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H Wichman, , "Space Flight Certification Requirements for Civilian Passengers", Space Transportation Association Conference. Session Four: Medical Science Panel. June 24,1999. Washington, D.C..
Also downloadable from flight certification for civilian passengers.shtml

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Space Flight Certification Requirements for Civilian Passengers
Harvey Wichman, Ph.D.

As we look to the future of regular civilian space flight employing reusable rockets to gain access to space, we can parse this future into three distinct developmental epochs.

  1. Immediate Future
  2. Near Future
  3. More Distant Future
The Immediate Future

The first civilian space flights will probably be suborbital flights to altitudes somewhat in excess of 100 kilometers (The beginning of space). They will be of very short duration, perhaps up to 10 or 15 minutes and in very small passenger compartments similar to those found in smaller corporate jet airplanes.

The Near Future

The next civilian space flights likely will be orbital flights in low earth orbit ( LEO) of one to four days duration. The habitats will be passenger modules carried in the cargo bays of vehicles designed to carry cargo to LEO. Such habitats are expected to be on the order of 5 meters in diameter and 10 meters long.

The More Distant Future

At a later time much larger habitats will remain in orbit and passengers will be shuttled up and down to these space hotels (which might more accurately be characterized as space cruise ships). The passenger compartments in the shuttling vehicles will probably be similar in size and shape to those just described for the near future. However, they will be designed to carry many more passengers for the short trips to and from the orbiting habitats. The space hotels will permit much longer stays, especially for crew members. They will have much more room and possibly have areas in which g forces are experienced, such as Bigelow Aerospace's plan for a .4 g spinning space hotel.

Thus in the immediate future space flight will not be much different from high altitude, high speed flight in the Concorde. We already have regulations that are adequate for such flights and little will have to be added to extend the altitude from 18 to 100 kilometers for very brief periods.

Developing regulations for flights in the more distant future is best left for a later time when we have accumulated more information during the near future when the first orbital flights take place around the earth. Thus, in the rest of this paper I will address only certification issues related to the near future, or early low earth orbit flights of up to a week's duration.

To begin to decide how future regulations must differ from current regulations for high altitude commercial aircraft flight we can ask, "in what ways will space flight differ from current commercial passenger flights?"


It seems unlikely that acceleration loads in future space flights will exceed two gs, equal to what is experienced in a sixty-degree banked turn in an airliner. New rockets being designed for carrying freight to space are not expected to exceed two gs on the way to orbit. Part of the reason for this is that objects built for use in orbit can be designed structurally for zero g loads. Thus there is a great advantage in not having to make things sturdier than necessary just to be able to survive the eight- or ten-minute flight to orbit. Passengers will benefit from this factor. Orienting passengers during acceleration on departure, and deceleration on reentry so that g forces are experienced from front to back across the long axis of the body will be sufficient to manage such loads for almost anyone. The high g loads experienced by astronauts and cosmonauts riding in spacecraft derived from ballistic missiles will become a thing of the past.


Weightlessness will be one of the primary differences between orbital flight and airliner flights. The effects of weightlessness are profound and pervasive, and their significance must not be underestimated. For example, since convection currents do not occur in weightless environments, air circulation that seems natural on earth does not take place in spacecraft. Warm air does not rise. Thus the failure of a small room fan in a cozy stateroom can be fatal. Any air that is to be moved in weightlessness must be moved mechanically. This is the major cause of the loudness in current spacecraft (about 72 db in the shuttle-like driving on a freeway at 60 mph with the windows down). Quieting spacecraft while assuring that there will be no stagnant air will be a serious challenge.

Managing liquids in weightlessness is simply a monumental problem for earthlings. Anything drunk must be sipped through a straw with a shutoff valve, toilets cannot use water, spitting out toothpaste and rinse water in a basin is not acceptable, nor is pouring from one container into another during cooking. Without the effect of gravity to spread water thinly over surfaces, water behaves peculiarly and its considerable surface tension causes it to clump up and behave much like Jello does on earth. Finally, urine collection and vomiting will require special training for space flyers. Vomitus is very corrosive and must not be drawn into apparatus via air currents. Its odor is very repulsive and thus it must not get into filters. The simple "barf bags" provided in seat-back pockets on airliners are not adequate for space flight. Fortunately, bags are now marketed which are very satisfactory for either space flight or terrestrial flight. Nevertheless, training in the management of stomach upsets will be required for space fight but is not required for airliner flight.

Another issue associated with weightlessness is that it requires a whole new set of social norms that must be learned before a successful space flight. For example, food that comes loose from a fork or spoon does not fall down. People in weightlessness must be very sensitive to such spills because astronauts tell us that other people's loose food floating by is repulsive and irritating because the person who discovers it must quickly retrieve it from the air currents. Dirty socks dropped on the floor don't remain there--they drift away. A pen set down on a surface also drifts away.

