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231 Cards in this Set

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Scientific Notation Examples

100 = 1 x 10^2


1,000,000 = 1 x 10^6

Science (and most countries) use SI units aka _____________

metric system

T(Kelvins) = T(Celsius) + __________

T(Kelvins) = T(Celsius) + 273.15

Radius of Sun

Radius of Sun = 6.96 x 10^8 m
= 1 R
Most Stars: Radius ~ 0.1 to 30 R (Giants 1000 R)

Mass of Sun

Mass of Sun = 2.0 x 10^30 kg
= 1 M
Most Stars: Mass ~ 0.1 M to 100 M

Luminosity of Sun

Luminosity of Sun = 3.8 x 10^26 Watt
= 1 L
Most Stars: L ~ 0.001L to 106 L

Astronomical Unit

Use to measure Planetary distances.
Average distance Sun to Earth = 1 AU
= 1.5 x 10^11 m

Light year

A measure of distance, NOT time.
The distance traveled by light in 1 year.
Light travels at a CONSTANT speed of 3.0 x 105 km/s (186,000
miles per sec).

1 light year = ?? m

9.46 x 10^15 m


Pittsburgh and California = 0.02 light seconds


Earth and Moon = 1.3 light seconds

Age of Universe:

13.7 ± 0.13 billion years ( ~14 x 109 years).

Scale comparison:
Age of Universe:


Formation of Earth (4.5 x 109 yrs old)


Rise of Invertebrate life:


Earliest Human ancestors:

Scale comparison:
Age of Universe: 1 year
Formation of Earth (4.5 x 109 yrs old) August
Rise of Invertebrate life: 13th December
Rise of Dinosaurs 25th December
Earliest Human ancestors 9:00 pm, December 31
Modern humans evolve 11:58 pm, December 31
Kepler and Galileo 11:58:59 pm

What makes up a Planet?

Object (solid or gaseous) that orbits a star. Radius > 1000 km.

Moon (Satellite):

"Rocky or icy" object that orbits a planet.

Asteroid:

Small rocky object that orbits a star.

Comet:

Small icy object that orbits a star.

Solar System:

Star (or more) plus the planets, etc that orbit the star.

Characteristics of Our Galaxy

Spiral galaxy composed of a highly flattened disk and a central
“elliptical” bulge. The disk is about 100,000 light years (30kpc)
in diameter.

Composition of universe: Today

Today:
Atoms (baryonic matter): 4.6%
Dark matter: 23%
Dark energy (energy associated with space): 72%

Composition of universe: Atoms

Initially Today
Hydrogen 75% 70%
Helium 25% 28%
Metals 0% 2%

The Scientific Method: Science and how it uses it.

Evident in all aspects of life.
Understanding the laws that govern the universe on all scales.
Quantitative predictions provide a means to test the laws.
Modern scientists (generally) do not try to answer the ultimate question, i.e., why the Universe formed

The Scientific Method

Interplay between
Observation &
Experiment &
Theory
Gather Data -> Form Theory -> Test Theory -> Gather Data

Experiments require:

Careful design.
Control experiments (e.g., Placebo in medicine).
Understanding of measurement errors.

Einstein's concept for gravity is called....

General Relativity. Which based on geometry and Mass (or Energy) causes space to be curved.

Order of Planets from the Sun

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, & Neptune.

Mass Distribution Within the Solar System

99.85% Sun
0.135% Planets
Remainder Dwarf planets
Comets
Satellites
Minor Planets or Asteroids
Interplanetary Medium

Inner Terrestrial planets

Mercury, Venus, Earth & Mars


Near the Sun, Small, Low mass , Slow rotation ( P ~ 1 day), No rings, High density, Mostly solid (rocks, metals), Thin atmosphere, Few moons

Outer Jovian planets

Jupiter, Saturn, Uranus, Neptune.


Far from the Sun, Large, Great mass, Fast rotation ( P < 1 day), Rings, Low density, Mostly liquid & gas, H, He, H compounds, Dense atmosphere, Many moons

Asteroids, 2 Types and The one close to earth are called....

75% are C-type (carbonaceous): Lots of carbon
15% are S-type: Silicate/rock material
M-type: Iron rich

Apollo asteroids:

Asteroids whose path cross the orbit of Earth
Typical diameter: 1km.

