The idea that the average person would some day travel in space has been an age long dream. Being able to travel by spacecraft seems closer to reality because of the Space Station "Mir", already in orbit since February, 1986, and by plans to operate the Space Station "Freedom" by 1998. Our imagination has also been stimulated by future life styles seen in science fiction movies and other media.

The desire to travel is rapidly expanding reflecting economic development and higher living standards. As a result, the travel industry has expanded into a giant market worth $500 billion. There is even a prediction that, by the end of the next century, tourism will be the world's largest industry.

Preparations have already begun for space travel. According to a survey done in England by American Express Co. (1), about 50% of those under 49 and 69% of those under 25 wanted to spend holidays in space. This increased interest is natural as the world's nations continue to explore the unknown.

A space plane designed to take off from a runway just like a conventional plane will ease the way for ordinary space travel. Travelers will not have to go through the tough training required for astronauts who use a existing-launch vehicle.

The popularization of space travel is expected to strengthen support for space exploration, speed development in the space industry, and have an impact on other areas.

Development of space tourism is expected to be in three stages.

1. Travel by Space Shuttle or space plane to earth orbit (Travel time of several hours)
2. A stay in an earth orbiting space hotel (Travel time of several days)
3. Travel to the moon and/or other planets (Mars, Venus, etc.) (Travel time of several weeks or more)

The first practical program for space tourism as a business proposition is Project Space Voyage, developed by Society Expeditions Co., Ltd, a Seattle based company specializing in exotic trips. This program was designed to send up to twenty tourists into a low earth orbit using the Phoenix E, a single booster rocket to be developed by Pacific American Launch Systems. The flight would orbit the earth about five to eight times and take about eight to twelve hours. By 1987,186 people made down payments of$5,000 on a total expense of $50,000. Delay in developing the Phoenix E has, however, vastly swollen costs, grounding the project indefinitely. This clearly shows, however, the market potential for space tourism and the obstacles that stand in the way of a successful program.

The purpose of this paper is to study the feasibility of tourists staying at an earth orbiting space station hotel (Development Stage 2). The economic viability of this idea will be emphasized. A space station hotel proposed this year by Shimizu Corporation was used as a model (See Fig. 4-1). Simulations were run on the transportation costs, which will greatly affect the demand for space travel and its total costs. Cost considerations have a direct relationship on future demand for space travel. In this paper we have tried to clarify a number of conditions essential for putting a space station hotel into orbit on a commercial base.

The space hotel model used in the cost simulation is designed to meet the specific environmental requirements with adequate facility size and function. Some of the hotel's main features are described below.

The hotel consists of the following elements (Fig. 5-1)

1. Platform area

   The platform is used for docking and releasing a space plane with passengers and cargo.

2. Energy support area

   The section contains a solar battery panel, a radiator panel, other energy facilities, and a control center.

3. Hotel public area

   The section contains a space hall truncated octahedron 4.62 and a theme module of, and serves as an amusement facility for all hotel guests.

4. Guest room area

   This section contains guest rooms and supply modules. Artificial gravity is provided.

The hotel guests are usually in a normal gravity environment (close to 1G) but can experience zero gravity whenever they choose; such an arrangement is essential for an enriched space travel experience. To achieve this, we propose applying artificial gravity to each guest room area. This will eliminate the inconveniences of zero-gravity (i.e. showering, toiletting, and washing) and make for a more enjoyable resort experience.

A controlled simulation demonstrated a gravity of 0.7G, a hotel revolution of 3 rpm, and a rotation radius of 70 meters. See Fig. 5-2 for the relationship between these factors and the comfort areas.

A guest room module facing the earth (Fig. 5-3) will be connected to one isle module (5 degrees min.) placed on a 70 meter radius circle producing artificial gravity of 0.7G. The modules measure 7 meters in length and 4 meters in width. Of the nine isle modules (45 degrees min.), one is connected to a transfer tunnel extending from the vertical shaft and serves as an elevator hall. Because of this a total of sixty-four guest room modules can be installed, In other words, within a 45 degree area there will be eight guest rooms modules in one group, one elevator hall module, and two crew modules, one utility module, and one supply module which face opposite to earth (see Fig. 5-4), The number of guest rooms is consistent with ideas proposed in the early 1980s by Rockwell International and in 1988 by Space Habitation Design Associates that the Space Shuttle's payload bay passenger capacity of 72-74.

