Exploring Outer SpaceExploring Outer SpaceFact vs. FictionFact vs. Fiction

Produced by and for the Outreach Lecture Series of the Environmental Science Institute. We request that the use of any of these materials include

an acknowledgement of Dr. Wallace Fowler and the Outreach Lecture Series of the Environmental Science Institute of the University of Texas at

Austin. We hope you find these materials educational and enjoyable.

by Dr. Wallace FowlerOutreach Lecture Series Volume 33

Exploring Outer Space: Exploring Outer Space: Fact vs. FictionFact vs. Fiction

Wallace FowlerWallace FowlerProfessor of Aerospace Engineering and Professor of Aerospace Engineering and Engineering MechanicsEngineering MechanicsThe University of Texas at AustinThe University of Texas at Austin

OutlineOutline

Misconceptions about Misconceptions about Exploring Outer SpaceExploring Outer Space

Gravity Gravity Living in spaceLiving in space RocketsRockets Atmospheric entryAtmospheric entry Space solar powerSpace solar power

Outline (cont.)Outline (cont.)

Myths about ExploringMyths about ExploringOuter SpaceOuter Space

Costs/benefits of space explorationCosts/benefits of space explorationSpaceShipOneSpaceShipOne implicationsimplicationsStar Trek Star Trek Space mythsSpace myths

GravityGravity

Shooting down satellitesShooting down satellitesFalling into the sunFalling into the sunSatellites hovering over citiesSatellites hovering over citiesDropping bombs from satellitesDropping bombs from satellitesWeightlessness, zero gravity & free fallWeightlessness, zero gravity & free fallEscaping Earth’s gravityEscaping Earth’s gravityZero-gravity rooms at NASAZero-gravity rooms at NASA

Shooting Satellites DownShooting Satellites Down

Fiction:

Satellites would fall to Earth if we were to “shoot them down”

Satellite “Shoot Down”Satellite “Shoot Down”

FACT:FACT:

Satellites shattered Satellites shattered in a “shoot down” in a “shoot down” would just stay in would just stay in orbit – making more orbit – making more space debrisspace debris

Dropping Bombs from SatellitesDropping Bombs from Satellites

Fiction:Fiction:Satellites are good bomb platforms – Satellites are good bomb platforms – others could drop bombs on us from others could drop bombs on us from satellitessatellites

Fact:Fact: The bombs are also in orbit. When The bombs are also in orbit. When “dropped”, they would fly right along “dropped”, they would fly right along with the satellite that dropped themwith the satellite that dropped them

Falling into the Sun

Fiction:Fiction:

If not careful, a spacecraft could fall into If not careful, a spacecraft could fall into the Sunthe Sun

Falling into the SunFalling into the Sun

Fact: Fact: It is It is muchmuch easier to escape the solar easier to escape the solar system than to fall into the Sunsystem than to fall into the Sun

From Low Earth Orbit to the Sun requires a speed From Low Earth Orbit to the Sun requires a speed of 48,340 mphof 48,340 mph

From Low Earth Orbit to solar system escape From Low Earth Orbit to solar system escape requires a speed of 19,636 mphrequires a speed of 19,636 mph

PLUS:PLUS: It takes about 20,800 mph to reach Low Earth It takes about 20,800 mph to reach Low Earth

Orbit from the launch padOrbit from the launch pad

Satellites Hovering Over CitiesSatellites Hovering Over Cities

Fiction:Fiction: Satellites can hover over any city on EarthSatellites can hover over any city on Earth

Fact:Fact: Satellites can hover only over cities that Satellites can hover only over cities that lie on the equator and only at a specific lie on the equator and only at a specific (geosynchronous) altitude(geosynchronous) altitude

Geostationary Satellites Geostationary Satellites (in geosynchronous orbit)(in geosynchronous orbit)

Weightlessness, Zero-Gravity, Weightlessness, Zero-Gravity, and Free Falland Free Fall

Zero-Gravity or WeightlessnessZero-Gravity or Weightlessness

Fiction:Fiction:

In orbit, there is zero gravity. Things In orbit, there is zero gravity. Things and people are weightless.and people are weightless.

Consequence of Zero-GravityConsequence of Zero-Gravity

Fact:Fact:

In true zero-gravity, In true zero-gravity, orbits are impossible. orbits are impossible. Things in orbit would Things in orbit would move away from the move away from the Earth in a straight line. Earth in a straight line. All astronauts would All astronauts would be “Lost in Space”.be “Lost in Space”.

