Satellites and how we use them
Objectives:
• Students will identify how satellites are used in their everyday life.
• Students will understand that a satellite contains some very important
components.
• Students will understand the geosynchronous orbit used by
communication satellites.
• Students will understand that satellites transmit numbers in a code to
observe the Earth and to create pictures.
Suggested Grade Levels:
Fourth through sixth grade
Subject Areas:
Science
Technology
Reading
Timeline:
Three sessions lasting between 45 minutes to an hour
National Education Standards:
Science 4: Earth and Space Science:
Science 5: Science and Technology
Reading 1
Background:
Satellite orbits
Many types of orbits exist, but most artificial satellites orbiting Earth travel in one
of four types: (1) high altitude, geosynchronous; (2) medium altitude, (3) sunsynchronous, polar; and (4) low altitude. Most orbits of these four types are
circular.
A high altitude, geosynchronous orbit lies above the equator at an altitude of
about 22,300 miles (35,900 kilometers). A satellite in this orbit travels around
Earth's axis in exactly the same time, and in the same direction, as Earth rotates
about its axis. Thus, as seen from Earth, the satellite always appears at the same
place in the sky overhead. To boost a satellite into this orbit requires a large,
powerful launch vehicle.
Some weather satellites are placed in high altitude, geosynchronous orbits. From
these orbits, they can always observe weather activity over nearly half the
surface of Earth at the same time. These satellites photograph changing cloud
formations. They also produce infrared images, which show the amount of heat
coming from Earth and the clouds.
Communications satellites serve as relay stations, receiving radio signals from
one location and transmitting them to another. A communications satellite can
relay several television programs or many thousands of telephone calls at once.
Communications satellites are usually put in a high altitude, geosynchronous
orbit over a ground station. A ground station has a large dish antenna for
transmitting and receiving radio signals. Sometimes, a group of low orbit
communications satellites arranged in a network, called a constellation, work
together by relaying information to each other and to users on the ground.
Countries and commercial organizations, such as television broadcasters and
telephone companies, use these satellites continuously.
Building a satellite
Every satellite carries special instruments that enable it to perform its mission.
For example, a satellite that studies the universe has a telescope. A satellite that
helps forecast the weather carries cameras to track the movement of clouds.
In addition to such mission-specific instruments, all satellites have basic
subsystems, groups of devices that help the instruments work together and keep
the satellite operating. For example, a power subsystem generates, stores, and
distributes a satellite's electric power. This subsystem may include panels of
solar cells that gather energy from the sun. Command and data handling
subsystems consist of computers that gather and process data from the
instruments and execute commands from Earth.
A satellite's instruments and subsystems are designed, built, and tested
individually. Workers install them on the satellite one at a time until the satellite is
complete. Then the satellite is tested under conditions like those that the satellite
will encounter during launch and while in space. If the satellite passes all tests, it
is ready to be launched.
Launching the satellite
Space shuttles carry some satellites into space, but most satellites are launched
by rockets that fall into the ocean after their fuel is spent. Many satellites require
minor adjustments of their orbit before they begin to perform their function. Builtin rockets called thrusters make these adjustments. Once a satellite is placed
into a stable orbit, it can remain there for a long time without further adjustment.
Performing the mission
Most satellites operate are directed from a control center on Earth. Computers
and human operators at the control center monitor the satellite's position, send
instructions to its computers, and retrieve information that the satellite has
gathered. The control center communicates with the satellite by radio. Ground
stations within the satellite's range send and receive the radio signals.
A satellite does not usually receive constant direction from its control center. It is
like an orbiting robot. It controls its solar panels to keep them pointed toward the
sun and keeps its antennas ready to receive commands. Its instruments
automatically collect information.
Satellites in a high altitude, geosynchronous orbit are always in contact with
Earth. Ground stations can contact satellites in low orbits as often as 12 times a
day. During each contact, the satellite transmits information and receives
instructions. Each contact must be completed during the time the satellite passes
overhead -- about 10 minutes.
