A Study Conference on Space Tourism was first held on April 14 1993, as a part of the JRS Annual Meeting in Tokyo. At the suggestion by Professor Nagatomo of ISAS (the Institute of Space and Astronautical Science), the theme Space Tourism was then selected as an academic research program of the JRS. [1] Soon the Transportation Research Committee was established to prepare a conceptual design of a vehicle suitable for Space Tourism, which has been led by Kawasaki Heavy Industries. The members of the committee include staff from Japanese major aerospace industries, such as Mitsubishi Heavy Industries, Fuji Heavy Industries, Nissan Motor Company, All Nippon Airways, Teisan. The ISAS, the National Development Agency (NASDA) and Japan Aircraft Development Agency (JADC) have also been participated in the meeting of the committee as observers.

The Transportation Research Committee has already seven years in its history of Space Tourism study as shown in Fig. 1. Now the activity has got into the third phase.

Fig. 1 Space tourism research program of JRS

A reference model of the space tour vehicle was studied in the first phase of the study program from 1993 to 1994 in order to study passenger service, medical aspects and business development (Fig. 1). The model capable of carrying 50 passengers resulted in atakeoff weight of 550 tons and a body length of 22m (Fig. 2). [2]

In the next study program phase, the Transportation Research Committee prepared a development schedule in detail including the total development and manufacturing cost. [3] The cost estimation activity was then transferred to the Business Research Committee, which studied the issues of vehicle operations. The cost study, which is based to a large extent on the development cost of the Japanse H2 rocket and on the experience of aircraft development in the past, has been first evaluated using a cost engineering model by Koelle. [4]

Due to the growing international recognition of JRS Space Tourism study program with the vehicle's name of Kankoh-maru, it was decided to continue it through third phase. In order to ship such kind of space tour vehicles into the commercial based market and to the passenger transportation services, it has been gradually recognized that the establishment of a regulation is necessary for certifying their safeties. The selected main subject by the Transportation Research Committee was to give considerations on the safety standard for the space tour vehicles in contrast with the existing airworthiness of Japanese aviation regulations. [5]

Fig. 2 Space ship " Kankoh-maru"

The third phase study has begun to review the existing Japanese aviation regulations that specify the airworthiness of airplanes and helicopters, which have been established by the Civil Aircraft Bureau of the Ministry of Transportation. The main purpose of the preparatory step is to understand the safety design philosophy of aircraft based on many decades of experience in certification with commercial context.

The lessons learned through reviewing the airworthiness of aircraft gave us an amount of considerations what are going to be needed for certifying space tour vehicles with the same reliability and safety standards as the current commercial aircraft.

Since the space tour vehicles operate beyond the regimes in speed and altitudes of subsonic and supersonic aircraft, the certification regulations are to be tailored, modified and added with new issues of environmental conditions during exo-atmospheric and reentry flight. The issues of safety standard that are unique for space transportation have been discussed and listed.

The Transportation Research Committee is now working on arranging the draft of the safety standards, which will be expected to become a regulation model of "spaceworthiness". The final report of the research is going to be summarized at the end of the fiscal year 1998^*.

The Japanese aviation regulations were first established in 1952, which cover all the types of aircraft for piloted airplanes, rotorcrafts, gliders and air-ships.

The original model of the regulations was completed based on the Federal Aviation Regulations (FAR) containing flight, structure, design/construction, power plant, equipment and operating limitations/information. The aviation regulation applied to the category of airplane is equivalent to the FAR Part 25, and that of rotorcraft corresponds to the FAR 29.

Although the existing aviation regulations do not cover all the issues of space-oriented design, production, test and evaluation, and operations, the new regulations for the space tour vehicles should first start with the basis of what is required for the commercial aircraft with respect to fail safe design and maintenance. The aircraft has been succeeded in the business of commercial passenger transportation with adequate reliability and public safety.

The authors agree with Gaubatz's idea on the "integrated certification process" that the space tour vehicles should be designed with "built-in" safety margins using existing commercial aircraft fail-safe design rules and method. [6]

The Space Transportation Committee has conducted to assess the applicability of the Japanese aviation regulations specified for the airplane category type T and the rotorcraft category type TA/TB to space tour vehicles. The summary of the assessment shown in Table 1 is that for the airplane category type T.

The vertical takeoff and vertical landing type ( VTVL) space tour vehicle has no wings. Thus the operation will be significantly different from an airplane. The particular airworthiness with respect to the issues of flight must be modified or newly defined.