Ptolemaic Model of Solar System (AD 140)

Copernicus (1473–1543):

Credited with advancing the notion that the planets (including the Earth) revolve around the Sun.
Provides a simple explanation for retrograde motion.

Galileo’s Observations (1564-1642)

1. Moon was cratered, and had mountains
2. Sun showed sunspots.
3. Four small moons were seen to be orbiting
Jupiter.
4. Venus showed phases like the Moon - easily
explained in a Sun- centered solar system.
5. His telescope revealed that there were many
more stars than previously believed.

Johannes Kepler (1571-1630)

His work on using positional planetary data of
Tycho Brahe (Danish nobleman)(1546-1601)
resulted in the development of three laws of planetary motion.

Kepler’s First Law of Planetary Motion

Each planet’s path around the Sun is an ellipse, with the Sun at one
focus of the ellipse (the other focus is empty).

Describe the Picture Kepler’s First Law of Planetary Motion

Perihelion

nearest point to the Sun in Orbit

Aphelion

Farthest point from the Sun's Orbit

The ellipse

The ellipse is a geometrical shape every point of which is the same total distance from two fixed points (the foci).
Eccentricity is the distance between the foci divided by the longest
distance across (major axis).

The 4 Conic sections

Ellipse equations

Define AA` as the distance between A and A'.
2a = AA' = Length of major axis
a = AC= (Length of ) semi-major axis
2b = BB'= Length of minor axis
 = FF'/2a = FC/a = SQRT(a^2 - b^2)/a
b = a SQRT(1 - 2)
2a = FX + F'X (X is an arbitrary point on the ellipse)

Kepler’s Second Law of Planetary Motion

A planet moves along its elliptical path with a speed that
changes in such a way that a line from the planet to the Sun
sweeps out equal areas in equal intervals of time.

Kepler’s Third Law

The ratio of the cube of a planet’s semi major axis, a, to the
square of its orbital period, p, is the same for each planet:
a³/p² = Constant

Planetary Motion Facts

All planetary orbits are ellipses, but all (except Pluto’s orbit) are nearly circular.


Each of the planets revolves around the Sun in a counterclockwise direction as viewed from above the Earth's north pole.

Inclination of a planet’s orbit is

Inclination of a planet’s orbit is the angle between the plane of a planet’s orbit and the “ecliptic plane”, which is the plane of Earth’s orbit. Similarly most planets (exceptions are Venus, Uranus, & Pluto) rotate in a counterclockwise direction about their own axis.

Obliquity:

Orientation of rotation axis with respect to the
normal of the planet's orbital plane about the Sun.

Latitude:

Draw line from location to center of Earth. Angle of the line to
equatorial plane is your latitude.

Longitude:

Great circles running through the North and South Poles of the Earth (called meridians). Measured in degrees, with 0 degrees defined by the line of longitude that passes through Greenwich (prime meridian).

A GPS receiver can determine your location using

TRIANGULATION.


Accuracy: ~ 15 meters

For GPS , you need at LEAST how many satalittes to get 3D position information.

You need at LEAST 4 to get 3D position information.

Zenith

The Point Directly Above you.

Horizon

A great Circle on the celestial sphere, 90 degrees from the zenith.

Nadir

Point directly below zenith

The Cardinal Directions

North, South, East, West

Celestial Sphere

An imaginary sphere around the Earth on which are "pinned" the Sun, moon, planets and the stars.

Annual Motion

The Earth revolves around the Sun approximately once each
year (365 days).

At which location(s) would the following occur:


Stars Never Rise:


Stars Never Set:


Stars Rise and Set:

Stars Never Rise: South Pole


Stars Never Set: North Pole (Looks like a Circle)


Stars Rise and Set: Equator

Declination (DEC) & Right Ascension (RA):

A coordinate system, similar to latitude and longitude, is imposed on the celestial sphere by projecting Earth's rotation axis on the sphere to identify the celestial north pole and celestial south pole. The projection of the Earth's equator onto the celestial sphere defines the celestial equator.

A sidereal day is ? minutes shorter than a solar day.

A sidereal day is 4 minutes shorter than a solar day.


Every Observatory has its own unique local sidereal time.
A star is on the meridian when it's RA is equal to the local sidereal time.

Each day the Sun moves about ? degree(s) east with respect to the background stars (since a circle has 360 degrees).

Each day the Sun moves about 1 degree east with respect to the background stars (since a circle has 360 degrees).

