The idea of taking a space holiday, once the stuff of science fiction, is no longer a far flung fantasy. The major hurdle to a viable commercial space holiday venture has long been the provision of a reusable launch system. Until an orbital launch system similar to the reusability of aircraft is developed, we will remain earthbound. Efforts to overcome this barrier have been underway since an international conference on the subject in Bremmen, Germany in 1997. More recently, the Space X reusable launch system development program has progressed to the active test program stage.
The possibilities that these advances have opened in terms of space leisure are tantalizing. The imaginations of science enthusiasts and future astronomical entrepreneurs have been running wild with the possibilities. One of the most intriguing concepts is that of an artificial gravity swimming pool.
Space hotels will, inevitably, offer their guests recreational options to occupy themselves and enhance the experience beyond the novelty of simply being in space. And, just as no self-respecting hotel on earth would open for business without a swimming pool, it seems likely that their orbiting counterparts will find a way to do the same. This, however, does present a challenge. The zero gravity environment of space means that water acts a whole lot differently to the way it does on earth. As explained in detail in a new paper published on Space Future , a space swimming pool presents some very interesting physics dilemmas.
The lack of gravity means that, without some sort of artificial compensator, you’re not going to get a pool that resembles anything you’re used to. For a layman’s explanation of the limitations of zero gravity swimming (along with a cool experiment), click onto this article:
For space patrons to dive into anything resembling the familiar is going to require the addition of artificial gravity. How can man recreate gravity? With the benefit of inertia. An example of inertia creating a gravitational effect is when spinning a bucket overhead. For this reason most space habitat designs use a rotating design. While a tethered section of a hotel with a rotating pool is a possibility, the length of tether required to create the required gee force is not practical. More feasible is a rotating, cylindrical pool design. This could be accomplished in three ways:
(1) The entire hotel rotates around the same axis as the pool
(2) The pool is the only rotating part of the hotel requiring an arm attaching it to the hotel
(3) The pool is housed in a portion of the hotel that rotates around the same axis as the pool
The Space Future article details each of the functional and logistical requirements that the above options entail, with a focus on the third option. These include the water management system, which will have to include an efficient anti-sloshing system to prevent excessive oscillation of the pool’s structure. Several options are offered, but most of them would provide some level of inconvenience for swimmers. Water retention is another issue, with a greater likelihood of leakage in an artificial gravity pool than in a 1-g earth bound pool. Water purification systems would also be necessary, although there would be no need to modify the processes used on earth, as microbes and moulds act the same in both environments.
The logistical requirements of the rotating joint that connects the rotating pool room with the stationary main part of the complex are considered in some detail. Limitations identified include the transport limitations of launch vehicles. The largest single assembly component would be the rotating joint, while the transport of the water to fill the pool would take the most time. A volume of 600 cubic meters would require approximately 100 dedicated flights to transport to it’s space hotel destination.
In order for the concept of a space hotel, along with it’s artificial gravity water sports facilities, to ever venture beyond the design stage, a number of safety concerns must be addressed. Prime among them is eliminating the problems associated with orbital debris. A collision would smash the man-made structure to oblivion. To combat this danger, a range of methods have been developed to remove debris from the atmosphere. The most viable – and cost effective – method involves the use of ground-based lasers.
The only physical health problems associated with short term space travel involve solar flares, which are brief bursts of intense energy emanating from the Sun. On earth we are protected from the effects of solar radiation by the earth’s atmosphere and magnetic field. In space, however, there is no such protection. To protect against solar flares, storm shelters will have to be built.
The effects of the living in a weightless environment on the human body present further challenges. In the absence of gravity, our key balancing mechanism, the vestibulary system, would be disoriented, making it difficult to distinguish direction and orientation. This had led to what is known as Space Adaptation Syndrome, a condition which results in feelings of nausea and vomiting. In space there is no force to keep our internal body fluids – water, blood and other liquids – flowing to the bottom of the body. This results in too much fluid migrating to the head, with resultant sinus problems along with puffy faces and shrunken legs. More seriously, because the heart no longer needs to pump blood around the body, the heart shrinks. Muscles, no longer required to work against gravity, also atrophy, as do bones.
The article also discusses the feasibility of such a project from a commercial vantage point. Potential costs are analyzed and from them some basic end user costings are proposed. The end analysis concludes that an artificial gravity swimming pool as part of a space hotel complex would be an attractive commercial proposition to at least some hotel operators.
The major limiting factor to any commercial space development remains the cost of launching. While such costs are still prohibitive for the majority of consumers, robust competition is already taking shape which will, inevitably, drive prices down. Once this occurs, the article makes it clear, space hotels with inbuilt water sports facilities will surely follow.