A Review of Space Tourism Research
Iztok Bončina
University of Primorska, Ph.D. student at Faculty of Tourism Studies - Turistica iztok.boncina@guest.arnes.si
Since 2001, when the first tourist flew to the International Space Station and then six others after him, space tourism can be considered a reality. Although space tourism remains in its pioneering stage, it has been attracting research studies since the beginning of the 1990s. As a relatively new tourism industry, it is opening up new aspects of research in the fields of technology, economics, sociology, law, medicine, safety, insurance, and others. The purpose of this paper is a comprehensive review of the research areas of space tourism. The available scientific articles, books, contributions to scientific conferences, symposia and workshops dealing with space tourism have been reviewed. Following careful analysis, we have identified the most important space tourism research trends, as well as the scientists who have contributed the largest number of publications. We have also recognized the under-represented areas that would be suitable for further studies. The PhD program is partially co-financed by the European Union through the European Social Fund. Co-financing is carried out under the framework of the Operational Programme for Human Resources Development for the period 2007-2013, ESF priority area: Promoting entrepreneurship and adaptability; priority axis 1.3: Scholarship Schemes.
Keywords: space; tourism; flights; orbit; literature
Introduction
Space tourism has become a reality, although it remains in its pioneering stage. Currently, only people who can afford to spend between 20 and 30 million dollars can fly to the International Space Station, orbiting the Earth. However, as predicted by Ciccarel-li and DeMicco (2008, p. 15), the 21st century might see the greatest development of space tourism in the context of the tourism industry, which is constantly looking for new products and destinations. Studies have shown a desire to travel into space. Since the 1980s, many organizations have attempted to introduce space tourism, but high costs have prevented commercial forms of spaceflight (Klemm & Mark-kanen, 2011). Until 2001, when the first tourist flew into space, only a very minor part of the scientific literature was dedicated to the study of space tourism. Since 2001, tourism studies have begun to explore commercial spaceflight in many areas, although to
date only a handful of tourists have flown in Earth's orbit, and we still await the first suborbital passenger. The number of scientific publications, conferences and symposia dedicated to space tourism has also increased. In this review, we will examine the current publications of the scientific literature in the field of space tourism and attempt to identify the most important investigation guidelines of this new tourist industry.
The Purpose of the Literature Review
The purpose of this literature review is to identify the most important areas of this new tourist industry in the making, studied by the authors around the world. The review aims to discover the main trends of research of space tourism as well as the areas that receive less attention. We want to identify the most relevant authors, the most useful literature, and the scientific contributions in the field of space tourism.
The Current State of Space Tourism
The term "space tourist" is not currently widely accepted, but it is the most commonly used. To Klemm and Markkanen (2011, p. 95), the more appropriate term seems "public journey into space" or "private space flight". The European Space Agency (ESA) (2008, p. 19) use the term space tourism "[...] to mean suborbital flights by privately funded and/or privately operated vehicles and the associated technology development driven by the space tourism market."
Goehlich (2007, p. 215) suggests two definitions of space tourists. The first defines space tourists as passengers who pay for a flight into space, above Earth's atmosphere. The second defines the space tourists in a broader sense, as visitors to the attractions that simulating the "experience" of space (space theme parks, camps to prepare for space flights, virtual reality centres, interactive multimedia games, etc.) or tourists who take part in a variety of flights in the atmosphere, which, however, do not reach outer space (stratospheric and parabolic air flights). In this study, we will focus mainly to the two forms that can currently reach space: orbital and suborbital tourist flights.
Orbital Flights
Orbital flight occurs when a spacecraft reaches Earth orbit (an orbit is a gravitationally curved path of an object around a point in space) high above the atmosphere. The height of the so-called low-Earth orbit is somewhere between 160 and 2,000 kilometres. Orbital spacecraft are capable of extended periods in space, from two weeks (e.g. a Space Shuttle) to months and years for orbiting platforms, such as the International Space Station (Anderson, 2005, p. 58).