Annual motion of Sun

Vernal (Spring) Equinox approx Date

(approx. Mar 21)

Autumnal Equinox approx date

(approx. Sep 22)

Seasons are Caused by:

Tilt of the Earth's axis, &
orbital motion of the Earth about the Sun.

Northern Summer:


Northern hemisphere is pointed ???? the Sun.

Northern hemisphere is pointed towards the Sun.

Northern Winter:


Northern hemisphere is pointed ???? from the Sun.

Northern hemisphere is pointed away from the Sun.

Summer months warmer because:

Sun spends longer above the horizon.
Rays strike the ground more perpendicularly.

Earth at Winter Solstice, Summer

Science has 2 beliefs

1 An objective rality exists
2 humans can gain knowledge

The Scientific Method.

Must be falsifiable to be tested


Testing is Observation, logic, and skepticism.


It is only true as of now.

Moon completes one orbit around the Earth (as defined by the
stars) in approximately ?? days. This is called a ______________

Moon completes one orbit around the Earth (as defined by the
stars) in approximately 27.3 days. This is one sidereal month.

one synodic (or lunar) month.

Defined by the position of the Moon relative to the Earth and
Sun. It takes approximately 29.5 days to complete a full cycle of
phases

Sidereal Year

Time taken for Sun to return to same position as defined by the
stars = 365.2564 days.

Tropical Year

Time taken for the Sun to return to the Vernal Equinox = 365.2422
days.
Shorter than Sidereal year due to the precession of the Equinoxes.

Speed:

Speed:
How fast an object is moving:
Rate of change of distance with time
Average speed = (Distance traveled) / (Time taken)
= (Distance traveled) / (Change in time)
= d / t

Velocity (v):

Speed & direction:
e.g., 50km/hr due east

Acceleration (a):

A measure of the change per unit time of the velocity of an object. A change in velocity can occur because of:
(1) a change in speed, or a
(2) a change in direction

Vectors

Vectors
Vectors are used to show the direction of motion.
They can be used to show displacement,and velocities.
Vectors may be added and subtracted.

Energy

Ability to do work.
Measured in Joules: 1 Joule= 1 kg m^2 s-^2

Kinetic Energy (KE)

Energy of motion.
Kinetic energy= ½mass x speed x speed
= ½mv2

Potential Energy (PE)

Energy stored for later use.
Weight above the ground (gravitational PE)
Compressed Spring
Chemical potential energy

Radiative Energy

Energy carried by Electromagnetic Radiation (e.g, light)
Sunlight
Heat from radiator

Thermal Energy

Random kinetic energy of mater:
Vibrational
Kinetic

Mass-energy

Equivalence of mass and energy.


E=mc2

Conservation of Energy

The total energy of an enclosed system is constant. Energy may be converted from one form to another but not created or destroyed.
Fundamental principal / law of physics.

Thermal (or heat) energy depends on:

Temperature
Amount of material
Type of material and its state.
It is the collective thermal energy of the individual particles.

Temperature Comparing

Summary of Temperature properties for a gas:

Temperature measures the AVERAGE kinetic energy (KE) of the particles.
Higher T =>Higher KE.


Average speed of the molecules depends on the temperature of the gas.
Higher T =>Higher speed.


The average kinetic energy of the particles is independent of mass.


At the same temperature, less massive molecules have greater speed.
Lower mass = >Faster speed.

Planetary Atmospheres and Escape Velocity (Speed):


Earth:


Moon:


Phobos:

Earth: Vesc= 11 km/s.


Moon: Vesc= 2.5 km/s.


Phobos: Vesc= 50 km/hr.

Why doesn't the Moon have an atmosphere?

The gas molecules have sufficient energy to escape from the Moon's gravitational pull.

Sir Isaac Newton (1642-1727)

English physicist and mathematician, conducted fundamental work on calculus and mechanics, & gravity.

Newton's First Law of Motion (Law of Inertia)

A body remains at rest, or moves in a straight line at constant speed, unless acted on by an outside force.

Newton's Second Law of Motion

When a force F acts on a body of mass m it will experience an acceleration a given by
F = m a

Newton's Third Law of Motion

When one body exerts a force on a second body, the second body exerts an equal and opposite force on the first body.



Gravitational force exerted by Earth on Moon, is exactly the same as the gravitational force exerted by the Moon on the Earth.


Inertia

Tendency of a body at rest to remain at rest,and
for a body in motion to remain in motion.