Geosynchronous Communications Satellites
The solution to the problem of availability, of course, lay in the use of the
geosynchronous orbit. In 1963, the necessary rocket booster power was
available for the first time and the first geosynchronous satellite, Syncom 2, was
launched by NASA. For those who could "see" it, the satellite was available
100% of the time, 24 hours a day. The satellite could view approximately 42% of
the earth. For those outside of that viewing area, of course, the satellite was
NEVER available.
Syncom II Communications Satellite
However, a system of three such satellites, with the ability to relay messages
from one to the other could interconnect virtually all of the earth except the polar
regions. The one disadvantage (for some purposes) of the geosynchronous orbit
is that the time to transmit a signal from earth to the satellite and back is
approximately ¼ of a second - the time required to travel 22,000 miles up and
22,000 miles back down at the speed of light. For telephone conversations, this
delay can sometimes be annoying. For data transmission and most other uses it
is not significant. In any event, once Syncom had demonstrated the technology
necessary to launch a geosynchronous satellite, a virtual explosion of such
satellites followed.
Today, there are approximately 500 communications satellites in orbit, with over
300 in geosynchronous orbit. One of the biggest sponsors of satellite
development was Intelsat, an internationally-owned corporation which has
launched 8 different series of satellites (4 or 5 of each series) over a period of
more than 30 years. Spreading their satellites around the globe and making
provision to relay from one satellite to another, they made it possible to transmit
1000s of phone calls between almost any two points on the earth. It was also
possible for the first time, due to the large capacity of the satellites, to transmit
live television pictures between virtually any two points on earth. By 1964 (if you
could stay up late enough), you could for the first time watch the Olympic Games
live from Tokyo. A few years later of course you could watch the Vietnam War
live on the evening news.
A geosynchronous satellite must orbit at 22,300 miles altitude and it must be over
the earth's equator. As a result, there are a limited number of "slots" for satellites.
The allocation of these slots is carefully regulated by an international governing
body. Needless to say, both processes are highly political inasmuch as (1) there
are billions of dollars to be made, and (2) few things are more prestigious for a
small, newly independent country than to be able to say, "We have our own
satellite." To date (and for the foreseeable future) satellite communications is the
biggest and virtually only money-making business in space.
Ground Station
Geosynchronous Orbit (GEO): 35,786 km above the earth
•
Orbiting at the height of 22,282 miles above the equator (35,786 km), the
satellite travels in the same direction and at the same speed as the Earth's
rotation on its axis, taking 24 hours to complete a full trip around the
globe. Thus, as long as a satellite is positioned over the equator in an
assigned orbital location, it will appear to be "stationary" with respect to a
specific location on the Earth.
Communications data passes through a satellite using a signal path known as a
transponder. Typically satellites have between 24 and 72 transponders. A single
transponder is capable of handling up to 155 million bits of information per
second. With this immense capacity, today's communication satellites are an
ideal medium for transmitting and receiving almost any kind of content - from
simple voice or data to the most complex and bandwidth-intensive video, audio
and Internet content.
Diagrammatic Representation of a Satellite
Simplex Transmission
Applications for simplex services include broadcast transmissions such as:
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TV and video services
Radio services
XM Satellite Radio
XM Radio uses two Boeing HS 702 satellites, appropriately dubbed "Rock" and
"Roll," placed in parallel geostationary orbit, one at 85 degrees west longitude
and the other at 115 degrees west longitude. Geostationary Earth orbit (GEO) is
about 22,223 miles (35,764 km) above Earth, and is the type of orbit most
commonly used for communications satellites. The first XM satellite, "Rock," was
launched on March 18, 2001, with "Roll" following on May 8. XM Radio has a
third HS-702 satellite on the ground ready to be launched in case one of the two
orbiting satellites fails.
Photo courtesy XM Satellite Radio
This graphic illustrates how the XM Radio system
works.
