Final Project

Joshua G.

Legislator:  Dan Ellis, Representative

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For a mission to Mars to ever be attempted, it is prudent that the spacecraft used harnesses the ability to create artificial gravity by using a spinning habitat in the spacecraft, as I suggested in Lesson 9. The exterior of the spacecraft would remain “still” while in transit (save for a passive thermal control roll). While a habitat on the inside of the spacecraft would spin, producing one to two g’s. There are problems with having the habitat spin, however, some of these include consumable distribution, stress on the spacecraft, power consumption, etc. There are also advantages to this type of a spacecraft, which include a way to fight muscle atrophy, blood loss, bone de-calcification, etc.

The habitat would be within the spacecraft, as before stated. It would therefore, not have the problem in the movie Mission to Mars of sealing a spinning object against one that stays still. The outer hull would keep the pressure in, while in case of a hull breach, the various sections would have to be sealed off. The spinning habitat would be more like the one in the movie 2001: Space Odyssey. There are differences from that one, however, also. This habitat would have none of the spacecraft’s control, such as engine and thruster control, etc. The habitat would basically be crew quarters, and recreation. As far as a spinning habitat goes, the bigger, the better. The bigger the recreation areas, and the more that the astronaut crew has to do, the less likely they will go crazy during a long mission. It would also be preferable to leave a section of the habitat for a greenhouse. That would not only help with oxygen production, but it would also aid in the astronauts home sickness. This greenhouse, for this purpose, should have grass on the floor, and small trees, etc. The astronauts would also have one more thing to occupy their time during the mission. It would work especially well if any of them enjoyed gardening.

Power distribution is a problem. The problem comes in where you have the spacecraft, which is not, or is only barely rotating, with the habitat which is rotating at several revolutions per minute. If there was any kind of wiring, it would all twist and break. One possibility, is that in the setup, instead of wires, or cables connecting the electricity, there is a large conductive metal ring that is receiving the power, which is then sent to the habitat by conductive metal rollers that are in constant contact with the ring. After that, the electricity can be directed through the rest of the habitat by normal electrical wiring.

The consumables, such as oxygen, water, etc. would also be a problem to distribute throughout the ship. Best possibility, is that all of the consumables for the habitat are stored above the 1 g deck. Above it, there is less than 1 g, and there is no problem with the spinning affecting the distribution. The other possibility, is to have the spinning portion of the habitat open with vents in every room, and the consumables and filters and CO₂ scrubbers and such in the portion of the habitat that doesn’t spin. In that manner, the air would simply flow out of the spinning habitat and through the scrubbers, and back, possibly using fans in the vents to help the process be more efficient.

The spinning of the habitat would put stress on the spacecraft, in that it would have to be designed like a normal structure on Earth because of the gravity. However, the artificial gravity of the spacecraft is not exactly the same al the gravity of the Earth. It is produced by a spin, and therefore the stress will come from the sides, instead of pressure pushing everything toward the floor. Some of the stress would come when the spin is started, however, if it is started gradually, and let to speed up over a period of several minutes, that will be less of a problem. The same conditions apply for stopping the spin on the habitat. The spin must not be started or stopped quickly, but must be done gradually to reduce stress on the equipment.

One of the problems with sending a  crew into space today, and leaving them up for six months or so, is the adverse effects of micro-gravity on the human body. The human body was designed for living and working in a 1g environment. When taken away from that, our muscles, for one, begin to atrophy. The muscle problem is serious, because when the astronauts return to Earth, they, in some cases, are unable to even stand up. They have to be pushed around in wheel chairs for a while. At least until they can get their strength up. There are probably other “cures” to this problem. Exercise in one way to minimize the problem of muscle atrophy, the only problem with exercise is that, in micro-gravity, there are less exercises that the astronauts can do. For instance, they can not lift weights effectively. There are other exercises, such as the treadmill, that have already been proven to work on the space shuttle. A spinning habitat, however, would help the astronauts retain some of their strength without doing anything. Just by being there, it would help fight off the effects of micro-gravity.

Another health problem to the astronauts, is the loss of blood during a space flight. While a person is on Earth, gravity pulls everything down, including our blood. Because of this, the human body has to produce more blood to make up the difference, since a large concentration is in the legs. When an astronaut ventures into space, however, the gravity that kept all of their blood in their legs is no longer present. In micro-gravity, the blood shifts to the chest. When there is too much blood there, the body then expels it in waste fluids, attaining again the right amount of blood needed throughout the body. The problem arises, when that astronaut returns to Earth. After landing, the gravity begins pulling on them again, and much of their blood returns to their legs and feet. The problem with this, is that now there is not enough blood in the chest and head, making it much easier to black out when standing. Using the artificial gravity of the spinning habitat, they would retain most of their blood during the flight. This way, after they land, their bodies do not have to replace much if any of their blood, because they still have the right amount. They also don’t have the problem of blacking out when they want to stand up.

Probably the worst problem that the astronauts face is the bone de-calcification during extended periods of stay in micro-gravity. Bone de-calcification, as I understand it, is irreversible. That right there is a good reason to have artificial gravity aboard the spacecraft. The goal of space flight is to conduct experiments, and to explore, and to prove that we can go somewhere, and safely return to the Earth. Having an astronaut’s bones de-calcified makes them easier to break. The more fragile that the astronauts become, the more difficult it is to keep them unharmed during a mission. The more astronauts get hurt, the more public relations are worsened.

For those reasons, it seems fairly prudent to build spacecraft with artificial gravity if for no other reason than for the safety of the astronauts that will be flying them. There are problems with designing anything that is going to be a life support system, and spin at the same time. Some of those problems were addressed and possibly even answered here. There are others that we will just have to work on.

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Last Updated:  09/07/01