Escaping Earth’s GravityEscaping Earth’s Gravity

Fiction:Fiction:In orbit, we have escaped Earth’s gravityIn orbit, we have escaped Earth’s gravity

Fact:Fact:There is gravity in orbitThere is gravity in orbit

Fact:Fact:If we get far enough away from Earth, the If we get far enough away from Earth, the

gravity of the Sun makes Earth’s gravity gravity of the Sun makes Earth’s gravity negligible negligible

Zero-Gravity Rooms at NASAZero-Gravity Rooms at NASA

Fiction:Fiction:There is a “room” at NASA where the There is a “room” at NASA where the astronauts can go to experience “zero astronauts can go to experience “zero gravitygravity”.”.

Fact:Fact:““Zero Gravity” is free fall, we can free fall Zero Gravity” is free fall, we can free fall for seconds off of a diving board, for seconds off of a diving board, minutes in SpaceShipOne, etc., but never minutes in SpaceShipOne, etc., but never standing in a room on Earth.standing in a room on Earth.

Forces On EarthForces On Earth

Forces In SpaceForces In Space

NASA’s “Zero-g” SimulatorsNASA’s “Zero-g” Simulators

KC -135A Neutral Buoyancy LaboratoryKC -135A Neutral Buoyancy Laboratory

KC-135 Flight ProfileKC-135 Flight Profile

NASA’s KC-135A - “Vomit Comet”NASA’s KC-135A - “Vomit Comet”

0 20 45 65

Maneuver Time, Seconds

Alti

tude

, F

eet

24 000

26 000

28 000

30 000

32 000

34 000

1.8g Zero-g 1.8g

350 Kias

45° Nose High 45° Nose High

350 Kias

Neutral Buoyancy LaboratoryNeutral Buoyancy LaboratoryJohnson Space Center, Houston TexasJohnson Space Center, Houston Texas

Neutral Buoyancy Laboratory

Neutral Buoyancy Laboratory Neutral Buoyancy Laboratory is a big deep pool!is a big deep pool!

102 ft. wide by 202 ft. long102 ft. wide by 202 ft. long40 ft. deep40 ft. deepCapacityCapacity

Volume = 824,160 cubic feet Volume = 824,160 cubic feet 6.2 million gallons of water 6.2 million gallons of water 49.6 million pounds of water49.6 million pounds of water

Living in Space:Living in Space:Space is a hostile environmentSpace is a hostile environment

Unexpected MotionsUnexpected MotionsPressure Pressure SoundsSounds

Unexpected MotionsUnexpected Motions

Fiction:Fiction:Earthbound intuition about how you Earthbound intuition about how you move applies when you are in orbitmove applies when you are in orbit

Fact:Fact:Orbit removes most normal and frictional Orbit removes most normal and frictional forces forces unexpected motion (or lack of unexpected motion (or lack of motion)motion)

Loose Items in SpacecraftLoose Items in Spacecraft

Fiction:Fiction:If you lose something in a spacecraft, you If you lose something in a spacecraft, you have little hope of finding it, because it have little hope of finding it, because it could drift anywherecould drift anywhere

Fact:Fact:Always look in the same placeAlways look in the same place

Problems with moving in orbitProblems with moving in orbitGemini 9A astronaut maneuvering unit (AMU)Gemini 9A astronaut maneuvering unit (AMU)

Problems with moving in orbitProblems with moving in orbitGemini 9A photo “float”Gemini 9A photo “float”

cockpit

There is no airThere is no airconvection in orbitconvection in orbit

(Hot air does not rise)(Hot air does not rise)

Fiction:Fiction:Fires burn well in orbitFires burn well in orbit

Fact:Fact:Combustion gasses extinguish fire Combustion gasses extinguish fire

Caution:Caution:Do not sleep in an unventilated area!Do not sleep in an unventilated area!

PressurePressure

Fiction: Fiction: If suit pressure fails, the astronaut explodes.If suit pressure fails, the astronaut explodes.

