Early Space Missions What is a rocket?: Spacecraft equipped with special engines that carry their own fuel. Video: Space Exploration.

Early Space Missions Rockets can be identified by the type of fuel they use. What are the types of fuel rockets? –Solid propellant rockets can not be shut down after they are ignited. –Liquid propellant rockets can be shut down and restarted. –Rockets do not require air to burn their fuel. Therefore, they can work is space which has no air.

Early Space Missions How does a rocket work? Have you noticed what happens if you let the air out of a balloon? The air goes one way and the balloon moves in the opposite direction. Rockets work in much the same way. Exhaust gases coming out of the engine nozzle at high speed push the rocket forward.

Early Space Missions How Rockets Move Activity: 1.Thread the string through the straw. 2.Inflate the balloon and hold the end closed. 3.Tape the straw to the side of the balloon. 4.Two students hold the ends of the string taunt. 5.Release the balloon. 6.Observe gases escaping from behind the balloon pushing it forward along the string.

Early Space Missions How does gravity work? Gravity is the force that pulls small objects toward larger objects. Ex. apple to Earth

Early Space Missions Why does a rocket need such a large amount of fuel? Rockets need so much fuel in order to overcome Earth’s gravity. Only when they reach a speed of km/h are they travelling fast enough to enter orbit.

Early Space Missions Most rockets are made up of two or three stages. When a stage has used up all of its fuel, it is separated to get rid of the dead weight. It then falls back (usually into the ocean and far from populated areas) or burns up in the atmosphere.

Early Space Missions What is a satellite?: Any object that revolves around another object.

Early Space Missions What nation sent the first satellite into orbit? –The former Soviet Union. What was the name of the first satellite? –Sputnik

Early Space Missions According to Newton’s Law an object in motion will continue moving in a straight line unless a force acts upon it. –Why do satellites travel in a circular motion around the Earth? Earth’s gravity pulls the object toward the Earth. Why don’t the satellites then crash back on Earth?

Early Space Missions To make something move in a circle it must be moving and have a force that is always at right angles to the motion so that it constantly changes direction. This force is called the centripetal force. Video: Newton’s Third Law

Early Space Missions Question: What would happen to satellites if we switched Earth’s gravity off? –Satellites would fly off into space in a straight line and continue to do so unless acted upon by another object. –Video: Gravity in space

Early Space Missions Question: If satellites orbit the Earth, how do space probes leave Earth’s orbit and continue out into space? –For interplanetary travel, a spacecraft must use its engines to leave Earth orbit.interplanetary travel

Early Space Missions What is an orbit?: Curved path followed by a satellite as it revolves around an object.

Early Space Missions What are uses for satellites? Astronomy satellites - Atmospheric Studies satellites Communications satellites - Navigation satellites - Reconnaissance satellites, Remote Sensing satellites - Search and Rescue satellites - Space Exploration satellites - Weather satellites

Early Space Missions What is a space probe?: An instrument that gathers information and sends it back to Earth.

Early Space Missions Is a space probe a satellite? No, a space probe travels into the solar system and possibly beyond.

Early Space Missions Who was the 1 st human in space? Yuri Gagarin a Soviet cosmonaut in 1961.

Early Space Missions What was the goal of Project Mercury? To orbit a piloted spacecraft around the Earth and return. Video: Proj. Mercury

Early Space Missions Who was the 1st US citizen in space? Alan Shepard in May Video Who was the 1 st US citizen to orbit the Earth? John Glenn in1962

Early Space Missions What was the final stage of the U.S. program to reach the moon called? - Project Apollo –July 20, 1969 Apollo 11 landed on the moon. –Neil Armstrong was the first human to set foot on the moon.