Aerospace Medicine involves the study of the physiological, psychological, environmental, and operational risk factors encountered during aviation and space flights, and their potentially adverse impact on the health and safety of human beings.  Traditionally, when dealing with space crews who are directly responsible for flight safety, the focus of Aerospace Medicine practitioners has been to ensure the health and aeromedical fitness of generally “normal” individuals that operate in “abnormal” aviation and space environments.  More specifically, the most critical objective of Aerospace Medicine has been to prevent sudden inflight medical incapacitation or performance impairment of flight crews while they operate aviation and space vehicles.  Regarding passengers, Aerospace Medicine’s role has been to ensure that all individuals, whose health status may vary from clinically normal to pathological, will not experience inflight medical emergencies and will safely reach their final destination.

On October 4, 2004, the sub-orbital space vehicle SpaceShipOne became the first private reusable launch vehicle (RLV) to successfully fly above 328,000 feet (100 kilometers), twice within two weeks, while carrying one civilian astronaut and the equivalent weight of two additional occupants. The highest altitude reached by SpaceShipOne was 367,442 feet (112 km), which surpassed the altitude of 354,200 ft (108 km) reached by an X-15 on August 22, 1963.  SpaceShipOne was built by Burt Rutan’s Scaled Composites and funded by Microsoft co-founder Paul G. Allen through his company Mojave Aerospace Ventures.  Sir Richard Branson established Virgin Galactic, the first commercial space line. He licensed the SpaceShipOne technology owned by Mojave Aerospace Ventures and signed a contract with Burt Rutan’s Scaled Composites to build a larger version named SpaceShipTwo, which will be capable of carrying six passengers on a sub-orbital flight.  Several SpaceShipTwo vehicles are being built.  As of today, about 250 people from 30 countries have applied to fly as passengers with Virgin Galactic, and the first 100 (Founders) have undergone initial medical screening.  There are several other private companies developing manned sub-orbital and orbital commercial space vehicles, including Armadillo Aerospace, BensonSpace, Blue Origin, Boeing, Bristol Aerospace, Canadian Arrow, Energia Kliper, Excalibur Almaz, PlanetSpace, Rocketplane, Sierra Nevada, Starchaser Industries, SpaceX, TGV Rockets, Transformational Space, and Xcor. 

This presentation will discuss a number of physiological, operational and environmental risk factors (actual and potential) for the occupants of commercial space vehicles. Actual risks include exposure to: 1) High acceleration and deceleration flight profiles, 2) Microgravity or weightlessness, 3) Solar and cosmic radiation, 4) Noise and vibration, 5) Unfamiliar motion (space sickness), 6) A sealed cabin environment. Of particular concern are the effects of exposure to microgravity on the cardiovascular, neurological, endocrinological, muscle-skeletal, and gastro-intestinal systems, on both healthy and diseased passengers. In addition, there is no clear scientific understanding of the metabolism and effectiveness of a number of medications used by individuals during exposure to microgravity.  There is evidence of decreased efficacy of antibiotics and other medications in microgravity, and increased virulence of microorganisms in space.  Furthermore, U.S. and Russian experience regarding space physiology and medicine involve short-term and long-term space flights, but does not address the effects of: 1) Frequent repetitive exposure (several times a week) to flight profiles involving: normal gravity (pre-flight) - acceleration (launch/take off) - microgravity (space) - deceleration (return) - normal gravity (post-flight), 2) Frequent repetitive exposure to solar and cosmic radiation, and 3) Exposure to microgravity among individuals who have select medical pathology. There is also a potential for occupant injuries during intra vehicular activities in microgravity. Other potential risk factors for the occupants of commercial space vehicles include unexpected exposure to: very low or absent barometric pressure (rapid and/or explosive decompressions), temperature extremes (heat and cold), humidity extremes, in-flight cabin fire, cabin air contaminants (biological, chemical, particulates, etc.), electricity, non-ionizing radiation, structural cabin hazards, impact forces during crash landings, post-crash fire, emergency evacuation, and post-evacuation survival.

