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Space tourism companies like Virgin Galactic need to weigh health requirements that protect prospective customers against requirements that could prohibit a significant fraction of their customer base from flying. (credit: Virgin Galactic)

Revisiting “Tourists in Space”

In order to support the fledgling commercial human space industry, it is important to provide rational medical guidelines based on a current and evolving understanding of the physical, psychological, social, and regulatory requirements involved in flying non-professional space flight participants. (Space fight participants is understood to mean passengers and others who serve non-flight safety related roles.) Similarly, minimal medical requirements for commercial space pilots are necessary in order to assure flight safety.

While there have been some regulatory and general medical guidelines published by the FAA and aerospace medicine specialty groups1,2,3 little has been published so far that can be considered useful reference materials for either prospective space flight participants (SFP) or the developing human space flight operators.

To that end, I eagerly read Erik Seedhouse’s recent book Tourists in Space: A Practical Guide, which was written with the purpose to fill this void (see “Review: Tourists in Space”, The Space Review, July 14, 2008). The introduction and the first two chapters are a very nice summary of the history and current status of the commercial space tourism industry and contain useful information with regards to descriptions of the various current human space flight companies. Unfortunately, the remainder of the book is disappointing, in that it not only falls short of being a practical guide, but more importantly, contains serious inaccuracies regarding medical standards and training requirements for both SFPs and crew.

The book not only falls short of being a practical guide, but more importantly, contains serious inaccuracies regarding medical standards and training requirements for both SFPs and crew.

Dr. Seedhouse begins his third chapter, titled “Medical and training requirements for suborbital flight”, and sets an inaccurate tone that is carried throughout the remainder of the book. He refers to the FAA document titled “Human Space Flight Requirements for Crew and Space Flight Participants: Final Rule”, published in the Federal Register on December 15, 2006, stating that this document contains rules pertaining to crew qualifications as well as training guidelines for SFPs. Although this is true to a point, it certainly is not valid to the extent that he implies. Other than the requirement that crew members with safety-critical roles (the pilots, basically) hold a Class II FAA Medical Certificate, there are currently no other medical requirements for commercial space pilots, and certainly none at all for the passengers. The referenced FAA rule states only that the prospective SFPs be informed of the risk profile of the prospective space flight, that they sign a waiver of claim against the US government, that operators must train each SFP before flight how to respond to emergency situations (including smoke, fire, loss of cabin pressure and emergency exit—sound familiar?), and to implement security requirements to prevent passengers from bringing explosives and weapons on board. Just as in the airline industry, the FAA does not have a legal mandate over the commercial space industry to regulate passenger health—only safety.

As mentioned above, the aerospace medical community and the FAA have published documents concerning medical guidelines for SFPs. These are all based on some general principles and assumptions and are therefore broad in nature. They certainly neither meet the criteria for being standards nor requirements. They are primarily based on the premise to screen for medical conditions that could result in an in-flight medical emergency or death, or that may compromise the health and safety of any of the other occupants. These considerations are based on the understanding that the space flight environment may aggravate certain pre-existing medical conditions. This approach is in contrast to the system that has been in place for many years regarding the screening of professional astronauts. This is a fundamental paradigm shift in thinking from the previous governmental astronaut medical screening procedures as it leans toward being inclusive rather than exclusive with regard to medical conditions.

Unfortunately, Dr. Seedhouse veers from this approach and suggests instead that there are rigorous FAA medical requirements in place for SFPs, whether for suborbital or orbital flight. He then goes on to create screening and training scenarios that are rather unrealistic, and by doing so further enhances the concept that these are mandated requirements.