The first manned space flights to Earth orbit was on 12 April 1961, when Yuri Gagarin flew the Vostok 1 spaceship to orbit, and remained there for 108 minutes. Forty years later, in April 2001, the first space tourist Dennis Tito flew into space. He spent a week at the International Space Station (ISS) and paid the Russian Space Agency $20 million for this flight. He became a symbol of the development of space tourism (Livingston, 2001). Since Tito, there have been six space tourists in orbit: Mark Shuttleworth (South Africa) in 2002, Gregory Olsen (USA) in 2005, Anousheh Ansari (USA/Iran), Charles Si-monyi (USA) in 2007 and in 2009, Richard Garriott
(USA) in 2008 and Guy Laliberté (Canada) in 2009. These are the seven participants that can currently be characterized as space tourists1. The Space Adventure travel agency from Virginia, which organizes tourist flights into orbit in cooperation with the Russian Space Agency, announced a new tourist space flight for 2015. The flight is scheduled for the singer Sarah Brightman (Giacalone, 2013: 643).
Suborbital Flights
A suborbital flight is each flight of a special craft reaching a height of 100 kilometres2 and returning to Earth. It takes anywhere from 2.5 to 3 hours, with passengers experiencing weightlessness for about five minutes. The leading company for the suborbital flights is currently Virgin Galactic, which won the Ansari X-Prize and received $10 million for successfully launching the SpaceShipOne above 100 km twice within two weeks in 2004. (Burić & Bo-jkić, 2007). Their new craft, SpaceShipTwo, can carry six passengers to a height of 110 km. Virgin Galactic has already received over 700 passenger payments ($200,000 each) for participation in suborbital flights. Other companies actively testing craft for suborbital flights include Armadillo Aerospace, Bigelow Aerospace, Blue Origin, Planet Space, Space Dev, SpaceX.
Methodology of the Literature Review
We have reviewed the scholarly books in the field of space tourism available at some of the largest online bookstores (Amazon, Barnes & Noble, Books at Half, Google Books), published mainly in English, and have identified 23 publications that focus directly on space tourism. We also searched for scholarly books and articles with the help of the online scientific information databased Science Direct and Space Future. The latter offers over 220 papers focusing on space tourism. Further titles were discovered by reviewing the references in the published literature. The literature was then further analysed and divided
1	Some authors consider the first tourist to be Japanese journalist Toyohira Akiyamo, who flew to the Russian space station Mir in 1990. The flight was paid by the Japanese television company TBS (Akiyama, 1993).
2	The boundary at 100 km is called the Karman line and roughly represents the administrative border between Earth's atmosphere and space. It was defined by the International Aeronautical Association.
into eight space tourism study areas addressed by the authors. Given the fact that we can consider the year 2001 to be the start of orbital space tourism and that the suborbital commercial spaceflight began three years later (although, due to the technical and administrative reasons, no tourist has yet to make such a flight), priority was given to the selection of literature published after 2001.
The Most Important Authors and Fields of Space Tourism Investigation
Examination of the selected literature identified eight in-depth researched areas or aspects of space tourism:
Research area
Author
Space tourism market research
Abitzsch, S. (1996) Barrett, O. (1999) Burić, T., & Bojkić, L. (2007) Collins, P., et al. (1995) Crouch, G. I., & Laing, J. H. (2004) Devinney, T., et al. (2006) O'Neil, D. et al. (1998a, 1998b) Reddy, M.V. et al. (2012). Webber, D. et al. (2002) Webber, D., & Reifert, J. (2006)
Economic aspects of space tourism
Bensoussan, D. (2010)
Collins, P. (2006a)
Collins, P., & Autino, A. (2008)
Eilingsfeld, F., & Schaetzler, D. (2002)
Goehlich, A. R. (2007)
Livingston, D. M. (2000a, 2001a)
Legal aspects of space tourism
