Rockets
Rockets :
Rockets propel spacecraft away from Earth's gravity and into space.
How does a rocket work?
Like all objects, rockets are held to Earth's surface by the pull of gravity. Rockets need to achieve a speed of 11 kilometres per second or 40000 kilometres per hour to escape Earth's gravity. Rockets have different sections or stages which help them to achieve this.
Two or three stages are stocked on top of each other to form the rocket. Each stage has its own engines as well as separate tanks of liquid fuel and liquid oxygen. The liquid fuel and liquid oxygen are pumped into a combustion chamber within the engine where they mix and burn. Hot gases are produced and rush backwards out of the engine. It is the escape of these gases that propels the rocket forward.
The stages burn their fuel one after the other. Once the fuel in a stage has been used, the stage falls away from the rest of the rocket. The rest of the rocket has less weight to carry into space.
Amazing Facts about Space :
Before people ventured into spoce, scientists sent animals, so they could observe how the animals coped with being in spoce. The dog, Laika, was the first mammal from Earth to orbit the planet. Laika died from stress and overheating during her 1957 space mission in the Russian spacecraft Sputnik 2.
As telescopes have become more powerful, they have allowed us to observe planets, galaxies and nebulae in greater detail. In 1990 the Hubble telescope was sent into orbit
Galileo discovered four moons orbiting Jupiter in January 1610.
The Indian Astronomical Observatory which sits 4517 metres above sea level, in Hanle, India, is the world's highest observatory telescope.
Amateur astronomers use refracting telescopes The earliest telescopes were all refracting telescopes including the famous and very simple telescope used by Galileo Galilei in the early 1600s.
The Keck telescopes, the world's largest optical telescopes, are located on the dormant Mauna Kea volcano on the island of Hawaii.
Hubble is the size of a large school bus. It fits inside the cargo bay of a space shuttle.
The Hubble Space Telescope spotted young brown dwarfs for the first time in the Orion Nebula. Brown dwarfs are so-called failed stars because they are too small to be ordinary stars — they cannot sustain nuclear fusion in their cores the way our Sun does.
Hubble is serviced and newer technology is installed by astronouts on space walks. This means that Hubble can benefit from the same advances as ground-based telescopes.
The Hubble Space Telescope completes one full orbit of Earth every 97 minutes.
A three-stage rocket, Saturn V, was used to take astronauts to the Moon in the Apollo spacecraft. Stage 1 burnt its fuel over 2 minutes and 30 seconds - then separated from the rest of the rocket ond fell back to Earth. Stage 2 then fired and lifted the astronauts into space. It too fell away. Finally, Stage 3 fired for 2 minutes and 30 seconds and sent Apollo into orbit around Earth. Stage 3 fired again for over five minutes to send Apollo towards the Moon. It then fell away from the spacecraft. All spacecraft and satellites are taken into space by rockets.
The largest and most powerful rocket ever built was the Saturn V rocket.
Rockets :
