chapter 16 space research and...

486 Chapter 16

Space Research andExploration

C H A P T E R

16Getting Started

16C H A P T E R

1 This is what the International Space Station (ISS) will look like whenit is completed. The ISS will be the biggest technologicalproject ever built. It involves the cooperationof many different countries, includingCanada. What is Canada’s role inthe ISS? What would it belike to work up inspace? ISS is a kindof satellite. Whatis the purposeof othersatellites?

Space Research and Exploration 487

2 Although Canada’s population is relatively small, our contributionto space technology is impressive. How does Canada contribute tospace research, telecommunications, and international spaceprograms? What are the positive and negative effects of thiscontribution on Canadians and on the rest of the world?

3 Astronauts travelling in a spacecraft in orbit around Earthlook as if they are floating around in the craft. Why doesthis happen? How does this type of motion affect thehuman body and contents of the craft?

ReflectingThink about the questions in

, , . What ideas do you

already have? What other

questions do you have about

satellites and humans in space?

Think about your answers and

questions as you read the chapter.

1 2 3

A Packing List

Make a packing list of all your personalrequirements for a three-month workingtour on the Space Station. Your essentialneeds are air, warmth, water, and food.

1. Consider a typical day in your lifehere on Earth. Make a list of theactivities you perform and what youneed to carry out those activities.

2. Decide which of your daily needs onEarth you could live without for threemonths in space. Alter your listaccordingly.

3. Consider what you would require inspace that you would not require onEarth. Again, alter your needs listaccordingly.

4. Assume that you will be in space forthree months. Complete your needslist for the trip.

5. Compare your list with that of otherstudents or groups. If necessary, makechanges to your list.

488 Chapter 16

A basic human characteristic is curiosity—our drive to explore. Peoplehave crossed the oceans, climbed Earth’s highest mountains, andwalked on the Moon. The biggest single frontier left to explore is outerspace, which is everything outside of Earth’s atmosphere. Theatmosphere—the air and everything it holds, such as water vapour—extends upward from Earth’s surface, gradually becoming less denseuntil it finally becomes almost nothing at an altitude of about 150 km.This is where “outer space” begins.

Comparing Aircraft and Spacecraft

Can an aircraft travel in outer space? Can a spacecraft travel in Earth’satmosphere with no engines operating, as it can in outer space? Theanswer to both questions is no. To find out why, we need to considerthe characteristics of each type of craft.

An aircraft is a vehicle that travels through the air; examplesinclude jet airplanes, propeller airplanes, and helicopters. The enginesof these vehicles must operate continuously to keep them above theground. The engines use oxygen in the air to burn the fuel they needto travel. Most aircraft do not travel higher than about 20 km aboveEarth’s surface. If they go too high, there is not enough oxygen tosupport the burning of the fuel. Also, air isneeded to support the aircraft. Whether it is ahelicopter or a plane, air keeps the aircraftaloft. The rotors or wings are curved so thatthe air pressure below them is greater than thatabove (Figure 1), so they are forced upward.Without the air, an aircraft would plummettoward Earth.

A spacecraft is a vehicle designed to travelin the near vacuum of space, usually 200 km ormore above Earth’s surface (Figure 2). Oncethe spacecraft rises above the atmosphereand is travelling extremely fast parallel toEarth’s surface (which tends to make it leaveEarth), its forward speed balances the pull ofgravity (which tends to make things falltoward Earth). When these two opposingpulls are perfectly balanced, the spacecraftno longer needs to operate its engine full-time in order to travel around Earth. Thespacecraft must be above the atmosphere,otherwise air resistance (the friction of the airmolecules brushing past the craft) would slowit down.

Getting into Space

16.116.1

Did You Know

The first artificialsatellite, Sputnik, was

launched into space in1957 by the Soviet Union.Canada’s first satellite,Alouette 1, was launchedin 1962. Since then,hundreds of satelliteshave been sent into spaceto orbit Earth.

air

low pressure

high pressure

wing

Events in SpaceExploration

Make an illustrated time line of the majorevents in space exploration. Use referencebooks and CD-ROM resources to help youdesign interesting illustrations. Earlyevents include Konstantin Tsiolkovsky’sexplanation of rocketry in 1903 andRobert Goddard’s first liquid-fuelledrocket launch in 1926.

Figure 1


Although many spacecraft travelin orbits around Earth, some go tothe Moon or to other parts of thesolar system. A spacecraft must carryits own fuel and source of oxygen,and it must travel fast enough so itdoesn’t fall back to Earth.

Unpiloted and PilotedSpacecraft

Spacecraft can be piloted (withpeople on board) or unpiloted (alsocalled robotic spacecraft). Satellitesare the most common type ofspacecraft. As you’ve learned, asatellite is an object that travels in anorbit around another object; forexample, the Moon is a naturalsatellite of the Earth. Anotherimportant type of spacecraft, called aspace probe, is one with manyinstruments on board that is sent todiscover more about moons, planets,comets, the Sun, and other parts ofthe solar system.

The first piloted spacecraft wassent into space in 1961 by the formerSoviet Union(Russia and its allies).The cosmonaut aboard was YuriGagarin. Piloted craft tend to gainmore public attention thanunpiloted spacecraft, but the addedexpense of sending humans intospace is a disadvantage. Piloted spacecraft always have to be brought back to Earth, whereas unpiloted craft oftendo not have to return.

One type of piloted spacecraft is the spacestation. The first one, Salyut 1, was placed into orbit in 1971. A newer station is theInternational Space Station (ISS), shown onpage 486. It is designed to stay in space formany years, allowing people to live and workin space. Figure 3 shows an example ofanother piloted spacecraft: the space shuttlebuilt by the United States. One task of theshuttle is to take materials and astronauts toand from the ISS.

Figure 3

This U.S. space shuttle is about to land. What clues revealthat it is a piloted spacecraft rather than an unpiloted one?

Earth

highestmountain

very fewair particles

low density air

highest density air

curvature of the Earth

Altitude abovesea level

0

300 km

200 km

100 km

400 km

500 km

Figure 2

Vehicles in Earth’s atmosphere and in outer space beyond

fuel

oxygen –containingchemicalpump

combustionchambernozzle necknozzle mouth

thrust

exhaust gases

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Payloads and Launchers

If you were to throw a ball to a friend, your arm could becalled the launcher, and the ball, the payload. In spaceexploration, a payload is any satellite, piloted spacecraft, orcargo launched into space. The launcher is the device thatcarries a payload into space. Its main part is a rocket engine.

What happens if you try to throw a ball straight up? Itsoon falls back down, pulled by gravity. Large bodies, suchas Earth, exert a strong force of gravity on nearby objects.A vehicle can be launched into space only bycounteracting Earth’s strong force of gravity. The hugeforce needed to counteract gravity is provided by apowerful rocket engine.

A toy balloon is a simple model that helps explain howa rocket engine works. When the air in an inflated balloonis released, the balloon flies quickly and uncontrollablyaround the room. As the air under pressure inside theballoon escapes from the open neck, the balloon is forcedin the opposite direction. The force that causes an objectto move is called thrust. In the case of the balloon, thethrust is exerted by the pressure of the gas coming out ofthe balloon. If the air is escaping to the left, the thrust onthe balloon is to the right (Figure 4).

Like a balloon, a rocket engine is enclosedexcept at the nozzle end. Unlike a balloon, arocket engine operates through theaction of two chemicals. Figure 5shows that exhaust gasestravelling rapidly in onedirection cause thrust onthe rocket in the oppositedirection.

Understanding Concepts1. Name the force that must be

overcome in order to launch avehicle into space.

2. Classify each of the following as apayload or a launcher:

(a) a weather satellite

(b) a rocket

(c) an astronaut

3. Describe thrust and how it causesa rocket to move.

Making Connections4. Why do humans want to explore

space? Give reasons to supportyour views.

5. Suppose you needed rawmaterials to build a space colonyon another planet. What would besome of the advantages ofobtaining those materials from theMoon rather than from Earth?

Exploring6. How could you make a flying

balloon into a payload-carryingdevice? What might anappropriate payload be? With yourteacher’s approval, try “launching”a rocket balloon (Figure 4) withand without the payload. Accountfor your observations.

Figure 4

A balloon can demonstrate thrust. To guide the balloon, feedfishing line through two pieces of a drinking straw taped to ablown-up balloon. When the balloon is released, air leaves theopen neck rapidly in one direction, creating a thrust on theballoon in the opposite direction.

Figure 5

This represents the basic design of a liquid-fuelled rocket engine.The fuel and an oxygen-containing chemical are pumped into thecombustion chamber where the fuel burns rapidly, producinggases under high pressure. The gas molecules speed up as theyescape through the nozzle neck; then they speed up even fasterwhen they get to the nozzle mouth. These escaping gasmolecules exert an upward thrust on the rocket engine.

directionof air

directionof thrust

Space Research and Exploration 491Controlled ExperimentsSKILLS HANDBOOK: 2A

Making Connections1. Compare the operations of a water rocket

and a rocket fuelled by chemicals. Includeboth similarities and differences.

Exploring2. If possible, use simulation software to

research rocket launching.3. Find information about a model rocketry club

in your area. Invite a member of the club toshare ideas about launching rockets and, ifpossible, demonstrate a model rocket launch.

A toy water rocket is a safe and easy way tostudy how rockets work. Although it ispowered only by water and air, it works on thesame principles as a rocket powered bychemical fuels. Your challenge is to designmodifications to make the water rocket go ashigh as possible.

Materials

Question

Ask a question that your experiment willanswer.