Collins, P., & Yonemoto, K. (1998) Dunk, F. G. (2013)
Eilingsfeld, F., & Schaetzler, D. (2002) Livingston, D. M. (2001b, 2002) Masson-Zwaan, T., & Freeland, S. (2010) Seedhouse, E. (2008) Yehia, J. A., & Schrogl, K. U. (2010)
Medical aspects of space tourism
Apel, U. (1999) Kluge, G., et al. (2013) Marsh, M. S. (2006) Mitarai, G. (1993) Seedhouse, E. (2008)
Spaceflights directly connecting places on Earth (point-to-point)
Peeters, W. (2010) Webber, D. (2010, 2013a)
Technological aspect of space tourism
Anderson, C. E. (2005) Zakaria, N. R., et al. (2011) Goehlich, A. R., et al. (2013) Collins, P., et al. (1994b) Livingston, D. M. (2000d) Giacalone, J. A. (2013) Rogers, L. (2008) Torikai, T., et al. (1999) Webber, D. (2005)
Research area	Author
The analogy of space tourism with some other areas of tourism Fawkes, S., & Collins, P. (1999)
Robson, S. (2003) Spennemann, H. R. D. (2007a) Stine, G. H. (1996) Webber, D. (2003)
Development trends in space tourism	Collins, P. (2002, 2003a, 2003b, 2006c)
Favatà, P. (2001) Genta, G., & Rycroft, M. (2006) Goehlich, A. R., & Schumann, D. (2004) Hilton, B. (1967) Kramer, R.W. (2011) Martinez, V. (2009) Nair, G. M., et al. (2008) Spennemann, H. R. D. (2007a, b) Srivastava, M., & Srivastava, S. (2010) Webber, D. (2012)
Based on the number of articles in various scientific journals and papers at various scientific conferences, symposia and workshops, the following authors were identified as the most important in the field of space tourism: P. Collins, D. Webber, D. M. Livingston, G.I. Crouch, D. Ashford, R. A. Goehlich.
Space Tourism Market Research
Since the early 1990s, approximately ten in-depth market studies of space tourism have been conducted. Particularly in industrialized countries, the studies were carried out by independent researchers, governments, various organizations or private companies that wanted to support their intention to invest in space tourism with concrete numbers (Crouch, 2001). Most studies have been conducted by Collins and others who have studied public interest in tourist space flights in Japan (Collins et al., 1994; Collins, Stockmans, & Maita, 1995) as well as in Canada and the United States (Collins, Stockmans, & Maita, 1995). The results of studies conducted in the U.S. on a sample of 1,500 American families were reported by O'Neil and others (1998a, b); this study was jointly conducted by the National Aeronautics and Space Administration (NASA), the Space Transportation Association (STA) and Georgetown University. Ab-itzsch (1996) studied the German market in 1996, and Barrett (1999) repeated his studies three years later, this time in the UK. How interested Australians were in space travel and how much they would willing to pay for it was studied by Crouch and Laing (2004). One of the most extensive and in-depth market stud-
ies of space tourism was conducted by Futron/Zogby in 2002. The study was expanded and complemented in 2006 (Futron, 2006). It is considered a reference for orbital and suborbital flights (Webber et al., 2002; Webber, 2003; Ziliotto, 2010).
Economic Aspects of Space Tourism
The authors agree that space tourism as a future new tourist industry can be economically and socially highly beneficial. Primarily, it can create new jobs in the field of transport, astronautics, tourism and related fields (Livingston, 2001a; Collins, 2006, Collins & Autino, 2008). While authors in the 1990s were still doubtful whether there was a potential market for tourist space flights (Collins, 1997), in the 21st century their focus is on the process of development of space tourism (Beery, 2012), the financial model for the maintenance of space tourism (Livingston, 2000a; Eilingsfeld & Schaetzler, 2002) and the development of products and services related to space tourism (Goehlich, 2007). Space tourism also raises new demands and risks, as well as new opportunities in the insurance sector. As Bensoussan writes (2010, p. 1633), the design of an adequate and affordable insurance regime for future space tourists is an important step towards the development of space tourism market.
