Horsehead Nebula in Orion
UNIT 5 SPACE EXPLORATION
Focussing Questions
What technologies have been developed to observe
objects in the sky, and what discoveries were made
with them?
How has the development of these technologies
contributed to the exploration, use, and understanding
of space?
How have technologies designed for space science
been applied to produce benefits on Earth?
Exploring

The first moon landing by Apollo 11
on July 20, 1969, would not have
been possible without many prior
technological advancements.

Increase in scientific knowledge
gained by the moon missions
promoted the development of new
inventions on Earth for scientific
and everyday use.
Exploring



Technology is a tool
that helps solve a
problem.
Science is one method
of acquiring further
knowledge.
Technology advances
scientific knowledge,
and science in turn
develops new
technology for solving
new problems.
Topic 1 For Our Eyes Only

Ancient cultures used the regular cycles of the Sun,
Moon, stars, constellations and visible planets to mark
the passage of time.

Knowledge was passed on orally or in writing from
generation to generation and culture to culture often
in the form of legends and folklore.

Finding patterns in time was essential in predicting
the changing of the seasons and marking important
events in peoples’ lives.
The Big Dipper
What Our Ancestors Saw

Ancient peoples used their eyes, calendars and monuments
to track important changes:

Examples
– lunar cycles scraped on antler
– Stonehenge - summer solstice
– Chichen Itza - spring and fall equinoxes
– Khufu Pyramid - Thuban (former North Star)
– First Nations medicine circles in Alberta - rising of Sirius
Position of Objects in Space
Our reference point for measuring the position of
objects in space is usually the Earth.
The two measurements required are:
1) compass direction (azimuth)
North = bearing 00
2) altitude above the horizon (max. = zenith)
horizon = 00
Models of Planetary Motion

The first calendars were lunar (Moon). They were accurate
enough for nomadic hunters, gatherers and fisherman.

The settled societies that followed needed more precise
solar (Sun) calendars to predict planting and harvest times.

Figuring out how the regular motions of the Sun and Moon
fit in with the irregular wandering paths of the five known
planets was a puzzle that took thousands of years to solve.

How the Earth fit into this puzzle was also a mystery.
The Geocentric Model
The Ancient Greek Ptolemy first proposed that the
universe was Earth-centered. His conclusion made sense
given the knowledge and technology of the time and the
everyday experience of people.
Ptolemy thought the Sun and five known planets orbited
the Earth, while the stars were fixed in place on a domed
ceiling called the celestial sphere.
The Heliocentric Model
For thousands of years, math and geometry were the only
tools available for studying the universe, but with the
development of optical instruments, modern astronomers
began to make discoveries that questioned the geocentric
model.
In 1530, Nicholas Copernicus made observations that led
him to conclude that the Sun was at the center of the
universe while the Earth and other planets revolved around
the Sun.
The Heliocentric Model
In 1610, Galileo Galilei provided evidence for Copernicus’s
hypothesis using a telescope. Wandering planets made
sense if they revolved around the Sun along with Earth. He
was also able to observe lunar mountains, bumps on Saturn
(rings), four moons orbiting Jupiter, sunspots and the
phases of Venus.
Observations of planetary motion by Tycho Brahe and
mathematical calculations by Johannes Kepler led Kepler to
conclude that planetary orbits were elliptical instead of
circular. The heliocentric model was now fully developed.
An ellipse is oval or egg-shaped.
The Sun is off center from a planet’s orbital path.
TOPIC 1 READING ASSIGNMENT
For Our Eyes Only - Answers
If you look at the sky the sun and moon appear to move
across the horizon. These objects rise in the east and set in
the west. This motion is caused by the Earth’s rotation.
However, as we look in the sky our common sense tells us
that the Earth is not really moving. It seems that everything
else is moving around our planet. When we make these
observations it is because we are using the Earth as a fixed
frame of reference.
If you are riding in a vehicle that is moving at a rate of 100Km
per hour you feel stationary inside because you do not move
relative to the vehicle. When you look out it feels as though the
road is moving towards you at a rate of 100 km per hour. If you
think this way you are using the vehicle as a frame of reference.
A person standing next to the road would be using the Earth as
their frame of reference. They would say that you and the
vehicle were moving at 100km/h relative to the ground. Each
frame of reference is neither correct nor incorrect. They are just
two different reference frames – two different points of view.
What Our Ancestors Saw (short answer)
Describe 4 things that ancient peoples learned by watching the
celestial bodies in the sky.
1.Stars make unchanging patterns in the sky – they looked like objects and
were grouped and called constellations.
2. On successive days a star would rise and set 4 minutes earlier than the day befor
- different stars would be in the night sky over a period of months.
3. The sun rises and sets at a rate different than the stars
The Moon also rises and sets at a rate different than the stars. The moon
shows phases.
4. Five other solar bodies rise and set at rates different than the stars – Mercury,
Venus, Mars, Jupiter, and Saturn. These special bodies were called planets.
Sky Co-ordinates (paragraphs)
Ancient peoples not only told stories about the celestial bodies in the sky, but
they also made attempts to measure the celestial bodies locations in the sky.
To do this they would give a celestial body two co-ordinates measured in
degrees. In two or three paragraphs describe this process of measurement.
Make sure to use the following terms in your description: azimuth, altitude,
altitude-azimuth co-ordinates, astrolabe, and compass.
The azimuth (first angle) is measured clockwise from the north. The next
measurement taken is the altitude which is the celestial bodies angle (in
degrees) above the horizon. The angles that are used to describe the coordinates are referred to as altitude-azimuth co-ordinates. These coordinates show the position of a celestial body relative to a fixed Earth (as if
the bodies were revolving around the Earth). These measurements will
change depending on the time of day that they are taken.
Accurate measurements of celestial and Earth objects depend on available
technology. An astrolabe is a device that measures the altitude of an object.
Te azimuth angle can be measured with a compass.
Models (Questions)
1. Knowing what we know about the solar system now, what was the main problem
with Aristotle’s earth-centered model.
In actuality the stars do not revolve around the Earth. Although the model
provided a means of predicting the dates and times when celestial bodies
rose and set, it required up to 55 different inner spheres to account for the
motions, which was cumbersome, and it was difficult to explain why Mars,
Jupiter & Saturn sometimes reversed their direction (retrograde motion).
2. Aristotle’s earth centered model was replaced with the heliocentric model. Why
was this model better?
This model more accurately reflects what actually happens with the motion of
stars, and our solar system.
Topic 2- Stronger Eyes and Better
Numbers