Hypothesis

Write a hypothesis and predict how eachcontrolled variable will affect thedependent variable.

Experimental Design

Examine the water rocket (Figure 1) andread the instruction manual. Design acontrolled experiment in which you varyone factor—“controlled variable”—at atime. The height reached by the rocket isthe “dependent variable.”

(a)Make a list of the steps you would taketo safely launch the water rocket,including safetyprecautions,measurement ofvariables, andrecording your data.Ask your teacher toapprove the steps.

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2

1

Launching Water Rockets

16.2 Investigation16.2 Investigation

Figure 1

After adding some water to a water rocket, you canuse the pump to increase the air pressure inside therocket. What factors do you think control how highthe rocket will fly? Which of these could becomecontrolled variables?

Procedure

Discuss with your group how you willdetermine the height the rocket reaches.(Think of triangulation, measuring angles,and drawing scale diagrams.)(a) Record the steps you will take to

measure the height. Ask your teacherto approve these steps.

After your design has been approved,carry out your investigation outdoors.(a) Record your observations,

measurements, and calculations.Operate the rocket outdoors only. Do not aim it at anybody.Stand clear of the line of flight. Wear safety goggles.

Analysis and Communication

Analyze your observations by answeringthe following questions:(a) How did the height of the rocket

change as you altered each controlledvariable?

(b)How is thrust obtained in a waterrocket?

(c) Explain the factors that affect thethrust.

(d)Write up your investigation in acompete lab report.

(e)Do your results support yourhypothesis? Explain.

6

5

4

• toy water-rocket kit• instruction manual for

the rocket

• clean water• safety goggles• astrolabe

SKILLS MENUQuestioning Conducting AnalyzingHypothesizing Recording CommunicatingPlanning

2A

492 Chapter 16

Have you ever watched a “live” event on television as it ishappening in a country halfway around the world? Such livecoverage on TV is made possible by satellites that continually orbitEarth relaying signals from place to place.

Satellites in Low Earth Orbit

In 1962, Canada became the third country in the world to send asatellite into space. Alouette 1 was used for scientific research: tostudy particles in Earth’s upper atmosphere by circling above itand collecting data.

Alouette 1 was an example of a satellite in low Earth orbit, an orbit at an altitude of between 200 km and 1000 km. At speedsof about 28 000 km/h, such satellites take only about 1.5 h totravel once around Earth (Figure 1).

Besides carrying out scientific research, the main function oflow Earth-orbit satellites is remote sensing: making observations from adistance using imaging devices. We are familiar with images made fromlight: photographs. They can be recorded usingtraditional film cameras, but satellites use digitalcameras so that the images can be sent back toEarth. Other types of images are created frominfrared (heat) waves, radio waves, and otherinvisible waves of the electromagnetic spectrum.Each type of radiation registers differentinformation and is used to watch for differentphenomena (events). For example, radio wavescan pass through cloud, so they can be used tocreate images of events that would otherwise behidden by cloud cover. Satellites detect thesedifferent kinds of waves by using special camerasor antennas. The information gathered by thesatellites is beamed to Earth using radio waves(Figure 2), which travel at the speed of light. OnEarth, the signals are analyzed by computers andconverted into visible images. Certain features of the image may havecharacteristics that make them particularly visible. For example,vegetation appears red in an image constructed from infraredradiation. This makes the image specially useful to foresters monitoringthe regrowth of trees in a clear-cut area.

Weather forecasting relies heavily on remote sensing, using imagesof cloud patterns around the world. With experience, weatherforecasters can interpret these images to help predict what the weatherwill be like locally. They may even save lives by providing informationon approaching storms, such as hurricanes (Figure 3).

Earth-Orbit Satellites

16.316.3

Figure 1

Examples of low Earth orbits may bearound the equator, around the poles, orat any angle between the equator andthe poles.

equator

polar orbit

receiver

satellite

Earth

light fromthe Sun

Figure 2

In daylight, visible light from the Sun reflects off Earth’ssurface or clouds. Digital cameras aboard a satellitecapture the reflected light; then antennas on the satellitebeam the digital information, using invisible radio waves,to a receiver on Earth.

Did You Know

The cameras aboardsome spy satellites

are so sensitive that theyare able to read lettersand numbers about thesize of a person’s handfrom hundreds ofkilometres away.


Remote sensing is also used by the military.For example, some nations have spy satellitesthat obtain images of other nations’ activitieson Earth’s surface.

Scientists also use images from satellites tostudy water resources, crop management,forests, insect damage, animal migration,pollution, and fault lines on Earth’s surface.

Remote sensing satellites do not detect onlynaturally occurring radiation. They can alsoemit their own radiation and then pick up thereflections (Figure 4). Computers analyze thereflected signals and convert them into images.The types of radiation most often used areradio waves and microwaves. A Canadiansatellite system called RADARSAT, featured onpage 496, is used to construct radio-waveimages of Earth’s surface.

Satellites in low Earth orbit can also be directed out toward space.To astronomers looking out into space from Earth’s surface, theatmosphere acts like a fog, reducing their ability to see the stars,galaxies, and other parts of the universe clearly. Furthermore, there areparts of the electromagnetic spectrum that never get through Earth’satmosphere. Astronomers have known for a long time that they couldimprove their understanding of the universe if they could observe itfrom above the atmosphere. Telescopes aboard orbiting satellites, suchas the Hubble Space Telescope, now enable them to make observationsfrom space.

Figure 3

A satellite image showing a hurricane

area scanned bymicrowave beams

satellite

receiver

Earth

Figure 4

This satellite sends out beams of microwaves that can passthrough clouds and reflect off Earth’s surface. The satellitereceives the reflected waves and converts the information todigital format and beams it back to a receiver on Earth.

Did You Know

Satellite phones andpagers can be used

anywhere in the world ifthey are part of acommunications networkcalled Iridium. The systemconsists of 66 satellites inlow Earth orbit (780 km).

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Satellites in Higher Orbits

Our lives would be very different if we did nothave telephones, televisions, and radios, andif we could not transmit computer data almostinstantaneously. These products of thetelecommunications industry help uscommunicate over small and large distances.(The prefix “tele” is from the Greek word tele,meaning “far.”) People who live and work inremote areas are especially reliant on satellitesto keep in contact with the rest of the world.

Satellites in low Earth orbits have a majordisadvantage if used for TV communication.Imagine a television satellite dish trying toreceive signals from such a satellite. The dishwould have to track the satellite as it movedacross the sky. Then the satellite would gobelow the horizon, and all signals from thesatellite would be lost. In order for a satellitedish to receive signals constantly, the satellitewould have to remain in the same locationabove Earth’s surface.

The orbit of such a satellite is called ageosynchronous orbit. “Geo” means Earth and “synchronous” meanstaking place at the same rate. Since it takes Earth 24 h to turn onceon its own axis, a satellite in geosynchronous orbit must travel at thecorrect speed so that it takes 24 h to orbit Earth. This speed must becarefully calculated, taking altitude into account, so that the satelliteneither hurtles off into space nor crashes to Earth. From the ground,it appears that the satellite is not moving at all. The easiest place tocontrol such an orbit is directly above Earth’s equator, atan altitude of 36 000 km above sea level,which is much higher than low-orbit satellites. To keep itsposition at this altitude, thesatellite must travel at aspeed of 11 060 km/h(Figure 5).

Dish Hunt

What are the characteristics of the dishesthat receive signals from televisioncommunication satellites? To answer thisquestion, look at several satellite dishes inyour area, answering these questions:

1. What are the size, shape, and designof the dishes?

2. Which way are they pointed?

3. Are they all pointed in the samedirection?

4. Hypothesize why the dishes have thecharacteristics you observed. In yourhypothesis, refer to shapes of curvedreflectors, focal length, focal point,and wavelengths of waves.

South Pole

North Pole

36 000 km

equator

satellite

Did You Know

When Earth passesthrough a comet’s

tail, tiny particles of thetail can seriously damagea satellite, tearing its solarpanels or even knocking itout of orbit.

Figure 5

A geosynchronous orbit liesabove the equator. A satellitelocated there receives signalsfrom Earth-based transmittersand sends signals back toEarth-based receivers.


Canada has become a leader in telecommunications.The first satellite for domestic communications put intogeosynchronous orbit was Canada’s Anik 1, launched in1972. There have been many versions of the Anik series,improving the area of coverage and the quality of radio,telephone, and TV signals. A recent technological advanceincludes a satellite that sends and receives signals frommobile telephones in cars, trucks, ships, and airplanes.

Some satellites not used for TV communication travelin orbits somewhat lower than geosynchronous orbits. Forexample, 24 satellites used for search and rescueoperations travel in 12-hour orbits, 20 000 km aboveEarth’s surface. They form the Global Positioning System(GPS). A portable GPS receiver is a small device thatreceives signals from three or more of the orbitingsatellites. It then uses accurate clocks and preprogrammedinformation to calculate and display its own position. Thisposition could then, if necessary, be relayed by radio toother people, such as a rescue team searching for adowned plane or a lost hiker.

Space Junk

As you have now read, we receive many benefits fromorbiting satellites. Unfortunately there are also somedisadvantages. One is the huge expense. Another is theaccumulation of useless artificial objects orbiting Earth,commonly referred to as space junk. Satellites, for instance,are not designed to return to Earth once they becomeobsolete or malfunction. Another concern is that chunksof satellites and space stations could fall to Earth. Thereare other pieces of space junk,ranging in size from microscopicto huge pieces: blown-out bolts;bits and pieces from accidentalexplosions; discarded rocketengines; and even real garbagefrom piloted craft. These piecesare spread far apart in theirorbits, so are difficult to cleanup. Countries involved in thespace program are discussingwhat to do about the problem of space junk.

