Space Exploration SPACE EXPLORATION: FROM THE PAST TO THE FUTURE Ever since the beginning of time, mankind has been fascinated with wonders of space. Before the mid-1900s, all mankind could do was gaze at the stars from Earth and wonder what it would be like to go into space. Man would look through telescopes and make theories on how the universe worked. During the mid-1900s, mankind finally was able to send a man into space and explore the wonders of space first hand. So why do humans explore space? Well, it is our fascination with the unknown. At first, all mankind did was look up and wonder how things became what they are now.
We started to think that all celestial bodies revolved around the Earth, and the Earth was the center of the entire universe. Galileo Galelie later disproved this theory. Even with growing knowledge in the field, it was not until 1957 when the first Earth orbiter, the Soviet’s Sputnik 1, was sent into space and placed in orbit at an altitude of 1,370 miles and weighed 184 pounds. Later in that year, the Soviets sent Sputnik 2 into space with a dog named Laika. Laika was the first animal to venture into space. Then in 1985, the United States successfully sent their very own satellite into space.
In 1960, the Soviets launched to dogs into space and successfully returned them to Earth. From this point started the space race. The space race was a challenge between the USSR and the United States to see who could land a man on the moon first. In 1961, the first man in space was cosmonaut Yuri Gagarin who was in space for 60 minutes before returning to Earth in Vostok 1 and was sent by the USSR. Astronaut Shepard flew the first manned sub-orbital space-flight by the Americans. The first true American orbital flight was by John Glen and he stayed in space for five hours in Mercury 6 in 1962.
Then in 1963, the USSR sent the first woman into space; her name was Valentina Tereshkova-Nikaleva. They also had the first person to take a space-walk in 1965. In 1968, the National Aeronautics and Space Administration or NASA tested the first Saturn 5 rocket, which would be used for the Apollo missions. The first manned Apollo missions and the first flight around the moon took place in 1968. Finally, on July 21, 1969, the United States placed the first man on the moon winning the space race.
The challenge for mankind at present is placing a human on Mars. We have already sent probes on to Mars and roamed some of its terrain with the rover known as Sojourner. Sojourner was taken to Mars on NASA’s Mars Pathfinder and was the first wheeled vehicle to operate on another planetary surface. The Mars pathfinder sent photographs, atmospheric measurements, and a few other important data that will contribute to taking a man to Mars. While pathfinder sent data, Sojourner examined rocks and soil samples with a camera and Alpha Proton X-ray Spectrometer, providing useful data on chemical compositions and radiation bounced back from rocks and dust.
The mission finally ended when the Pathfinder stopped responding to commands from NASA. NASA has sent two other probes to Mars, but both malfunctioned and were destroyed on impact on the Martian surface. The US and a few other countries have joined together and are constructing the International Space Station or the ISS. The ISS is scheduled to be completed in 2004 and will be continuously occupied by up to seven crewmembers. The space station is envisioned to be a world-class research facility in which scientist can study Earth and space, as well as explore the medical effects of long durations of weightlessness in space and the behavior of materials in a weightlessness environment, and the practicality of space manufacturing techniques. Now, the future of space exploration depends on many factors.
Some of these factors are as followed: how much technology advances, how political forces change rivalries as well as partnerships with other nations, and how important space exploration is to the general public. NASA is working on a single-stage-to-orbit (SSTO) vehicle, but until it is until then, NASA plans to us the space shuttle fleet to the year 2012. It is clear that mankind has devoted itself to the exploration of the unknown and that we are committed to find new planets on which man cal live and prosper. Missiles were first used to take man into space. In the Gemini and Mercury missions, missiles without warheads and a compartment for the astronauts was used to get into space.
On the other hand, the Saturn 5 Rockets were used in the Apollo missions to reach orbit and land on the moon. This method became too expensive so NASA was forced to develop a reusable space craft. As a result, NASA designed the space shuttle, which is used today. The shuttle takes off like a rocket with an external fuel tank and two solid rocket boosters. The two rocket boosters, which are attached to the external fuel tank, provide additional thrust during lift off and are discarded after first two minutes from take off.
They are then retrieved from the ocean to be fixed, refueled, and reused. The external fuel tank supply additional fuel to the three onboard engines and is detached from the shuttle, orbiter, after reaching orbit. Another spacecraft is the X-33 is a single stage orbiter and a smaller version of the venture star. Both of these crafts will be launched like a shuttle but without any additional boosters. They will be able to land, get refueled and loaded with cargo, positioned vertically, and take off within hours. It will make travel to space faster, safer and cheaper.