Legal Aspects of Space Tourism
Collins (1998) was one of the first authors to propose the preparation and regulation of both national and international legislation concerning future space
flights. In his opinion, the most suitable model that could be emulated is that of the civil aviation industry. Wollersheim (1999) agrees but points to a number of complications that may arise in adapting existing laws to the new space tourism industry. He finds the preparation of entirely new legislation in this area to be a more sensible approach. Dunk (2011) notes that this issue is crucial and remains unresolved. In addition to the aviation law, he refers to legislation in the field of adventure tourism as a useful model for space tourism. The only author writing about the importance of ethical standards in space is Livingston (1999, 2000b, 2001b, 2002). He proposes the creation of an ethics code for commercial spaceflight that would, among other things, establish relationships between employees in the aerospace industry, respect for environmental values, and relations between prospective settlers and visitors to the Moon.
Medical Aspects of Space Tourism
Various factors (take-off and landing forces, weightlessness, vibrations, noise, radiation, etc.) affecting the human body during space flight have been explored on cosmonauts and astronauts for decades, ever since the first space launch; preparations and exercises are also adapted to these factors. Therefore, the medical aspect of commercial spaceflight is the most comprehensively covered of all the aspects of this literature review. However, as noted by Apel (1999), professional astronauts are chosen very carefully, mostly from among the best air pilots. For future space tourists, the trainings and stress tolerance during space flight will have to be adapted to different ages, genders, cultural backgrounds and levels of physical fitness. In order to avoid health problems, it will be necessary to take into account certain medical standards of both crew and passengers on commercial spacecraft (Seedhouse, 2008). For Marsh (2006), an important ethical aspect of spaceflight is ensuring that passengers and their personal physicians are well informed about potential health hazards of such tourism.
Spaceflights Directly Connecting Places on Earth (point-to-point)
One of the promising future forms of spaceflight that will be useful for tourist are the commercial spacecraft flights that directly connect places on Earth.
In this case, the spacecraft is launched into lower or higher orbit at one point the Earth's surface and then lands on another. In this manner, the flight time can be shortened; a flight from New York to Tokyo by plane usually takes 13 hours, while in this case would only last an hour and a half (Peeters, 2010). A relatively high ticket price will be offset by time savings, and we expect these flights to be of interest to business executives (Ibid.). Webber (2013) does not entirely agree with this and presents an analogy of point-to-point flights to the Concord, where more than 20 per cent of passengers were wealthy individuals, film stars, athletes, etc. Webber (2010) also points out the lack of research on the potential market for space flight directly connecting places on Earth, about which is so little is known.
Technological Aspect of Space Tourism
Space tourism is highly dependent on the development of space technology. Currently, orbital tourists can only stay on the International Space Station and fly on spacecraft intended and designed for professional astronauts or cosmonauts. Crafts for tourist suborbital flights have already been built but remain in the testing phase. Therefore, authors writing about the technological aspects of space tourism consider safe, reusable spacecraft, adjusted for tourist flights (Torikai, 1999; Livingston, 2000d; Anderson, 2005; Seedhouse, 2008). Collins, Akiyama, Shiraishi and Nagase (1994b) go a step further and point out the necessity for a suitable interior design of spacecraft and services that the passengers will enjoy during the flight. Alongside the construction of these technologies, it will be necessary to devise suitable launch facilities or "spaceports", where the prospective tourists will board the spacecraft (Webber, 2005; Zakar-ia et al., 2011).
The Analogy of Space Tourism with Some Other Areas of Tourism
Space tourism is a new tourist industry still in the phase of developing its own standards, requirements and needs. To improve the presentation and perception of space tourism, some authors, therefore, look for analogies with other, long-established forms of tourism. Most often, they make comparisons with the development of flights (Webber, 2003, 2013b) and adventure or extreme tourism (Spenneman, 2007).
Even before the beginning of the space tourism, an interesting analogy was made by Fawkes and Collins (1999). Future hotels in orbit were compared to passenger cruise ships that sail on the high seas, are self-sufficient, and the passengers cannot leave them whenever they want. The authors also speculate that, based on experience with cruis e s, some shipping companies could become major investors the future orbital hotels (Ibid.).