When passengers walk about in an airliner they are all oriented with their heads in the same direction. Our feet are down on the floor for walking and our heads are up where we can greet each other with nods and smiles to assure each other of our non-threatening status. Not so in weightlessness, where one person passing another (called translating-since walking can't be done in weightlessness) might be inverted and pass by "fanny to face" instead of face to face. Cosmonauts have reported that this gets experienced as impolite after awhile and people must learn to reorient themselves before pushing-off to translate past another person. When one is translating one is drifting helplessly until one comes in contact with another mass. Thus it is necessary to look about before pushing off to assure that one won't end up on a collision course with someone already adrift. All of this requires training in new social norms that not needed for airliner flight.

Social Training

As this is being written I am tempted to say that airlines have no obligation to teach people how to behave except in emergencies. However, there currently is much public and airline industry interest in what is sometimes referred to as passenger rage or passenger misbehavior. At the same time there is much concern expressed in the media that airlines are not living up to their service obligations. Regardless of where the fault lies, it is too frequently the case that disorderly behavior occurs either among passengers or between passengers and crewmembers such that an airliner makes an unscheduled stop to remove one or more passengers. This is not possible in orbital flight so actions must be taken before hand to dramatically reduce the likelihood of such behavioral problems. Recent interviews that I have conducted with airline managers and flight attendants make it clear that alcohol ingestion is frequently associated with in-flight misbehavior. Probably the use of alcohol should be banned on space flights.

There is a significant difference between orbital flight and airline flight in the motivations of some passengers. Airline transportation is often for the purpose of getting from one place to another. The first orbital space flights will be for purposes of vacation and adventure. It is important that passengers be well behaved for safety's sake but also in order for everyone to have a good time. In my laboratory we have demonstrated, in 48-hour civilian space flight simulations, that negative interpersonal interactions among passengers can be dramatically reduced by simply giving two hours of pretraining before a simulated space flight.

All of this suggests that the cursory preflight training for emergencies conducted by airlines as airliners are preparing for takeoff will be inadequate for space flights. Astronauts and cosmonauts are normally socially prepared for space flights by careful screening and long periods of working together before a flight. They also occupy the role of employees not paying passengers.

It will probably be necessary for passengers to be certificated for space flights. Instead of a three- to five-minute spiel by flight attendants while taxiing out for takeoff, space passengers will need something like a 24-hour indoctrination in which they learn emergency procedures, group behavior dynamics, how to use a space toilet, liquid management, and space flight norms and mores. This will also give people a pre-flight opportunity to test how well they respond to the cramped quarters that will be typical of the first orbital flights. Just as air crews are now trained in high fidelity flight simulators, space passengers will need to be trained in simulators and then given certificates good for some fixed period of time after which they must be renewed.

Simulator training may also be required because passengers on space flights may need to assist flight attendants with chores and other functional activities. In fact, it is often the case on adventure tours of one sort or another, that part of the satisfaction in the trip is derived from actively participating in a meaningful way.

Duration of Flight

Another primary way in which space flight differs from airline flight is in the duration of the nights. Because space nights will last more than a full day, the opportunity for full-body cleansing and changing of clothes will be required. Airlines don't have to deal with such issues. The problems of water management make this a serious issue. Certainly showers will come late in the evolution of space flight. Once again, simulator training for whole-body cleaning with moist towels will be important.

Airlines with flights that seldom exceed 12 hours in length feel no obligation to provide passengers with facilities in which to engage in sexual behavior. Nevertheless, it does take place and generally falls within the category of nuisance-type passenger misbehavior. However, with the longer duration of space flights many passengers will be disappointed if they don't have the opportunity to engage in sexual behavior while in orbit. Normally, in our society, we simply do not discuss such things publicly. But the management of body fluids in weightlessness where they could be ingested by inhalation is a very serious matter that must be discussed from the beginning. Arranging the necessary restraints to enable a couple to engage in coitus during weightlessness is a significant ergonomic challenge. No less difficult will be devising ways to be sure that all associated body fluids are properly restrained. Awkward and difficult as this may seem, it may be necessary for some simulator training to assure that this activity does not endanger either those engaging in the behavior or others on board the craft.

It seems clear from the above that future space passengers will not dash up to a departure counter at the last minute and hop aboard a spacecraft. Some sort of significant high fidelity simulator training will be required. This simulator experience will serve to train people for flights and give those who find the encapsulated experience aversive an opportunity to self-select out before it is too late.

H Wichman, , "Space Flight Certification Requirements for Civilian Passengers", Space Transportation Association Conference. Session Four: Medical Science Panel. June 24,1999. Washington, D.C..
Also downloadable from flight certification for civilian passengers.shtml

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