Loss of PressureLoss of Pressure

Fact:Fact:BendsBends

Air leaves lungsAir leaves lungs

SuffocationSuffocation

No bulging eyes No bulging eyes or exploding peopleor exploding people

Sounds in SpaceSounds in Space

Sound comes from molecular collisions Sound comes from molecular collisions

Collisions form pressure waves Collisions form pressure waves

Waves of molecules strike eardrumsWaves of molecules strike eardrums

We detect the impacts with our earsWe detect the impacts with our ears

Sounds in SpaceSounds in Space

Fiction:Fiction:

There are no sounds in spaceThere are no sounds in space

Fact:Fact:

Space is not empty Space is not empty

Extremely thin “atmosphere” Extremely thin “atmosphere”

Molecular collisions occurMolecular collisions occur

There is sound, but we cannot hear itThere is sound, but we cannot hear it

Sounds on MarsSounds on Mars

Fiction:Fiction: We could hear, unaided on Mars, We could hear, unaided on Mars, because it has an atmospherebecause it has an atmosphere

Fact:Fact: Must wear Mars suitsMust wear Mars suits

Ears alone won’t workEars alone won’t work

Microphones and amplifiers neededMicrophones and amplifiers needed

How Rockets WorkHow Rockets Work

Fiction: Fiction: Rockets pushRockets push

against the air.against the air.

Rockets mustRockets must

thrust to stay up.thrust to stay up.

Fact: Fact: Rockets work better in a vacuum. Rockets work better in a vacuum.

They work by ejecting mass, andThey work by ejecting mass, and

can coast in orbit.can coast in orbit.

Atmospheric EntryAtmospheric Entry

Fiction: Fiction: Air friction heats shuttle and Air friction heats shuttle and

causes the entry fireballcauses the entry fireball

Shuttle Entry Plasma TrailShuttle Entry Plasma Trail

Fact: Fact:

Spacecraft ionizes the air. Spacecraft ionizes the air.

Ions glow like a neon light.Ions glow like a neon light.

Space Solar PowerSpace Solar Power

Fiction:Fiction:

An array of solar power satellites An array of solar power satellites could supply Earth’s electrical could supply Earth’s electrical powerpower

Fact:Fact:

TheThe technology exists but…technology exists but…

the size and mass required are the size and mass required are prohibitiveprohibitive

Solar Power Satellite ConceptsSolar Power Satellite Concepts

Earth’s Power NeedsEarth’s Power Needs

US Power: ~ 6 kilowatts/personUS Power: ~ 6 kilowatts/personEurope: ~ 3 kilowatts/personEurope: ~ 3 kilowatts/personProjected Earth Population in Projected Earth Population in

2050: 8 to 10 billion 2050: 8 to 10 billion Assume: ~ 3 kilowatts/personAssume: ~ 3 kilowatts/person

Size of Required Solar ArraySize of Required Solar Array

A satellite solar panel produces 1.3 A satellite solar panel produces 1.3 kilowatts of energy per square meterkilowatts of energy per square meter

Requirement:Requirement: One Titan 4B launch One Titan 4B launch PER DAY (EVERY DAY ) PER DAY (EVERY DAY ) for over 4000 yearsfor over 4000 years

NOT THE SOLUTIONNOT THE SOLUTION

Solar Array DeploymentSolar Array Deployment

Costs of Space ProgramCosts of Space Program

Fiction:Fiction:NASA’s expenditures are our primary NASA’s expenditures are our primary national expenditure on spacenational expenditure on space

Fact:Fact:Other U.S. space programs spend about Other U.S. space programs spend about twice what NASA spendstwice what NASA spends

-- The militaryThe military - The National Reconnaisance Office - The National Reconnaisance Office

(part of the Department of Defense)(part of the Department of Defense)

Copyright ©2000-2002 Brian Doberstein

$

$

$

$

How expensive is the space How expensive is the space program?program?

Fiction:Fiction:NASA’s expenditures are large compared NASA’s expenditures are large compared to other federal programsto other federal programs

Fact:Fact:NASA’s expenditures are only a very NASA’s expenditures are only a very small percentage of the federal budget. small percentage of the federal budget. In 2001, NASA’s budget was 0.69% of the In 2001, NASA’s budget was 0.69% of the Federal BudgetFederal Budget. .

$

$

$

$$

$

$

$

$

$

$

$

$

$

$

$$

$

$$

$

$

$

Benefits of the Space ProgramBenefits of the Space Program

Fiction:Fiction:Tang and Velcro are typical Tang and Velcro are typical

civil benefits of the space programcivil benefits of the space program

Fact:Fact:Substantial civil benefits include:Substantial civil benefits include:Satellite communications (phone, TV, etc.)Satellite communications (phone, TV, etc.)Enhanced medical diagnostics and monitoring Enhanced medical diagnostics and monitoring And …….And …….