As one such example, he states that the space flight operator would provide the prospective SFP a list of FAA-certified flight surgeons (Aviation Medical Examiners, or AMEs) together with a file containing the medical standards required for certification of SFPs (which, as stated above, does not exist). He includes a table of medical standards that are very similar to those that the FAA uses for pilot medical certification, which may lead the reader to believe that these indeed are required regulatory standards. To make his point, he includes a table called “Medical standards for suborbital spaceflight participants”, which he adapted from the FAA Guide for Aviation Medical Examiners which, again, is intended for airplane pilots. He continues on by stating the “flight surgeon can issue, defer or even deny an applicant’s medical application”, a process which definitely does not exist for passengers! It seems that Dr. Seedhouse has confused the FAA medical requirements for pilots with his own interpretation of guidelines for SFPs. It should be pointed out that at this point in time, the FAA only recommends a health questionnaire be submitted prior to each suborbital flight3. Of course this health questionnaire should be reviewed by a physician knowledgeable in aerospace medicine—most likely the operator’s “company doctor” or private aerospace medicine consultant—but certainly not necessarily an FAA-designated AME for pilots. This is because AMEs who perform FAA medical examinations on aviation pilots are not necessarily trained in space physiology, and conversely, many space medicine physicians are not necessarily AMEs.

Dr. Seedhouse makes the same errors when discussing his medical standards for orbital SFPs. Although he is correct in stating that these flights will necessitate a more extensive health examination than the simple health questionnaire currently recommended for suborbital SPFs, it by no means needs to be “an extensive, prolonged and fairly uncomfortable medical examination” as he suggests. Once again, these statements may lead the reader to believe that these are regulatory requirements when in fact they are not. Furthermore, these proposed “standards” for SFPs are far more rigorous than those that the FAA currently requires of commercial space pilots.

It seems that Dr. Seedhouse has confused the FAA medical requirements for pilots with his own interpretation of guidelines for SFPs.

Lastly, these proposed standards would likely disqualify a significant portion of prospective SFPs. Current demographics indicate a significant rise in the older proportion of the population, many of whom have the wealth to afford a ride into space but are likely to have a variety of medical problems associated with increasing age. An interesting insight into this group of people was provided at a Commercial Human Spaceflight workshop at the 2008 Aerospace Medicine Association Annual Scientific Meeting, where representatives from Virgin Galactic shared information regarding the medical conditions found among their Founders. (The Founders are the first 100 prospective SFPs that pre-paid the full fare of $200,000 for a suborbital flight with Virgin Galactic.) Not surprisingly, their medical conditions included hypertension, heart disease, and spinal symptoms, all of which are problems that can be aggravated by space flight. Additionally, 33% admitted to taking regular medications and 12% had a “significant” illness within the past 5 years. Seven percent currently smoked, 64% currently drank, and 20% admitted to being heavy drinkers. All of these situations could be problematic for space flight and would therefore need further evaluation, but to disqualify them because they do not meet unrealistically high standards is not likely to be a viable option for the space tourism industry.

To create standards that would disqualify a significant segment of the customer base is too high of a threshold to be able to sustain the industry. Without sacrificing safety, it must be kept in mind that these are essentially passive passengers who in general do not need to have a mission-critical role and therefore should to be medically evaluated according to well-thought out principles, rather than standards that seem to come out of professional astronaut training manuals.

One example of a commonly encountered medical condition that would be disqualifying condition in Dr. Seedhouse’s opinion is diabetes requiring oral medication. According to that algorithm, even a SFP who wants to experience a suborbital flight would be disqualified. Exactly how a brief flight of about one to two hours can adversely affect a well-controlled diabetic is unclear to me. It makes little sense that this individual would have to obtain the same type of “wavier” that a pilot needs for this condition, as this would not impart a greater degree of safety for the flight.

Another puzzling example is Dr. Seedhouse’s proposal that prospective orbital SFPs obtain extensive neurological evaluations, including brain wave studies. This type of test has virtually no diagnostic capability in an individual who has no history of seizures, but yet has a relatively high “false positive” test result, which means that the test may indicate a problem when none actually exists. Not only would an abnormal brain wave test then disqualify an individual without providing any flight safety enhancement, it would also instill anxiety in an otherwise entirely normal individual. It should be pointed out that even airline pilots are not required to undergo these types of tests by the FAA, so why should SFPs?

Furthermore, Dr. Seedhouse’s hearing and vision requirements are also quite arbitrary. Just as in the airline world, a passenger should not be required to have minimum vision or hearing standards, as his or her role on the flight is purely passive and has no obligatory roles to fulfill that would impact the safety of the flight, unless the flight was so designed as to require active participation of the passengers as a mission-critical crew member. One should be able to fly with any kind of physical handicap as long as one would not impair the safety of the flight.