Newton's Third Law of Motion:


Mass (kg)

A measure of inertia ---the amount of matter an object contains.
Intrinsic property.
The mass of an object on the Earth is the same as its mass on the Moon.
Mass can be measured by comparing the object to objects of known mass using a "balance"

Newton's Third Law of Motion:


Weight (kg m s-2)

Weight (kg m s-2)
The force with which an object presses onto the ground.
Weight is not an intrinsic property of a body.
An object weighs less on the Moon than on the Earth.
A spring scale measures weight, not mass.

(T/F) Mass and Weight are the same.

FALSE Mass and Weight are NOT the same.

Galileo Galilei (1564-1642)

found that the higher an object is when it is dropped, the greater its speed when it hits the ground.The object is accelerated.


According to legend, Galilei dropped a bullet and a cannonball from the leaning tower of Pisa in Italy to show that all objects fall with the same acceleration.

Surface Gravity (g )

Acceleration experienced by a body at a planet (or stars) surface. Given the symbol g. We will use a plain "g" for the Earth's surface gravity. More correctly called the surface acceleration due to gravity.

When an object is free of any restraints --no friction, air or otherwise --and falls under the influence of gravity alone, it is in _________.

When an object is free of any restraints --no friction, air or otherwise --and falls under the influence of gravity alone, it is in free fall.

During each second of a free fall, the object gains a speed of about 10 m/s. This gain per second is called its _________________.

During each second of the fall, the object gains a speed of about 10 m/s. This gain per second is its acceleration.

For an object beginning at rest:
what are the equations?


Speed?


Velocity? V


gravity? g


time? t

speed = V = gt
distance traveled = d = ½gt^2\2

Motion of Free Fall Chart

Weight on the Moon =

Weight on Moon =


Weight on Earth x ( acceleration on the Moon / acceleration on Earth )



Weight on Earth is 150 lbs.
Weight on the Moon = 150 lbs x (1.6 m/s^2 / 10 m/s^2) = 24 lbs.

My weight on the Moon is ___________of my weight on Earth, although my mass is ___________.

My weight on the Moon is only a little over 1/6 of my weight on Earth, although my mass is the same.

Acceleration Graph

Linear momentum chart

Linear momentum

Linear momentum=


mass x velocity = mv ( a vector)
The linear momentum of an object is constant unless it is acted on
by an EXTERNAL force.

Newton's Law of Gravity

Two bodies attract each other with a force that is directly proportional to the product of their masses, and inversely proportional to the square of the distance, d, between them.


square of the distance, d, between them.
(G)(M1)(M2)
F= -------------------------G is the gravitational constant.
d^2

Two Types of Orbits:

Bound (Elliptical)


and


UnBound (Parabolic
Hyperbolic)

Vorb=

Object in circular orbit of
radius r orbiting planet (star)
of mass M:
Vorb= ( GM / r )^(1/2)


The orbital velocity (speed)
is INDEPENDENT of m, the
mass of the object.

Some Basic Facts:


At the Earth's surface:
Vesc =
Vorb =
Porb =

Some Basic Facts:


At the Earth's surface:
Vesc = (2GM⊕ / R⊕ )^½ = 11.2 km/s (25,000 miles/hr)
Vorb = (GM⊕ / R⊕ )^½ = 7.9 km/s (18,000 miles/hr)
Porb = 2 πR⊕ / Vorb= 84.5 minutes

THRUST

Strength of rocket engine (often measured in pounds of thrust).
It is a force.
1 lb of thrust = 4.45 Newtons.
It is the force required to keep a 1lb (i.e., 0.45 kg) object from falling due to
Earth's gravity.

1 lb of thrust = ????? Newtons.

1 lb of thrust = 4.45 Newtons.

SPUTNIK

Launched on October 4th, 1957.


3 Stage Rocket


First artificial satellite to be launched into space.


Russian made


Scare the beJesus out of everyone.

Sputnik 2 (3 Nov, 1957)

162 days in orbit
Live dog, Laika
Recording instruments attached to body.

Explorer 1

Explorer 1
14 kg satellite
Launched: Jan 31, 1958

Yuri Gagarin (1934-1968)


First manned space flight: April 12, 1961
Vostok 1 spacecraft (475 tons).
Peak velocity: 27,400 km/hr.
1 orbit: 112 to 203 miles
Flight time: 108 minutes.
Slowed by retro rockets, and parachute.

