progress is being achieved in part by including components and technologies purchased from abroad. Consequently it is possible that the estimate of Kankoh-maru's development cost is significantly higher than it would be if based on international prices.

In addition to cost estimates made by each participating company, the "TRANSCOST" model (Ref. 5) for estimating development costs of launch systems was used to provide a check of the results. Interestingly, the originator of the TRANSCOST model, Dr. Koelle has himself also estimated Kankoh-maru's development cost, and reached a figure of $2.2 billion, excluding the development of new rocket engines, which is significantly lower than the JRS estimate (Ref. 6). It is also notable that, in his paper discussing the cost of Kankoh-maru, Koelle estimated the cost per flight at flight rates of 10 flights/year, 100 flights per year and 1,000 flights per year, which are much lower than the rates of up to more than 15,000 flights per year considered in the JRS study. In this connection Koelle stated "... the conditions for 1000 or more launches per year are very difficult to assess with present data base and experience" (Ref. 6).

This idea has also been expressed recently in a 1996 AIAA paper (Ref. 7), namely that the lower launch costs of reusable rockets will enable economies of scale to be obtained in operating costs, which can become as significant as those in large-volume manufacturing. Consequently all conclusions about both manufacturing and operating costs of a fully reusable passenger launch vehicle such as Kankoh-maru designed for a high usage rate contain considerable uncertainty as to how low costs may fall. This uncertainty is mainly a reflection of the lack of experience of operating reusable rocket powered vehicles, in contrast to the growth of many orders of magnitude in airline operations to reach their current scale of more than 1 billion passengers per year, and which has led to a dramatic reduction in cost per passenger, making air travel a common experience for middle-income people.

During 1994 and early 1995 a series of meetings were also held to discuss business aspects of the Kankoh-maru project. As a result of their studies the members of the Transportation Research Committee had become keen to develop and manufacture the Kankoh-maru passenger vehicle and the associated parts and propellant supplies required for its operation. However, as in the aircraft industry, investment in developing Kankoh-maru could not be committed until firm orders were placed with the makers. And before operating companies could place firm orders to purchase or operate Kankoh-maru, they need a clear understanding of many issues concerning its operation, which were not decided in the initial study. It was therefore understood that these issues needed to be studied further.

Another foundation of these discussions was the understanding that unless a space tourism service was planned to grow to a substantial level - that is, of the order of some hundreds of thousands of passengers per year or more, requiring the operation of 50 or so Kankoh-maru vehicles - the development of this vehicle would probably not be feasible as a commercial project. From the results of market research performed in Japan since 1993 and in Canada, Germany and USA in 1995, a global market of as many as 1 million passengers per year seems feasible if the price of a flight could be brought as low as about \2 million ($20,000) per person (Ref.s 8, 9, 10). Aiming at a market of this size has important implications for selecting the subjects that need to be studied.

The establishment of the JRS Space Tourism Business Research Committee was formally approved in April 1995, and meetings were held monthly thereafter. Attendees at these meetings included staff of Kawasaki Heavy Industries, Dentsu Communications, Shimizu Corporation, the Institute of Space and Astronautical Science, Tokyo University, Teisan, Rocket Systems Company and retired experts from Chiyoda Corporation and All Nippon Airways. The following are some of the main issues considered by the Committee.

A major implication of aiming at a market of hundreds of thousands of people per year is that this would involve reaching a level of activity of tens of flights per day. Although this level of activity would be less than 0.1% that of commercial aviation, which carries some 3 million passengers per day, space travel will nevertheless become a relatively large-scale activity, and an "ordinary" means of travel for members of the public. Since it is necessary to strictly minimize costs in order to reach the price target of \2 million per passenger, building dedicated "spaceports" costing tens of \ billions would not be attractive; it will be far preferable to use existing airports. This is itself a major change of image for the future of space flight, which has for decades been considered to require expensive, specialized facilities. But that flights to orbit should take off from ordinary airports between airline flights to terrestrial destinations is a firm conclusion revealed by straightforward business considerations.