Technology has been used for thousands of years to
measure time. Examples include:
– sundial
– merkhet (Ancient Egyptians) to predict star motion
– quadrant (also Egyptian) to measure star altitude
– astrolabe (Arabs) to chart star positions
– cross-staff (Gurson 1300s) to measure angle between
Moon and stars
– first optical telescope (1500s)
Discovery Through Technology

As lens grinding technology improved and telescopes
became more powerful, it became obvious that distance and
size as we know them on Earth are minute compared to the
scale of space and the objects in it.

Earth is a small planet orbiting an average star half- way out
on one arm of the Milky Way galaxy. The Milky Way itself is
but one galaxy in a local neighbourhood of 20 other galaxies
surrounded by billions of others.
Distance & Time in Space

The kilometre is too small a unit to measure the vast
distances in space. The two units commonly used are the:
– astronomical unit (AU) for local solar system distances

1 AU equals the average distance between the center of the Sun
and center of the Earth, and
– light-year for interstellar and intergalactic distances
 1 light-year is the distance light travels in one year
– because the speed of light is 300 000 km/s in a
vacuum, a light year is about 9.5 trillion kilometres
Distance & Time in Space

Distance is not the only quantity that is immense in space. If
light takes time to travel between two points, then we are
actually looking back in time when observing distant objects
in space. Given the small distances on Earth, light only
appears to instantly move from place to place. In fact, it
takes light:
– 1 second to reach Earth from the Moon
– 8 minutes to reach Earth from the Sun
– 5 hours to reach Earth from Pluto
– over 4 years to reach Earth from Proxima Centauri, the
next closest star
– 25 000 years to reach Earth from the Milky Way’s center!
Birth of a Star

The life cycle of a star can be compared to the birth, growth
and death of a living organism.
– Gravity pulls gas and dust in a nebula together into a
rotating sphere.
– The accumulation of more matter in the core causes the
temperature to rise and possibly start to glow (protostar).
– Heating in the core to 10 000 000 0C will cause the fusion
of hydrogen into helium. A Star is born as huge amounts
of radiation are given off.
Life & Death of a Star

A star continues to emit radiation for millions or even billions
of years.

Depending on its mass, a star can be either:
– Sun-like (main sequence in the H-R diagram), or
– massive.
A star reaches the end of its life cycle when the supply of
hydrogen fuel runs out.
Star Life Cycles


