launch-vehicle

 launch vehicle 

   Space is only 100km above Earth's surface and takes less than 10 minutes to reach in a rocket​. Although the journey is short,it takes tremendous power to escape​ the pull of Earth's gravity. Lupaunch vehicles are built to make the journey only one time,and most of their weight is fuel.



Would's largest rocket

   Saturn V,wich sent astronauts to the moon,was the largest rocket ever built. It Soviet rival,the N1,was launched four times but each attempt ended in disaster​.,Ariane 4 (Europe)-59m,Long March 2(China)62 m,DeltaIV,heavy(USA)-72m,N1(USSR)-105m,Saturn V (USA)-111 m

Launch sites 

   Many countries have spaceflight launch sites. Sites closer to the equator can launch heavier cargo, because rockets there are given a boost by the speed of Earth’s spin.

Living in space

   Astronauts must adapt to a zero-gravity environment when living in space. Although floating weightlessly can be fun, it can also cause medical problems.Space stations are cramped places with few luxuries. Astronauts eat ready-made meals that are either freeze-dried or served in pouches. All water is recycled, including the water vapour from human brath. Astronauts clean themselves with speciel shampoos and soaps that don’t need water,and they use space toilets that suck away waste rather than flushing with water.

Effects on the body

   When the human body spends a long time in space , it changes. Witout gravity pulling on the spin, the body gets about 5 cm (2 in)taller. Body fluids that flow downwards on Earth build up in the head. This gives astronauts swollen faces and blocked noses, making food seem tasteless. When astronauts come back to Earth, the return of full gravity can make them feel extremelym weak.

Space stations

   A space station is a crewed satellite-a kind of orbiting laboratory in which astronauts and scientists live and work. The USSR launched the first station,salyut 1, in 1971. The USA soon followed with Skylab, in 1973. Russia’s Mir,in use from 1986 to 2001, was the most successful station until the USA,Russia. And more than 10 other countries joined forces to build the International Space Station, in orbit since 1998. China’s own space station prototype, Tiangong-1, was launched in 2011.



Satellites

   About 1,000 operational satellites orbit Earth, carrying out tasks such as beaming TV signals around the world, gathering data for weather forecasters, and spying for the military. Many thuusands more pieces of space junk-old satellites, discarded rocket parts, and debris from collisions- also circle our planet . the growing cloud of space debris is a hazard to spacecraft.