In addition to the aerodynamic, the flight conditions that the structural design has to take into account are the cyclic thermal loads due to cryogenic propellant and reentry heating. The space radiation, debris, meteoroid and out-gas and off-gas of material are the new issues specified for operating in orbit.

Since the VTVL space tour vehicle is propelled by rocket system, most of the detailed issues of certification concerning airbreathing engine will be modified.

The role of the pilot who operates the VTVL vehicle may be similar to that of a modern airliner with highly automated flight management system using fly-by-wire. They shall retain ultimate responsibility for the flight. But concerning the launch and landing configuration, there will be significant differences in the actual attitude control from that of the aircraft. [7]

Based on the assessment of aviation regulations, the following standard issues typical for space tour vehicles are found as summarized in Table 2.

1. Type certification will need to be defined according to the vehicle's launch and landing configurations.

2. Critical design conditions involve space radiation, space debris, the high vacuum environment in orbit, and the thermal loads caused by reentry and by the use of cryogenic propellants.

3. Since Kankoh-maru and other space tour vehicles will have highly autonomous flight control systems, the control authority given to the pilots within the flight management system is a critical topic for the safety design standard.

4. Flight operations need to be defined for both nominal and abort conditions in the event of various vehicle failures.

5. Structural verification procedures on the ground need to be studied.

6. Redundancy requirements to ensure the ability to shift to safe abort flight in the event of engine failures need to be studied.

7. Design requirements for onboard equipment, such as the environmental control and life support system and space clothing, need to be defined.

8. Requirements for the flight manual must be carefully considered for Kankoh-maru and for every type of space tour vehicle.

As a provisional result of the phase 3 study, the spaceworthiness content is listed in Table 3 for the vertical takeoff and vertical landing type vehicle.

The regulation is divided into three parts, the first of which specifies the safety design issues of the vehicle design, the second part deals with the propulsion and the third with the reaction control system.

It is believed that the present study program by the Transportation Research Committee of JRS on the safety standard of space tour vehicle is one of the important steps to realize the commercialization of space transportation, after the forerunner of aircraft operated routinely all over the world for public utilization.

The safety standard required for the certification of space tour vehicles does not restrict their design, but changes the fundamental operation process from probabilistic launch to deterministic takeoff and landing with enough reliability and safety like aircraft. Thus it is increasingly recognized that the existing legal/regulatory environment needs also to be reformed for promoting the commercial passenger flights to and from space. [8]

The authors are grateful to the persons concerned with the Space Tourism study of the Transportation Research Committee ; especially Professor M. Nagatomo (ISAS), Associate Professor Y. Inatani (ISAS), Mr. Y. Naruo (ISAS), Mr. T. Torikai (Fuji Aerospace Technology), Mr. A. Watanabe (NASDA) and Dr. P. Collins (NASDA) for their kind advises and useful discussions.

1. M Nagatomo, 1993, "On JRS Space Tourism Study Program", the Journal of Space Technology and Science, Special Issue on Space Tourism, Vol. 9, No. 1, pp. 3-7,.
2. K Isozaki, A Taniuchi, K Yonemoto, H Kikukawa and T Maruyama, 1995, " Consideration on Vehicle Design Criteria for Space Tourism", Acta Astronautica Vol. 37, pp. 223-237.
3. P Collins and K Isozaki, 1997, "The JRS Space Tourism Study Program Phase 2", Proceedings of 7th ISCOPS, Nagasaki Japan.
4. D E Koelle, 1997, " Requirements for Space Tourism Launch Vehicles", IAA-97-IAA.1.2.05, 48th International Astronautical Congress, Turin Italy.
5. P Collins and K Isozaki, 1997, " Recent Progress in Japanese Space Tourism Research", IAA-97-IAA.1.2.02, 48th International Astronautical Congress, Turin Italy.
6. W A Gaubatz, 1998, "Reusable Space Transportation - The Key Infrastructure Element in Opening the Space Frontier to the Public", 98-o-1-01V, 21st International Symposium on Space Technology and Science, Omiya Japan.
7. E Anderson and P Collins, 1997, "Pilot Procedure for Kankoh-maru Operations", Proceedings of 7th ISCOPS, Nagasaki Japan.
8. P Collins and K Yonemoto, 1998, " Legal and Regulatory Issues for Passengers Space Travel", the 4th Session of the IISL.