Sun-like Stars
– become a red giant in their second stage as the outer
layers expand and cool
– become a white dwarf in their third stage as fusion stops
and the remaining material collapses inward
– further cooling may create a black dwarf
Massive Stars
– become a red supergiant in their second stage
– gravity causes them to collapse so rapidly in the third
stage that an outgoing shock wave makes the outer
layers explode as a supernova
– supernova remnants form a neutron star or black hole
Star Definitions

red giant -a relatively cool, large-diameter stage of a
Sun-like star
 red supergiant - a larger-diameter red giant from an
aging massive star
 white dwarf - a low-pressure, fusion-less collapsed star
with a small diameter
 black dwarf - the death stage of a Sun-like star
 supernova - the explosion of a red supergiant following
collapse
 neutron star - a rapidly spinning star remnant
 black hole - a dense star remnant not allowing light to
escape
Topic 4 – Bigger and Smarter Telescopes
Adaptive Optics - Latest Advances
The latest advances in telescope design are adaptive optics and
multiple mirror interferometry. Adaptive optics involves
combining lasers with computers to sense the turbulence of the
atmosphere. This information is relayed to machines under the
telescope’s objective mirror that distort the mirror to cancel the
effect of the atmosphere on the image.
Multiple Mirror Interferometry
This telescope advance combines the images from more than
one mirror to create, in effect, a mirror the size of the distance
between the mirrors.
TOPIC 5 NOTES
There are many types of radiation that come from stars. The
type of radiation that we are most familiar with is light
radiation. Other types are:
•radio waves
• microwaves
• infrared radiation
• ultra violet radiation
• x-rays
•gamma rays
Astronomers use radio waves to tell them things about distant
stars. Technology had provided science with radio telescopes
– devices that can intercept and track radio wave emissions
from far away stars. Radio telescopes gave scientists
information about planets that they never had before.
As radio telescope technology improved, scientists were able
to match radio signals to the optical telescopes that they had
previously used. This resulted in much clearer images of
distant stars. Taking this one step further, scientists started
linking radio telescopes together. They then processed their
images with computer technology in a process called
interferometry. This is like seeing with many eyes instead of
one.
Topic 6 – Above the Atmosphere
and Under Control
Technologies for Space Transport

The greatest challenges in space travel have been:
– achieving escape velocity to break free of Earth’s
gravitational force
– designing materials and equipment able to
withstand the extreme environment of space
– transporting people out and back safely

Satellite technology is used for many Earth-based
applications, including:
– telecommunications
– navigation
– remote sensing, and
– weather forecasting.
Satellites, unmanned space probes and manned
spacecraft need a velocity of about 28 000 km/h, or
11 km/s, to escape Earth’s gravity!
The Achievements of Rocket Science
Early experiments in rocket propulsion included:
- Archytas’s steam-powered pigeon (Ancient Greece)
- gunpowder arrows for warfare (China 1st C A.D.)
- Robert Goddard’s liquid fuel rockets (1920s)
- Wernher von Braun’s V2 rockets (1940s)
- Sputnik I, the first artificial satellite (October 4, 1957)
- Sputnik II, with Laika, the first space traveller (1957)
The father of modern rocketry is
considered to be Robert Goddard.
Along with Konstantin Tsiolkovsky of
Russia and Hermann Oberth of
Germany, Goddard envisioned the
exploration of space. Goddard was a
physicist with a unique genius for
invention.
By 1926, Goddard had
constructed and successfully tested
the first liquid-fuel rocket with a rocket
flight on March 16,1926, at Auburn,
Massachusetts.
Wernher von Braun was
one of the first and foremost
rocket engineers and a leading
authority on space travel. His
will to expand knowledge
through the exploration of space
led to the development of the
Explorer satellites, the Saturn
rockets, and Skylab, the world's
first space station. In addition,
his determination led to humans
landing on the moon.
The V2 rocket was
developed during
World War II using a
fuel of alcohol and
oxygen.
The Apollo 17 capsule making a parachute
landing in the ocean in December 1972
Rocket Basics
Three Parts
• mechanical elements (currently about 3% of mass)
- includes rocket, engines, storage tanks, fins
• payload (currently about 6% of mass)
- includes crew cabins, crew, food, water, air
• fuel (currently about 91% of mass)
What is currently the major challenge in rocket design?
TOPIC 6 READING ASSIGNMENT - Key
Fill in the Blanks
Rockets were invented long ago and were used for fireworks
as well as weapons. A rocket is a tube that contains
_combustible_ material______ in one end. On the other end
of the rocket is the _payload_____, which is what the rocket
will transport. The principle that makes a rocket work is called
the _action/reaction____________ principle.
Rockets must have some type of fuel to make them work.
The escaping exhaust in the combustion reaction within the
rocket is called the _exhaust____ _velocity____. This is
one factor that determines how far the rocket will be able to
go. The first scientist to launch a liquid fuel rocket in 1926
was _Robert_____ __Goddard___. He also realized that
that a _staged________ ___rocket________ would be able
to fly higher and faster.
A _ballistic____ _missile_______ is a bomb that is
powered by a rocket engine.
American and Russian scientists were able to calculate and
control orbits by using _computers________. The early outer
space flights were controlled by _computers__ on _the
ground________________. Eventually technology improved
to the point where the craft could be controlled from
_within________.
Short Answer
Read the section on “Using Gravity” on page 402.
Describe gravitational assist.
This is a method of increasing acceleration by using
the gravity of a planet. The spacecraft is sent around
one planet. Its gravity attracts the craft causing it to
speed up and change direction. The spacecraft
slingshots away from the planet at a higher velocity.
Tell how the Hubble Space Telescope was put into outer space.
The bus sized telescope was aboard the space shuttle
Discovery, and was deployed by the astronauts aboard the
craft.
Describe how the world has become a “global village” of instant
communications.
With the deployment of satellites in a geosynchronous orbit,
we are able to have improved radio and television signals.
Paragraphs
Read about Global Positioning Systems on page 407. In a few
paragraphs tell how GPS devices work and how they can be now
used for non-military applications.
Main points to mention:
US military deployed many NAVSTAR (navigation satellite
tracking and ranging) satellites 20 000 km above Earth.
GPS satellites take about 12 hours to complete one orbit.
Many satellites in orbit – always at least 3 above the horizon
Satellites send out radio signals that tell the exact time and
location.
Hand-held GPS units use computer technology to calculate
distances and locations on Earth.
Future Propulsion Technologies
Finding alternatives to liquid or gas burning fuels would
decrease our reliance on inefficient fossil fuels and the
mass problems associated with storing and transporting
all that fuel.
Possible alternatives for the future include:
1) ion drives (using electrically-charged xenon gas)
2) solar sails (using carbon-fibre sails to absorb photons)
Shuttles, Probes & Space Stations
The International Space Station (ISS) is a modularized
permanent laboratory that will also serve as a base for
building and launching rockets for interplanetary travel.
What are the advantages and disadvantages of building
and launching spacecraft from Earth orbit or the Moon?
Sounds of Earth
recording carried by
Voyager
The Voyager I and II
space probes were
launched in 1977
Image of
Saturn by
Voyager 2,
1981
International Space Station
Canadarm2
Living in Space