Understanding Concepts1. What are the features of a low

Earth orbit?

2. What is a geosynchronous orbit,and what type of satellite mustuse this orbit? Explain why.

3. What is the advantage of havingan observatory in space?

4. Using the data given in the textand the equation

speed = distance/time, calculate the speeds (in kilometresper hour) of(a) a geosynchronous satellite;(b) a satellite with an orbit

200 km above Earth’s surface.

Assume that Earth’s radius is6400 km. Compare your answerswith the values given in the text.

Making Connections5. Who should be responsible for the

cleanup of pieces of spacecraftthat crash to Earth? Give reasons.Are your answers affectedknowing that some of these fallingvehicles contain nuclear powerplants?

Exploring6. What else would you like to know

about satellites? Make a list ofquestions, then try to findanswers.

7. Search the Internet for satelliteimages of Ontario. What types ofelectromagnetic radiation are usedto compile each image? Whatfeatures do they reveal?

Did You Know

In January 1978, theRussian nuclear satellite

Cosmos 954 crashed intothe Thelon GameSanctuary in theNorthwest Territories,narrowly missing someexplorers camping in thewilderness. Picking upevery piece took monthsand, although it wassomebody else’s garbage,Canadian taxpayers had topay most of the bill.

Identify Canada’s role and useof satellites to include in yourinformation package.

Make a three-dimensional scalemodel of Earth and spacebeyond it to show the locationof various satellites in orbit foryour planetarium show.

(d)Why might it be better to search forunderground resources by usingRADARSAT images than by groundsurveying?

In order to provide a healthy planet forfuture generations, humans must learn toprotect our environment. Satellites help usmonitor the environment and make wisedecisions about our actions.

(e)RADARSAT is an expensive system, but itprovides great benefits. Is it worth thecost? How do we decide?

Understanding Concepts1. In a list, summarize the benefits of using

RADARSAT.

Exploring2. Compare the properties of radio waves

with the properties of other parts of theelectromagnetic spectrum. (For moreinformation about the electromagneticspectrum refer to Section 14.6, page 449, or use a separate resource.)

3. Research other animals, besides bats, thatuse a ranging/detection system similar toRADARSAT. Compare the systems.

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In the spring of 1997, people in Manitobawere faced with one of the worst floods intheir history. Soon after the flood began,satellite images helped emergency crews plandisaster control and relief (Figure 1). Theseimages were provided by RADARSAT, a highlysuccessful satellite system designed, built, andoperated by Canadians.

Helping in emergencies is only one of themany uses of RADARSAT, as you will see.

The word radar is short for “radiodetection and ranging.” This means that aradar device emits bursts of radio waves andpicks up their reflections to detect objects(detection) and find out how far away they are(ranging). Radio waves travel at the speed oflight and can pass through clouds, so they canbe used in all types of weather and at night.

(a) What are advantages of radio waves overvisible light?

(b)Brainstorm some other uses of radar.

As its name suggests, RADARSAT is asatellite system that employs radar. It looks atfeatures on land and on oceans using radiowaves. Bats use a similar system of emittinghigh-pitched sounds and interpreting thereflections off obstacles or food sources.

In addition to floods, RADARSAT helps invarious large-scale emergencies, such asearthquakes, mudslides, ice storms, ice jams,and oil spills on the ocean.

(c) How might RADARSAT help in your localarea?

Many industries benefit from RADARSATimages. Many resources, such as oil, naturalgas, water, and minerals are foundunderground. Often the surface features onthe ground help scientists predict where theseresources are. These surface features aremuch easier to find using satellite images.Images also let us monitor crop conditions,forests, soil humidity, river flows, fish stocks,and shipping conditions.

RADARSAT

16.416.4 Case Study

Figure 1

This radar image of part of Manitoba has been computerenhanced, so different features show up as different colours.The red line shows the normal course of the river. The bluearea shows the area under floodwaters in 1997.

Understanding Concepts1. Why can we see human-made objects in the

night sky?2. If you observe two satellites in the sky and

they take different times to travel all the wayacross the sky, what can you judge about themotion or path of the satellites? Explain.

3. Do you think you would be able to seegeosynchronous satellites in the sky? Explain.

4. Write a short report for the studentnewspaper, describing what satellites orother artificial objects can be seen at whattimes. Include appropriate safety precautions.

Exploring5. Find out why people in Canada are unable to

see the Hubble Space Telescope in the sky,yet people in the southern United States can.Share what you discover with your class.

Reflecting6. Describe features of the software or Internet

site you used that (a) you liked and (b) youthink could be improved.

Have you ever looked up into the sky on aclear evening just after sunset and seen abright object slowly drifting across the sky? Itcould have been a satellite, a space shuttle, orperhaps even the International Space Station. Inthis activity, you will perform research to findout when satellites and other objects might beseen, then you can try to observe them andtrack their paths.

Materials• access to the Internet or appropriate software• copy of seasonal star map (or a planisphere)• observation sheets• binoculars (optional)

Procedure

Research which large satellites (or otherhuman-made objects) will be passing overyour region in the next few weeks.Interpret the maps showing the satellites’paths (Figure 1).

(a) Describe what you have learned aboutpredicting where and when to see ahuman-made object in the sky.

On your star map, trace the paths of twoor more objects that may soon be visibleon a clear evening. Label when the objectsmight be seen at various parts of the path.(Be sure to correct to local time if yourresources use standard time.)

Choose a time to view the sky. Rememberthat just after sunset the sky will be darkbut the satellite will still be in brightsunlight, and also that it will be difficult tosee a satellite near the Moon.Always obtain your parent or guardian‘s permission beforegoing out to watch the night sky. Dress appropriately.

On a clear evening, try to observe thesatellites you have researched. Binocularsmight help you view the satellite once youhave located it.

(a) Record whether or not you observedthe satellites. Give reasons.

4

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Tracking Satellites and Other Objects

16.5 Activity16.5 Activity

Figure 1

Example of a world map showing paths of satellites


150˚W 120˚W 90˚W 60˚W 30˚W 0˚ 30˚E 60˚E 90˚E 120˚E 150˚E

60˚S

30˚S

0˚

30˚N

60˚N

60˚S

30˚S

0˚

30˚N

60˚N

150˚W 120˚W 90˚W 60˚W 30˚W 0˚ 30˚E 60˚E 90˚E 120˚E 150˚E

Many people are unaware that satellites areoften visible overhead. How would you tryto increase that awareness in yourplanetarium show?

498 Chapter 16

Long before humans are able to colonize places like the Moon or Mars,we need to learn more about how the human body can survive inspace. Much of the research on living in space can be carried out inspace stations orbiting Earth. The first space station was Salyut, followedby Skylab. The first continuously occupied station, Mir, was constructedand controlled by the former Soviet Union and visited by astronautsand cosmonauts from many other countries. For many years, studies onsurviving in space, and the function of the space station itself, provideddata for scientists planning the next big space project: the InternationalSpace Station.

The International Space Station (ISS) is the biggest technologicalproject ever built by humans. It involves the cooperation of spaceagencies from Brazil, Canada, Europe, Japan, Russia, and the U.S.A.When it is complete, it will have four research modules, a servicemodule, a habitation module, remote robotic controls, a cargo block, adocking station for shuttle craft, and huge solar panels, all connectedto a central truss over 100 m long. Forty-five launches of space shuttlesand Russian boosters will carry up the more than 100 pieces—totalling4.5 × 105 kg—for construction about 450 km above Earth’s surface.

On board the station, six astronauts will live for three months at atime, performing numerous science experiments related to plants,animals, humans, materials research, crystal growth, chemicalreactions, the environment, and other areas. Many of theseexperiments depend on the constant free fall (microgravity) conditionsof the space station. The astronauts will also retrieve and repairsatellites. This research could lead to better medicines, better crops,and better liquid fuels.

An artist’s impression of the ISS is shownon page 486.

Canada’s Contribution to theInternational Space Station

Canada’s space exploration activities fallunder the control of the Canadian SpaceAgency (CSA). The National ResearchCouncil of Canada (NRC) is also involved inthe development of technology for use inspace. Canada, with its reputation for buildingsophisticated robots (Figure 1) as well asvisual systems used on the ground and inspace, is an important contributor to the ISS.Figure 2 describes the robotic and visualsystems designed, built, and maintained byCanadians.

The International Space Station

16.616.6

Did You Know

The Canadianastronaut program,

part of the CSA, holdsrecruiting drives everyfew years, searching forapplicants with the rightaptitude andqualifications. Thesequalifications includescientific studies inmedicine, physics, orengineering.

Manual Dexterity

While working outside the ISS, astronautshave to wear bulky space suits to protectthem from the cold, the vacuum of space,and the Sun’s radiation. At the same time,they have to perform delicate procedureswith extremely sensitive equipment. Toget an idea of the challenge faced byastronauts, try the following tasks whilewearing bulky or heavy gloves:• tighten a nut on a bolt• operate a VCR• use tweezers to pick up a feather


Understanding Concepts1. Describe uses of space stations.

2. What areas of expertise doCanadians bring to theInternational Space Station?

Making Connections3. Assume you have to design a

robot to turn the pages of a book.What features would you use inyour design? Start by breakingdown the task into its componentparts.

Exploring4. To learn why Canada has a good

reputation in the robotics industry,find out more about theCanadarm used on spaceshuttles. Identify the role of theNational Research Council ofCanada in its development. Makea visual presentation of what youdiscover.