The Business Research Committee therefore studied the requirements for operating Kankoh-maru from existing airports (Ref. 11). Airport modifications required to permit Kankoh-maru operations include cryogenic propellant facilities; a dedicated "Departure and Landing Facility" (DLF); passenger handling arrangements; compliance with noise regulations; integration into air traffic management systems, and other matters. Among other results, it was found that for an airport built on an artificial island such as the new Kansai international airport, the noise of launch would probably not be a serious problem since the nuisance to the public depends not only on the loudness of the noise, but also on how often it is repeated. Even a traffic level of 1 million passengers per year requires only some 60 flights per day world-wide, and so the number of flights from any one airport would be very few compared to airline flights (Ref. 11).

Using existing airports will also be appropriate for realizing point-to-point sub-orbital transport of passengers and cargo, which are considered to be potentially lucrative additional commercial markets for Kankoh-maru. By using existing airports rather than separate launch sites, these services could be readily integrated with existing transport systems. The Committee is considering certain airports around the world as candidates for case studies as first-generation space tourism service sites.

As shown in Table 3, the Transportation Research Committee estimated the cost of development, production of four vehicles and 1200 flight-tests (including financing) as approximately \1365 billion, (about US$12 billion), and the selling price as \71.7 billion (about US$630 million) per vehicle. Based on these estimates, Kankoh-maru's operating costs have been estimated, and a reference scenario for the possible growth of a commercial space tourism industry was prepared. This helps to reveal the commercial potential of space tourism activities in more detail, by identifying the financial flows that would arise, the relative shares of participating industries, critical cost targets, and other aspects.

Figure 1 Image of Airport Facilities for Kankoh-maru Operation

The rate of production of 8 Kankoh-maru vehicles per year was selected as being feasible both for vehicle and engine manufacturers, and for the growth of cryogenic propellant production. That is, since each vehicle's life is to be 10 years, a constant production rate of 8 Kankoh-maru vehicles per year entails a growth rate of flight activities of 2,400 flights/year/year, or some 100,000 passengers/year/year. In this case the production of cryogenic propellants will grow by approximately 1,000,000 tons/year/year, of which some 140,000 tons/year/year is liquid hydrogen. Because of the high cost of transporting LOX relative to its production cost it was concluded that it would be most economical for LOX to be produced on site at the airport, using the local electricity supply. LH2 would be imported in tankers from low-cost suppliers such as Canada and Australia. For this reason also, airports sited on artificial islands or beside the sea seem particularly suitable for Kankoh-maru operations.

Since Kankoh-maru has 12 main engines, the rate of production of rocket engines is some 96 per year. However, the engines will require regular overhauls, and so parts production will grow in proportion to the cumulative number of Kankoh-maru vehicles in operation giving good potential for reducing unit costs through large scale production. More specifically, the sets of engine spare parts replaced during overhaul assumed necessary every 100 flights will increase by 288 sets (ie 3 x 96) per year per year to 1800 sets per year once 50 Kankoh-maru are in operation, providing scope for cost reduction through automation.

Preparing such a scenario facilitates understanding of the potential industrial, commercial and financial impacts that could be expected from creating a space tourism industry based on Kankoh-maru. For example, launch vehicle manufacturers, rocket engine and aerospace component makers, propellant producers and materials companies will all participate in the cash-flows received from the public by the vehicle operating companies. New business opportunities will also arise for companies providing investment, insurance, leasing, banking, marketing, media and law services. Growing at a rate of 100,000 customers/year/year, such a service would grow within a few years to generate annual revenues of more than \1 trillion year (US$10 billion), as shown in Figure 2. Such an infusion of new life into the aerospace industry of participating countries is particularly desirable since the aerospace industry around the world has been contracting sharply since the end of the Cold War (Ref. 12).