Development Trends in Space Tourism
Although space tourism is at an early stage, many authors have discussed more far-reaching goals of development of this industry in the future. Technologies for certain forms of space tourism already exist (suborbital and orbital flights, flight to the Moon and back), while the rest remains to be developed (Srivas-tava, 2010, p. 47). Most authors considering the future of space tourism refer to the development of space habitats (hotels) in orbit (Favata, 2001; Goehlich & Schumann, 2004; Martinez, 2007, 2009). The idea of a hotel in the Earth's orbit is not new, as it was introduced by Baron Hilton well over a decade ago (1997) at a conference of the American Astronaut Association. More futuristic forecasts of space tourism in the articles deal with commercial flights to the Moon and back (Collins, 2006c; Spennemann, 2007a, b) and permanent settlements on the Moon and Mars (Nair et al., 2008). Tourists' interest for these destinations can encourage potential investors (Spenne-mann, 2007). Broader discussions on commercial tourist flights to the other reachable Solar System bodies (mostly asteroids and moons of major planets) were not found in the literature. Due to the technological and human factors, manned space flights to these bodies are currently impossible and are not expected in the next few decades.
Conclusion
The literature on space tourism reflects the fact that this is a new kind of tourism in the making. There are simply not enough tourists going into space in order to draw in-depth conclusions; even the few tourists that have gone have only experienced the orbital flight. However, based on the number of articles published in scientific journals, contributions to numerous scientific conferences and published scientific books, we can conclude that the interest among
scientists for following the exploration of space tourism is considerable. Most of the contributions published in the 1990s predict that space tourism as an industry that will flourish in the near or distant future. We also found incorrect assumptions in the literature: for example, the anticipation of suborbital tourist flights before orbital flights (Fawkes & Collins, 1999). However, since 2001, when the first space tourist, Dennis Tito, flew into space followed by a few others, authors are discussing space tourism as a real fact of our time. More in-depth studies can be expected with the commencement of suborbital tourist flights. In the literature, we most often noted the interest in the study of space tourism from the perspective of economics, law, medicine, and historical analogies, such as development of the aviation industry, adventure tourism, etc. Some authors seek to address more futuristic predictions about the hotels in orbit, direct transport between places on Earth through space or tourist flights to the Moon and Mars. In addition to these areas, space tourism brings new avenues of research that the literature currently only scarcely covers. Apart from the contribution about space tourism in the book Cosmic Society: Towards a Sociology of the Universe (Dickens & Ormrod, 2007), we did not find a broader study of the sociological and psychological aspects of commercial space travel. With the exception of Livingston, there is also no research to be found on the ethics of space tourism or its ecological impact. Studies of motivation of potential space tourists are also insufficient. Some market surveys do ask questions about the motives for space travel, but the answers raise suspicions that the respondents were not informed about the specific features, requirements, preparations and dangers they can expect during space flight.
References
Akiyama, T. (1993). The pleasure of spaceflight, The Journal of Space Technology and Science, 9 (1), 21-23.
Apel, U. (1999). Human factors and health in space tourism. Paper presented on 2nd International symposium of Space Tourism , Bremen, Germany. Retrieved from http://www.spacefuture.com Ashford, D. (1998). Space tourism - The key to low cost access to space. Paper presented on work-
shop EXPLOSPACE, Sardinia, Italy. Retrieved from: http://www.spacefuture.com Abitzsch, S. (1996). Prospects of space tourism. Paper presented on 9th European Aerospace Congress - Visions and Limits of Long-Term Aerospace Developments, Berlin, Germany. Retrieved from http://www.spacefuture.com/archive/pro-spects_of_space_tourism.shtml Barrett, O. (1999). An evaluation of the potential demand for space tourism within the United Kingdom. Dorset, England: Bornemouth University. Beard, S. S., & Starzyk, J. (2002). Space tourism market study: Orbital space travel & destinations with suborbital space travel, Futron Corporation. Retrieved from http://www.futron.com Beery, J. (2012). State, capital and spaceships: A terrestrial geography of space tourism. Geoforum 43(i), 25-34
Bensoussan, D. (2010). Space tourism risks: A space insurance perspective. Acta Astronautica, 66 (1), 1633-1638
Burić, T., & Bojkić, L. (2007). Studija izvedivosti svemirskog turizma u Hrvatskoj. Research report. Ciccarelli, S., & DeMicco, F. J. (2008). Outer Space as a new frontier for hospitality and tourism. Hos-teur, 17 (2), 15-22. Collins, P., Iwasaki, Y., Kanayama, H., & Ohnuki, M. (1994a). Commercial implications of market research on space tourism. Journal of Space Technology and Science: Special Issue on Space Tourism, part 2, 10(2), 3-11. Collins, P., Akiyama, T., Shiraishi, I., & Nagase, T. (1994b). Services expected for the first phase of space tourism. Paper presented on 19th International Symposium of Space Technology and Science, Yokohama, Japan. Retrieved from http:// www.spacefuture.com Collins, P., Stockmans, R., & Maita, M. (1995). Demand for space tourism in America and Japan, and its implications for future space activities. American Astronautical Society paper, 91, 601610.
