Also see background information for Health in Space.
Humans are exploring space. While our current human exploration is through the International Space Station and transportation to and from it, future activities could include missions to the Moon, Mars, and other locations in the Solar System. These require rockets to launch from the Earth or Moon or a space station, landing capsules, and some type of facilities or colony from which to explore the Moon and Mars.
Human space exploration needs to meet the requirements for healthy life and productivity: air, food, water, energy, communications, transportation, productivity areas and tools, and recreation.
- Air Supply: transportation vehicles, stations, and colonies need breathable air ((78% nitrogen, 21% oxygen, and 1% other gases). Modules and living areas have to be enclosed, to keep the air from escaping. Rockets, space capsules, and space stations need to bring the air with them. A space colony or large space station could create oxygen from water by splitting water molecules into hydrogen and oxygen, using electrolysis, or through photosynthesis from plants. There is also a process that extracts the oxygen contained in minerals in the rocks and soil. While we breathe nitrogen and oxygen, we exhale carbon dioxide. It would be dangerous to allow this to build up; it needs to be filtered from the atmosphere as the air is recycled.
- Food: Transportation vehicles and space stations need to bring food with them, and space for producing food is very limited in a colony. In any self-contained colony, food must be renewable, as replacement stock will not be available from Earth. Some foods under consideration for use in space missions are soybeans and wheat, which take up a small amount of space and are very nutritious. Food crops can also be used to purify water and to produce oxygen from carbon dioxide using photosynthesis. A greenhouse will be a necessary addition to any space base.
- Water: Humans need a great deal of water for drinking, washing, watering plants, etc. Recycling and purifying systems can recapture water from daily washing, moisture in the air from breathing, moisture from the heating and cooling systems, and water from urine. Plans need to include water storage and recycling and possibly water production facilities.
- Temperature: Space stations, capsules, and colonies need to be insulated from extreme temperatures, such as the cold temperatures on Mars, night on the Moon and on space stations, and the high daytime temperatures on the Moon and in sunlight on space stations. Electronic equipment can also generate excess heat, which may need to be vented into space.
- Waste Removal: Living and working in space creates waste. Much of that waste — like water waste — will eventually be recycled and reused. Efforts are made to create as little waste as possible. Some may need to be returned to Earth, vented into space, or stored outside of the colony for future use.
- Energy: What energy source(s) will power the space vehicles/stations/colonies? Plans need to determine whether power will be generated through solar or nuclear energy, and need to include a back-up and energy storage system, such as batteries to store solar energy at night.
- Production and Research: What kinds of production will take place at your station or colony? Some examples may include mining for resources, science laboratories, telescopes, and facilities to produce fuel or water.
- Living Quarters: Consider whether each space explorer needs a private living space, which may depend on how long they will spend at this facility. Every square foot requires more resources, but people are happier when they feel they have sufficient space and privacy.
- Communications: How will people communicate with one another? Determine how the space explorers will communicate with each other (for instance, with those exploring in a rover), as well as with Earth. Plans may require satellites and antennas.
- Transportation: What kinds of trips will the crews need to make? Transportation such as EVA equipment and rovers needs to be planned for getting space explorers to space stations and colonies, but also for exploring the space and region around them, as well as for returning to Earth. Fuel or an appropriate energy source will need to be planned as well.
- Recreation Facilities: Remember that the mind needs exercise as well as the body. How will these recreation facilities be different from those on Earth? Consider the limited space and the lower gravity on the Moon (one-sixth that of Earth) and on Mars (one-third that of Earth), as well as the microgravity of a space station in orbit.
Modules and Technology
A space station or space colony will need different sections:
- Habitation Modules – Living quarters that may include showers, private rooms, eating areas, etc.
- Laboratory Modules – Work quarters where the crew conducts experiments.
- Greenhouses – Used to grow food and contribute to the oxygen environment; also a way to use excess carbon dioxide.
- Solar Arrays – Used to collect and store electricity to power various systems and activities.
- Antennas – Used for communications back to Earth and with other spacecraft.
- Surface Rovers –Pressurized rovers for long trips and open rovers for short trips.
- Resource Utilization Facilities –Used to mine the resources of the Moon or planet for use in the base or for manufacturing propellant (fuel) for space ships.
- Docking Facilities –Used for supply ships.
- Escape System –Used in case of an emergency.
- Telescopes - On the Moon where there is no atmosphere, telescopes would provide scientists and astronomers a great view of deep space beyond Earth's atmosphere.
- Supply Ships - Spacecraft used to bring crews and supplies to and from the space base.
- Space Suits - Astronauts will need to wear space suits for construction and repair of a space station or colony, as well as for any research excursions onto the surface of another planet or moon.
A rocket essentially is a container propelled in one direction by exhaust going in the opposite direction. Rockets help spacecraft get into space, stay in space, and maneuver in space. The main parts of a rocket include the nose cone (the leading, tapered section that reduces aerodynamic drag), the body tube ( the central structure, which includes the engine, propellant tanks, and payload), and the fins (which guide the rocket).
