Flying To Space
It is hard to imagine a
time without space flight. Most of the people considered satellites and space flight to be
real science fiction but it is a impossible dream. Not everybody agreed. A few scientists
and engineers from around the world believed that the technology would soon exist to
launch satellites and people into the space. Military authorities in the USA and the
Soviet Union had a strong interest in rocket development because the rockets could launch
both missiles and satellites. In the autumn of 1957, those believing in space exploration
were proved right.
An orbiter is a space plane. The STS carries one orbiter but has a choice of four, that is Discovery, Atlantis, Columbia and Endeavour. Each orbiter carry seven crew members and stay in orbit for at least 10 days. The orbiter's cabins have three decks such as flight deck, mid deck and a lower deck that houses life support equipment.
LIVING IN SPACE Engineers design space stations so that astronauts can live for long periods in the hostile environment of space, where there is no oxygen, no soil in which to grow food, no water, and no air pressure. Life support systems on board must provide oxygen and filter the carbon dioxide that people breathe out. The air also has to be pressurized to levels close to those on Earth and temperature maintained at comfortable levels. In future, food may be grown in space, but to date crews have had to be supplied with food and water.
MIR SPACE STATIONMir is the longest surviving space station. It consists of a core module, with six additional modules added over the first 10 year of its life. The space station has been staffed continuously since 1987, some cosmonauts remaining on board for more than a year at a time. Solar panels and batteries supply the modules with power. Each day an alarm awakens the crew at 8 a. m. Moscow time, and mission control sends the cosmonauts their work schedule. Mir can contact ground controllers only once every 90 minutes when it passes over a receiving station.
SCIENCE IN SPACE
Gravity keeps peoples feet on the ground and
influences the way a plants roots sink into the soil or how two fluids mix. The
force of gravity cannot be changed on Earth, so scientists go into orbit to carry out
gravity experiments. In orbit, bodies do not escape the effects of Earths gravity,
but if an astronaut drop s a pencil it will float. This is because the spacecraft, the
astronaut, and the pencil are al in free fall towards Earth (even though they will never
get there). All are experiencing weightlessness, also know as microgravity.
STATION EKEMENTSThe International Space Station is made up of more than 100 elements. The biggest contribution - including a connecting node, solar panels, habitation module, an unpressurized module, and two laboratories - is from the USA. A core module, providing living quarters for the first few years, comes from Russia. Canada is providing a robot arm. Two connecting nodes originate in Europe. Most of the participating space agencies will help to transport supplies to the station.
FUTURE SPACEPLANESGetting into space is expensive. It typically costs more then $20,000 for each kilogram of payload carried. Huge amounts of money are wasted when using a multistage rocket to reach orbit, because much of the spacecraft is simply lost. One way to reduce costs is to use vehicles that reach orbit in just one stage. Single stage to orbit (SSTO) spacecraft is an obvious way of getting around the problem. Modern technology such as light but strong materials and new engines, are building SSTO a reality. A single stage reusable space plane called X - 33 began final testing in 1999 but NASA's spacecraft designers are already looking ahead. INTERPLANETARY TRAVEL
The planets are very far away. A spacecraft traveling at 100 km/h - a typical speed of a car on a motorway could take about 60 years to reach Mars. Fortunately, rockets travel much faster than this. The Voyager probes speed from the Earth at 52,000 km/h. even in this speed, travel to the planets takes a long time. Space scientists are using today's probes to test the technology critical for future interplanetary travel. They also work out how to grow crops in space and to live for long periods with limited resources. This will help interplanetary travelers to be self sufficient or essential for spending years in space.
DEEP SPACE 1
A new series of small NASA spacecraft, also known as deep space probes, are testing risky technologies that have never been used in space before. The first of these, Deep Space 1 (DS1), was launched in 1998. The spacecraft guided itself to the asteroids 1992 KD with an automated navigation system. DS1 also tested more efficient solar cells and anew type of rocket knows as an ion drive.
FUTURISTIC STARSHIPSBeyond the solar system, the Earth's nearest neighbour, the alpha Centauri star system, is about 40 trillion km away. Using the fastest current technology, it would take spacecraft about 10,000 years to get there, even if it were possible to carry enough propellant to complete the journey. Light is the fastest ting known in the universe, it could reach Alpha Centauri in a little over four years. For routine interstellar exploration such as that aboard Star Trek's USS Enterprise, the space ship would need to travel faster than light. Nobody knows yet whether this would be possible or not.
SPEED LIMITIONThis theory shows that travel at the space of light is impossible. For an example, the faster an object moves, the heavier it becomes true. Spacecraft traveling at the speed of light would have infinite mass. In Einstein's theory, only electromagnetic radiation which has no mass could travel at the speed of light about 300,00 km/s.