XM Radio's ground station transmits a signal to its two GEO satellites, which
bounce the signals back down to radio receivers on the ground. The radio
receivers are programmed to receive and unscramble the digital data signal,
which contains up to 100 channels of digital audio. In addition to the encoded
sound, the signal contains additional information about the broadcast. The song
title, artist and genre of music are all displayed on the radio. In urban areas,
where buildings can block out the satellite signal, XM's broadcasting system is
supplemented by ground transmitters.
Sirius Satellite Radio
Unlike XM, Sirius does not use GEO satellites. Instead, its three SS/L-1300
satellites form an inclined elliptical satellite constellation. Sirius says the elliptical
path of its satellite constellation ensures that each satellite spends about 16
hours a day over the continental United States, with at least one satellite over the
country at all times. Sirius completed its three-satellite constellation on November
30, 2000. A fourth satellite will remain on the ground, ready to be launched if any
of the three active satellites encounter transmission problems.
Satellite Remote Sensing and its Role in Global Change Research
From a general perspective, remote sensing is the science of acquiring and
analyzing information about objects or phenomena from a distance. As humans,
we are intimately familiar with remote sensing in that we rely on visual perception
to provide us with much of the information about our surroundings. As sensors,
however, our eyes are greatly limited by 1) sensitivity to only the visible range of
electromagnetic energy; 2) viewing perspectives dictated by the location of our
bodies; and 3) the inability to form a lasting record of what we view. Because of
these limitations, humans have continuously sought to develop the technological
means to increase our ability to see and record the physical properties of our
environment.
Beginning with the early use of aerial photography, remote sensing has been
recognized as a valuable tool for viewing, analyzing, characterizing, and making
decisions about our environment. In the past few decades, remote sensing
technology has advanced on three fronts: 1) from predominantly military uses to
a variety of environmental analysis applications that relate to land, ocean, and
atmosphere issues; 2) from photographic systems to sensors that convert energy
from many parts of the electromagnetic spectrum to electronic signals; and 3)
from aircraft to satellite platforms. Today, we define satellite remote sensing as
the use of satellite-borne sensors to observe, measure, and record the
electromagnetic radiation reflected or emitted by the Earth and its environment
for subsequent analysis and extraction of information.
Materials:
Science Journal
Kids Discover Magazine, “Solar System”, New York, 2003.
http://www.nasa.gov/worldbook/artificial_satellites_worldbook.html
http://ctd.grc.nasa.gov/rleonard/
http://www.intelsat.com/network/satellite/
Introduction to Satellites Power Point written by Bryan DeBates and found on the
Space Technologies CD provided at the end of the class
Introduction to Orbital Mechanics Power Point written by Tina Cox of AGI and
found in the AGI bag provided
Various Google Earth Pictures
Digital Art Activity worksheets (see addendums)
Science Textbook
Lesson:
Day 1- Introduction to Natural and Artificial Satellites
1. Ask students about satellites. What are they for? Who uses them? Why
do we need satellites?
2. Introduce the definition of a satellite. Then distinguish between natural
and artificial satellites. Have students write down the definitions and an
example of each. An artificial satellite is a manufactured object that
continuously orbits Earth or some other body in space.
Satellite - An object that orbits another object.
Natural satellite - A small or secondary planet which revolves around a
larger one.
Artificial satellite - A man-made object placed (or designed to be
placed) in orbit around an astronomical body (usu. the earth).
Sphere - A geometrical solid figure formed by the complete revolution
of a semicircle about its diameter; a round body of which the surface is
at all points equidistant from the center.
Orbit - The path or course of a heavenly body; the curved path
described by a planet or comet about the sun, by a satellite about its
primary, or by one star of a binary system about the other.
Revolve - To perform a circular motion in a regular orbit about or round
a fixed point outside the body.
Rotate - To perform a circular motion in a regular orbit about or round a
fixed point inside the body
3. Have the students look at various pictures of natural satellites like moons,
comets, planets, (even the Earth is a satellite of the Sun). Look at various
pictures of artificial satellites that man has placed into orbit including the
International Space Station, the Space Shuttle, many communication
satellites, and anything considered “space junk” such as burned-out rocket
boosters and empty fuel tanks that have not fallen to Earth.