5. Find out about robotic uses inspace other than thosementioned in this section. Make alist of the uses you discover. In agroup, create a mural thatillustrates past accomplishmentsof and future expectations forrobots in space.

6. The Russian space station, Mir,experienced many technicaldifficulties in the 1990s,sometimes threatening the livesof the crew. Research theseproblems and how they weresolved.

Figure 2

• Space Station Remote ManipulatorSystem (SSRMS): This “spacearm” is used to assemble the ISS.After helping in the construction, itwill assist in moving cargo intoand out of the station, dockingvisiting shuttles, sending satellitesout from the station and retrievingthem, and assisting astronautsworking outside the station. This device is controlled by anastronaut inside the station andcan manipulate masses up to 100 000 kg!

• Mobile Remote Servicer BaseSystem (MBS): This is a slidingplatform on the ISS’s main framethat moves the space arm.

• Special Purpose DextrousManipulators (SPDM): These aretwo “space hands” used tomanipulate tools and other objectsin space and conduct repairs.

• Canadian Space Vision System(SVS): Small cameras are used tolocate objects near the ISS andallow astronauts using virtualreality headsets to operate therobotic controls from inside thestation.

• Ground-Based Vision Systems:These virtual reality systems areused for testing robotic devicesand training astronauts inpreparation for their mission.

Robotics

Canadian Space

Technology

Vision Systems

Research SkillsSKILLS HANDBOOK: 3A

3A

Which experiments on theISS will be necessary to knowhow to survive on a spacecolony? How would yousimplify an understanding ofthe significance of Canada’srole in space technology for ayounger audience?

Figure 1

The Canadarm is the mostfamous of Canada’s spacerobots.

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Dr. Valeri Polyakov has spent a total of 22 months in space. He alsoholds the record for the most consecutive time in space: 14 months! He was a cosmonaut aboard the Mir space station, the first spacecraftdesigned to keep people in orbit for extended periods of time. Thefirst module was launched in 1986, and several other components havebeen added since. It has housed between two and six cosmonauts andastronauts at a time, including Canadian Chris Hadfield, all of whomare transported to and from Mir by space shuttles. Several of the crewhave remained in Mir for over a year.

Imagine that you are one of Canada’s astronauts about to be takenin the space shuttle to the International Space Station. You are a payloadspecialist: an expert on the scientific research you will be doing.Another job you have is to replace the fuel tank and replace a damagedpart of a Canadian communications satellite.

As the shuttle blasts off from the launch pad, the sound istremendous, and you are pushed back in your seat with a force thatmakes you feel three times as heavy asnormal. Within two minutes, you feel a joltas the solid rocket boosters separate fromthe shuttle. About six minutes later, you feelanother jolt as the main fuel tank separates.The force pushing you back eases off, andyou feel as if you are floating; only the seatbelt keeps you in your seat.

Floating in Space: A Result ofFree Fall

Often people and objects in orbitingspacecraft appear to be floating (Figure 1).In an effort to explain this effect, the terms“zero gravity” or “microgravity” aresometimes used. These expressions aremisleading: there is plenty of gravity actingon the spacecraft and everything in it. TheISS, for example, operates at 450 km abovethe ground. At that altitude, the pull ofEarth’s gravity is almost 90% of what itwould be on the ground, which is far fromzero! In fact, without the force of gravitypulling on it, the ISS could not orbit Earthat all. For a spacecraft to follow Earth’scurvature, the downward motion caused bygravity is essential. The floating occursbecause the spacecraft and its contents are

Humans in Space

16.716.7

Did You Know

In 1997 there was anaccident on Mir. The

space station collidedwith a spacecraftattempting manualdocking, puncturing partof the station. Fortunately,the crew was able to takeemergency measures,contain the leak, assessthe damage, and stabilizeMir.

Figure 1

Canadian astronaut Chris Hadfield appears to be floating. What isreally happening to create this effect?


continuously falling toward Earth at the same time as they are speedingforward almost fast enough to shoot out into space. This continuousfalling is called free fall. The result ofcontinuous free fall is that thespacecraft and everything in it remainbalanced in orbit (Figure 2).

Sometimes the expression“weightless” is used to describe theeffect of constant free fall. Weight is theforce of gravity acting on an object.When an Earthbound object feelsheavy, it is because your muscles mustexert a large upward force to overcomethe downward pull of gravity, whether itis yourself or some other object you aremoving. Although the force of gravitypulls you down, your awareness ofgravity comes mainly from the upwardforces you must exert to oppose it. Inan orbiting spacecraft, the craft andeverything in it are continuously fallingat the same rate, so the astronaut doesnot have to exert an upward force tohold onto anything in the spacecraft.Thus, astronauts feel as if there is nogravity; they feel weightless. However, asthere is gravity, “weightless” is a poorexpression to use.

Living on the ISS

After the shuttle docks with the ISS, you enter the station and aregreeted by other crew memberswho have been there for threemonths. With them, you eat yourfirst space meal, part of which isprepared by adding water to a dry,crumbly mixture in a plastic pouch(Figure 3). The other part of themeal consists of fresh vegetablesgrown on the station as anexperiment to help absorb carbondioxide from the air and provideoxygen for the crew. Water, bothhot and cold, is available as abyproduct of the fuel cells thatproduce some of the energy aboard the station.

Figure 2

This diagram illustrates constant free fall. Imagine six steel balls thatleave a tall tower. Ball A falls straight down while balls B to F get shotoutward. Only ball E has the right speed to travel in an orbit around Earth.It follows a curved path just like the spacecraft G, in which astronauts andobjects fall together toward Earth as they travel forward at great speed.

Figure 3

Food in sealed plastic bags is heated ina food warmer.

G

A

BC

D E

F

too fast: Earth's gravity is not strong enough to

keep it in orbit, so it escapes

just fast enough to travel in orbit

as it falls continuously

toward Earth

too slow to travel around Earth

just fast enough to travel in orbit

as it falls continuously

toward Earth

falls straightdown

too fast: Earth’s gravity is not strong enough to

keep it in orbit, so it escapes

falls straightdown

too slow to travel around Earth

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You do your share of work to help keep the station clean. Sanitationis important in space because microorganisms can grow rapidly inconditions of continuous free fall and an enclosed system like aspacecraft. Allowed to grow unchecked, these microorganisms couldcause infections in the astronauts, so the eating equipment, diningarea, toilet, and sleeping facilities must be cleaned regularly. Garbageand worn clothing are sealed in airtight bags to be returned to Earthlater.

After doing some work at a computer terminal, you talk to yourfamily on Earth and spend a long time exercising on the speciallydesigned treadmills, cycles, and rowing equipment. You must exerciseevery day to keep your muscles and bones strong and your bloodcirculating properly. Then, after another meal and relaxation, youfasten yourself into the sleeping hammock tied to one wall.

You spend the next few days working at computers and practisingthe use of the manipulator arms. You are not allowed to leave thestation to carry out your repair tasks until you have been in space atleast three days, adapting to continuous free fall.

On the fourth day, you prepare for your first space walk byspending a few hours in a sealed area, breathing pure oxygen, sincethis is what you will be breathing in your space-walking suit. Breathingpure oxygen means that the air pressure inside your suit can be muchlower than in the ISS, which allows your joints to be much moremanoeuvrable (Figure 4)than they would be if your suit pressure washigh. Protected by the suit from the vacuum of space and from harmfulultraviolet radiation from the Sun, you go outside the station andattach yourself to the Mobile Remote Servicer Base System (MBS).Using the manipulator system, you grab the satellite that has movedclose to the station and pull it close to you. You then replace thesatellite’s used fuel tank with a fresh one and use the small manipulatorarms to replace the damaged part. After testing the satellite, you use thelarge manipulator arm to push the satellite safely away from the ISS.

Did You Know

You can calculate yourown weight by using

the equation F = mg,where F is the force ofgravity, or weight,measured in newtons (N),m is your mass inkilograms (kg), and g is agravity constant equal to9.8 N/kg on Earth’ssurface. On differentplanets g is different, soyour weight would vary!So where would you betruly weightless? Onlywhere you are so far awayfrom all large bodies thatthe gravity constant, g, iszero. In other words, wayout in space!

Artificial Gravity

How can you make “up” into “down”? Thismodel of artificial gravity will show you.

This activity should be done outdoors.

You will need a plastic bucket with astrong handle, a small rubber duck, andwater. Half fill the bucket with water. Placethe duck in the water. Swing the bucketback and forth until you are ready to swingit in a complete, vertical circle at a fairlyhigh speed. Try not to spill the water as youbring the bucket to a stop.

1. Does the water fall out of the bucketwhen it is swung quickly in a verticalloop? Explain.

2. From the duck’s point of view at the topof the loop, how important is Earth’sgravity and which way is down?

3. In what way is this activity a model for“artificial gravity”?

4. How could you apply what you havelearned in this activity to a space vehiclethat takes humans to and from Mars?


Earth-based controllers then startup the satellite’s engines to get itback into its proper orbit.

After three busy months onthe ISS, you board the shuttle foryour trip back to Earth. When theshuttle lands, you may needassistance as you step out and tryto walk under the influence ofgravity. You feel very heavy at first,but soon you get used to beingback on Earth.

Understanding Concepts1. In your own words, describe why

astronauts appear to be floatingin the ISS or a space shuttle inorbit around Earth, even thoughgravity is pulling on them.

2. Neither weightlessness normicrogravity are accurate waysto describe the conditionsexperienced by astronauts.Explain why. What is a moreaccurate term?

3. Draw a diagram to show how anastronaut who is working outsidethe ISS can use a backpackmaneuvering unit (the EMU) tomove from left to right.