Figure 2 Scale of Business Opportunities Arising from Kankoh-maru Operations

This scenario is also useful in understanding the solution to the "50:50 Problem" facing makers of expendable rockets. Today, about 50 expendable rockets are made per year, which are used to launch about 50 satellites, earning revenues of some $3-4 billion per year worldwide. Although this business is quite small (by comparison, for example, with car manufacturing, in which many individual companies earn more than $30 billion per year) it is relatively stable. If a single reusable launch vehicle is made which can launch one satellite per week, expendable launch vehicle makers would have no more business. In the absence of large new markets, it is thus clearly against the corporate interests of existing makers to develop a reusable launch vehicle (Ref. 13). However, operating Kankoh-maru fleets like airlines to serve the enormous demand for passenger travel to orbit will generate revenues many times greater than the current launch market, and will enable the launch industry to escape from this obstacle to the growth of space activities. To date no other potential launch market has been proposed that offers the same potential.

Another subject which the Committee has considered arises from the fact that a large majority of those who wish to travel to space state that they would prefer to stay in orbit for several days rather than for only a few hours (Refs 8, 9, 10). Carrying out more detailed market research is highly desirable, in order to understand the requirements and potential of this market better. However, the Committee have provisionally assumed that in order for demand for orbital travel to reach the level of hundreds of thousands of passengers per year, it will be necessary to offer customers the possibility of staying in orbiting accommodation for a few days. The Committee have therefore also been studying the requirements for "space hotels", although only at a preliminary level to date.

Although no detailed estimates have been published of the relative costs of a flight to orbit and of a stay in orbital accommodation, it is clear that as guests stay for longer periods the growth potential is substantial. A few hundred thousand passengers per year staying in orbit for even 2 or 3 days on average will create a simultaneous orbital population of several thousand guests - and an additional population of more than 1000 hotel staff. Preliminary cost estimates show that this new business activity of orbital accommodation services will also grow to a substantial scale, as shown in Figure 3. In addition to launch service providers and propellant producers, the new businesses of architecture, construction, component production, interior design, building utilities, food, drink and entertainment services will all participate in the cash-flows of the companies operating accommodation in Earth orbit. At the same time, investment in new facilities will generate additional activity on a similar scale.

During its meetings, the Business Research Committee identified a number of other topics that require further study. These include the possible benefits of demonstrator vehicles, the potential of media support for space tourism, and regulatory issues. The latter include changes in regulations needed to permit Kankoh-maru to operate from airports, revision of space law, and building safety regulations for accommodation facilities in orbit (Ref. 14).

JRS ROCKET SYMPOSIA

In addition to the regular meetings of the JRS's two Space Tourism Research Committees, during 1996 and 1997 a series of four "Rocket Symposiums" were held in order to discuss and disseminate the issues raised by these Committees' research. These symposiums were proposed and coordinated by Professor Makoto Nagatomo, the current President of the JRS. Topics covered in these symposia also included related research performed outside the JRS study program. To date this research includes wind tunnel experiments on re-entry and precision landing of Kankoh-maru; rocket nozzle design to reduce noise; feasibility of Kankoh-maru attitude-control using differential engine throttling rather than engine gimballing; precision fuel management; selection of suitable orbital paths for Earth sight-seeing, and other topics.

Liquid propellant rocket engineering began some 50 years ago, and is commonly thought of as a mature field of technology, with a wealth of accumulated knowledge about different engine cycles and configurations, optimal propellant combinations, high-performance materials, and many other matters. However, the topics covered in this series of JRS Symposiums have shown clearly that rocket engineering is far from being a mature field, since rockets are still operated in a way very different from a mature transportation industry, and that a different kind of development work is needed before rocket operations will be integrated into society as a routine means of transport. The JRS Rocket Symposium Proceedings are being published as a book (Ref. 15), which it is hoped will shift the paradigm of rockets from being seen essentially as missiles to being seen as passenger-vehicles ("norimono" in Japanese).

Over the four years of the JRS study to date, the concept of space tourism has received increasing and increasingly serious attention from a growing range of different organizations. In Europe a preliminary feasibility study of the "Spacecab" low-cost passenger-carrying spaceplane was commissioned by ESA (Ref. 16), and its positive conclusions were subsequently confirmed by British government researchers (Ref. 17). In the USA a joint study of space tourism by NASA and the Space Transportation Association (STA) was initiated in 1995 (Ref. 18), of which the Steering Committee reached the view in 1996 that the problems facing the establishment of a space tourism business could be overcome within 15 years (Ref. 19). In February 1997 a workshop was held in Washington DC, from which the Final Report of the STA-NASA study is being prepared.

