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SPACE TOURISM TO TAKE OFF?

It would have been too perfect. In spring 1998 the London Sunday Times announced that the Hilton International hotel chain is planning a five star hostelry on the moon. The "Lunar Hilton" was to be several hundred meters high and be fitted out with 5,000 beds and all "mod cons", to be expected from a luxury hotel, including its own beach on the shores of a manmade sea. In the meantime these plans have turned out to be a red herring generated by the PR media, and the Hilton Group has only recently distanced itself from such a plan.

Regardless of the technical problems of transporting people and building materials to the moon or even Mars, "ticket prices" would amount to hundreds of millions. Apart from this after the Apollo moon program was completed in the 70's, there are no space vehicles readily available today to transport people to far away stars.

Creating the required transport infrastructure would swallow up investment costing billions, which means that moon and Mars will not play a role for tourism in the first half of the 21st century. It has to be said that Mars with its many earthlike factors and possible life forms is one of the most interesting destinations in the planetary system. Nevertheless, space tourism will concentrate for the immediate future on the space nearer to the Earth that is much easier to get to.

To this end serious research has been going on since the middle of the 60's. For the last ten years various future scenarios with regards to the transport and accommodation of tourists have been analysed in Japan as requested by the local industry. In America NASA and the Space Transportation Association have just completed a study into the feasibility of space tourism, with promising results.

In Europe and Germany this topic could become more important in the next few years. The European Space Agency (ESA) commissioned the German Research Center (DLR) to check a variety of space tourism scenarios to find out if they are economically viable. Dasa currently occupies a team of experts in Bremen to look into this topic.

All these activities indicate that space tourism is gaining more and more importance globally. Parabolic Atmospheric flights in commercial aircraft, which briefly simulate weightlessness, can be booked today and furthermore you can put your name down for future flights into Earth orbit - after you have paid a deposit. However, cost efficient technologies for the latter are still not available.

As soon as a ticket into space is on offer for some DM10,000, which might happen in the next few decades - at best at a price of a comparable Concorde flight from Europe to America - a global market for tourism into near Earth space will be established. First national and international market analyses show that even today a considerable number of people are prepared to part with a lot of money for a short trip into space. On principle 4.3 per cent of all Germans are willing to spend a year's income on such a trip.

Various studies indicate that the number of passengers is directly dependent on the cost for a ticket into space. The current forecast for a space ticket is tens of millions. There will not be many takers for these tickets. However, the number of passengers rises sharply with sinking "fares". At a price of $1,000, 20 million passengers are expected annually. Even at a ticket price of $50,000 one million passengers would fly into space every year.

The fact that tourism in space flight has not yet taken off must result from the high cost of manned space flight. To transport a human into the close Earth orbit with the Russian carrier rocket Sojus for example, currently costs some DM10mio. Based on today's space transport infrastructure, space tourism is not affordable to the general public.

A drastic reduction in the cost of flight tickets of some DM10,000's to DM100,000 can probably only be expected from the 2nd next generation of space craft. These will be used for frequent launches, will be low in maintenance costs and the operation can be compared to today's commercially operated aircraft fleets. Globally, and especially in the USA, there are numerous companies, which are working on concepts for space transport vehicles.

In the next decade the so-called sub-orbital flights might be leading the way in space travel. These make possible a stay in space from two minutes up to two hours and landing after a vertical ascent into space or after orbiting Earth from where they took off.

In order to enable longer stays in space for tourists, the development of adequate "hotels" is required as well as the necessary transport craft. These "hotels" have to be stationed in orbit close to Earth. In the past, various concepts have already been looked into for this purpose.

In Japan industry has commissioned several designs for space hotels. The design of the Shimizu Company envisages a huge construction weighing 8,000 tonnes. However, this project will not be realised for a few decades to come. It might represent the penultimate generation of space hotels, which can be expected in the second half of the 21st century.

The Space Hotel Berlin that was designed as part of the above-mentioned ESA study, points into another direction. One would utilise existing technologies, by linking up modified crew modules of the International Space Station (eg the European Columbus Oribtal Facility, COF) to make up a circular "apartment complex".

The individual cylindrical apartment modules each have a big panoramic window and offer shelter against life threatening conditions in space and accommodation for up to four persons. Solar cells are fitted to these modules, which together with a battery charging system ensure the necessary energy supply. This is important when the space hotel enters the Earth's shadow for about 40min on its orbit.

Furthermore a connecting node with multiple functions, which also serves as a gangway, is docked onto each apartment and which has five further docking ports onto which depending on how far the extension has progressed, further modules can be connected. For safety reasons a rescue capsule is connected to each node, which safeguards the tourists' return to Earth in emergencies.

Each connecting intersection is angled at 30 degrees towards the module's main axle, which results in the circular structure of the Space Hotel Berlin by connecting twelve basic elements. The hotel can accommodate about 50 tourists. By rotating this circular structure at different speeds, different levels of artificial weightlessness can be achieved.

A further development of this concept is the Space Hotel Europe. The circular structure of the Hotel Berlin is expanded by numerous apartment modules and rescue capsules, which are arranged parallel to the main axis. A big central triangular solar cell module at the top end of the main rotating axle supplies the hotel with energy. Fixed docking modules are situated at the bottom, which are not connected to the rotating space hotel. In this way approaching and departing spacecraft can dock or undock more easily.

As far as their mass and the relevant costs of the two space hotels are concerned, they are more the International Space Station, for which the first construction flights have already been completed successfully. First analyses as to the economics of the space station indicate that the price of an overnight stay in the orbital space hotel will be at a sum of around five figures. The space hotels of the first generation will therefore be the world's most expensive hotels. It will be a big challenge for spaceflight engineers to lower the cost of transport and accommodation of people in space drastically. Only then will a ticket into space be affordable for the general public.

From page 56 of FLUG REVUE 12/99