Wikijunior:Solar System/Space exploration
Space exploration — A long dream
Going into space was always one of the biggest dreams people had, even thousands of years ago. Many science fiction authors wrote about traveling in space even before the first airplane flight in 1903. One of the most famous science fiction books on space travel is From the Earth to the Moon by Jules Verne — it was written in 1865, more than one hundred years before the first person walked on the moon. Jules Verne's idea was to use a giant cannon! That might seem silly today, but it shows how much our ideas on space travel have changed.
The first exploration of space
Space begins about 100 km or 62 miles above the earth. A more realistic way to travel in space is with a rocket. Within a rocket is a controlled explosion. However, exhaust (things left over after burning) is only allowed to leave the rocket in one direction. As a result, the rocket is pushed in the other direction. In 1942, the German rocket A-4 became the first to reach that height, but it wasn't meant to do anything but fall straight down again and so wasn't terribly useful. Still, it was an advance in rocket technology.
The Soviets were the first to put anything in space that would stay up: they launched the Sputnik 1 satellite on October 4, 1957. Within a month, the Soviets launched Sputnik 2, and in that spacecraft was the first space traveler: a dog called Laika.
The launch of the Sputnik started the Space Race, a competition between the United States and the Soviet Union to obtain more and more advanced space technology. Americans were very surprised that the Soviets could have launched 'Sputnik', and began to design rockets and satellites of their own. The race would last for the next few decades.
A man in Space
On April 12, 1961, the first person was sent into space: Yuri Gagarin, a Soviet, riding in the spacecraft Vostok 1. The Soviets would send more people into space over the next few decades, and so would the Americans, but it wouldn't be until 2003 that another country would launch a spacecraft with a person in it: China, with the Shenzhou 5.
The race to the moon
At the beginning of the 1960s, American president John F. Kennedy made a famous speech in which he said that the U.S. was going to send people to the moon within the next 10 years. And that's what happened: in July of 1969, Neil Armstrong stepped off the there spacecraft and said "One small step for [a] man and one giant leap for mankind". He and Buzz Aldrin walked on the moon where they put an American flag. Their footprints are still there because there is no wind or water on the Moon to wash them away.
The Space Shuttle
After the Apollo program that sent people to the Moon, the U.S. built the Space Shuttle, that is like a jet-plane that can go to space and return! (With the help of rockets of course). The Space Shuttle helped construct the ISS (International Space Station) among another things.
The last space shuttle mission is on June 28 2011, but it will be replaced with new vehicles that will take mankind to the Moon, Mars, and beyond!
Spaceships of the future
Right now, spaceships are not very efficient. The Saturn V rocket was 363 feet tall, and it could only take people to the moon! To get people further, better rockets must be invented. One of the most popular ideas for a rocket is the antimatter rocket. This type of rocket collides a small amount of antimatter with an equal amount of normal matter to create a large amount of energy!
Other ideas for going into space, that don't need rockets, have been thought of by scientists and astronomers. One of these is a space elevator. A space elevator is basically a big lift into space. It will cost a lot less to get things up into space if a space elevator is built.
Another idea, a bit like the Jules Verne idea, is an electromagnetic catapult. This catapult works by accelerating the spaceship along a rail, similar to a maglev train. Unfortunately, the air on Earth would set spaceships on fire as they launched, but scientists aren't thinking of putting one there: one could go on the Moon! The catapult on the moon could send metal and other resources to Earth's orbit, where a space station could collect them.
Exploration beyond the Solar System
Many people dream of the day when humans can travel to another star and explore other worlds, some people wonder what's out there some belive that aliens or other life may live on another plant. But, if this ever does happen probably won't happen for a very long time. The stars are so spread out that there are trillions of miles between stars that are "neighbors". Maybe one day, your great grandchildren will be standing atop an alien world wondering about their ancient ancestors?
The eye beyond Earth
Many people say the very best invention ever (not just in space technology) was the Hubble space telescope (HST). Others say it's just the space station being selfish having the best technology in the world.
The Hubble Space telescope is a giant telescope that is in orbit around the Earth. Because there is no atmosphere, the Hubble Space Telescope has a clear view of even distant galaxies. One of the pictures the Hubble space telescope has made is called the 'Hubble Deep Field'. The Hubble Deep Field is a picture of some of the most distant galaxies, and it gives a snapshot of what the universe looked like when it was younger.
Even bigger telescopes are also in the planning, so we might be able to see right to the edge of the universe some day soon.