Transcript Satellites - Noadswood Science

Satellites
D. Crowley, 2008
Satellites
 To know how a satellite gets into
space, and what they are used for
Gravity
 Complete the gravity
worksheet
Gravity
 Force; equal; greater; attractive;
mass; gravitational; closer
Satellite
 What is a satellite?
 A satellite is any object that orbits another object
 Satellites must travel at a given speed to stay in their orbits
 There are two types of satellite: – Natural satellites
– Artificial satellites
Natural Satellites
 The moon is the natural satellite of the Earth
 Gravitational forces between the moon and the Earth keep it in orbit
 The moon is not a luminous object (it does not make its own light) but it
does reflect light from the Sun
 A satellite has to travel at the correct
speed to stay in orbit at a particular
distance from a planet. It takes the moon
28 days to make a complete orbit of the
Earth (as it orbits, we see different
amounts of the moon (different phases))
Artificial Satellites
 An artificial satellite is an object made by and put into orbit by humans
 Artificial satellites can have different type of orbits: – Geostationary satellites
– Polar orbit satellites
 There are lots of artificial satellites in orbit around the Earth and they
have many different uses, including: –
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Communications, (TV broadcasting, telephone relays etc…)
Global Positioning System (GPS) & Galileo satellites for navigation
Weather forecasting
Scientific surveys of the Earth's surface & space (e.g. Hubble)
Map making
Spying
Geostationary Satellites
 Stay above the same point on
Earth
 Speed of orbit matches the
Earth’s rotation, so orbit time is
24 hours
 Used for communications,
satellite TV, weather forecasting,
intelligence, global positioning
etc…
Polar Orbit Satellites
 Low orbit around the Earth,
passing over North and South
poles
 Earth rotates underneath them
as they orbit
 Used for large-scale mapping
and global weather monitoring
Satellites
Space Travel
 How difficult is it to get into space?
 What about getting to the moon?
 How about other planets… or solar systems?!
 Space travel is never routine - it is extremely dangerous (space is very
hostile) and if a rocket malfunctions you don’t usually walk away…
Going To The Moon
 Complete the going to the moon
worksheet
Going To The Moon
Lots of Earth’s
gravity
Moon’s gravity
affects lander
Gravity of Earth
still strong
Moon’ gravity
still affects
space craft
Moon’s gravity
affects lander
Moon’s gravity
tries to pull
orbiter down
Moon’s gravity
weakens,
Earth’s
increases
Earth’s gravity
very strong