That is not to say that there should be no medical standards for SFP’s just because the FAA doesn’t have any. On the contrary, it is prudent for the operators to consider adhering to well-designed medical standards for SFPs (and perhaps even pilots) that are higher than what is legally required, but not to adhere to unrealistically high standards that would neither improve flight safety, nor are realistic for the customer base.

I do I agree with Dr. Seedhouse that there are training modalities that are not only safety-critical, but would also enhance the SFP’s experience.

The subsequent chapters outlining the physical training requirements also seemed to bear little relevance to suborbital or even orbital space tourists. Dr. Seedhouse suggests that passengers who are along for the pleasure of the ride need the same training as mission-critical crew members. Once again, his proposed training programs belong to the realm of professional astronauts and bear little relevance to the space tourist environment. For example, he indicates that for a rather short orbital mission between five and seven days in length, the operators will require the prospective SFP to commence an intense exercise training program for five weeks prior to launch in order to be able to perform emergency egress activities. The proposed intense survival training curriculum is far and above anything that most customers would want to endure, is certainly not required by any regulatory agency, and may not be within the capabilities of most operators to provide.

The chapter regarding emergency medical training is also unrealistic, as it goes into detail of requiring intense space-based emergency medical training of the SFP. This would be analogous to requiring airline passengers to be certified in advanced life support techniques prior to boarding a flight. Additionally, many of these so-called life-saving techniques are useless in the setting of space flight as any resuscitation endeavors generally require subsequent medical treatment in an intensive care unit. In comparison, the reason defibrillators are potentially useful on board commercial aircraft is because of the possibility that an emergency landing can be undertaken so that the sick passenger can be transported to an appropriate hospital for further care following a successful resuscitation on board.

Having said that, I do I agree with Dr. Seedhouse that there are training modalities that are not only safety-critical, but would also enhance the SFP’s experience. These are centrifuge training and “zero-G” flights. Both suborbital and orbital SPFs will encounter significant G-forces, and centrifuge training that exactly simulates the flight profile will not only provide the necessary countermeasure training to avoid unpleasant G-induced loss of consciousness (G-LOC), but will also provide the necessary preflight experience as to what these G forces will feel like so that the SFP will not be frightened during the high G-force portions of the flight. Additionally, “zero-G” training in parabolic flight maneuvers would also enhance the eventual orbital weightlessness experience.

For those readers who have a basic understanding of medical guidelines for commercial space travel, it is difficult to maintain interest in reading much of this book as one is faced with so many flawed concepts early on. More importantly, those readers who do not have this basic knowledge may be misled into believing that these strict standards are in fact requirements, and become totally discouraged regarding the possibilities of normal people to travel into space.

With all the problems of this book, there is one important observation that Dr. Seedhouse correctly makes. He points out that medical information should be gathered from SFPs during training and space flight, and these data should be made available to the scientific community in order to continuously add to the knowledge base pertaining to the human experience in the space environment. This is critical in order to continuously improve the safety and enjoyment of future commercial space travel, and to base any changes in medical guidelines on scientific evidence.

In summary, it is disappointing that Dr. Seedhouse endeavors to apply NASA-type astronaut requirements to non-professional space travelers, as doing so will not increase the safety of SPFs. Furthermore, if his proposals were to be implemented, the space tourism industry would struggle to find a qualified customer base, and the industry could therefore fail before it even got off the ground. Thus, a practical guide for tourists in space has yet to be written.


  1. Medical Guidelines for Space Passengers. Aviation, Space and Environmental Medicine. 72, no. 10, 2001: 948-950 and Part II. 73, no.11, 2002: 1132-1134.
  2. Medical Guidelines for Space Passengers – II. Aviation, Space, and Environmental Medicine, Vol. 73, No. 11, pp. 1132-1134, Nov. 2002.
  3. Guidance for Medical Screening of Commercial Aerospace Passengers. DOT/FAA/AM-06/1, January 2006
  4. Medical Safety and Liability Issues for Short-Duration Commercial Orbital Space Flights. International Academy of Astronautics, January 2009.