Science 9: Unit E: Science 9: Unit E: Space ExplorationSpace Exploration

Topic 6: Above the Topic 6: Above the Atmosphere and Under Atmosphere and Under

ControlControl

RocketsRockets

► Rockets were invented in ancient China and Rockets were invented in ancient China and used mostly for fireworks and cannon fire.used mostly for fireworks and cannon fire.

► A rocket is made up of three parts:A rocket is made up of three parts:► The combustible fuel (used to be gunpowder The combustible fuel (used to be gunpowder

now is mostly liquid hydrogen and oxygen)now is mostly liquid hydrogen and oxygen)► The payload – the device, material, or persons The payload – the device, material, or persons

that the rocket is delivering. It can be anything that the rocket is delivering. It can be anything from a nuclear warhead to a Russian from a nuclear warhead to a Russian cosmonaut.cosmonaut.

► A tube connecting the first two parts together.A tube connecting the first two parts together.

Thrust and Escape VelocityThrust and Escape Velocity

►The thrust/force that powers a rocket up The thrust/force that powers a rocket up is achieved by the rocket forcing down is achieved by the rocket forcing down the exhaust from the fuel. The speed that the exhaust from the fuel. The speed that the exhaust fuel leaves the rocket is the exhaust fuel leaves the rocket is called the exhaust velocity. The faster called the exhaust velocity. The faster the exhaust velocity the further the the exhaust velocity the further the rocket travels. The action-reaction rocket travels. The action-reaction principle of pushing down the fuel is principle of pushing down the fuel is similar to a basketball player jumping up similar to a basketball player jumping up to the hoop by pushing down on the to the hoop by pushing down on the floor.floor.

The Evolution of RocketsThe Evolution of Rockets

► Rockets started out using solid fuels such as Rockets started out using solid fuels such as gunpowder. Modern rockets now used liquid gunpowder. Modern rockets now used liquid fuels which have higher exhaust velocities fuels which have higher exhaust velocities and are lighter than solid fuels.and are lighter than solid fuels.

► Older rockets were one single object. These Older rockets were one single object. These were called single-stage rockets. Later were called single-stage rockets. Later rockets were designed as multi-stage rockets: rockets were designed as multi-stage rockets: as pieces of the rockets become unnecessary as pieces of the rockets become unnecessary they drop off and the rocket continues they drop off and the rocket continues moving up with a lighter mass. The multi-moving up with a lighter mass. The multi-stage rocket can therefore travel farther.stage rocket can therefore travel farther.

Modern RocketsModern Rockets► The modern rocket was invented in Nazi Germany The modern rocket was invented in Nazi Germany

during WWII by Werner von Braun. The name of during WWII by Werner von Braun. The name of this rocket was the V-2 rocket and it was used as this rocket was the V-2 rocket and it was used as a long range missile against Britain.a long range missile against Britain.

► von Braun was later abducted by the Americans von Braun was later abducted by the Americans who put him in charge of their space program. who put him in charge of their space program. Thus you can say that putting the man on the Thus you can say that putting the man on the moon wouldn’t be possible without the help of moon wouldn’t be possible without the help of Nazi scientists.Nazi scientists.

► Russians created their own competing space Russians created their own competing space program creating three models of rockets program creating three models of rockets themselves: the Vostok, Voshkod, and Soyuz themselves: the Vostok, Voshkod, and Soyuz rockets. The Soyuz rocket is still used today to rockets. The Soyuz rocket is still used today to deliver payloads to the International Space deliver payloads to the International Space Station. Station.

Guiding the Rockets: Guiding the Rockets: ComputersComputers

►To keep rockets on their set course, and To keep rockets on their set course, and to keep the thousands of satellites from to keep the thousands of satellites from crashing into each other, astronomers rely crashing into each other, astronomers rely on computers to calculate and monitor the on computers to calculate and monitor the orbital paths of all spacecraft.orbital paths of all spacecraft.

►Computers on the ground are capable of Computers on the ground are capable of communicating with computers on board communicating with computers on board the satellites ordering them to fire a the satellites ordering them to fire a certain thrust, for how long, and in which certain thrust, for how long, and in which direction.direction.

Escape Velocity and Escape Velocity and Gravitational AssistGravitational Assist

► It takes a lot of force to get an object to a fast It takes a lot of force to get an object to a fast enough escape velocity so that it can overcome enough escape velocity so that it can overcome Earth’s gravity. It takes even more force to Earth’s gravity. It takes even more force to move the spacecraft to a fast enough speed so move the spacecraft to a fast enough speed so that it can move to another planet. To help that it can move to another planet. To help with this, rockets use with this, rockets use gravitational assistsgravitational assists to to help accelerate the spacecraft to a quicker help accelerate the spacecraft to a quicker speed. This involves getting an object close speed. This involves getting an object close enough to a large planet like Jupiter so that it is enough to a large planet like Jupiter so that it is accelerated by the planet’s gravity and reach accelerated by the planet’s gravity and reach its destination sooner.its destination sooner.

SatellitesSatellites

►Any object created by humans that is Any object created by humans that is circling the Earth or any other planet is circling the Earth or any other planet is called an artificial satellite. These called an artificial satellite. These include communication and TV include communication and TV satellites, space telescopes, space satellites, space telescopes, space stations and probes. Natural satellites stations and probes. Natural satellites include moons and planets themselves include moons and planets themselves (they’re technically satellites of the (they’re technically satellites of the Sun).Sun).

OrbitsOrbits►OrbitsOrbits► There are two main kinds of orbits used for There are two main kinds of orbits used for

satellites: Low Earth Orbits and satellites: Low Earth Orbits and Geosynchronous orbits.Geosynchronous orbits.

OrbitOrbit Low Earth OrbitLow Earth Orbit Geosynchronous Geosynchronous OrbitOrbit

RangeRange 200-800 km 200-800 km above Earth above Earth

36000 km above 36000 km above Earth Earth

Orbital PeriodOrbital Period One rotation One rotation every 1.5 h every 1.5 h

One rotation One rotation every 24 h every 24 h

Used ForUsed For Telephone/Telephone/communication communication satellites satellites

TV satellites TV satellites

Tracked ByTracked By Moving antenna Moving antenna Stationary Stationary antenna antenna

Remote Sensing and GPSRemote Sensing and GPS

► Remote Sensing: The use of space satellites Remote Sensing: The use of space satellites to study features on the Earth or other to study features on the Earth or other planets. Usually used to study weather planets. Usually used to study weather patterns, pollution, and military sites.patterns, pollution, and military sites.

► Stands for global positioning system. A Stands for global positioning system. A technology created by US military to provide technology created by US military to provide a reliable navigation system. a reliable navigation system.

► The technology is used to pinpoint certain The technology is used to pinpoint certain locations by triangulating your position with locations by triangulating your position with at least two GPS satellites in the sky. The at least two GPS satellites in the sky. The distance between the satellites provides the distance between the satellites provides the baseline.baseline.