Because a long stay in space may negatively influence the body's condition, visits to the space hotel will be rather short. Another consideration is to allow as many people as possible to have this experience. Therefore, a six day long space travel package has been devised. The schedule includes passengers receiving a simple two day training program and lectures on space life at a spacepoint on the earth. On the afternoon of the third day, they will leave the earth for the space hotel for a two night stay (48 hours) and wll return to earth on the afternoon of the fifth day (Fig.5-5).

DAY	1ST	2ND	3RD	4TH	5TH	6TH
AM	(SP) Arrival	(SP) Training	(SP)	(SSH)	(SSH)	Dismissal
PM	Orientation	Lecture	SP Departure SSH Arrival	(SSH)	SSH Departure SP Arrival Party

Assuming that the Space Shuttle will be used to send construction materials into space, transportation expenses will he the most expensive factor in the construction of the hotel. In other words, construction costs are determined by tonnage of materials to be launched. The following shows the total estimated weight of various sections of the hotel.

a. Modules

Guest rooms and utilities: 96 units x 15 tons/unit=1,440 tons
Theme modules: 8 units x 30 tons/tinit=240 tons
Theme modules: 4 units x 45 tons/unit=180 tons
Total=1,860 tons

b. Torus Section

Torus: Approx. 68 bays
Pyramid: 96 bays (large), 72 bays (small) -> approximately 250 bays
The weight of the truss section will be:
250 bays x 0.06 ton (60 kg/bay) = 15 tons

c. Shaft Section

Vertical shaft (equivalent to 20 small modules)
Torus cross part (equivalent to 28 small modules)
The weight of the shaft section will be:
48 x 15 tons/unit=720 tons

d. Facilities

The Space Station "Freedom" has a module/facility weight ratio of 1:2. Using this ratio the weight of the facility will be:
1,860 tons x 2 = 3,720 tons

e. Space Hall

Assuming that the truncated octahedron weighs 25 tons/unit, the total weight of 50 units will be:
25 tons x 50 = 1,250 tons

f. Solar Panel

The panel has a surface area of 3,000 sq m and weighs less than one ton.

In total, the space station hotel will weigh approximately 7,500 tons. Assuming that the Space Shuttle transportation cost will be $110 million/29.5 tons (as of 1987), the total construction cost will be close to: $110M/29.5 x 7500 = $28 billion

1. Define Premise

2. List major cost elements

3. Develop a formula for a financial break-even point between revenues and expenditures

4. Demonstrate the interrelationship between the annual guest number, travel costs per person, and transportation costs (using current U.S. costs at 100)

5. Present the survey results of the relationship between travel fees and number of travelers conducted by Society Expeditions in 1985 as an index for demand.

6. With the graph used in item 5 (above) take the maximum number ofannual guests (maximum capacity of the hotel) and find the point where the price would be suitable for the hotel to be fully occupied. Draw a transportation curve that will bisect the point.

Through the above procedures and based on the survey conducted by Society Expeditions, a rough estimate can be made of the appropriate travel and transportation costs needed to operate the hotel on a successful basis.

1. Price (P) including flight fee and accommodation is for one travel package

2. Travel package means 2 nights at a space hotel. (Actual stay on orbit would be about 2 days)

3. Workers (W) are those who work on a space hotel.

4. There is only one space hotel in orbit.

5. Maximum capacity of the space hotel is 64 guests per day.
   (Thus, if it is fully occupied, the space hotel would have 11,520 guests a year (64x360/2))

6. Transportation capacity and cost are based upon current U.S. Space Shuttle.

7. Fixed costs are assumed to be 10% of the total construction cost.

8. R & D costs of the space hotel and other facilities will not be taken into the consideration described here.

9. The depreciation period of the hotel is 25 years.

Revenues and costs are expressed as follows:

Revenue=G x P

Cost=TC+TS+PE+FC+DEP

G =

Total number of guests (tourists) per year at a space hotel

P =

Price of trip that tourist pays for the package tour

TC =

Transportation cost
Amount of dollar required for transport mankind

TS =

Total supply cost
Amount of dollar required for transport supplies

PE =

Personnel expense
Total amount ofsalary paid in one year

FC =

Fixed costs
Utility, communication, insurance etc.