Collins, P. (1997). Space tourism - The surprising new industry. Paper presented at conference IEEE Aerospace, Aspen, CO. Retrieved from http://www. spacefuture.com Collins, P., & Yonemoto, K. (1998). Legal and regulatory issues for passenger space travel. Paper pre-
sented on 49th International Symposium Space Law, Melbourne, Australia. Retrieved from http://www.spacefuture.com
Collins, P. (2002). Space hotels - Civil engineering's new frontier. Journal of Aerospace Engineering,
15(1), 10-19.
Collins, P. (2003a). The future of lunar tourism. Paper presented at International Lunar Conference in Havaii, USA. Retrieved from 15.12. 2013 s http:// www.spacefuture.com/
Collins, P. (2003b). Growing popular interest in space tourism: Challenge and opportunity for space agencies. Paper presented at 54th International Astronautical Congress, Bremen, Germany. Retrieved from http://www.spacefuture.com
Collins, P. (2006a). Economic benefits of space tor-ism to Europe. Paper presented at symposium BIS „European Development of Space Tourism". Sag-amihara, Japan.
Collins, P. (2006b). The economic benefits of space tourism. The Journal of the British Interplanetary Society, 59, 400-411.
Collins, P. (2006c). Space tourism: From Earth orbit to the Moon. Advances in Space Research, 37, 116122.
Collins, P., & Autino, A. (2008). What the growth of a space tourism industry could contribute to employment, economic growth, environmental protection, education, culture and world peace. Paper presented at Plenary Session of the International Academy of Astronautics' 1st Symposium on Private Human Access to Space, Arcachon, France. Retrieved from http://www.spacefuture. com/
Crouch, G. I., & Laing, J. H. (2004). Australian public interest in space tourism and a cross-cultural comparison. The Journal of Tourism Studies, 15(2), 26-36.
Devinney, T., Crouch, G. I., & Louviere, J. (2006). Going where no tourist has gone before:
The future demand for space tourism, Research report. Australia: Future Choice Initiative.
Dickens, P., & Ormrod, S. J. (2007). Cosmic society: Towards a sociology of the universe. New York, NY: Taylor & Francis e-Library.
Dunk, F. G. (2011). Space tourism, private spaceflight and the law: Key aspects. Space Policy, 27, 146 -152.