Manned commercial space operations represent a new challenge for medical personnel.  As of today, most of the accumulated Aerospace Medicine experience involves healthy, professional astronauts and cosmonauts (career space crews) 35 to 50 years old.  Due to medical privacy regulations and astronaut-career considerations, individual medical data from career space crews are not readily available for study by the scientific community, nor to be used in support of the manned commercial space industry.  There is some medical information available to the public that provides classifications of medical pathologies that had occurred among career space crews during: 1) Ground medical events, 2) Short-duration space shuttle flights, 3) Long-duration MIR space station flights, and 4) Long-duration MIR/NASA flights.  In addition, very limited medical information has been collected and analyzed from the seven private space passengers who have been involved in short-duration (up to 2 weeks) orbital flights arranged through Space Adventures Ltd.  Publicly available medical and space flight information from travelers who have moderate-to-severe pathology is very limited (quantitatively and qualitatively).  Such an insufficient level of medical knowledge represents a great challenge for medical personnel who are or will be responsible for the medical screening and/or evaluation of prospective commercial space passengers who have a wide range of health and fitness levels.  Therefore, several reports have been published by governmental and professional organizations to address operational medical safety issues in regards to orbital space flight participants (1,2), suborbital space flight participants (3,4), and suborbital crewmembers (5,6).

Presently, the U.S. is the only country that has established Federal licensing requirements (including medical) for manned commercial space operations. On 09/9/1992, Space Services Inc. conducted the first commercial space launch (Conestoga I).  However, there were no statutes, policies, or regulations in the U.S. governing commercial space operations.  Therefore, in February 1984, President Reagan issued an executive order assigning to the U.S. Department of Transportation (DOT) the responsibility to oversee all U.S. commercial space operations (1984 Commercial Space Launch Act).  In November 1995, the DOT transferred such responsibility to the Federal Aviation Administration (FAA), thus creating the Office of Commercial Space Transportation (AST).  In October 1998, Congress expanded AST’s role to include licensing of reentries and reentry sites.  AST issues licenses for commercial space operations, including commercial launch sites, reentry operations, and reentry sites.  AST carries out this responsibility consistent with public health and safety, safety of property (on the ground), and the national security and foreign policy interests of the U.S.  The U.S. Commercial Space Launch Amendments Act of 2004 (H.R. 5382) laid out the definition of a sub-orbital space passenger vehicle, clarified the process for licensing such vehicles, and allowed paying passengers to fly into space at their own risk.  The 2004 Act authorizes the FAA to issue permits allowing commercial space vehicle operators to carry paying passengers into space.  This Act requires passengers to be fully informed (in writing) about all the risks of participating in commercial space flights.  By allowing passengers to fly at their own risk, this Act was intended to limit the operators’ liability for passenger safety, thus giving the emerging manned commercial space transportation industry an opportunity to succeed.  The FAA will have to wait until 2012 to begin issuing regulations to protect the safety of space passengers. In the meantime, the FAA may restrict space vehicle design features or operating practices only if they have resulted in a serious or fatal injury to passengers or crew (accident), or caused an unsafe unplanned event (incident). 

Manned commercial space travel will continue to generate its own kind of medical and human factors issues that must be dealt with to protect the health and safety of all individuals involved in such operations.  Soon, the general public (not only career space crews) will have the opportunity to participate in space flights. Therefore, the medical community must be prepared to meet their challenging obligations and responsibilities in support of manned commercial space transportation.

REFERENCES:

1.   Medical Guidelines for Space Passengers.  Aerospace Medical Association (AsMA) Task Force on Space Travel. Aviation Space & Environmental Medicine Journal, 72:948-950. 2001.

2.   Medical Safety and Liability Issues for Short-Duration Commercial Orbital Space Flights.  Study Group 2.6, Commission 2 (Life Sciences), International Academy of Astronautics. 2009.

3.   Medical Guidelines for Space Passengers -II. AsMA Task Force on Space Travel.  Aviation Space & Environmental Medicine, 73:1132-1134. 2002.

4.   Guidance for Medical Screening of Commercial Aerospace Passengers.  Federal Aviation Administration, Office of Aerospace Medicine, Washington, D.C. 2006.  Technical Report No. DOT-FAA-AM-06-1

5.   Medical Certification for Pilots of Commercial Suborbital Space Flights.  AsMA Ad Hoc Committee. Aviation Space & Environmental Medicine Journal, 80: 824-826. 2009.

6.   Suborbital Commercial Space Flight Crewmember Medical Issues.  Special Report. AsMA Space Flight Working Group. 2010.