9J Gravity and space...Rockets and space exploration
lesson
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Rockets and space exploration
In the late fifties and early sixties, rockets were being developed that would take first probes
(Sputnik I), animals (Laika the dog) and finally humans (Yuri Gagarin) into space. Escaping
Earth’s gravity is not easy, requiring massive amounts of thrust and an escape velocity of
over 40,000kmhr-1. This is produced by using millions of litres of rocket fuel during take off.
The Saturn series of rockets that launched the Apollo missions to the moon, were single
use multi stage rockets. Recently they have been replaced by multi use rockets like those
used to launch the space shuttle. What fuel does the space shuttle use during take off ?
Rockets and their uses:
Launch Take off Other rockets
Diagram
Gravity
Gravity
Up thrust
Up thrust
Notes At launch, to escape Earth’s During take off, the thrust force Other famous rockets:
gravitational pull, millions of is larger than the gravitation A: Saturn five (Apollo missions)
Newtons of thrust needs to be pull, therefore accelerating the B: Titan (Satellites)
produced by the space shuttle’s space shuttle towards outer
C: Delta (Deep impact mission)
engines. space.

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Satellites
Artificial satellites are placed in their orbits by rockets. These satellites orbit the Earth
in three ways. They can either have a Equatorial, Polar or Geostationary orbit. Like the
moon, they are held in their orbits by the gravitational pull of the Earth. They have
many applications including communications, weather observations and military uses.
All satellites use microwaves for sending information. These waves travel at the speed
of light in a narrow straight beam and are able to pass through the Earth’s atmosphere.
On Earth we can receive satellite data using collection dishes.
Satellites:
Satellites Artificial satellites and their orbits
Satellites Polar orbit Geostationary orbit
Equatorial orbit
36,000km
There are three types of artificial satellite orbits. Equatorial and polar orbits tend to be used by
the military to observe many different countries and their military activities. A single satellite
can take images of different countries as it moves across the globe. The fixed geostationary
orbits are used to monitor the weather and send and receive telecommunication data.

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Space exploration one
In the late fifties and early sixties, while America was playing catch up, the Russians were
winning the space race. In the late fifties, the Russians sent Yuri Gagarin into space,
orbiting the Earth several times before landing safely back on Earth. This maiden
spaceflight shortly after the successful launch of Sputnik I & II shocked the Americans and
led to the ‘space race.’ In the sixties, the Americans and Russians raced to put the first man
on the moon, spending billions of pounds on research and development. Despite America’s
late entry into space exploration, they landed the first man on the moon in 1969. What was
the name of the first man on the moon ?
First orbit around the Earth:
Yuri Gagarin At launch
Yuri Gagarin prior to launch
Yuri Gagarin
Yuri Gagarin made the first successful orbit of Earth. A Russian cosmonaut he signified the
beginning of the space race between America and The Soviet Union. Although, America finally won
the race to the moon, without Sputnik I & II and Yuri Gagarin, the Apollo missions and the landing on
the moon would not have been possible.

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Space exploration two Sputnik I & II
In 1957 October 4th space exploration began. The Russians launched Sputnik I which orbited the
Earth and sent back simple radio messages. This shocked the Americans into joining the space
race. The next month, the Russians had launched sputnik II (November 2nd 1957) which carried
the first animal into space. An astonished World witnessed the launch of the first living thing to go
into orbit – a stray dog called Laika. The animal had been a stray wandering the streets of
Moscow, when she was captured and prepared for this historic space mission. Shortly after
launch, the Soviets said that Laika was not destined to return alive and would die in space. This
statement caused outrage to many observers.
Sputnik I & II:
Sputnik probe Laika (first animal in space) Commemorative stamp
Sputnik
Laika, the first living creature to orbit Earth, did not live nearly as long as Soviet officials led the World to
believe. The animal, launched on a one-way trip on board Sputnik 2 in November 1957, was said to have
died painlessly in orbit about a week after launch. Now, it has been revealed she died from overheating and
panic just a few hours after the mission started, despite having access to water, food, oxygen and a cooling
system.

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Space exploration three
In the late seventies and early eighties, NASA developed the space shuttle, a reusable craft
that has visited space and launched many satellites over the last two decades. The space
shuttle has failed twice, once on launch, where faulty seals allowed explosive propellant to
leak causing a catastrophic explosion. The other disaster was on re-entry, when a heat
resistant tile failed and the space shuttle burned up within seconds. Despite this, the space
shuttle has been extremely successful and now routinely carries astronauts into space and
occasionally to the international space station, a joint project co funded by America and
Russia. When did the first space shuttle disaster occur ?
Space shuttle:
Space shuttle launch Orbit around Earth Space walk
Space shuttle
The space shuttle is a reusable launch module that was designed to reduced the overall cost of space
exploration. However it has still proved very costly and unlike the Saturn series of rockets, the space shuttle
has cost the lives of fifteen astronauts during its 20 years service. Commercial operators like Virgin are now
offering space travel to private individuals for up to 100,000 dollars per person.

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Space exploration four
Mars is probably the next destination for a manned mission, following the spectacular
pictures sent back of the Martian surface by the pathfinder mission in 2002. Landing
on Mars would require new technologies to overcome the very long journey and the
lack of a life supporting atmosphere. If a mission was launched, it would take about
two years to go there and return and many billions of pounds. One question that could
be answered, does simple life exist on a planet other than Earth ?
Mission to Mars:
Mars Mission Pathfinder The surface of Mars
Mars
The Mars pathfinder project landed a roving module that was capable of surveying the surface of
Mars. The pictures beamed back from pathfinder shows a surface similar to a desert landscape here
on Earth. Following the success of this mission other similar projects have been planned, although
the most recent probe; Beagle II failed on landing on the Martian surface, wasting many millions of
pounds.