Exploring-the-planets

Exploring the planets 

 The planets are too far for manned missions,so robotic spacecraft are sent instead. The first to visit another planet was mariner 2,a US craft that flew past venus in1962.since then, and despite anumber of early failures,hundreds of spacecraft NBA have visited the solar system's planets, moon, asteroids,and comets. Most spacecraft either fly past or orbit their target,but some also release lancers that touch down on the surface.

Robot explorers 

Robotic spacecraft can visit places too far or dangerous for human beings. Launched into space by rocket, they travel vast distances across space and may take years to reach their target. There are various types of spacecraft,each suited to a particular mission.

Flyby spacecraft 

Some spacecraft observe a target as they fly past.NASA's famous voyager 1 and voyager 2 fleww past several planets.

Orbiter 

An orbiter flies around a planet repeatedly, giving it plenty of time to study its target. Orbiters have visited the moon and all the planets except Uranus and Neptune.

Pioneer spacecraft 

Pioneers 10 and 11 made flybys of Jupiter and Saturn. They are now heading out of the solar system into deep space.

Atmospheric probe 

This type of craft enters a planet's atmosphere. The Galileo probe dived into Jupiter's stormy atmosphere in 2005.

Lander 

Some craft can touch down on the surface of another world. In 1976, Viking 1 became the first craft to successfully land on Mars.

Rover 

A rover is a robotic lander with wheels that can drive about. Rovers sent to Mars have studied its rocks for signs of ancient life.

Penetrator 

A penetrator is designed to hit its target at high speed and bury itself. In 2005,deep impact penetrated the surface of comet.

Solar System missions 

In little mor then 50 years, around 200 spacecraft have left Earth’s orbit and headed off to explore the Solar System. More than half the missions havw been to Earth’s nearest neighabours in space: the Moon and the planets Mars and Venus .

Space exploration 

Star and planets have fascinated people since ancient times, but it wasn’t until the 20th century that exploring space became possible. In recent decaded we have sent astronauts to the Moon, robotic spacecraft to the outer reaches of the Solar Systen, and used huge telescopes to peer across the vastness of the Universe .

Satellite orbits 

Some satellites are a few hundred kilometres above Earth’s surface, but others are much further. Some of the highest ones, such as weather, TV ,and phone satellites, have geostationary orbits, wich means they stay over a fixed point on Earth. Satellites with lower orbits change position all the time