In 1996 a development path for space tourism services was conceptualized at NASDA through four phases - low Earth orbit, highly elliptical orbits with apogees providing views of distant Earth, orbital accommodation, and lunar excursions (Ref. 20), and in early 1997 as part of a NASDA study of the potential for popularization of space activities ("taishuuka" in Japanese), the development of space hotels was considered as a possible target (Ref. 21).

In May 1996 the $10 million "X Prize" was announced for the first private company to transport people safely to an altitude of 100 km twice within a period of two weeks (Ref. 22). This has generated considerable press interest, and to date entries from 15 different companies have been announced. In September the Space Tourism Society was established in Los Angeles, and its first international symposium is being planned to be held in 1998.

In February 1997 at the IEEE Aerospace Conference, three papers were presented on the topic of space tourism, including a design of a vehicle intended for space tourism by researchers at the Aerospace Corporation (Ref.s 23, 24, 12). In March the first ever International Symposium on Space Tourism was held in Bremen, where some 20 papers were presented, receiving national media coverage in Germany (Ref. 25). In early 1997 also the US National Space Society (founded by Werner von Braun) formally adopted the promotion of space tourism as one of its objectives. And in October the IAF Congress will for the first time have a session devoted to space tourism.

In addition, the results of the JRS Study Program, including both the Kankoh-maru reference vehicle design, and the feasibility of establishing a space tourism business, are receiving growing attention in the mass media both in Japan and abroad. The JRS's work has been the subject of newspaper articles in Asahi Shinbun, Sankei Shinbun and Yomiuri Shinbun in Japan, and in the Financial Times, Guardian and Daily Telegraph in England; in magazines including Dagian, L5 and Aera in Japan, and in Aerospace America (Ref. 26) and Aviation Week in the USA (Ref. 27); and also in books (Ref.s 28, 29, 30). The 1/20 scale model of Kankoh-maru built by Kawasaki Heavy Industries in 1994 has a full schedule of exhibition appearances, both national and international, and has appeared on both local and national television channels in Japan, Britain, Germany and USA.

JRS SPACE TOURISM STUDY PROGRAM PHASE 3

Due to the success of the JRS Space Tourism Study Program to date, and the growing international recognition which it has achieved, it was decided that the study should continue through a 3rd phase. In addition to the publication of the reports of the two Research Committees, and a book of the proceedings of the four Rocket Symposiums held during 1996 fiscal year, it has been decided that in addition to the Committees continuing their work, a promotional video will also be made about the Kankoh-maru project.

Although the credibility of the idea of space tourism has progressed a long way in recent years, it is still not very widely known. That is, although apparently most of the population would like to visit space, nevertheless most people believe that this will not be possible for many decades. Among the reasons for this situation is the widespread misunderstanding that traveling to space is stressful, and so only exceptional people can go to space. NASDA's astronauts have been making valuable contributions towards overcoming this misunderstanding. For example, Dr Chiaki Mukai has explained that astronauts' long training is primarily needed for the busy work-schedule that they must achieve while in orbit - not because living in space is stressful, and has stated that "anyone can go to space" (Ref. 28). And Dr Mamoru Mohri has explained that "space sickness" is a form of motion sickness and is cured by modern travel sickness medicines (Ref. 28); the reason why many people who travel on the space shuttle are sick is because NASA staff ask them not to take medication before take-off, because they wish to collect data for research purposes. It is hoped that the video about the Kankoh-maru project will make the growing body of work on space tourism more accessible to many more journalists, and will accelerate the acceptance of space tourism as a desirable new direction for space activities.