Enos:

Enos:
5½ year old chimpanzee. American
Made two orbits of Earth in Mercury Spacecraft, on Nov 29, 1961
In flight it ate, drank and performed simple tests.

John Glenn (1921- )

20 February, 1962
Friendship 7 (Mercury 6)
4 hrs, 55 minutes. (3 orbits)
Entire trip covered by
television & press.

Man on the Moon

At 10:56 pm, 20 July 1969, Armstrong stepped onto the surface of the Moon.

Apollo 11 Crew:

Neil A. Armstrong
Michael Collins
Edward E. “Buzz” Aldrin, Jr.

Apollo 8 (Dec 1968)

First
manned spacecraft to
orbit moon.

the earliest use of Rockets was...

Rockets have been known and
used since 400 BC. The earliest
uses were for fireworks, and for
warfare (around 1000AD).

the volume of 1gm liquid Water:



the volume of 1gm of Steam:

1gm of liquid water has a volume of 1 cm^3


1gm of steam at 100 C (373 K) has a volume of over 1700 cm^3 (at
sea level).

Types of Explosives not so good for rockets

Gunpowder


Nitroglycerine :high explosive, rapid detonation


TNT(Trinitrotoluene)


Ammonium nitrate (NH4NO3) - Fertilizer

Bishop Franci Godwin (1566-1633)

The Man in the Moon


Hero (Domingo Gonsales) utilizes
swan like creatures (gansas) to
carry him on their annual migration
to the Moon.


Moon inhabited by “Lunars”, who
sleep during the day, and live in
Earthshine.

Hector Savinien Cyrano de Bergerac
French nobleman

Other Worlds (published posthumously) (around 1657)


Rockets:
Fanciful spaceships
Elaborate aliens (bird-men who live on other side of the Sun).

Jules Verne (1828-1905)

From the Earth to The Moon (1865)



wrote fiction about how we could get to space via a "gun." bad Idea tho


"A Traveler starting in such a way will be turned into fine jelly
spread against the walls of his craft" (Patrick Moore 1969).

Konstantin Tsiolkovsky (1857-1935)

Often called the father of modern astronautics.


Space exploration by rocket. Suggested (1903) the use of liquid propellants for rockets. Artificial satellite. Different fuel mixtures: Liquid O2 an H2 (used by Saturn V!) Gasoline, kerosene, alcohol, methane Anticipated use of air-locks for spacewalks. Cabin with life support systems. Multi-stage rockets. Fundamental formulae for rocket motion.

_______________ 's 16 Stages of Space Exploration.

1. Design of rocket-propelled airplanes with wings.
2. Progressively increasing the speeds and altitudes reached with these
airplanes.
3. Designing of a pure rocket without wings.
4. Developing the ability to land on the ocean surface by rocket.
5. Reaching of escape velocity and first flight into space.
6. Lengthening of the rocket flight time into space.
7. Experimental use of plants to make an artificial atmosphere in spacecraft.
8. Using of pressurised space suits for activity outside spacecraft.
9. Making of orbital greenhouses for plants.
10. Building of the large orbital habitats around the earth.
11. Using solar radiation to grow food, to heat space quarters, and for transport
needs throughout the solar system.
12. Colonization of the asteroid belt.
13. Colonization of the entire solar system and beyond.
14. Achievement of individual and social perfection.
15. Overcrowding of the solar system and galaxy colonization.
16. The sun begins to die and the people remaining in the solar system's
population move to other solar systems.

Dr. Robert H. Goddard (1882-1945)

The Father of American Rocketry


Equations of rocketry
Theory and experiment
Efficiency
Earliest experiments were with
solid-propellant rockets.

Who launched the first successful liquid fuel rocket?

Dr. Robert H. Goddard


First successful test of liquid
fuel rocket, March 16, 1926.
Liquid oxygen/gasoline rocket:
184 feet.
2.5 seconds
average speed = 64 m/hr

Dr. Robert H. Goddard


In 1914, patents covering ????

In 1914, patents covering combustion chambers, nozzles,propellant feed systems, and multistage rockets.

Prof. Hermann Oberth (1894-1989)

His dissertation became the celebrated book The Rocket into Planetary
Space (pub.1923) , in which he recognized and proposed solutions to a
very wide spectrum of rocketry and space travel problems:
Enormous amount of fuel required, Hazards of solid propellants, Handling of volatile fuels, The abnormal effects of pressure upon the human body, Rockets can operate in a void, Rockets can move faster than the speed of its exhaust gases, All of this was more than 40
years before space flight became a reality.

