Space Flashcards
Explain why the angle of re-entry poses a challenge.
The angle of re-entry to the atmosphere is important
- too steep and the change in kinetic energy being transferred to heat is too fast resulting in overheating and possible rocket break-up
- If the angle is too shallow you will skip off the atmosphere.
What is meant by a light year?
The distance that light could travel in one year.
Explain why re-entering the atmosphere poses a challenge.
- When a space craft is in space there is no friction as space is a vacuum.
- When you re-enter the Earth’s atmosphere you go from no friction to lots of friction (caused by the atmosphere).
- The result is that the space craft loses kinetic energy and slows down.
- However due to conservation of energy, the energy is not lost but is converted to heat.
- The outside of the space craft becomes incredibly hot.
- This means that the space vehicle requires thermal shielding.
What information can be extracted from the spectral lines from a star?
The elements present in the star.
What is a geostationary satellite?
Satellites with a period of 24 hours and orbit at a height of 36000km.
State two challenges of space exploration.
- Travelling the large distances
- Manoeuvring
- Maintaining energy
How can you calculate the distance that is one light year?
- d=vt
- d = 3 x 108 x (365.25 x 24 x 60 x 60)
Explain how a satellite stays in orbit.
Satellite has a constant horizontal velocity.
Satellite has a constant vertical acceleration due to the gravitational field strength of the planet.
This gives a curved trajectory.
The planet is curved so the satellite remains in orbit.
What are the issues of pressure differential?
Pressure in space is so low it is almost zero. Space suits and pressurised space craft are required to protect astronauts otherwise they would lose conciousness and suffocate or their blood could boil.
What is the estimated age of the universe?
14 billion years
What are the issues of potential exposure to radiation?
Can cause
- cataracts
- increased risk of cancer
- damage to DNA and genetic material
What is an exoplanet?
A planet orbiting a sun outside our solar system.
State one way that travelling the large distance in space could be overcome.
- Use an ion drive
- Gravity assist (catapult) from a planet, moon or fast moving asteroid
Using Newton’s 3rd Law explain how a space rocket takes off.
Engines push exhaust gases downwards. Exhaust gases push engines upwards.
What are the two main challenges of re-entry?
- Angle of re-entry
- High temperatures / heating effect
How does the observable universe let us estimate the age of the universe?
The furthest point that we can detect is the distance which light must have travelled for the whole age of the universe.
This allows us to work out the approximate time of travel and so teh age of the universe.
What is a planet?
A ball of mass that
- orbits a sun
- has enough mass to be almost round
- is not a moon of another object
- has removed debris from the area round the orbit
Why is maintaining energy such a big issue in space exploration?
Energy is required to maintain life support systems. It would be difficult to carry enough fuel so energy must be generated in space.
What are the issues with fuel load on take-off?
There is a massive amount of fuel being carried and a huge amount of heat is produced. This could lead to an explosion.