4. Compare a day of living on ISSwith a day on Earth. What arethe similarities and differences?

Exploring5. Design an amusement park ride

that produces artificial gravity.

6. Research one of the followingCanadian astronauts’qualifications, background,interests, and contributions tothe space program: RobertaBondar; Marc Garneau; ChrisHadfield; Steve MacLean; JuliePayette; Robert Thirsk; BjarniTryggvason; Dave Williams.

7. Compose an application letter tojoin the CSA’s astronaut-in-training program. Indicate whyyou want to become anastronaut, what you can add tothe space program, and otherdetails.

Figure 4

Space-walking astronauts move around with the help of a backpack called anExtravehicular Maneuvering Unit (EMU). The unit contains compressed nitrogengas, which can be released through a nozzle. How does the EMU resemble theballoon rocket model or the rocket engine model in Section 16.1, Figures 4 and 5?

Did You Know

The extravehicularmaneuvering unit

(EMU) has two aluminumtanks with enoughnitrogen to last for sixhours of activity. It and theentire spacesuit must bewell insulated againsttemperature extremes,which can range from120°C down to –150°C.

Humans have designedspecial features and productsto survive in spacecraft. Whatfeatures and products do youneed to consider for thespace colony challenge?

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Have you ever been on an amusement parkride that lets you fall straight downward? If so,you were in free fall. Astronauts on spaceshuttles or the International Space Stationexperience free fall continuously.

Part 1: Weight and “Weightlessness”

QuestionWhat do the astronauts feel and why?

Hypothesis

Write a hypothesis about the relationshipbetween mass and weight of an astronautin orbit.

Materials• spring scale that measures weight in newtons (N)• a hanging mass that registers about halfway on the

spring scale• pillow

Procedure

Squat down, then jump up vertically ashigh off the floor as you can.

(a) Describe what you feel in your legmuscles(i) as your legs are pushing off the

floor;(ii) when you are in

the air;(iii) as you are

landing backon the floor.

Hang the mass onthe hook at thebase of the springscale. Determinethe apparentweight of themass (asregistered onthe springscale) when

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(i) the mass is resting on the floor;(ii) the mass is jerked gently upward;(iii) the mass is suspended in midair;(iv) the mass and spring scale are

allowed to fall freely toward apillow on the floor.

(a) Record the four readings you observed.

Repeat step 3 twice.

(a) Average your readings for the threetrials.


Analyze your observations by answeringthe following questions:

(a) When, in step 2, did(i) your weight feel normal?(ii) you feel heavier than normal?(iii) you feel lighter than normal?

(b)What are the differences between massand weight?

Relate your measurements in steps 3 and 4to the sensations you felt in step 2.

Part 2: What Affects Free Fall?

QuestionWhat factors affect how fast something fallsfrom a person’s raised hand to the floor?

Hypothesis

Write a hypothesis to answer the question.

Experimental Design

Design an experiment to test yourhypothesis.

(a) Identify the factors you will investigateand describe how you think each willaffect the motion of the falling objects.

(b)List the materials you will need.

(c) Write out your procedure. Include anyuseful diagrams.

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Gravity and Free Fall

16.8 Investigation16.8 InvestigationSKILLS MENU

Questioning Conducting AnalyzingHypothesizing Recording CommunicatingPlanning

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Designing a ProcedureSKILLS HANDBOOK: 4B

4B


Understanding Concepts1. As the ISS travels in its path around Earth, it is

always undergoing free fall. Astronauts insidethe station are also experiencing free fall. Howdoes this relate to what you observe aboutastronauts’ motion in the station?

2. Imagine you are in an elevator that is fallingfreely. You hold out a pen and let it drop. How will its motion compare with yours?

3. Under what circumstances would an astronauttruly be weightless?

Exploring4. When astronauts train, they experience free fall

by going up in a special airplane that fallstoward Earth for several seconds at a time.Sometimes the astronauts suffer from motionsickness on this airplane.

(a) Research information about this airplaneand share what you discover with the restof your class.

(b) Find out how the actors in the movie Apollo13 experienced free fall to make their flightlook authentic.

Figure 1

Fold the cardboard and place thecoins on it as shown. When youflip the launcher sideways,can you tell which coin willfall straight downwardand which will flysideways? Which coin doyou think will land first?

Procedure

Make the coin-launching apparatus.

After your teacher approves your design,conduct your investigation.Do not aim the coins at anybody. Launch them only wherethey will land safely.

(a) Record your observations.


Does the sideways motion of a fallingobject affect its downward falling? Explain.

Write a lab report describing and givingreasons for the different types of motionyou observed.

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Reporting Your Work8A

4B

Procedure

After your teacher has approved yourprocedural steps and materials list, carryout the steps.

(a) Record what you observe.


What can you conclude from yourobservations?

A 500-g ball and a 200-g ball are allowed tofall freely from the same height to thefloor. Predict how their motions compare.

A piece of paper and a marble are allowedto fall toward the floor from the sameheight. Compare the motions of the twoobjects if

(i) the paper is flat;(ii) the paper is crumpled into a ball.

Part 3: Falling While Moving in a Path

QuestionWhat effect does horizontal motion have onthe “falling time” of an object?

Hypothesis

Write a hypothesis and predict what willhappen when you launch one coinhorizontally, compared with what willhappen when you allow a coin to fall freelydownward.

Materials• coin-launching apparatus (shown in Figure 1)• 2 coins

Experimental Design

Design an experiment that uses a coin-launching apparatus to test yourhypothesis.

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8A

What is “artificial gravity” and how might itbe applied for long-term space flights? Whatconsiderations related to gravity do you haveto consider for Challenge 2?

Understanding Concepts1. What is meant by the term “spinoff”?

2. Which spinoffs listed in this section are mostlikely linked to Canada’s contribution to spacescience and technology?

Making Connections3. List some space spinoffs that are now part of

your daily life, both at school and at home.

4. What can we learn in space that wouldbenefit the elderly?

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How do the hard plastics used for in-lineskates, safety helmets, and many otherproducts, relate to space technology? Hardplastics were first designed by the spaceprogram to fulfill a specific need, thenapplied to the products we use (Figure 1).This is just one of many examples of aspinoff—an extra benefit from technologyoriginally developed for another purpose.

How important will space science be in the21st century? People who oppose spending onspace missions argue that the money would bebetter spent cleaning up the environment andreducing poverty on Earth. People whopromote space exploration argue that themoney spent on space missions is only a smallportion (under 2%) of any nation’s budget.Furthermore, they point out, society benefitsfrom space exploration (Table 1).

Procedure

Choose a recently developed product, andresearch how its development began withthe space program (see Table 1 forexamples).

Design a poster or give an oral presentationtracking your product’s research anddevelopment, evaluating the product, andgiving your opinion on whether to invest inthe spinoff.

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Spinoffs from the Space Industry

16.9 Activity16.9 Activity

Table 1 Types and Examples of SpinoffsArea of Research Examples

microelectronics digital watches, home computers, pacemakers, hand-held calculators

new materials nylon strips used to fasten clothing and objects, nonstick coating, flame-resistant materials (Figure 2)

metal alloys dental braces

hard plastics safety helmets, in-line skates

robotics mining, industry, and offshore oilexploration where the conditions are too dangerous or the tasks too precise or repetitive for humans

vehicle controllers controller for those with disabilities

safety devices smoke detectors

recycling processes water recycling

energy storage solar cells, chemical batteries

food freeze-dried convenience foods

pharmaceutics antinausea medication to overcome the effects of motion sickness or the side effects of other drugs

pump therapy method to provide insulin continuously to diabetes patients

scanning medical scanning using imaging techniques developed for satellites

space vision satellite data applied to improving the technology efficiency of agricultural spraying

lasers improved laser surgery

Figure 1 Figure 2


A myn Samji is not your typicalengineer, but he was the one onNASA’s graveyard shift monitoring

Canada’s famous robot, the Canadarm. Hehad to help remedy the problem oficicle growth on the shuttle.

“It’s a long way from Overlea Secondary School to sitting at aconsole at NASA’s Johnson Space Centre,” he quietly muses.

Amyn Samji was born in Tanzania, Africa and came toToronto with his family when he was eight years old. At first hestruggled with mathematics, but things changed in high school.“I began to understand relationships and patterns.” He joinedthe mathematics club and a special geometry class.

At the University of Waterloo, Samji took a co-op course inApplied Mathematics and Engineering, followed by a Mastersdegree in Aerospace Science at the University of TorontoInstitute for Aerospace Studies.

Samji’s research on robots began when he joined Spar Aerospace,developing computer models for the assembly of International SpaceStation (ISS). Spar engineers were developing the Space Station RemoteManipulator System (SSRMS). Samji developedcomputer simulations to show how astronauts wouldexchange parts of the SSRMS.

Later, at NASA’s Johnson Space Center, Samjiassumed flight support duties, monitoring theCanadarm during missions and solving operationproblems. “At 4:00 a.m. on one shift the SSRMSbreak slip (alarm) went off during a thruster firing.NASA was trying to shake loose an icicle on theorbiter. It was tense. We solved it. It was O.K.,” hesmiles.

Samji then became the manager of the MobileServicing System (MSS) program, Canada’s proudcontribution to the International Space Station.

Exploring

1. If you were designing a space robot, how wouldyou deal with the harsh conditions it wouldencounter in outer space?

2. Identify several important characteristics thatmake a successful project manager.

3. Research post-secondary institutions in your areaproviding programs that could lead to a careerin the space field.

Aerospace Engineer

”“Becoming a team player, learningto solve problems, and workinghard are important to success in

the space business.