The hazards of space consist of:
–
–
–
–
–
–
–
no air (near vacuum) or air pressure
no water
cosmic rays
solar radiation (esp. solar flares)
debris and objects in space
temperature extremes
psychological stress due to confinement and
isolation
– physical stress due to lack of gravity and exercise
combined with extended time in space
Space Suit Technology

Suits must be designed to mimic an Earth environment
capable of sustaining human life for periods long enough to
work outside a spacecraft or space station.

What features must be built into a suit?
– 1)
– 2)
– 3)
– 4)
– 5)
– 6)
Space Station Technology

Essential features include:
– clean water (electrolysis + recycling nearly 100%)
– breathable air (removing CO2, microorganisms,
dust and moisture)
– suitable temperature and air pressure
– a source of power
Meeting Human Needs on Earth

How do satellites transmit and receive information from the
ground? Data is relayed using radio waves.

Some satellites, such as those used in weather forecasting,
are placed in geosynchronous orbit, which means the satellite
moves so it is over the same location at all times.

Other satellites, such as RADARSAT and LANDSAT,
monitor global activities such as shipping, soil, fires and
potential resources. They are not placed in
geosynchronous orbits for these reasons.
A sample satellite
Remote Sensing

Satellites can monitor changes in:
–
–
–
–
global temperature
soil and vegetation patterns
the atmosphere
industry and urbanization.
• In addition, remote sensing can locate mineral and fuel
resources hidden undersea and underground.
Global Positioning Systems (GPS)

Twenty-four satellites transmit location data back to Earth
from orbit. 1) What minimum number of satellites would it
take to pinpoint the compass position of an object on the
surface? 2) How many satellites would be needed to
establish the altitude at that same latitude and longitude on
Earth as in 1) above?
HINT: The navigating principle that is also used by
GPS technology is called triangulation.
Space
Age Systems & Materials
 Examples
– Computer: virtual reality software
– Consumer: improved bike helmets
– Medicine: digital imaging for detecting cancers
– Industrial: micro-lasers for cutting and melting
– Transportation: improved traction on winter tires
– Public Safety: emergency response robots
Topic 7 The Solar System Up Close
Planet Facts
• The inner planets are smaller and rocky (terrestrial)
Mercury, Venus, Earth, Mars
• The outer planets are larger and gaseous (Jovian)
Jupiter, Saturn, Uranus, Neptune, (Pluto)
Why do the inner and outer planets differ?
Topic 7 - Continued
Other Bodies
• asteroids - rocky, metallic bodies between Mars and
Jupiter (Kuiper Belt)
• comets -
dirty snowballs of dust and ice that orbit
another body in the solar system such
as the Sun (e.g. Halley’s comet)
• meteors & meteorites - rocky bodies that do
(meteorite) or do not (shooting star =
meteor) impact Earth’s surface
• meteoroids = meteors + meteorites
Asteroid Ida viewed by the space probe Galileo enroute to Jupiter.