The Transportation Research Committee is currently planning three main subjects for study in its 3rd phase of activity. First, the regulations governing aviation, and particularly commercial passenger transportation, will be studied with a view to determining how far Kankoh-maru could comply with them, and how far it may be necessary, desirable and feasible to revise the regulations in order to permit the development of a commercial passenger space transportation industry.

Second, the design of the Kankoh-maru will be revised with the specific intention of meeting the requirements of certification for passenger carrying. In the initial design phase of Kankoh-maru, this was considered too difficult a target. It would also have involved discussions with regulatory authorities at a time when the concept of commercial space tourism was still unfamiliar; no clear picture existed of how it might develop; and even its feasibility was still doubted. However, it is now considered both feasible and timely to tackle this next stage of design detail which is necessary in order to finalise plans for a commercially viable passenger launch vehicle.

Third, the design of a cargo version of Kankoh-maru will be prepared. At the low launch costs envisaged for Kankoh-maru, there will be substantial demand for cargo launch services. In addition, as discussed elsewhere, there is a large potential demand for accommodation in orbit which will require the construction of hotels in orbit. This will need some thousands of tons of components to be launched into low Earth orbit, as well as continuing resupply of consumables, creating substantial demand for a dedicated reusable cargo launch vehicle. In aviation it is normal for cargo transport aircraft to be developed from a passenger aircraft, thereby achieving major economies in development and operating costs. This seems an attractive means of maximizing the benefit from developing Kankoh-maru.

The Business Research Committee is considering a range of follow-on activities, although it has not yet been decided in detail in what form it will be most appropriate to continue. Eventually it is intended that the Business Research Committee should be succeeded by a Business Committee, chaired by a senior figure from the Japanese business community with the objective of raising the investment required to develop a space tourism business. However, it is felt that further progress needs to be made in the following subjects before that stage is reached.

Safety standards and regulatory reform. Like aviation and other transportation systems, passenger space travel will need insurance, which in turn necessitates a range of appropriate technical standards. In each of the fields of passenger launch vehicle certification, airport accommodation of rocket vehicles, and design, construction and operation of orbital accommodation, various regulatory bodies, both national and international, play important roles. Work has begun on these issues in the USA. For example, the Office of Commercial Space Transportation was moved into the FAA in 1995 and a panel was held in 1996 to consider regulation of reusable rocket operations (Ref. 31). Proposals concerning regulation of commercial facilities in orbit have also been made (Refs 32, 33). International participation in these discussions from as early a stage as possible could facilitate achieving harmonious international standards.

The environment for initiation of space tourism services today is much more regulated than the environment in which aviation services were initiated early this century. Consequently, unless existing regulatory bodies do the necessary research and create an accommodating environment, this new business cannot start. That is, creating an encouraging regulatory environment is as essential as the development of the necessary technology, and as the articulation of adequate market demand. Institutional and bureaucratic change are difficult, but countries in which government organisations resist these changes will fail in this new field of international economic competition. Countries which participate in providing reliable, low cost access to space will have a leading role in a profitable space tourism industry, and in the new commercial space activities that will arise.

Reusable rocket demonstration project. Like other transport activities, the safety of commercial space tourism will depend ultimately on the demonstrated reliability of the vehicles, as measured by accumulated operating statistics. The very high level of safety achieved in the aviation industry is fundamentally based on statistics, which have been accumulated over decades of global operations. It is also based on one of the foundations of "aviation philosophy", namely that piloted vehicles are safer than unpiloted vehicles.

In aiming to establish a passenger launch service it is therefore highly desirable to start to accumulate experience of reusable rocket operations as soon as possible. Although the concept of passenger-carrying rockets seems unfamiliar today, during the 1950s Rocket-Assisted Take-Off ( RATO) aircraft employing reusable rocket engines were operated on a regular basis in the air forces of several countries', and a RATO version of the de Havilland "Comet" jet-liner was even certified for passenger carrying (Ref. 34). From 1993 to 1996 the unpiloted DC-X and DC-XA re-usable VTOL rocket vehicles performed 15 rocket-powered flights in the USA.