Career ProfileCareer Profile

508 Chapter 16

Human health is an important issue. The study of human health inspace—space medicine—is not only fascinating, it is also a great benefitbecause it helps us learn more about human health on Earth.

Three of Canada’s astronauts, Roberta Bondar, Robert Thirsk, andDave Williams, are medical doctors working in the field of spacemedicine. Dr. Williams is director of NASA’s Spaceand Life Sciences program.

Space Sickness

An immediate and annoying problem for ahuman body in orbit is space sickness, a typeof motion sickness. During constant free fall,signals from the eyes, skin, joints, muscles,and the balance organs get rearranged. Theconflicting clues lead to signs and symptomsof space sickness, such as dizziness, nausea,and vomiting. Figure 1 explains how thebalance organ, located in the inner ear,functions.

Space Medicine

16.1016.10

Your Sense of Balance

Here are two simple activities you can useto test your sense of balance. How doesyour sense of balance compare with that ofother students?

1. Stand on one leg with your eyes open.Then close both eyes and try tomaintain your balance.

2. Stand on one leg facing a striped sheetor blanket held by two students. Try tomaintain your balance as the blanket ismoved sideways, as shown in Figure 2.Have two spotters nearby in case you lose your balance.

Figure 1

The drawing shows the structure of the inner ear of a human.The three fluid-filled tubes, called the semicircular canals, areresponsible for balance. The fluid moves when the headmoves: side to side, spinning around, or up and down.

Figure 2

The moving stripes may fool your brain intothinking that you are moving, so your musclescompensate, and you fall over!


Other Effects of Space Flight

Imagine you have had a full-length cast on one leg forthree months. The broken bones have healed, and yourdoctor removes the cast. But your leg still doesn’t worknormally: although the bones have healed, the muscleshave weakened and shrunk from lack of use. It willprobably take weeks or even months for you to regain thenormal use of your muscles.

Similar problems occur when astronauts are inconstant free fall while orbiting Earth. On Earth, yourawareness of gravity comes mainly from the upward forcesneeded to oppose it. But in free fall, astronauts are notaware of this gravitational pull. They feel weightless, justlike the hanging mass that fell with the scale inInvestigation 16.8. The lack of forces against the bodycauses the muscles to become smaller and the bones tolose calcium and become brittle. It seems as though thenormal aging process is vastly speeded up. This processcan be slowed with a vigorous exercise program during thespace flight, but it is not yet known whether this processcan be stopped entirely. The data collected during spacemissions is used in research into the normal aging process.Scientists would like to reduce the deterioration thatoccurs during both processes.

Another possibly dangerous side effect of space travelinvolves body fluids. Because of constant free fall, abouttwo extra litres of blood remain in the upper half of thebody, swelling the heart and the blood vessels and makingthe astronauts’ faces look puffy and their legs look thinner.More importantly, this condition alters the fluid balance ofthe body and, in turn, affects the kidneys and causesexcess urination. Much is yet to belearned about long-term effects,and research is ongoing.

Astronauts are also exposed tomore cosmic radiation on a singletrip than they would experience inseveral years on Earth. We do notyet know whether this exposure isharmful because any effects mightnot show up for several years.Thus, scientists continue to checkthe health of space travellerscarefully. Space medicine is still ayoung science, and much remainsto be learned about the effects ofspace travel on the human body.

Understanding Concepts1. Describe the effects of constant

free fall on the human body. Whydo these effects occur?

2. Astronauts must spend a longtime exercising each day. Why?

Making Connections3. How do you think an exercise

program in space might be appliedto design an exercise program forseniors on Earth?

4. Choose one of the healthproblems described. How doesthe research related to it affectthe lives of other people notinvolved in space flight?

Exploring5. Research the invention of the

antigravity suit by Canadian,Dr. W. R. Franks in 1940. Writeyour own short story about it.

6. Make up an exercise program forastronauts either while aboard theISS or when they return to Earth.

Did You Know

When 77-year-oldJohn Glenn went

on a space shuttle flight in1998 to performexperiments on aging,some of the experimentswere designed byCanadian scientists. Onestudy related toosteoporosis, a conditionof the bones. This wasGlenn’s second spaceflight: in 1962 he was thefirst American to orbitEarth.

Check the NASA web site toobtain more information aboutNASA’s Space and Life Scienceprogram. Which contributionshave Canadians made to thisprogram?

510 Chapter 16

experiment that will prove useful either tofuture space flight or to life here on Earth.

(a) Write out the question yourexperiment will attempt to answer.

Hypothesis

Write a hypothesis to answer the question.

Predict what results you would expectfrom your experiment.

(a) Write out your prediction, includingthe controlled and dependent variables.

Experimental Design

Design a controlled experiment to answeryour question. List the materials needed,the procedural steps, and any safetyconsiderations. Also mention how youwould analyze the results.

(a) Write out your experimental designand have it approved by your teacher.

Procedure

Conduct your experiment.


Create a proposal that would persuade aspace agency to conduct your experiment,then submit your proposal.

How does performing experiments inspace differ from performing experimentson Earth?

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Making Connections1. How do you think your proposed experiment

could benefit people or things on Earth?

Exploring2. Write a short letter, including a relevant

question, to a Canadian astronaut on the ISS.

Did you know that you are slightly taller whenyou get up in the morning than when you goto bed? In the daytime, when you are upright,the force of gravity pulls on your spinalcolumn, causing it to crush together. Whenyou are lying down, this crushing is reduced,so the bones spread apart a bit.

This same thing happens to astronauts inconstant free fall: they become severalcentimetres taller. What is more, their boneslose mass, and their muscles weaken becausethey don’t have to work against gravity. Manyof their experiments involve finding out whathappens to human bodies in space and why.Knowing the answers will help future spaceexploration as well as the treatment of agingproblems on Earth.

In this investigation, you will design anexperiment suitable for astronauts to performon the ISS or for the Canadian Space Agency(CSA) to send on a space probe mission.

Question

Choose one area of research from Table 1that interests you. Plan how you will findout more about that area.

Find the information, then choose onetopic on which you will base an

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Experimenting in Free-Fall Conditions

16.11 Investigation16.11 Investigation

Table 1 Canada’s Specialties in Space ScienceArea of Research Examples of Topics Researched

Space Life bone and muscle loss, neurobiology, early Sciences development, radiation, heart and circulation

system research

Science in crystals, including protein crystals, metals Constant Free research, fluids research, materials for Fall semi-conductors and fibre optics

Atmospheric global warming, Arctic-region research, ozoneSciences depletion, middle/upper atmosphere science

Space research using various parts of the Astronomy electromagnetic spectrum

Solar-Terrestrial Earth’s ionosphere and magnetosphere, theRelations ionosphere on Mars, solar wind, space

plasma, aurora research

SKILLS MENUQuestioning Conducting AnalyzingHypothesizing Recording CommunicatingPlanning

Our Future in Space

16.1216.12 Explore an Issue


If space stations are successful, the next stagesof space travel may be exploration of Earth’sMoon, and the planet Mars and its smallmoons, Phobos and Deimos. These objectscould be mined and the materials used tobuild structures in space. Eventually, humancolonies may be established on the Moon andon Mars.

Many problems must be overcome beforewe can travel to, and live on, Mars. One of thebiggest problems is the reaction of the humanbody to constant free fall. To reduce theeffects on long space trips, a feature of anypiloted trip to Mars will probably be artificialgravity, created by rotating the spacecraft(Figure 1). Once on Mars, the astronauts willfind a gravitational force only 38% of that onEarth. This may also cause problems for thehuman body over long periods of time.

Visitors to Mars will require water, food,oxygen, and warm shelter. Oxygen and smallamounts of water could be extracted from thelow-density atmosphere, which consists mostlyof carbon dioxide. Water could also beextracted from the permafrost on Mars andfrom the recycling of plant and human wastes.Large greenhouses could be used to growfruits and vegetables. Even though Mars isfarther from the Sun than Earth is, the Sun’sradiation is far more harmful there becausethe atmosphere on Mars has no ozone tooffer protection. As a result, living quarterswould have to be buried beneath the Martiansoil to protect humans from harmful solarradiation.

Some scientists predict that by the timehumans have settled on Mars, we will havepropulsion systems powerful enough to allowspacecraft to reach extremely high speeds.Perhaps such a craft, if unpiloted, would besent to explore neighbouring stars in ourgalaxy.

Figure 1

Artist’s concept of a spacecraft travelling to Mars

People in favour of space explorationgive many good reasons why it willbenefit the human race. People opposingspace exploration feel strongly that thereare drawbacks that outweigh the benefits.Working in a group, choose either asupporting or an opposing position onspace exploration.• Brainstorm a list of reasons that

support your group’s viewpoint.Consider economics, ethics,environmental issues, politics, andavailable technology as you brainstorm.

• Discuss these as a group and carry outfurther research where necessary.

• Prepare a 5-min presentation, puttingforth your position.

Space Exploration

Working TogetherSKILLS HANDBOOK: 9C

9C

What situations should you consider forsustained survival when designing a spacecolony?

