Travel to Space
Rockets
reaction
• Newton’s Third Law – for every action
there is an equal and opposite reaction
• rocket gas is under pressure in a tank
• when gas is released in a combustion
reaction it produces a downward thrust
• then the rocket lifts upward and away from
Earth in an opposite reaction
• rockets must reach an escape velocity of
28000 km/h to overcome Earth’s
gravitational pull
action
• there are 3 basic parts to a rocket
– the structural and mechanical parts (engines, storage spaces,
tanks, fins)
– fuel (can be various materials such as liquid oxygen, gasoline
or liquid hydrogen
– payload – what is being transported by the rocket (people,
food, water, air, cargo)
– what are possible payloads (what types of things are being
transported by rockets)
• Fins – are important because they stablilize the
rocket (so it does not wobble) and make it more
efficient
• designed in stages so empty fuel tanks can be
dropped when the fuel is used up… this makes rockets
more efficient
Technologies for Space Travel
(theoretical propulsion systems)
• Ion drives
– engines that use xenon gas instead of chemical fuel
– xenon is electrically charged in the engine, accelerated, then
emitted as exhaust
– exhaust creates thrust which pushes spacecraft in opposite
direction
• Solar Sails similar to wind pushing sailboats
– solar sails collect electromagnetic energy from the Sun… when
‘photons’ hit the sail they transfer energy which causes the
spacecraft to move forward
• Gravitational Assist
– fly a spacecraft toward a planet or star, then at the last minute pull
around it and away… creating a slingshot effect that shoots the
craft forward in the desired direction
Space Craft
• space shuttles are used to transport
people into space
• space probes are used for ‘non-manned’
exploration of space – they carry
instruments for recording info
– e.g. Pioneer 11 – flyby of Jupiter and Saturn
in 1974 - 79
– e.g. Mars Pathfinder – landed on Mars in
2000
• space stations are orbiting space craft
that have living quarters, work areas,
support systems… to allow for people to
live and work in space for extended
periods of time
Satellites and Probes
• natural satellites such as the moon
• man-made satellites such as used for
communication
– Communication satellites – “wireless”
technologies
– Observation and research satellites –
weather, tracking systems (e.g. radar)
– Remote sensing – imaging of earth surface
– Global Positioning Systems
Satellite Orbits
• Low Earth Orbit
– 200 – 1000 km altitude
– e.g. remote sensing satellites
• Geosynchronous Orbits
– medium or high Earth orbit
– satellite moves at the same
rate as the Earth… so it
records the same area of
the Earth at all times
– e.g. weather satellites
• Geostationary Orbits
– medium or high Earth orbit
– satellite stays in one place
while the Earth moves… so it
records a different area of
the Earth over time
– e.g. communication satellites
Hazards of Space Travel
• Launch hazards – combustion of fuel and
escape of Earth’s gravity are risky
• Cosmic and solar radiation – medically
hazardous for human health
• Collisions – natural hazards and man made
(space junk)
• Re-entry into an atmosphere – risk of burning
up due to friction of Earth’s atmosphere on
craft
• Fuel expenditure – running out of fuel
Living in Space
• Sustainable food and water supply
– need sophisticated wastewater recycling
capabilities to produce drinking water
– food provides high energy for low volume
and weight
• Environmental setting
– steady temperature, pressure & humidity
– passing electricity through water to
produce oxygen
• Waste management
– removing carbon dioxide from air
– filtering micro-organisms and dust from air
– handling biological waste and garbage
• Safety
– space is a vacuum – no air or water
– detection for fire, leaks, incoming risks like
meteorites
– protection from radiation and cold
– systems to handle emergencies like a fire
or loss of pressure/air
Water Recycling System –
International Space Station
SIA – page 422
• Movement outside
habitat requires:
–
–
–
–
–
space suit
supply of oxygen
water supply (& food)
temperature control
waste management
• carbon dioxide
• body waste
– communications
– attachment (to space
craft)
Physical and Psychological Risks
• microgravity – lower gravity
– produces lower stress on our bodies
– can result in loss of muscle mass, expansion
of bones, weakening of heart
– visual depth perception is affected
• confined living - isolation
– limited space
– limited companions
– no fresh air
Telescopes
• Optical telescopes → light collectors
– use a series of lenses or mirrors to collect
and focus light & images from space
– larger lens = more visibility
– operate in the visible light spectrum
– first developed in 1608 by Hans
Lippershey… but it was Galileo who is
credited with using telescopes to study the
night sky
• Reflecting Telescope
– 2 lenses gather and
focus light
– disadvantage is that
the lens will warp if
diameter > 1 m
• Refracting Telescope
– uses mirrors to gather
and focus the light
Radio Telescope
• resemble a large satellite dish
• gather radio waves
• advantage over optical telescopes,
because they are not affected by
weather, clouds, atmosphere or
pollution
• have greatly expanded our
knowledge of our solar system and
galaxy
Interferometry
• combining 2 or more optical OR radio
telescopes to detect objects with
better clarity at greater distances
Telescopes in Space
• telescopes located in space have a
better view because there is no
atmosphere to distort the images
• Hubble Space Telescope
– orbits 600 km above the Earth
– reflecting telescope
– launched in 1990
Electromagnetic Spectrum
Radio Telescopes
operate within
wider band of
radio waves
Optical Telescopes
operate within
narrow band of
visible light waves
Useful Inventions from Space
Exploration
SIA, page 431