Dunk, F. G. (2013). The integrated approach—Regulating private human spaceflight as space activity, aircraft operation, and high-risk adventure tourism. Acta Astronautica, 92(2), 199-208. Eilingsfeld, F., & Schaetzler, D. (2002). Developing viable financing models for space tourism. Paper presented at 53rd International Astronautical Congress, Houston, TX. Retrieved from http:// www.spacefuture.com Favatà, P. (2001). Changing the TransHab: An orbiting space hotel. Florence, Italy: University of Florence. Retrieved from http://www.spacefuture. com
Fawkes, S., & Collins, P. (1999). Space hotels: The cruise ship analogy. Paper presented on 2. International symposium Space Tourism, Bremen, Germany. Retrieved from http://www.spacefu-ture.com
Genta, G., & Rycroft, M. (2006). Will space actually be the final frontier of humankind? Acta Astronautica, 58, 287-295. Giacalone, J. A. (2013). The evolving private spaceflight industry: space tourism and cargo transport. Paper presented at conference American Society of Business and Behavioral Sciences (ASBBS), Las Vegas, NV. Retrieved from http:// www.spacefuture.com Goehlich, A. R., & Schumann, D. (2004). Zi-olkowski-module: A tourist module on the ISS as a key for a low-cost return to the Moon. Retrieved from http://www.spacefuture.com Goehlich, A. R. (2007). Space tourism. In R. Con-rady & M. Buck (Eds.), Trends and issues in global tourism 2007 (pp. 213-226). Berlin, Germany: Springer Berlin Heidelberg. Goehlich, A. R., Anderson, J. K., Harrold, N. N., Bemis, J. A., Nettleingham, M. T., Cobin, J. M., Zimmerman, B. R., Avni, B. L., Gonyea, M. D., & Ilchena, N. Y. (2013). Pilots for space tourism. Space Policy, 29(2), 1-10. Hilton, B. (1967). Hotels in space. Paper presented at conference AAS - American Astronautical Society, Las Cruces, NM. Retrieved from http://www. spacefuture.com/ Klemm, G., & Markkanen, S. (2011). Space tourism: Will we all become astronauts? In A. Papathanas-sis (Ed.), The long tail of tourism (pp. 95-103). Wiesbaden, Germany: Gabler Verlag.
Kluge, G., Stern, C., Trammer, M., Chaudhuri, I., Tuschi, P., & Gerzer, R. (2013). Commercial suborbital space tourism-proposal on passenger's medical selection. Acta Astronautica, 92(2), 187192.
Kramer, R. W. (2011). Colonizing mars—An opportunity for reconsidering bioethical standardsand obligations to future generations. Futures, 43(5),
545-551.
Livingston, D. M. (1999). The ethical commercialization of outer Space. Mars Society. Retrieved from http://www.spacefuture.com Livingston, D. M. (2000a). Space: The final financial frontier. Mars Society. Retrieved from: http:// www.spacefuture.com Livingston, D. M. (2000b). Lunar ethics and space commercialization. Presented at conference Lunar Development, Las Vegas, NV. Retrieved from http://www.spacefuture.com Livingston, D. M. (2000c). From Earth to Mars: A cooperative plan. Mars Society. Retrieved from http://www.spacefuture.com Livingston, D. M. (2000d). Space tourism and RLVs: You can't have one without the other! Paper presented at IAA conference, Rio de Janeiro, Brasil. Retrieved from http://www.spacefuture.com Livingston, D. M. (2001a). Space tourism after Dennis Tito. Retrieved from http://www.spacefuture. com
Livingston, D. M. (2001b). A code of ethics and standards for lunar development and outer-space commerce. Paper presented at conference Lunar Development in Las Vegas, NV. Retrieved from http://www.spacefuture.com Livingston, D. M. (2002). A code of ethics for Off-Earth commerce. Paper presented at conference World Space, Houston, TX. Retrieved from http://www.spacefuture.com Lyall, F. (2010). Who is an astronaut? The inadequacy of current international law. Acta Astronautica, 66(11), 1613-1617. Marsh, M. S. (2006). Ethical and medical dilemmas of space tourism. Advances in Space Research, 37(9), 1823-1827. Martinez, V. (2007). Architecture for space habitats. Role of architectural design in planning artificial environment for long time manned space missions. Acta Astronautica, 60(4-7), 588 -593.
Martinez, V. (2009). Architectural design for space tourism. Acta Astronautica, 64(2-3), 382-390.
Masson-Zwaan, T., & Freeland, S. (2010). Between heaven and earth: The legal challenges of human space travel. Acta Astronautica, 66(11-12), 15971607.
Mitarai, G. (1993). Space tourism and space medicine. Journal of Space Technology and Science, 9(1), 1315.
Nair, G. M., Murthi, K. R. S., & Prasad, M. J. S. (2008). Strategic, technological and ethical aspects of establishing colonies on Moon and Mars. Acta Astronautica, 63 (11-12), 1337-1342.