Chapter 16 ReviewChapter 16 Review

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Key ExpectationsThroughout the chapter, you have hadopportunities to do the following things:

• Describe and explain the effects of continuousfree fall (microgravity) on organisms and othercontents of orbiting spacecraft. (16.8, 16.9,16.11, 16.12)

• Investigate questions related to sendingsatellites and humans into space, and organize,record, analyze, and communicate results.(16.2, 16.4, 16.6, 16.7, 16.9, 16.10, 16.12)

• Formulate and research questions related tospace exploration, and communicate results.(all sections)

• Describe, evaluate, and communicate theimpact of research and achievements in spaceon other fields of endeavour. (16.3, 16.4, 16.5,16.9, 16.10, 16.11, 16.12)

• Identify the purpose and accomplishments ofspace initiatives such as satellites, space probes,and the International Space Station. (16.1, 16.3,16.4, 16.5, 16.6, 16.7, 16.13)

• Investigate and provide examples of ways inwhich Canada participates in space researchand international space programs. (16.3, 16.5,16.7, 16.11)

• Explore careers related to space exploration.(Career Profile)

KEY TERMS

aircraft outer spacefree fall (microgravity) radargeosynchronous orbit remote sensingGlobal Positioning System space probeInternational Space Station spacecraftlauncher spinofflow Earth orbit thrustpayload weight

Understanding Concepts1. Make a concept map to summarize the

material that you have studied in this chapter.Start with the words “space exploration.”

2. What are the purposes of space stations?

3. During blast-off, an astronaut feels heavierthan usual; later, lighter than usual. Explainwhy.

4. What is “artificial gravity”? How might it becreated on a spacecraft?

5. List benefits of studying space medicine.

6. Classify each of the following vehicles as Earth-based, atmosphere-based, low Earth orbit, orgeosynchronous orbit: the International SpaceStation ; a space shuttle; a helicopter; a sailboat;a TV satellite; a remote-sensing satellite.

7. State the purpose or function of: remotesensing satellites, RADARSAT, GPS satellites,and an orbiting observatory.

8. Compare an aircraft engine and a rocketengine, explaining why an aircraft cannot flyin space.

9. Describe situations in which you haveexperienced free fall.

10. Why are robotics and vision systems importanton the International Space Station?

11. What would happen to a spacecraft in orbitaround Earth if its speed becomes too slow?Explain.

Reflecting• “Space exploration and the related technology

contribute to our understanding of Earth and the

universe and provide many useful applications for life

on Earth.” Reflect on this idea. How does it connect

with what you’ve done in this chapter? (To review,

check the sections indicated above.)

• Revise your answers to the questions raised in

Getting Started. How has your thinking changed?

• What new questions do you have? How will you

answer them?


12. Can a human be a payload? Explain youranswer.

13. Which electromagnetic waves, infrared orradar, would be better for viewing the heightsof mountains and craters on the moons ofplanets? Why?

14. Why are remote sensing satellites that useradar not used to predict daily weatherpatterns?

15. (a) Why is the expression “zero gravity”misleading for an astronaut inside aspacecraft in an Earth orbit?

(b) Under what condition(s) would theexpression “zero gravity” not bemisleading?

16. During the last few days, identify ways you havebenefited from space exploration. (Includeboth direct benefits and spinoffs.)

17. If you were standing on your head, your blooddistribution would change. Relate this changeto what an astronaut experiences in orbitaround Earth.

18. At the same instant, one car drives horizontallyoff a cliff at a high speed and another fallsstraight down.(a) Compare the times the cars take to land.(b) Relate your answer to space vehicles that

travel around Earth.

19. A sports event takes place in Australia, and atalmost the same time you are able to watchthat event on television. Describe how thisform of telecommunication works.

20. Space probes are sent to explore asteroids andcomets. How does this exploration help in thestudy of the origin of the solar system?

21. Why are we more protected from the Sun’sharmful radiation on Earth than astronautsare in space?

22. The air pressure in an ISS suit is less thanatmospheric pressure. Find out why, and whatadvantages and disadvantages this brings.

Applying Skills23. If a satellite takes 90 min to travel once

around the world, for about how long will it bein view, each orbit? Show your calculations.

24. Describe what conditions would allow you toobserve a satellite or the ISS travelling across

the sky. Draw a diagram to illustrate youranswer.

25. Find the results of a Canadian researchproject, involving students growing seeds thathad been in space.

26. Select a career in the field of astronomy orspace science, and find out what aptitudes andqualifications you would need to enter thiscareer. If possible, interview someone in thiscareer and prepare an audio report on theperson’s professional life.

27. Write a short science fiction story about spaceexploration using as many of the key terms asyou can.

28. Describe what steps you would take to discoverwhat fuels are used to launch a space shuttle.

29. Describe how to access information on theInternet about RADARSAT.

30. Assume you are an astronaut on the Mooncarrying out an investigation to determine thefactors affecting how fast objects fall. Describe indetail the steps you would take. Show that youunderstand what a controlled experiment is.

31. Draw a graph to predict how the speed of aballoon (vertical axis) depends on the airpressure inside the balloon.

Making Connections32. Create a chart of Canadian contributions to

the study of the universe, giving theCanadians’ names and outlining their work.

33. List two or three careers in the space industrythat require a background in (a) engineeringand (b) technical studies.

34. Choose five interesting space spinoffs and foreach, name at least one possible careerassociated with it.

35. To find out more about how the human bodyreacts in space, investigate Dr. Dave Williams’research on flight STS-90.

36. Defend or oppose one of the followingstatements:(a) Space exploration benefits the human

race.(b) Money spent on space exploration would

be better spent cleaning up the globalenvironment.

ChallengeChallenge

514 Unit 4

Scientists and technologists share ideas in many ways. They may designsimulations to understand concepts and to predict future events. Theymay develop technologies that improve our lives or that can be used tomake further scientific investigation possible. They may conductresearch and record and communicate what they discover. You canchoose one of these approaches in the challenges described below:

Planetarium Shows

A planetarium is a structure in which people canlearn more about astronomy. The night sky issimulated using a projection of points of lightrepresenting stars and other objects onto theinside of a dome. By moving the projector, theappearance of the night sky at any time and anydate can be represented. Planetariums usuallyoffer a variety of shows designed for differentpurposes and audiences.

Your job is to design and prepare three shows that could be used ina planetarium. One show should be designed to teach grade 6 studentsabout the solar system. The other two shows should be designed forthe general public. You must include a script for each show and beprepared to present one of them.

Your simulations should include:• models or other representations of year-round constellations,

seasonal constellations, planets, comets, and other natural objectsdiscussed in this unit

• representations of human-made objectssuch as satellites and space probes

• a model that demonstrates the motionsof as many of the objects as possible

• design features that take intoconsideration the size, construction,and layout of a large planetarium

A Space Research Colony

You are part of a company that hasdesigned a colony that would conductresearch in outer space. The company ispreparing to display its plans at theInternational Space Conference, in thehope of attracting investors for the project.

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Bringing Your Ideas Together

Design and create a display depicting a sustainablespace research colony suitable for permanent humanhabitation.

Your display should include:• a representation of the destination of your choice in

outer space• a demonstration of how the colony will be adapted to

the environment of the destination chosen• a plan that outlines how colonists will achieve self-

sufficiency in both the short and long terms• evidence of how knowledge gained from existing space

explorations and space technology will be used• proposals for the type of research that would be best

suited for the destination you chose• models and diagrams of relevant components

A Space Technology Information Package

Vast amounts of money are spent on technology related tospace exploration. The merits of this expenditure arefrequently debated in public. Your company has beencommissioned by the Canadian Space Agency to developan information package about the usefulness of spacetechnology. You are to demonstrate how the use of spacetechnology contributes to our understanding of theuniverse and how applications of that technology benefitus in our everyday lives. The package is designed fordistribution to the general public.

Design an information package that outlines thediverse tools used both in space exploration and the studyof astronomy and the influence they have had on our lives.

Your information package should include:• an organizational tool for accessing the information• examples of the uses of space technology• links to Canada’s role in the development of space

technology• illustrations of what we have

learned about the universeusing the technology

• examples ofapplications of thetechnology thatpositively affectour daily lives

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Space 515

Your completed challenge willbe assessed according to howwell you:

Process• understand the specific

challenge

• develop a plan

• choose and safely useappropriate tools,equipment, and materialswhen necessary

• conduct the plan applyingtechnical skills andprocedures when necessary

• analyze the results

Communication• prepare an appropriate

presentation of the task

• use correct terms, symbols,and SI units

• incorporate informationtechnology

Product• meet established criteria

• show understanding ofconcepts, principles, laws, and theories

• show effective use of materials

• address the identifiedsituation/problem

Unit 4 ReviewUnit 4 Review

516 Unit 4

Understanding Concepts1. In your notebook, write the letters (a) to (k),

then indicate the word(s) needed to completeeach statement below.(a) The _______ is everything that exists,

including all the matter and energyeverywhere.

(b) The four planets closest to the Sun can becalled the _______ planets or the _______planets.

(c) _______ was the first scientist to use atelescope to obtain evidence that starswere much farther away than planets.

(d) The _______ is a broad band of energiesthat can travel in a vacuum.

(e) The process used by stars to produceenergy is called _______ .

(f) Stars start and end their lives as clouds ofdust and gas called _______ .

(g) _______ is the force of attraction betweenall objects that have mass.

(h) A payload is to a _______ as an arrow is toa _______ .

(i) A satellite in _______ orbit appears toremain stationary when viewed from Earth.

(j) _______ is the force of gravity acting on anobject. In the metric system its unit is the_______ .

(k) A _______ is a benefit that comes fromspace science and technology research.

2. Indicate whether each of statements (a) to (o)is TRUE or FALSE. If you think the statementis FALSE, rewrite it to make it true.(a) Our Sun is the only star that has planets

orbiting around it.(b) An object that is 30 astronomical units

from the Sun could be either a gas giant ora comet.

(c) The light-year is a unit of time.(d) A comet’s tail is visible only when the

comet’s path is close to the Sun.(e) When using triangles to measure distances

to objects in the sky, the longest baselinepossible to observers on Earth is Earth’sdiameter at the equator.