Verein for Raumschiffahrt e.V. ([VfR]
(Society for Space Travel).

Formed in 1927
Oberth, Ritter, Braun (joined in 1930) …
Spawning ground for the men who were to make the
breakthrough into space.
Simple equipment.

Dr. Wernher von Braun (1912-1977 )

Hitler had ordered the execution of the German rocket team members, but execution was not carried out. In 1946, von Braun and his team arrived at White Sands, N.M. The U.S. space program was under way!
Until 1950, they helped the U.S. Army improve the V-2. In 1950, they were moved to the Army's Redstone Arsenal in Huntsville, Alabama, and von Braun became director of guided missile development.

Sergei Pavlovich Korolev (1907-1966 )

The Russian Masterbuilder.


Korolev's place in history was assured by
his direction of the launch of SPUTNIK,
the first artificial satellite, on October 4,
1957. Confirmation of his genius came
again on April 12, 1961 when another of
his designs carried Yuri Gagarin, the first
man in space, into orbit around the Earth.

Valentina V Tereshkova

June 1963
Valentina V Tereshkova (soviet cosmonaut)
first woman in space

March 1965 Alexei Leonov was the first to do what?

Alexei Leonov performs first spacewalk (lasts 10 minutes).
(James McDivitt, June 1965: spacewalks for 20 minutes and
maneuvers with gas gun).

March 1965 Virgil Grissim & John Young did what?

March 1965
Virgil Grissim & John Young orbit Earth in Gemini.
First US 2 man space mission. First spacecraft to maneuver
from one orbit to another.

January 1966
Lunar 9 becomes...

January 1966
Lunar 9 becomes 1st mechanical object, in working order, to
land on the moon. Sends back panoramic pictures.

January 1967 Apollo 1

January 1967
Crew of first manned Apollo mission (Apollo 1) die on launch
pad due to fire in their command module.

April 1981

First orbital test flight of Space Shuttle Columbia

Sally Ride

first American woman in space


June 1983

Space Shuttle Challenger

January, 26 1986
Space Shuttle Challenger is destroyed in mid-air explosion.
Next mission does not occur until late September, 1988.

Space Shuttle Columbia

February, 1 2003
Space Shuttle Columbia is destroyed on its descent back to Earth. Loss of the entire 7 person crew.

Orbital period:

The time it takes to go around the Earth once as
defined by the distant stars.

Geosynchronous Earth Orbit (GEO):

Orbiting about 23,000 miles above the equator with a period of exactly
one day, these satellites appear fixed to someone on the Earth.
Communication and meteorological satellites are often
geosynchronous.

Iridium Flashes

you've more
than likely seen sunlight reflecting off an Iridium communications
satellite. The satellites' antenna arrays are almost perfect mirrors.
And when they catch the Sun just right -- wow!

Polar Earth Orbit :

Polar Earth Orbit :Polar Earth Orbit :
These go over or near the poles - although they are usually in Low
Earth Orbit as well. Polar orbits have the convenience of going
over the entire Earth's surface. The DMSP satellites are in near
polar orbit.

The period of the orbit, P, can be found using

distance traveled in one orbit =


(orbital period of satellite) x (speed of satellite.)

What type of orbits can take advantage of the Earth’s rotation?

Posigrade orbits of low inclination.


The launch vehicle needs less propellant for
launch, or that a given vehicle can launch a more massive spacecraft into orbit.

To change orbit, rocket must do a...

controlled burn (i.e, fire
rocket engines).

In________ approximation,
burn is assumed to last for a short time compared with the
rocket’s orbital period.

IMPULSE

Dr. Walter Hohmann

His classical work on the calculation
of interplanetary trajectories was done
in his spare time; a hobby of his.
He is credited for work on return-to-
Earth and landing problems. The lunar
lander module used in the Apollo
program is a result of these ideas.

A _______________ transfer is a fuel efficient way to transfer from one circular orbit to another circular orbit that is in the same plane
(same inclination), but a different altitude.