The two crafts will use the spike engine that allows the craft to reach orbit without gong through different stages during lift off. The X-33 and the Venture Star will allow companies to put satellites in orbit for a cheaper cost. Space travel does take its effect on humans. Piloted space flights have to supply oxygen, food, and water for their occupants and even longer flights need to have a way to dispose of or recycle waste. The even longer flights, spacecrafts will eventually need to become mostly self-sufficient. The astronauts will have to exercise and since the astronauts will be weightless, the shuttle will need to provide more than just the core physical needs for the astronauts to stay healthy. The weight of the craft is so important that it plays a crucial role in the amount of food supplied by the spacecraft.
Most food provided to the astronauts is dehydrated, which is rehydrated by a device that is some what like a water gun, to save space as well as weight. However, some foods are given in their conventional form such as fruits, candy, and bread. Water is usually provided by fuel cells that also provide electricity to the whole ship. The reaction between Hydrogen and oxygen provides the electricity and creates water as well. A small amount of water is also carried onboard in case of emergencies.
Water is also recycled on long duration missions aboard space stations. In this process, drinkable water is extracted from a combination of waste water, urine, and moister from the atmosphere in the cabin. This system will be recycled was used on the MIR space station and is planned to be used on the International Space Station. Skylab, the first US space station, was the fist to offer its crew a chance to bathe in space by installing a collapsible shower. To prevent water from escaping and floating around the cabin, the astronauts sealed the shower once inside.
Astronauts had a hand-held nozzle to dispense water and then a vacuum to remove the water. On the space shuttle on Mir, where the showers malfunctioned, astronauts and cosmonauts have had to take sponge bathes in order to stay clean. On the International Space Station, showers will be provided in the habitual module. Most piloted spacecrafts carry their oxygen in the liquid state of matter in onboard tanks that keep the oxygen at cryogenic or super-cold temperatures to save space on the craft. The Russian space station MIR used special onboard generators to separate water into oxygen and hydrogen.
On the Mercury, Gemini, and Apollo missions, the cabin atmosphere consisted of one hundred percent oxygen. This gave the cabin a pressure of 0.3 kg/sq cm (about 5 lbs/sq in). However, on the space shuttle and the MIR space station, the atmosphere is a mixture of oxygen and nitrogen to provide an atmospheric pressure of 1.01 kg/sq cm (14.5 lbs/sq in), which is slightly lower than that of sea level. Before an astronaut could go on space walks, astronauts and cosmonauts had to breathe pure oxygen to rid their bloodstreams of nitrogen. This eliminated the chance that the space walker would get decompression sickness because of the different pressures from the space suit and the cabin. Since the suit had a pressure of 0.30 kg/sq.
cm, the sudden decompression would cause nitrogen bubbles to form in the bloodstream and other bodily organs and would result in a painful and potentially lethal condition. This atmospheric mixture is planned to be used in the International Space Station. A problem with micro gravity and weightlessness is that in long duration missions in this type of environment creates problems with the muscles weakening. In space, muscles do not have to exert much force to move and in turn get weaker. This creates a problem with a mission to Mars, the long duration in a weightless environment will weaken the muscles and when craft lands on Mars, the crew will have a difficult time adjusting to the new environment and completing their jobs.
To make this problem less severe, scientist are working on a way to create artificial gravity. This will make the environment in which the astronauts travel in more like that of Earth, so when the crew lands on Mars, they will have an easier time adjusting to the gravity of Mars. Space exploration has come a long way since the beginning. mankind has gone to the moon and back, we have sent probes to the furthest reaches of our solar system, we have sent a robot to roam the Martian terrain, we have made spaceships that are reusable, and we can see other galaxies that are billions of light years away. Now we brainstorm on how to explore space even further. Man kind is destined to go to the far reaches of the universe and make contact with other life forms.
With all things considered, humans are not far from colonizing space. Bibliography “Space Exploration.” Encarta Encyclopedia. October 2000. [Online] Available: http://encata.msn.com/”NASA Plans to Continue X-33 Space Plane Plan.” NASA. October 2000 [Online] Available: http://www.nasa.gov/today/index.html “NASA, Lockheed Martin Agree on X-33 Plan.” Mission Updates. October 2000 [Online] Available: http://www.venturestar.com/pages/missupd/pressrel/ 2000/09290001.html “X-33 Space Plane Program Moves Ahead.” X-33 News.
October 2000 [Online] Available: http://www.x33news.com/ or http://www1.msfc.nasa.gov/NEWSROOM/news/releases/2 000/00-284.html “Space Exploration.” Academic American Encyclopedia. pg. 120-120c. copyright 1998 Science Essays.