(f) The speed of electromagnetic waves in avacuum is 3 × 105 km/s.

(g) Auroras are caused by light pollution.(h) Most stars are bigger than the Sun.(i) The Sun is in the galaxy called the Milky

Way.(j) In the lives of stars, a red supergiant results

from stars that have a smaller mass thanthe Sun.

(k) Both stars and planets form from nebulas.(l) Evidence of an expanding universe comes

from red shift of the spectra of stars andgalaxies.

(m) Space probes have been sent to explorestars nearest to the solar system in ourgalaxy.

(n) RADARSAT uses waves that belong to theinvisible part of the electromagneticspectrum.

(o) The problems of increased body lengthand harmful radiation disappear afterastronauts have been in orbit for a week ormore.

3. Describe the similarities and/or differencesbetween each pair of objects listed below:(a) star constellation; star cluster(b) Earth’s rotation; Earth’s revolution(c) asteroid; comet(d) galaxy; star cluster(e) interplanetary distance; intergalactic

distance(f) solar flare; solar prominence(g) apparent magnitude; absolute magnitude(h) neutron star; black hole(i) aircraft; spacecraft(j) vacuum; atmosphere(k) natural satellite; artificial satellite(l) space shuttle; space station(m) geosynchronous orbit; low Earth orbit

For Questions 4 to 10, choose the best answer andwrite the full statement in your notebook.

4. Pointer stars:(a) can be used to locate planets in the night

sky

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Space 517

(b) are found only in the year-roundconstellations

(c) can be used to locate constellations andother stars

(d) appear to be pointed(e) all of the above

5. Compared with the terrestrial planets, the gasgiants tend to:(a) be hotter, rotate faster, and have a lower

density(b) be colder, rotate faster, and have a lower

density(c) be colder, rotate slower, and have a lower

density(d) be colder, rotate slower, and have a higher

density(e) be hotter, rotate faster, and have a higher

density

6. Which does not belong in this list?(a) radio waves(b) visible light(c) X rays(d) sound waves(e) infrared radiation

7. The order of stars from coolest to hottest is(a) blue, yellow, red(b) red, blue, yellow(c) yellow, red, blue (d) blue, red, yellow(e) red, yellow, blue

8. A possible order of events in the evolution ofstars is(a) nebula, energy produced through fusion,

core collapse(b) core collapse, energy produced through

fusion, nebula(c) nebula, core collapse, energy produced

through fusion(d) energy produced through fusion, core

collapse, nebula(e) energy produced through fusion, nebula,

core collapse

9. The force caused by expanding gases leaving arocket engine is called(a) chemical energy(b) gravity

(c) thrust(d) friction(e) air resistance

10. The best explanation of why orbitingastronauts appear to be floating is that theyare experiencing(a) microgravity(b) weightlessness(c) no gravity(d) continuous free fall(e) none of the above

11. Which planets are the most likely targets forexploring by robotic rovers in the near future?Give reasons for your choices.

12. Some planets cannot be explored by roboticrovers. What ways can be used to study theseplanets at close range?

13. Which planets tend to have the greatestnumber of moons? Explain why this situationoccurred as the solar system developed.

14. (a) What are sunspots?(b) How can they be safely observed?(c) What evidence do they provide of the

Sun’s rotation?

15. Stars move at great speeds. Why did peoplelong ago believe that stars were fixed in place?

16. Can two stars with the same luminosity havedifferent apparent magnitudes? Explain.

17. How are the temperatures and colours of starsrelated? Give examples.

18. Which types of stars tend to becomesupernovas? What happens after that stage?

19. The inner planets and gas giants formed atabout the same time. Which stages of theirformation were similar, and which weredifferent? Explain why there was a difference.

20. According to the present theory, what are themain stages of the evolution of the universe?

21. What happens to low Earth orbit satellites iftheir orbits become too low? Why?

22. (a) Describe the conditions needed for you tofeel you are weightless for a short periodof time.

(b) Relate your answer in (a) to whatastronauts experience in orbitingspacecraft.

518 Unit 4

23. (a) As you observe the night sky in theNorthern Hemisphere, which star appearsnot to move?

(b) Why does it appear not to move?(c) How long do constellations take to appear

to travel once around that star?

24. You are conducting an investigation tocompare the motions of planets andconstellations seen in the night sky.(a) How would the motions compare if you

made observations three hours apart?(b) How would the motions compare if you

made observations three weeks apart?(c) Explain the difference between

observations (a) and (b) above.

25. What is the Hubble Deep Field? Why is itimportant?

26. If you see two stars through a telescope andone looks bluish, the other yellowish, what canyou say about the difference between the stars?

27. What is the relationship between the speed ofa satellite and the height of its orbit?

Applying Skills28. In observing the night sky, it is important to

judge the differences between stars andplanets. Describe the main ways you havelearned to distinguish stars and planets.

29. A student records these observations in a logbook: “The constellation was 3 fists to the rightof south, and 4 fists up from the horizon.”Describe what these observations mean.

30. A certain comet, visible tonight, has a periodof 185 years.(a) Draw a diagram showing the basic orbit of

the comet around the Sun. Include Earthin your diagram as well as the comet’s tailat a few locations.

(b) Predict when the comet will again bevisible.

31. Write these measurements out in long form(a) 3.4 × 106 km(b) 7.9 × 1012 kg

32. Describe a safe way to make observations ofthe Sun when it is high in the sky.

33. The figure below shows a device in which arolling ball moves faster and faster, finallygetting gobbled into the centre. How is this amodel of a black hole? In what ways is themodel not realistic?

34. Describe briefly how each of the followingdevices helps in the exploration of theuniverse:(a) an orbiting observatory(b) a ground-based observatory(c) a radio telescope

35. Describe how any or all of the following havehelped you understand ideas in this unit:(a) modelling(b) performing student-designed investigations(c) drawing scale diagrams(d) graphing(e) operating computer simulations(f) researching information on the Internet

36. Table 1 indicates the speed, orbital radius(from the centre of Earth), and period ofrevolution of four types of artificial satellitesand the Moon.(a) Determine the information needed to

complete the table.(b) What patterns do you observe in your

completed table?(c) For the artificial satellites, plot a line graph

of period of revolution (vertical axis)

Table 1

Satellite Orbital Period of Average Radius Revolution Speed

remote sensing 6.67 × 103 km 1.5 h ?

Iridium 7.18 × 103 km 2.8 h ?

GPS 2.67 × 104 km 12 h ?

geosynchronous 4.24 × 104 km 24 h ?

the Moon 3.84 × 105 km 656 h ?

Space 519

48. Explain this statement: “Visual systems androbotics often operate together.”

49. Choose an area of scientific research carriedout by astronauts aboard the International SpaceStation. Describe what you know about thatresearch.

50. You are the leader of a team of scientists,engineers, and technologists who aredeveloping spinoffs of the space industry.Make a list of five problems you would like theteam to work on.

51. Robotic rovers designed to roam across theirregular surface of Mars will have to be“smart”; in other words, they will have to maketheir own decisions about whether it is safe tomove forward. Explain why such rovers couldnot be adequately controlled by Earth-basedcontrollers.

52. Research the latest developments incommunications systems that make use ofgeosynchronous satellites. How are theyimprovements on older systems?

53. Find out about one of the many traditionalreligions or cultures that base their calendaron the movements of the Sun and Moon.Create a display showing how the dates ofvarious celebrations are fixed.

54. Do spacecraft have to be aerodynamic inshape? Explain.

55. Many satellites are powered by electricityconverted by big shiny panels from solarenergy. Investigate the advantages anddisadvantages of this source of energy, andsuggest what design challenges the spacecraftengineers face and how they might overcomethese challenges.

56. Research into the specialized areas of science(such as fluid physics, or crystal growth) thatmake use of the free fall conditions in anorbiting laboratory.

57. What probes are in outer space this year?Research their purpose, and find out whatkinds of data they are sending to Earth. Howare these data changing our ideas aboutspace?

58. Investigate the “What’s New” page of theCanadian Space Agency’s web site to check onthe progress of the ISS. Prepare periodicverbal reports for your class, focussing onCanada’s contribution.

against the orbital radius. Use the line onthe graph to determine (i) the period of a satellite with an orbital radius of 3.5 × 104 km and (ii) the orbital radius of a planet with a period of 10 h.

(d) For each satellite, including the Moon,calculate the ratio of radius3 to period2.What do you discover?

37. Make a list of three important questions youwould like answered to help you understandmore about (a) astronomy and (b) spaceexploration.

Making Connections38. What were some skills achieved by

astronomers in ancient times?

39. What is the evidence that astronomy is a veryold science?

40. (a) What are observatories used for?(b) Does Canada operate or help operate any

observatories outside the country? If so,where?

41. Professional astronomers rely on amateurastronomers to find objects such as comets inthe sky. Why?

42. Give examples in which Canadians haveparticipated in discoveries and/or research inastronomy.

43. Many devices you use in your daily life aredigital, just like devices used in astronomy andspace exploration. Give examples of digitaldevices and describe why they are called“digital.”

44. How has Canada’s space technology helped ineach of these endeavours?(a) robotics(b) resource management(c) navigation(d) telecommunications

45. In what ways will future space probes helpincrease our understanding of the universe?

46. List three general areas that involve careers inspace technology. Within each area, name onespecific career, some of its aspects, and theeducation required for it.

47. Explain the advantages of using roboticsrather than piloted probes to explore theplanets and other bodies in the solar system.

chapter 16 space research and...

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