Apollo Guidance ComputerApollo Guidance Computer

Microcomputers – The primary legacy of ApolloMicrocomputers – The primary legacy of Apollo

Commercial Space Travel?Commercial Space Travel?

SpaceShipOne won the Ansari X-PrizeSpaceShipOne won the Ansari X-Prizeon October 4, 2004on October 4, 2004

Shuttle vs SpaceShipOneShuttle vs SpaceShipOne

Weight: 200,000 lb dry 6,800 lb dryWeight: 200,000 lb dry 6,800 lb dry

Speed: 17,500 mph / 385 miles 2,300 mph / 69.5 miles Speed: 17,500 mph / 385 miles 2,300 mph / 69.5 miles

Commercial Space Travel?Commercial Space Travel?

Fiction:Fiction: Now that civilians have “gone into space”, Now that civilians have “gone into space”, civilian flights around the Moon and back civilian flights around the Moon and back to Earth are only a few years away.to Earth are only a few years away.

Fact:Fact:The energy required to do an “up and The energy required to do an “up and down” flight like that of SpaceShipOne is down” flight like that of SpaceShipOne is much smaller than that required to go to much smaller than that required to go to orbit or to the Moon.orbit or to the Moon.

Energy RequiredEnergy Required

SpaceShipOne flew to about 100 km SpaceShipOne flew to about 100 km altitudealtitude

To put SpaceShipOne in orbit requires To put SpaceShipOne in orbit requires 85 times as much energy85 times as much energy

To take SpaceShipOne to the Moon To take SpaceShipOne to the Moon requires 150 times as much energy requires 150 times as much energy

Star TrekStar Trek

USS Enterprise

Warp DriveWarp Drive

Fiction:Fiction:By 2500, we will regularly travel faster By 2500, we will regularly travel faster than light – at “Warp” speedsthan light – at “Warp” speeds

Fact:Fact:No known source for energyNo known source for energy

Flight times to stars still too longFlight times to stars still too long

Medical TricorderMedical Tricorder

Fiction:Fiction:

Detects all anomalies without intruding into the Detects all anomalies without intruding into the bodybody

Fact:Fact:

We can only hope for devices like thisWe can only hope for devices like this

Transporter

Fiction:Fiction:Beam me up, ScottieBeam me up, Scottie

Fact:Fact:Major technical problems – revolution if solvedMajor technical problems – revolution if solved

Common Space MythsCommon Space Myths

We never went to the MoonWe never went to the MoonUFOsUFOsRoswell, New Mexico is the site Roswell, New Mexico is the site

of an alien spaceship crashof an alien spaceship crashAliens abduct Earthlings and Aliens abduct Earthlings and

then turn them loosethen turn them loose

Dr. Wallace FowlerDr. Wallace FowlerProfessor of Aerospace Engineering and Professor of Aerospace Engineering and

Engineering MechanicsEngineering Mechanics

The University of Texas at AustinThe University of Texas at Austin

Dr. Fowler's research focuses on the area of design and design methodology, the Dr. Fowler's research focuses on the area of design and design methodology, the

modeling and design of spacecraft, aircraft, and planetary exploration systems. He modeling and design of spacecraft, aircraft, and planetary exploration systems. He

has served on the College of Engineering faculty since 1965. He has three years of has served on the College of Engineering faculty since 1965. He has three years of

industrial experience, has published more than 50 technical articles and reports industrial experience, has published more than 50 technical articles and reports

and has co-authored two books. He is the recipient of 1997 Academy of and has co-authored two books. He is the recipient of 1997 Academy of

Distinguished Teachers Ex-Students Association Award and has recently been Distinguished Teachers Ex-Students Association Award and has recently been

elected as the new President-Elect of the American Society of Engineering elected as the new President-Elect of the American Society of Engineering

Education. In 1999 he was awarded the Engineering Foundation Advisory Council Education. In 1999 he was awarded the Engineering Foundation Advisory Council

Award. Dr. Fowler is Director of the Texas Space Grant Consortium (TSGC) and is Award. Dr. Fowler is Director of the Texas Space Grant Consortium (TSGC) and is

currently serving as the ASE Undergraduate Advisor.currently serving as the ASE Undergraduate Advisor.