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A space capsule is an often manned spacecraft which has a simple shape for the main section, without any wings or other features to create lift during atmospheric reentry. Capsules have been used in most of the manned space programs to date, including the Mercury and Gemini programs, as well as in Apollo and Soyuz. A capsule is the specified form for the Crew Exploration Vehicle. Manned space capsules must have everything necessary for every day life, including air, water and food. The space capsules must also protect the astronauts from the cold and radiation of space. For this the capsules are well insulated and have a system that controls the inside temperature and environment. They also must have a way that the astronauts won't be knocked around during launch or reentry. Additionally, since the inside will be weightless, there must be a way for the astronauts to stay in their seats and beds during the flight. For this each seat, bed, table and chair has a complicated system of straps and buckles. One of the most important things that a space capsule must have is a way to communicate with people back on Earth, or mission control.
Structure Space capsules have typically been smaller than 5 meters in diameter, although there is no engineering limit to larger sizes. As the capsule is both volumetrically efficient and structurally strong, it is typically possible to construct small capsules of performance comparable in all but lift-to-drag ratio to a lifting body or delta wing form for less cost. This has been especially pronounced in the case of the Soyuz manned spacecraft. Most space capsules have used an ablative heat shield for reentry and been non-reusable. The Crew Exploration Vehicle appear likely, as of December 2005, to be a ten-times reusable capsule with a replaceable ablative shield. There is no limit, save for lack of engineering experience, on using high-temperature ceramic tiles or ultra-high tempeature ceramic sheets on space capsules. Materials for the space capsule are designed in different ways, like the Apollo’s honey-combed structure of aluminum. Aluminum is very light, and the structure gives the space capsule extra strength. The early space craft had a coating of glass imbedded with synthetic resin and put in very high temperatures. Carbon fiber, reinforced plastics and ceramic are new materials that are constantly being made better for use in space exploration. Reentry Space capsules are well-suited to high-temperature and dynamic loading reentries. Whereas delta-wing gliders such as the Space Shuttle can reenter from Low Earth Orbit and lifting bodies are capable of entry from as far away as the Moon, it is rare to find designs from reentry vehicles from Mars that are not capsules. The current RKK Energia design for the Kliper, being capable of flights to Mars, is an exception. Engineers building a space capsule must take forces such as gravity and drag into consideration. The space capsule must be strong enough to slow down quickly, will endure extremely high or low temperatures, and can survive the landing. When the space capsule comes close to a planet’s or moon’s surface, it has to slow down at a very exact rate. If it slows down too quickly, every thing in the capsule will be crushed. If it doesn’t slow down quickly enough, it will crash into the surface and everything will be destroyed. The engineers tend to make the capsule in a rounded shape instead of a pointed one, as this has more resistance, and makes the capsule slow down. The down side of this is that it also creates more heat. Parachutes are also sometimes used to slow the capsule down by making more drag. The space capsules also have to be able to withstand the impact when they reach the Earth’s surface. The early capsules would crash land on water. Those space capsules were not self powered, and the astronauts could not steer the capsule themselves, so the capsule would just free fall through the atmosphere. Modern capsules are more like a plane. When they enter the atmosphere, a computer guides it through a bunch of maneuvers which would slow it down. As the space capsule approaches the runway, the capsule commander and pilot fly the capsule down for the landing. Gravity and drag
Landing on other planets Landing on other planets and moons is very different from reentry on Earth. One, currently, there are still no run ways, and two, there are no bodies of water to crash into. Most space capsules use parachutes to slow the drop, reduce the acceleration, and make a smaller landing. Some capsules, such as the Russian Soyuz space craft, use both parachutes and jets that fire right before landing to reduce the force of the hit. Three of the robotic space crafts to Mars used a combination of parachutes and air bags. The air bags would cushion the fall, but also make the craft bounce around too much to make it practical for a manned landing. Landing on the moon is harder for slowing space capsules. The moon has almost no atmosphere, so there are no molecules for the space capsule to pass through. This can be good and bad. The good thing is that there will be no friction, and consequently, no heat. The bad part is that it is very hard to slow down. Parachutes are of no use as there are no molecules for the parachute to pass through. Capsules that land on the moon have high powered rocket engines that are fired by the pilot to create lift. Lift is the thrust in the opposite direction of descent. This lift slows down the space capsule enough to make a soft landing on the moon. History
Weightlessness
Weakened immune system Another thing is that extended space flight might slow down the body’s ability to protect itself against diseases. Some of the problems are a weakened immune system and the activation of dormant viruses in the body. Radiation can cause both short and long term consequences to the blood marrow stem cells which create the blood and immune systems. Because a space capsule is so small, a weakened immune system and more active viruses in the body can lead to a fast spread of infection. Isolation When on long missions, astronauts will have to go through the isolation and confinement of a space environment. People isolated for a long time can go into all sorts of kinds of depression that can ruin the mission’s success. Not only do astronauts have to be almost totally isolated from the rest of the world, but they have virtually nowhere to move around. That can also cause some depression. When on long missions, astronauts will not be able to quickly return to Earth if a medical emergency occurs. For example, a scientist working in the south pole found a lump in her breast and had to wait a two months before a helicopter could come in. In space, even that is not an option. When a medical emergency happens, the astronauts have to rely on the crew and the computers to solve the problem. Patents | ||||||||||||||
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