4. Discuss the differences. Natural satellites are usually spherical, were not
always intended to be floating in space (asteroids and comets), and made
up of natural elements. Artificial satellites are made up of many different
shapes and many different materials that are both man-made and natural
to earth.
Day 2- Geosynchronous Communication Satellites
1. Show selected parts of the Introduction to Satellites Power Point written by
Bryan DeBates to teach students about what a satellite must have on
board during orbit in order to operate. Also, selected parts of the
Introduction to Orbital Mechanics Power Point by Tina Cox of AGI to teach
students about geosynchronous satellites and orbits. Have students take
notes in their science journals.
2. Pass around pictures and descriptions of various geosynchronous
satellites like, DirecTV, XM Radio, and weather satellites.
Day 3- Satellite Data Transmission
1. Show pictures from Google Earth. Ask students how satellites collect
information about the Earth. Explain that today’s activity will model how
satellites transmit their data to the computers on Earth.
2. Explain that satellites transmit numeric codes to the Earth that computers
interpret and change into images.
3. Pass out the Digital Art Activity sheet and go over the directions.
4. Pair up the students for the activity.
5. As an extension, students may add color that represents elements that
might be seen on earth to their digital art and have partners make up the
code.
6. Discuss with the class how amazing it is that we get pictures of the earth
from codes like that (which are much more advanced and faster than we
were today).
Evaluation:
• Students did understand and define natural satellite, artificial
satellite, and geosynchronous orbit.
• Students were able to draw a picture of where a geosynchronous
satellite is in relation to the Earth.
Resources:
Kids Discover Magazine, “Solar System”, New York, 2003.
http://ctd.grc.nasa.gov/rleonard/
http://www.intelsat.com/network/satellite/
Introduction to Satellites Power Point written by Bryan DeBates and found on the
Space Technologies CD provided at the end of the class
Introduction to Orbital Mechanics Power Point written by Tina Cox of AGI and
found in the AGI bag provided
Addendums:
Name ______________________
Date ______________
Digital Art Activity
Directions: (Do this activity with a partner.)
1. In your pair, choose one person to be the “sender” and one to be the
“receiver.”
2. Label grid A. Above the top row (horizontal), label from left to right using the
letters A to J. Next to the far left column (vertical), label from top to bottom using
numbers 1 to 10. Check to make sure your grid matches your partner’s grid.
3. If you are the sender, draw a simple black-and-white picture by coloring in
complete boxes in the grid. Each box should be completely filled or completely
empty. Do not show your picture to your partner. Use the manila file folder to
cover
your worksheet.
4. After the sender draws the picture, he/she will “read” their picture to the
receiver
using a “digital code.” The receiver will say “A1.” Then, the sender will answer
“0” if the box is empty or “1” if the box is filled in.
5. Continue step 4 until all the boxes are “read.” Compare pictures. Are they the
same?
6. Switch roles. Repeat steps 2 through 5.
Extension if time:
You and your partner decide upon a code to use that includes different colors.
Example: 0= White, 1= Black, 2= Green, 3= Red, and so on.
Name ______________________
Date ______________
Digital Art Worksheet
Grid A
Grid B
Grid C
Digital Art Sample Pictures
House with a sun shining on it
Happy face
Star
Extension Activities:
What Does an Artificial Satellite Do?
Objectives:
•
•
•
Students will learn that artificial satellites collect and return data.
Students will learn the major types of artificial satellites.
Students will understand the different functions of various artificial
satellites.
Estimated Lesson Time:
Two classes (2 hours)
Classroom strategies:
Begin with vocabulary and motivate the discussion with the fact that satellites all
collect data of some sort and send that data back to Earth. Use images/videos
(stills and/or WWW) and open-ended discussions of what they think the different
satellites do.