Hohmann transfer

Earth’s rotational motion

Vrotorb ≈1650 km/hr ≈ 0.46 km/s

Earth’s orbital motion

Vorb ≈100,000 km/hr ≈ 30 km/s

Michael
Minovitch

Pioneered the gravity assist technique

Aerobreaking

The process of decelerating a spacecraft by converting some of its energy of motion (its speed) into thermal energy (heat).

Aerocapture

Process of capturing a spacecraft from a solar orbit into a planetary orbit by using air friction. Much more difficult than aerobreaking!

The United States awards astronaut status to anyone who flies above
?? miles in altitude.

The United States awards astronaut status to anyone who flies above
50 miles in altitude.

Duel Nature of Light

Wave and Particle

Photons

aka Light Particles, have no charge and no mass, but possess energy

speed of light

3.0 x 10^8 m/s

Wavelength

spacing between crests, repetitions. Measured in nm (10^-9 meters)

Frequency

Number of wave crests that pass an observer in 1 second. Measured in Hz

Visible Radiation

aka light. Violet(shortest wave length) to Red(longest wave length)

Visible electromagnetic radiation that is visible is ____ nm to ____ nm

400nm to 700 nm the Hz is about >10^15 and the energy(electron-volts) is around 1

Atoms:

fundamental building block of matter


made of neutrons, protons and electrons

The Study of a spectrum can reveal...

Composition of the atmosphere

The Doppler Effect

Change in wavelength that results when a source of waves and the observer are moving relative to each other. like a

Modern telescopes are all

reflectors


-Light traveling through lens is refracted
differently depending on wavelength
• Some light traveling through lens is absorbed
• Large lens can be very heavy, and can only be
supported at edge
• A lens needs two optically acceptable
surfaces; mirror needs only one

Resolution is proportional to

wavelength and inversely
proportional to telescope size.
Larger telescopes are better!

Atmospheric blurring:

Due to air movements


Solutions:
• Put telescopes on mountaintops, especially in deserts
• Put telescopes in space

Active optics:

Control mirrors in real time to adjust for change
in focus of mirror due to minute changes in temperature and
orientation of mirror

Mission to Mars Basic Facts

a=1.52 AU, eccentricity=0.09
Round trip light travel time > 6.3 minutes (up to 40 minutes!)
Radius 3397 km (0.5 R)
Density 3.9 gm/cm3
Length of day: 24.6 hrs
Inclination: 25.2 degrees
Atmospheric pressure (1/150th of Earth)
95% CO2
2.7% N2
0.03% H2O
Temperature:
Typically 50 C cooler than Earth.
Can get to 27 C in summer, drop by 100 C at night.

Feb. 24, 1969 Mariner 6

USAFlyby July 31; successful mission

Oct. 14, 1960 Korabl 5

USSR Failed in Earth orbit

Dec. 4, 1996 Mars Pathfinder

USA Landed July 4, 1997, one year mission
exceeded goals.

April 7, 2001 Mars Odyssey

USA Entered Mars orbit October 24, 2001.
Still in operation

Nov. 7, 1996 Mars Global Surveyor

USA Arrived Sept, 1997, Prime mission
began March,
1999 and ended January, 2001.
Ended in 2007

Mariner 4

First flyby (10,000km) of Mars, July 1965.


Powered using solar panels.

November 26, 2011 Curiosity

NASA Rover, still operational

November 5, 2013 Mars Obiter Mission

ISRO Orbiter. Entered Mars orbit
on September 24, 2014

November 18, 2013 MAVEN

NASA Orbiter. Reached Mars
September 22, 2014

Viking I & Viking 2

Orbiter
Studied Mars from orbit
Landers:
Landed on Mars through thin atmosphere.
Powered by devices which generate heat from radioactive
plutonium (radioisotope thermoelectric generators). Required
70W of power.
Took pictures, performed biological experiments

Viking 1

Mapped planet at resolution of 100m
Landed 20 July, 1976 on slope of Chryse Planitia (Plains of Gold)
Lander transmitted data until Nov 11, 1982

Viking 2

Landed September, 1976
Lander transmitted data until April 11, 1980

Descent of Viking 1 Lander

Used:Aerobreaking
At 6 km altitude, parachute
At 1.6 km, fired 3 retro engines:
Landing speed: 2 m/s
(4.5miles/hr)
Landing was done WITHOUT
NASA ground control

Phobos

Irregularly shaped with a radius of only 11 km. (our Moon has
a radius > 1700 km)
Orbits closer to Mars than any other
known moon orbits its planet.
Orbit is so close (~6000 km) that it
orbits Mars faster than Mars rotates.
Phobos is seen to rise and set twice a
day from the surface of Mars.

