SPACE TRAVEL GUID ES SPACE EXPLORATION ED by Giles Sparrow I Smart Apple Media on
Leaving Earth In this book we're taking the trip of a lifetime exploring what it's like to be an astronaut We'll learn how spacecrafts leave the Earth and travel out across the solar system and what we have learned from space exploration so far We'll also be taking a look at the challenges and dangers astronauts may face in the future BREAKING FREE The edge of space is just 60 miles 100 km straight above your head But Earth's gravity is a powerful force that pulls you and everything else down onto its surface and prevents it from leaving You will have to overcome this gravitational pull first and for that you will need a rocket Once out in space you will orbit the Earth at hundreds of miles per hour in weightless conditions in a completely airless vacuum Looking down you will be able to see the thin shell of air that surrounds Earth the atmosphere This layer of gases supports life on the surface but makes returning from space very difficult Any object entering the atmosphere at high speeds will be heated to extreme temperatures and your spacecraft will need heat shields to stop it from being burned to a crisp The Mercury Atlas 9 rocket lifted off from Cape Canaveral Florida on May 15 1963 It was piloted by astronaut Gordo Cooper who was the last American to fly a solo mission to space III
BEY O N D THE E AR TH Despite all these dangers space is an amazing place and well worth the risk The ability to put satellites in orbit has helped to shape our modern society and our robot space probes have changed our view of the solar system One day soon human colonists on the Moon and other planets will open a new stage in the history of the human race TRAVELER S TALES ESCAPE VELO CITY Rocket scientists often talk about the Earth's escape velocity which is the speed you need to achieve in order to entirely escape Earth's gravity This is roughly 7 miles per second 11 2 km sec but you don't need to travel that fast to go into orbit a couple hundred miles up An orbit is a circular or oval path that one object follows around another such as a satellite going around the Earth A spacecraft such as a space shuttle see below needs to be pushed upward with a force or thrust that's strong enough to overcome Earth's gravity and speed the vehicle up enough to go into orbit In order to put a couple pounds of material into space a typical rocket has to use 100 200 pounds 50 100 kg of