Science background Information:
First satellites were built and launched by the Soviet Union and the US. Over
time, the more industrialized nations also built satellites (e.g., Canada). Now,
even small countries have their own satellites (e.g., Luxembourg). For a review of
satellite "firsts," see http://www.atek.com/satellite/index.html and the ABCs of
Satellite Communications. Provide background for each type of satellite:
•
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Weather: used for weather forecasts by measuring things like clouds,
winds, temperature of the atmosphere from space; also used for climate
changes like El Nino and global warming. First weather satellite - Explorer
7, Oct. 13, 1959.
Military: used for tracking battle zones, watching for missile launches,
watching for nuclear testing, as weapons, spying on hostile countries,
intercepting messages, tracking incoming objects like meteoroids and
defunct satellites. US launches its first spy satellite, Discoverer 1, part of
top-secret Corona program, Feb. 28, 1959. Discoverer 13 (Aug. 10, 1960)
is first unqualified success.
Telecommunication: used for cellular phones, long-distance phones,
beepers, TV broadcasts via satellite dishes, computer connections.
ECHO-1 was a plastic 30.5 m ball covered of mylar aluminized that
reflected radio signals.
It enabled the first satellite telephone link and the broadcast of a TV
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program from California to Massachusetts on 24 Feb 1962. The first
company-owned telecommunications satellite was TELSTAR, July 10,
1962. The first geostationary orbiting communication satellite was
SYNCOM3, Aug. 19, 1964.
Navigation: used for determining position using a large number of
satellites, used by airplanes for landing, ships for navigation, geologists for
prospecting, farmers for planting and fertilizing. The first Global
Positioning Satellite (GPS) was launched on November 22, 1978 - GPS is
now the standard navigation tool used by the military, scientists, and
industry.
Scientific: used for learning about the universe, for example: how stars
form (astronomy - Hubble Space Telescope), how the Sun and the Earth
interact (space weather - POLAR), what space is like (IMP), exploration of
the planets (Pioneer - outer planets, Voyager - outer planets and Venus,
Galileo - Jupiter, Mars Surveyor, Viking - Mars, Mariner - Mercury). First
American satellite - Explorer-1, Feb. 1, 1958.
It is important to note that not all satellites look alike, even within the same
category. Also, a single satellite might serve multiple purposes (i.e., both
scientific and military).
Vocabulary:
1. Data - Things given or granted; things known or assumed as fact, and
made as the basis of reasoning, measurement, or calculation; an
assumption or premise from which inferences are drawn.
2. Military - Having reference to armed forces or to the army; adapted to or
connected with a state of war; distinguished from civil, ecclesiastical, etc.
3. Navigation - The art or science of directing the movements of aircraft or
spacecraft, esp. in regard to a craft's position and course.
4. Telecommunication - Communication over long distances, esp. by
electrical means such as by telegraphy, telephony, or broadcasting; (usu.
in pl.) the branch of technology concerned with this.
5. Geostationary - A satellite with an orbital period of exactly 24 hours. When
placed in orbit in the Earth's equatorial plane at about 6.6 Earth radii from
the Earth, the satellite will remain fixed with respect to the rotating Earth
and therefore appear to be "geostationary."
6. Meteoroid - Any small rocky or icy object that fills interplanetary space.
When a meteoroid enters the Earth's atmosphere we call it a meteor. If a
meteor makes it to the surface of the Earth without burning up, it is called
a meteorite.
7. Weather - The condition of the atmosphere (at a given place and time)
with respect to heat or cold, quantity of sunshine, presence or absence of
rain, hail, snow, thunder, fog, etc., violence or gentleness of the winds.
Usually on a short time scale.
8. Climate - Condition (of a region or country) in relation to prevailing
atmospheric phenomena, as temperature, dryness or humidity, wind,
clearness or dullness of sky, etc., esp. as these affect human, animal, or
vegetable life. Usually refers to a long term time scale.
Materials and Equipment:
References on various satellites. Pictures of satellites (a typical example of each
kind). Videos.
Advance Preparation:
Gather appropriate materials.