DEP =

Space hotel depreciation per-year, 25 years

Each element is also be expressed as follows:

TC =

(STSPISTSC) xWTx (G+W+INS)

TS =

(STSP/STSC) >< S x (G+W'+ INS)

PE =

(W'+INS)XSAL

FC =

TCCXiO%

DEP =

TCC/25years=TCCXO.04

TCC =

(STSP/STSC) x SHM

Where,

STSP =

Launch price of Space Shuttle ($110,000,000)

STSC =

Payload capacity of Space Shuttle (29.5 tons)

WT =

Weight (a person + his/her baggage) (100kg =0.1 ton)

W =

Total number of workers who work on orbit. 20 workers shall stay in a space hotel for three months W = 20 x 4 = 80/year, W' = 20 x 180, TRIP=3600/year

S =

Weight of supply for one person per trip (2.78kg per day = 5.56kg for 2 days)

INS =

Total number of instructors (8 per trip, 1,440 per year)

SAL =

Amount of salary paid for 2 days ($800)

TCC =

Space hotel total construction cost

SHM =

Weight of a space hotel (7,500 tons)

The number of guests required for a break-even point to be reached is as follows:

Break-even point means Revenue = Cost, so G x P=TC+TS+PE+FC+DEP

By substituting known numerals the following is obtained:

G=	(STSP/STSC) x 1230 + 4,000,000
	P-(STSP/STSC) x 0.106

In Fig. 6-1, the X axis shows price P (unit: $1,000) and the Y axis shows the annual number of travelers (unit: 1,000 persons). The graph shows the relationship between price and the annual number of space travelers needed for a break-even operation when transportation costs are reduced from one to five percent of the Space Shuttle launch costs. SE shows the Society Expeditions 1985 survey of expected demand (see Fig. 6-2).

Taking the SE survey, the required number of tourist would be 11,520 when the price set around $43,500. A price-tourist curve throtigh this point (X: 43,500, Y: 11,520) has 4.3 points against 100.

A break-even point can be reached with this combination of $43,500 in price and 11,520 guests. The hotel will be fully booked with this guest number. Thus, transportation costs must be kept at 4.3% or less of the cost needed to launch a Space Shuttle.

If Society Expeditions demand expectation is correct the shaded area shown in Fig. 6-3 will generate profits or at least break-even under the following conditions.

1. The transportation cost is 4.3% or less.
2. The price-tourist curve does not exceed Society Expeditions curve.
3. The shaded area does not exceed 11,520 (the maximum number of possible accommodations)

In the shaded area which shows price of more than $43,500, a profit can be made but the hotel will not be fully booked. For example, at a point on the Society Expeditions demand expectation line which shows 5,000 guests, $50,000 in price, and about a 3.6% transportation cost, a break-even point can be reached but the hotel will not be fully booked.

COST/SEAT	SPACE TOURISTS/YEAR	TOTAL REVENUES
$5M	10	$50M
$1M	50	$50M
$500,000	100	$50M
$250,000	200	$50M
$100,000	500	$50M
$50,000	5,000	$250M
$25,000	30,000	$750M

This paper has proposed a space station hotel that meets various conditions required for space tourism in the 2nd development stage. The proposed hotel was used as a model in cost simulation. Successful operation of such a facility must include consideration of the following.

1. The potential demand from the general public for space tourism is high. Development of tourism will bring space closer to the average person while expanding the space industry.

2. Cost simulations have shown that the cost of transporting construction materials is the largest expense.

3. Reduced transportation cost will be necessary for the space tourism to be successful business.

4. Transportation costs need to be reduced to 4.3% or less against 100 (current Shuttle transportation costs per ton).

5. The space plane, expected to play a central role in future space mass transportation systems, should be operated at 4.3% of the cost needed to launch the current Space Shuttle.

1. American Express Co., Personal communication (1986)
2. Robert Citron, 1985, "The Space Tourist", AAS Space Development Conference
3. SICSA Outreach Vol.1, No.5
4. Tatsuo Yamanaka, " Gingatetsudou no Eki"
5. P Q Collins and D M Ashford, "Potential Economic Implications of the Development of Space Tourism"
6. Jerome Richard, June 1989, " In Search of the Ultimate Vacation", Final Frontier Vol.2
7. Patrick Collins, "Space Tourism - The Door into the Space Age", Analog Science Fiction/Science Fact
8. Makoto Nagatomo, " 1992 Uchukankouryokou", Yomuri Science-5