UNIT E SPACE EXPLORATION

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Horsehead Nebula in Orion
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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?

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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.

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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.

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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.

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The Big Dipper
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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

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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
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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.

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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.
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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.
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The Heliocentric Model
In 1610, Galileo Galilei provided evidence for
Copernicuss 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.
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An ellipse is oval or egg-shaped.
The Sun is off center from a planets orbital
path.
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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 Earths 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.
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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.
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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 before - 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.
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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 co-ordinates are
referred to as altitude-azimuth co-ordinates.
These co-ordinates 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.
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Models (Questions) 1. Knowing what we know about
the solar system now, what was the main problem
with Aristotles 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. Aristotles 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.
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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)

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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.

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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

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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 Ways
  center!

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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.

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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.
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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

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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

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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
telescopes 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.
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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

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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.
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Topic 6 Above the Atmosphere and Under Control
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Technologies for Space Transport

• The greatest challenges in space travel have
  been
• achieving escape velocity to break free of
  Earths gravitational force
• designing materials and equipment able to
  withstand the extreme environment of space
• transporting people out and back safely

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• 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 Earths gravity!
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The Achievements of Rocket Science Early
experiments in rocket propulsion included -
Archytass steam-powered pigeon (Ancient
Greece) - gunpowder arrows for warfare (China 1st
C A.D.) - Robert Goddards liquid fuel rockets
(1920s) - Wernher von Brauns V2 rockets
(1940s) - Sputnik I, the first artificial
satellite (October 4, 1957) - Sputnik II, with
Laika, the first space traveller (1957)
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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.
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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.
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The Apollo 17 capsule making a parachute landing
in the ocean in December 1972
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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?
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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.
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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.
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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________.
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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.
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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.
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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.
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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)
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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?
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Sounds of Earth recording carried by Voyager
Image of Saturn by Voyager 2, 1981
The Voyager I and II space probes were launched
in 1977
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International Space Station
Canadarm2
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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

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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)

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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

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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.

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A sample satellite
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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.
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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.
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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

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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?
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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. Halleys comet) meteors
meteorites - rocky bodies that do (meteorite)
or do not (shooting star meteor) impact
Earths surface meteoroids meteors
meteorites
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Asteroid Ida viewed by the space probe Galileo
enroute to Jupiter.