Science 9: Unit E: Space Exploration

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Science 9 Unit E Space Exploration

• Topic 6 Above the Atmosphere and Under Control

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Rockets

• Rockets were invented in ancient China and used
  mostly for fireworks and cannon fire.
• A rocket is made up of three parts
• The combustible fuel (used to be gunpowder now is
  mostly liquid hydrogen and oxygen)
• The payload the device, material, or persons
  that the rocket is delivering. It can be anything
  from a nuclear warhead to a Russian cosmonaut.
• A tube connecting the first two parts together.

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Thrust and Escape Velocity

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

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The Evolution of Rockets

• Rockets started out using solid fuels such as
  gunpowder. Modern rockets now used liquid fuels
  which have higher exhaust velocities and are
  lighter than solid fuels.
• Older rockets were one single object. These were
  called single-stage rockets. Later rockets were
  designed as multi-stage rockets as pieces of the
  rockets become unnecessary they drop off and the
  rocket continues moving up with a lighter mass.
  The multi-stage rocket can therefore travel
  farther.

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Modern Rockets

• The modern rocket was invented in Nazi Germany
  during WWII by Werner von Braun. The name of this
  rocket was the V-2 rocket and it was used as a
  long range missile against Britain.
• von Braun was later abducted by the Americans who
  put him in charge of their space program. Thus
  you can say that putting the man on the moon
  wouldnt be possible without the help of Nazi
  scientists.
• Russians created their own competing space
  program creating three models of rockets
  themselves the Vostok, Voshkod, and Soyuz
  rockets. The Soyuz rocket is still used today to
  deliver payloads to the International Space
  Station.

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Guiding the Rockets Computers

• To keep rockets on their set course, and to keep
  the thousands of satellites from crashing into
  each other, astronomers rely on computers to
  calculate and monitor the orbital paths of all
  spacecraft.
• Computers on the ground are capable of
  communicating with computers on board the
  satellites ordering them to fire a certain
  thrust, for how long, and in which direction.

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Escape Velocity and Gravitational Assist

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

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Satellites

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

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Orbits

• Orbits
• There are two main kinds of orbits used for
  satellites Low Earth Orbits and Geosynchronous
  orbits.

Orbit Low Earth Orbit Geosynchronous Orbit
Range 200-800 km above Earth 36000 km above Earth
Orbital Period One rotation every 1.5 h One rotation every 24 h
Used For Telephone/communication satellites TV satellites
Tracked By Moving antenna Stationary antenna
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Remote Sensing and GPS

• Remote Sensing The use of space satellites to
  study features on the Earth or other planets.
  Usually used to study weather patterns,
  pollution, and military sites.
• Stands for global positioning system. A
  technology created by US military to provide a
  reliable navigation system.
• The technology is used to pinpoint certain
  locations by triangulating your position with at
  least two GPS satellites in the sky. The distance
  between the satellites provides the baseline.