Space capsules are the compartments designed to support astronauts during their journey through space, and land people or instruments on the surface of Earth or another planet. They must contain the basic elements that astronauts need to live — air to breathe, water to drink, and food to eat. They also have to protect the astronauts from the cold of space and space radiation.
Space stations are platforms for long-term living and working in space that orbit Earth; in the future, they may orbit other planets or moons. Space stations can carry out scientific research in an environment not found on Earth; they allow scientists and engineers to test materials and designs for future space travel.
Space colonies on the Moon, Mars, asteroids, other worlds and in orbit around the Earth have been suggested, designed and promoted since the 1950's. Space colonies can include laboratories for unique or risky experiments, factories, observatories, and mining stations. There may eventually be a permanent lunar base for scientific research and mining, which would be a stepping stone to Mars. A lunar outpost could provide valuable information on the long-term physiological and psychological effects on humans living for long periods in space. The Moon could serve as a source for the large quantities of oxygen needed to fuel a spacecraft to Mars and back. In the more distant future, there may be bases on Mars, such as a Mars habitat that could be launched into orbit, eventually being delivered to Mars nearly 26 months prior to the first crew's arrival.
Research in Space
On Earth, gravity influences the way crystals, plants, and animals grow. In contrast, space stations and space colonies offer an environment where there is very little gravity. Research can help understand how weightlessness influences growth and development. In microgravity nearly perfect crystals can be grown; it may be possible to use these to create new and more efficient drugs and microchips for computers. Research is learning how plants can be grown in space to provide food, and how weightlessness influences calcium and tissue loss in humans — and how this can be prevented. Perhaps the most important reason for living in space is to determine how to keep humans healthy for the length of time that will be required by journeys of exploration to Mars and other planets.
Other research includes monitoring our Earth's atmosphere, weather, climate, oceans, land, and resources: space stations offer “the best seat in the house” to make observations of Earth's environments.
History of Human Space Exploration
Humans in Space
Prior to human exploration of space, test flights involved animals, including dogs, monkeys, and mice. In 1957, Russian scientists sent the first dog into space to allow them to investigate the effects of space flight on a living organism This was followed by other missions involving animals, leading up to the successful 108 minute Earth orbit by Cosmonaut Yuri Gagarin on 12 April 1961. Astronaut Alan Shepard was the first American astronaut to travel into space; he was aboard the Mercury capsule. The Gemini capsule carried the second generation of astronauts into Earth orbit for longer periods of time. The Apollo capsule took astronauts to the Moon, and the Lunar Module landed astronauts on the surface. Dozens of Russian cosmonauts have orbited Earth in the Russian Soyuz capsule. The Space Shuttle served as a means of transport and support for astronauts as they move between Earth and the International Space Station. Unlike earlier capsules, the Space Shuttle was designed to be used for many flights.
Space capsules have not always been successful and the price for exploration is high when counted in human lives; one early Soyuz capsule lost three cosmonauts when it depressurized upon re-entry. Two Space Shuttles, the Challenger and the Columbia, and their crews, were tragically destroyed due to malfunctions. The Challenger failed during lift-off, when a seal malfunctioned in the solid-rocket booster, causing the craft to explode 73 seconds after launch. The Columbia was destroyed on February 1, 2003, during re-entry, when a catastrophic failure occurred due to damage caused by foam that fell and struck the panels on the underside of the wing during launch.
Past space stations include:
- Salyut (Russian) — On April 19, 1971, the USSR launched Salyut 1, the world's first space station. By today's standards, Salyut was small — 20 meters long, 4 meters across, with an area of about 100 square meters. Inside, there was a vegetable garden, and two working compartments housed a dining area, recreation area, toilet, seven control stations, food and water storage, exercise equipment, and scientific equipment. There were six successful Salyut stations that flew from 1973 to 1985.
- Skylab (U.S.) — America's first experimental space station,3 three-man crews occupied Skylab in 1973 and 1974. It was the site of nearly 300 scientific and technical experiments, medical experiments on humans' adaptability to microgravity, solar observations, and detailed Earth-resource experiments.
- Mir (Russian) — Mir, which means “peace” in Russian, was launched in 1986 as a new-generation space station and successor to Salyut. With its kitchen and gym, Mir offered its crew a more comfortable environment in which to conduct their experiments than Salyut. One crew clocked 366 days on Mir, which was manned almost continually by Russian crews for 12 years. The Shuttle-Mir program brought several American astronauts to live and work onboard Mir in preparation for life onboard the International Space Station.
- International Space Station — The International Space Station (ISS) is the single largest international aerospace project ever undertaken, involving the United States, Canada, the 10 members of the European Space Agency, the United Kingdom, Japan, Russia, and Brazil. The station orbits Earth once every 90 minutes at a distance of 250 miles (400 kilometers) above the surface. The ISS enables long-term exploration of space in an orbiting science institute where scientists can conduct long-term research in material, life, and medical science.