Activity:
Divide up class into five groups. Each group will be assigned one of the following
types of satellites: weather satellites (GOES), telecommunication satellites
(ANIK), navigation satellites (GPS), scientific satellites (TERRIERS), and military
satellites (MILSTAR). Each group will try to determine the function of their type of
satellite through brainstorming first, then using resources provided by the
teacher. Each group will present their information to the class; teacher may need
to fill in missing elements. To the extent possible, have students add the first
launch of their satellite to the timeline at the appropriate date.
Homework Assignment:
Journal exercise - How many things in your life today were made possible by
satellites? What would have been different if all the satellites had stopped
working? (Teacher note: In May 1998 a critical satellite failed and 90% of all
beepers in the US stopped working which affected doctors on call and
emergency crews. It also interrupted cell phone and television operations for
several days. This was a worldwide effect.)
References:
NOVA on Earth-crossing Asteroids and Meteor Impacts; NOVA or Discovery
program on the history of spy satellites
Book with pictures and descriptions of specific satellites used in activity (maybe
from a web page for each?)
Traveling in Space (Troll Associates)
Connections:
Literature: 2001: A Space Odyssey (Arthur C. Clarke)
Music: Ground Control to Major Tom (David Bowie - Ziggy Stardust and the
Spiders From Mars)
Using GPS in the Classroom
Classroom time: 40 minutes
Material Covered:
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Applications of GPS
Global scientific collaborations that use GPS
Computers: Internet and electronic mail
Introduction to the Global Mapping Experiment.
Worksheet for Students: Applications of the Global Positioning System
Applications of GPS
The high precision of GPS makes it an impressive technique for any imaginable
application that requires the determination of positions (positioning), time (timing)
and/or direction of motion (navigation) anywhere on Earth under all weather
conditions. Although GPS is a relatively new technique, the highly creative minds
of many people around the globe have already devised and developed a myriad
of applications. The first applications were developed by the U.S. Department of
Defense, who took on the assignment of designing and developing the GPS
system. The applications in this category had a clear military orientation, like
navigating combat airplanes, guiding missiles, positioning troops and locating
military ships in a timely (real-time) manner.
Civilian applications, both commercial and scientific, already abound. In fact,
commercial and scientific applications now far outnumber the military
applications. We will mention just a few of them in the hope of stimulating the
imagination of the freshest and most creative minds among the ATLAS
participants to perhaps conceive new clever applications.
Reasonably enough, the GPS is helping more and more to guide cars and cabs,
trucks and trains, sailing boats and ships, airplanes and even other satellites.
Police and municipal services are using GPS for vehicle tracking. Rescue and
salvation crews are using GPS to locate and speed the assistance to people
during emergencies. Surveyors are using GPS to determine the boundaries,
area, or elevations of land, rivers and/or countries. Engineers are using GPS to
monitor the tiny motions and possible deformations of potentially hazardous
structures such as bridges, roads and dams. Farmers are using GPS to survey
their fields so that they can distribute fertilizer more efficiently. Airline pilots are
using GPS to cruise and land airplanes. Hikers are using GPS to guide
themselves on their mountain climbs. GPS systems are being extensively used
on bicycle tours, marathon runs, rally competitions, and in many other kinds of
sport events. Zoologists attach minuscule GPS receivers to penguins and polar
bears, whales and dolphins, eagles and condors, lions and gazelles to study their
behavior in their natural habitats. Cellular phones with GPS capabilities combine
voice communication needs with positional information with the purpose of, for
example, personal security and fleet management. Radio and television
broadcasting stations, financial institutions and international transactions,
computer networks and clocks around the world use the GPS signals for time
synchronization. Backpack GPS units are being developed to guide blind people
through the intricacies of the cities. The list goes on and on and on.
Global scientific collaborations that use GPS
Applications of GPS in Science are becoming increasingly popular. For example,
the timing information provided by GPS is being used at astronomical
observatories around the globe to coordinate observation of celestial bodies such
as planets, stars, galaxies and more exotic objects. Many space vehicles, such
as the Shuttle or the Space Station, carry a GPS system for navigation purposes.