O'Neil, D., Bekey, I., Mankins, J., Rogers, T. F., & Stallmer, E. W. (1998a). General Public Space Travel and Tourism Volume 1 - Executive Summary. Huntsville, AL: Marshall Space Flight Centre, National Aeronautics and Space Administration & Space Transportation Association.
O'Neil, D., Bekey, I., Mankins, J., Rogers, T. F., & Stallmer, E. W. (1998b). General Public Space Travel and Tourism Volume 2 - Executive Summary, , Summary of a Space Act Agreement Study, including a workshop held at Georgetown University, Washington, D.C. Huntsville, AL: Marshall Space Flight Centre, National Aeronautics and Space Administration & Space Transportation Association.
Peeters, W. (2010). From suborbital space tourism to commercial personal spaceflight. Acta Astronautica, 66(11), 1625-1632.
Robson, S. (2003). Thomas Cook to space tourism - Are they really that different? Retrieved from http://www.spacefuture.com
Rogers, L. (2008). It's ONLY rocket science: An introduction in plain English. New York, NY: Springer Science and Business Media
Seedhouse, E. (2008). Tourists in space: A practical guide. Chichester, England: Praxis Publishing Ltd.
Spennemann, H. R. D. (2007a). Extreme cultural tourism from Antarctica to the Moon. Annals of Tourism Research, 34(4), 898-918.
Spennemann, H. R. D. (2007b). Orbital, lunar and interplanetary tourism opportunities for different perspectives in star tourism. In C. Marin & J. Jafari (Eds.), Star light - A common heritage (pp.
161-173). Santa Cruz de Tenerife, Spain: Instituto de astrofisica de Canarias (IAC). Srivastava, M., & Srivastava, S. (2010). Space tourism: The future tourism. Management Insight, 6(2),
43-48.
Stine, G. H. (1996). Historical analogies potentially applicable to the commercialization of space activities. Retrieved from http://www.spacefuture. com
Torikai, T., Kitayama, O., Miyahara, A., Iwama, K., Okaya, S., & Kondo, S. (1999). A draft of safety standards for designing space tourism vehicles. Retrieved from http://www.spacefuture.com Webber, D. (2003). The first 100 years of public space travel. Paper presented at AIAA/ICAS International Air and Space Symposium, Dayton, OH. Retrieved from http://www.spacefuture.com Webber, D. (2005). Horses for courses - Spaceport types. Presented at International Space Development Conference (ISDC) in Washington, D.C. Retrieved from http://www.spacefuture.com Webber, D., & Reifert, J. (2006). "Filling in some gaps", executive summary of the adventurers' survey of public space travel. Bethesda, MD: Spaceport Associates. Webber, D. (2010). Point-to-point sub-orbital space tourism: Some initial considerations. Acta Astronautica, 66(11), 1645-1651. Webber, D. (2012). Space tourism - Essential step in human settlement of space. Presented at 63rd International Astronautical Congress, Naples, Italy. Retrieved from http://www.spacefuture.com Webber, D. (2013a). Point-to-point people with purpose - Exploring the possibility of a commercial traveler market for point-to-point suborbital space transportation. Acta Astronautica, 92(2), 193-198.
Webber, D. (2013b). Space tourism: Its history, future and importance. Acta Astronautica, 92(2), 138143.
Wollersheim, M. (1999). Considerations towards the legal framework of space tourism. Presented at 2nd International Symposium of Space Tourism, Bremen, Germany. Retrieved from http://www. spacefuture.com Yehia, J. A., & Schrogl, K. U. (2010). European regulation for private human space flight in the con-
tex of space traffic management. Acta Astronautica, 66(11-12), 1618-1624.
Zakaria, N. R., Nasrun, N., Abu, J., Jusoh, A., Azim, L., Said, A., & Ishak, S. (2011). The advantages, potentials and safety of VTOL suborbital space tourism operations. Presented at 5th Interna-
tional Association for the Advancement of Space Safety, Versailles, France. Retrieved from http:// www.spacefuture.com Ziliotto, V. (2010). Relevance of the futron/zogby survey conclusions to the current space tourism industry. Acta Astronautica, 66(11-12), 1547-1552.