In order to achieve certification for passenger carrying, hundreds of flights of piloted rocket-powered vehicles will be required. It is therefore very desirable to start to accumulate experience of operating rocket-powered vehicles hundreds of times, in order to demonstrate the necessary reliability. During 1995 and 1996 the Business Research Committee studied the possibility of cooperating with McDonnell Douglas Aerospace and others to perform flights of the DC-X in Japan, possibly as part of a "world tour". This possibility disappeared with the accident that destroyed the DC-XA in 1996.

Three main configurations of VTOL demonstrator vehicle are now being considered; all three candidates share a number of key features, but they differ in their level of performance, and in their likely cost. In order to have a close connection with Kankoh-maru these must be piloted, powered by liquid hydrogen rockets, VTOVL, designed to be re-used hundreds of times, and to operate from airports in several different countries. The smallest useful size would be capable of reaching an altitude of 100 kilometers, which would make it a candidate for the "X-Prize" competition. This requires reaching a velocity of less than Mach 5, and so is very much easier than reaching orbit at Mach 26. Considerably more demanding than this would be a true "X-plane" orbital vehicle. Like the original US "X-planes", this "SX-1" would carry a single pilot, and would perform an incremental test-flight program lasting several years, and leading to repeated orbital flights. A third possibility is a small-scale Kankoh-maru, designed to carry perhaps 5-10 people to low orbit and back. This was proposed as the "Mikado" project in 1995 (Ref. 35). As flights of such a VTOVL test-vehicle accumulate, it will be possible to fly it at air-shows. Such activities might be sponsored commercially, and could have a beneficial influence in both publicising the concept of space tourism and demonstrating the maturity of the technology involved.

Orbital accommodation. Another subject requiring further study is the design of orbital accommodation, or "space hotels". The basic technology required for accommodation in low Earth orbit has been available since the "Skylab" space station was in operation in 1973-74, because the technology needed for orbital accommodation is in many ways much simpler than that needed for a scientific research station such as the current international space station project. There is no need, for example, for the advanced technology used in space research such as super-computers, high data-rate communications, high pointing accuracy, high power generation, and low-vibration centrifuges.

However there are some new requirements, since fare-paying guests require a higher level of both comfort and safety than the US and Russian research facilities that have been operated in orbit to date. These new requirements include normal features of hotels such as private bedrooms with windows and bathrooms, communal dining-rooms, lounges, bars and "karaoke-boxes", rooms with large windows for looking outside, and entertainment facilities such as zero-gravity play-rooms.

Just as commercial buildings on Earth must comply with professional codes of practice and with government regulations, so new construction standards will be needed to ensure guests' safety in orbit. In these and other respects the development of orbital accommodation will be similar to real estate projects on Earth, as discussed by Lauer and colleagues in the USA (Ref. 36). There is thus a need for systematic study of orbital accommodation, including orbit selection (which has major implications for the launch vehicle design), resupply logistics, safety standards and procedures, construction methods and other topics.

As a result of the first four years' work of the JRS Space Tourism Study Program, it is believed that all the problems facing the establishment of a space tourism business are soluble, although more detailed work is required on a number of subjects. These include technical issues relating to the design of Kankoh-maru and its sub-systems including the engines, and operability issues, since it is a novel challenge for rocket engineers to design a reusable rocket vehicle to operate routinely like an aeroplane in order to reduce operating costs sufficiently to match the demand for travel to orbit. They also include ancillary matters such as developing certification rules for commercial passenger launch-vehicles, and revising space law and aviation law appropriately. Resolving these issues satisfactorily will require collaboration of experts in a wide range of fields, and will be most effective if performed internationally.

In recent years public support for national space agencies has been declining in many countries. In addition, the development of reusable launch vehicles capable of reducing launch costs substantially can be economically justified only if they can serve a launch market many times larger than the market for satellite launches. Fortunately the concept of space tourism is very popular throughout the industrialized world, and offers a potentially very attractive new business opportunity for reusable launch vehicle operators. Consequently the idea that developing a space tourism industry is a desirable near-term objective for space development activities should receive strong public support as it becomes more widely known.

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