Although the list here could also go on and on, we will concentrate on the
Geosciences, that is, the scientific study of the Earth. We concentrate on this
area not only because the Earth is our planet but also because the very nature of
the global scale of the ATLAS experiments is directly related to this application.
A few applications of GPS within the Geosciences are:
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•
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Seismology: Seismologists measure the surface deformations associated
with earthquakes
Volcanology: Volcanologists measure the deformations experienced by
volcanoes prior to eruption
Glaciology: Glaciologists measure the slow, steady flow of huge masses
of ice
Meteorology: Meteorologists measure the effect of the atmosphere on the
GPS signals to aid in weather forecasting
Geodesy: Geodesists measure the slow and rapid deformations of the
Earth’s crust
Geodesy is the oldest branch of Geophysics. The very global character of GPS
has caused a whole revolution in the way Geodesy is practiced and the results
that are obtained. The ATLAS experiments will simulate global geodetic
experiments.
Computers: Internet and electronic mail
The international collaborations described above could not be possible without a
fast, powerful and reliable way of communication and data transmission like the
Internet and electronic mail, or e-mail. Older methods of communicating data
involved sending storage media through the mail. These methods are highly
inefficient by today’s standards. In fact, the volume of data exchanged on a daily
basis over the Internet makes renders previous methods simply impossible to
use.
The Internet, a.k.a. the "Net," is a network of computers throughout the world that
are linked together. The computers communicate with each other in very much
the same way as people communicate with each other on the telephone, but very
much faster. In fact, the physical link that connects many of the computers to the
Internet is a regular telephone line. An important difference between the way
people and computers communicate, though, is the language. Whereas people in
different countries speak different languages and there are thousands of different
languages spoken in the world, all computers speak one and the same language.
This computer language is called "binary language."
The Internet includes, among other services, electronic mail and the World Wide
Web. We will be using these two as part of the ATLAS Project. Electronic mail,
a.k.a. e-mail, is a way to communicate using the Internet and is the most
common way of sending short, quick messages between people using computers
connected to the Internet. You only need to know the particular address where
you want to "send" information by e-mail. E-mail addresses are even easier than
postal addresses. For example, the email address of the ATLAS Project is
[email protected]. You will send your messages to [email protected]
and one of the scientists involved in the ATLAS Project will read them and
respond to you. In this way, you are becoming a member of an international
project that uses some of the most advanced technology available in Space and
Earth communications.
The World Wide Web, a.k.a. the "Web," is made up of web sites. A web site
consists of web pages which are stored in a particular computer. A web page is
made up of almost any form of communication: text, images, movies, video, and
sound. Web pages are just ordinary computer files with pointers added to tell the
computer some details about where to look for display and links. When you are
using the Internet to search for any information in other computers you are said
to be "navigating" or "surfing" the Web. Internet addresses are also easy. An
example is the address you should type on your computer to visit the site that
contains the information about the ATLAS Project. This address is: http://cfawww.harvard.edu/space_geodesy/ATLAS/.
The Internet is like a huge illustrated library in which you can find information
about almost anything imaginable. You can even post information about yourself
if you want to make it available to everybody using it.
Worksheet for Students: Applications of the Global Positioning System
The students may complete the worksheet Applications of the Global Positioning
System. This worksheet asks the students to design a system that incorporates
GPS receivers. Students are encouraged to consider how GPS might be
integrated into their daily lives.
Introduction to the Global Mapping Experiment
In the next section we describe the first of the two ATLAS experiments, the
Global Mapping Experiment (GME). By way of introduction to GME, the students
will use hand-held GPS receivers to determine the position of their schools on
the Earth and will exchange this information with their ATLAS participants around
the globe. Very much like in a global scientific experiment, all the participating
schools will be carrying out this experiment at nearly the same time. Timing and
coordination are therefore important aspects of this experiment.
Space Geodesy Group
Harvard-Smithsonian Center for Astrophysics
60 Garden St, MS 42
Cambridge, MA 02138-1516