| define universe | all the energy and matter that exists
consists of many galaxies separated by empty space |
| define galaxy | a large cluster of billions of stars, dust and gas held together by gravity |
| define star | a large ball of matter that is undergoing nuclear fusion and emitting light and other forms of electromagnetic radiation |
| define solar system | consists of a central star orbited by planets |
| define planet | a large ball of matter that orbits a star. They do not emit light themselves |
| define exoplanet | a planet existing around another star outside of our solar system |
| define moon | a lump of matter that orbits a planet |
| define dwarf planet | an object that orbits a star but is not large enough or roughly spherical enough to be classed as a small planet |
| define asteroid | an orbiting object that is even smaller than a dwarf planet. They are formed of rock and metals
when an asteroid enters a planets atmosephere, we call it a meteor |
| define comet | a relatively small (sun) orbiting object composed of mainly ice. They have vast orbits and can take centuries to complete one circuit. |
| what is a satellite | a moon, planet or machine tht orbits a planet or a star
the moon is the earth's natural satellite |
| how do artificial satellites orbit earth | by travelling at a high velocity at a set disstance above the planet |
| describe the main features of geostationary satellites | they travel around earth at the same rate as earth rotates on its axis
have to be at a height of 36,00km
have to travel at a velocity that means the satellite takes 24 hours to complete one revolution of the earth (period of 24 hours) |
| what are geostationery satellites used for? | communication
weather prediction
GPS |
| what is the relationship between satellite distance from earth and velocity at which they must travel to remain in geostationary orbit? | satellites that orbit closer to the earth can see more detail but have to travel at a greater velocity to stay in orbit of the earth
if satellites are further away from the earth they need a lower velocity to remain in geostationary orbit |
| what is the purpose/benefit of satellites that look out into space | play a vital role in the study and understanding of our universe
satellite telescopes have clearer images from deep space as there is no distortion from our atmosphere |
| what is the purpose/benefit of satellites that look towards the earth | they can view a large area of our globe, so they can collect more information than scientific equipment on the ground
this allows us to study and predict the weather, predict and track events like hurricanes and forest fires so we can give warnings to those in danger |
| give examples of aspects of our daily lives that are dependent on satellites | satellites with various detectors and telescopes observe distant objects and allow us to analyse them to increase our awareness of our universe (Eg, the Hubble telescope increased our awareness of space a lot)
GPS allows us to use our phones to determine our location within a few metres
TV Networks rely heavily on satellites to transfer signals from one area to another, for instance, live reporting from major events
Weather forecasts are based on data from satellite systems which have monitored the area around where we live. This allows us to receive up to d ate images of clouds, which are then shown on weather forecasts |
| give examples of the challenges of space travel | travelling large distances between objects in space
Manoeuvring a spacecraft in a zero-friction environment
maintaining sufficient energy to operate life support systems in a spacecraft as most of the energy used for a space mission is burnt off during launch, |
| how can we combat the challenge of travelling large distances between objects in space | Using a gravitational slingshot/catapult
Manoeuvre the travelling object to a planet or large asteroid so that it accelerates towards it but ultimately misses it.
As it heads towards the planet or asteroid, the object increases its velocity and flies past at a greater velocity than before
OR
Ion drive engines are designed to manoeuvre the ship or satellite using small amounts of fuel
Ions are ejected from the satellite at a very high velocity and this provides a small but constant thrust to increase the speed of the spacecraft |
| how to we combat the challenge of manoeuvring a spacecraft in a zero friction environment | Using a thruster (spacecraft propulsion device)
A thruster is fired and the ship will accelerate forward. When it stops firing the ship will continue at a constant velocity.
To stop the vehicle a thruster is fired in the opposite direction |
| how do we combat the challenge of using most of the fuel for a space mission during the launch | solar panels
This panel is capable of converting sunlight directly into electricity, which can be used to power the systems that make up the life support systems. As a space craft gets further from the sun the amount of radiant energy available to the solar panels decreases by the square of the distance. This means that the area of solar panels must be increased greatly for any missions with astronauts to places like Mars, because it is further away from the Sun. |
| Give examples of the risks of space travel | danger from impact damage to spacecraft or astronauts due to micrometeorites and space debris
danger from ionising radiation that could cause cancer from solar flares and radiation
there is no atmosphere in space but we need air to breathe and atmospheric pressure to stop our bodies from decompressing
space's temperatures are too extreme for humans to survive without protection (around -150 to 120 degrees Celsius)
on returning to Earth travelling fast creates high frictional forces and generates extremely high temperatures |
| how do we combat the risk of extreme high temperatures upon re entry to earth | spacecraft must be able to absorb certain amounts of heat energy and radiate heat energy back into the atmosphere
spacecraft have heat proof tiles on the underside to protect the occupants and the spacecraft from high temperatures |
| how do we manage the risk of space exploration with the need for further scientific information about space | we use robots such as NASA's spirit rover to explore for us
these robots can be controlled manually but often run independently, following pre-programmed instructions |
| what is meant by mass? | the amount of matter an object has, in kilograms |
| what is meant by weight | The gravitational force acting on an object in Newtons |
| What is the formula for weight | W=mg
Where W is weight in Newtons
Where m is mass in kg
g is gravitational field strength in Nkg-1 |