Deimos

Even smaller than Phobos (mean radius 6.2 km)
Because Deimos is further away it orbits
Mars slower than Phobos.
This means it is easier to get to, sunlit more
often, and easier to communicate with.

Conjunction Class

Spacecraft catches up with Mars on exactly the opposite side of the
Sun from Earth's original position.


To return, the astronauts wait until Mars is about 75o ahead of Earth,
Spacecraft is launched onto an inward arc, & Earth catches up with
them.

Opposition Class

Trajectories so called because Mars is at opposition at some point in the mission choreography.


the mission choreography.
Require more fuel.


These trajectories involve an extra burst of acceleration, administered en route.
Inbound (or outbound) mission (usually) swings by Venus

Long Stay Mission (Fast Transit)

Similar to conjunction missions.
Lower transit times (120 to 180 days).
Increase fuel use.
Longer time on Mars (up to 180 days).

Ion Class

Use low-thrust rockets (e.g., ion drive) to save fuel.
As rockets are too weak to pull free of Earth's gravity in one go,they slowly
expand their orbits spiraling outward.
Reaching escape velocity could take up to a year, which is a long time to
expose the crew to the Van Allen radiation belts that surround Earth.

Health Risks of Mars

Radiation: van Allen belts
Solar flares: Need shielded room for protection
Spacecraft damage?
Zero-g Spinning craft. Pressure suits
Bacterial infection. What if Mars does have bacteria? Different type so not dangerous?
(if crew member gets sick, do we bring them back?) Quarantine regulations? On Apollo missions, they were cumbersome, controversial & leaky.

In-Situ Fuel Production

React imported H2 with (Martian) atmospheric CO2 .


Liquid methane stored in tanks for the Martian Ascent Vehicle (MAV) for
methane/oxygen rocket engine.

Spirit & Opportunity

Both missions greatly outperformed their initial requirements. Spirit had a 90 Martian day mission. Was operational for 2269!
Became stuck in soft soil in May of 2009. Stopped communications in January 2010.
Opportunity is still operational having outperformed its designed lifetime by a factor of 40! Operational for almost 11years.

Thrust:

Force produced by rocket engine (thrust =M exhausts* Vexhaust ).

Exhaust Speed:

Speed at which gas is ejected from rocket.

ISP (Specific Impulse)

Measure of propellant efficiency. 1 pound of propellant with an ISP of
400 can produce one pound of thrust for 400 seconds.

Sample Burn Time:

How long a rocket engine must fire to accelerate a 25 ton payload
from LEO to escape velocity

Sample fuel ratio (i.e. mass fraction):

Fraction of total spacecraft mass taken up by propellant (for the 25
ton payload in LEO).

Chemical Rocket

Used by nearly all spacecraft launched to date.
Typically burn hydrogen and oxygen and use the expanding gases to
provide thrust.

Nuclear Fission:

An atom of high atomic number, like Uranium, is split into 2 lighter
atoms liberating energy. The 2 new atoms have LESS mass than the
initial atom, and hence ENERGY IS RELEASED.
Used to make electricity in Nuclear Power Plants.

1 pound of enriched Uranium (3% U235) is approximately equivalent to
??? gallons of gasoline!

1 pound of enriched Uranium (3% U235) is approximately equivalent to
10^6 gallons of gasoline!

Nuclear Fusion:

The joining of 2 elements of low atomic number to make a heavier element (e.g., hydrogen to helium). The mass of the new element is LESS than the combined mass of its constituents. In the process energy is liberated. IT IS THIS
PROCESS WHICH MAKES ENERGY IN THE SUN.

(T/F) Building a Nuclear Fusion
reactor is EXTREMELY
DIFFICULT. Still not
achieved!

TRUE

In the Sun the main energy producing nuclear reaction is

4 1H gives 4He + energy
Much of the energy produced is in the form of Gamma-Rays(very high energyMuch of the energy produced is in the form of Gamma-Rays
(very high energy electromagnetic radiation). The gamma rays are responsible for heating a star's core.

(T/F) Nuclear Fusion can only occur at very high temperatures, hence it can only occur in the inner core of the Sun.

True

(T/F) The reaction does not occur directly, but instead occurs in a series of steps.

True 3 Step Process

Nuclear Engines

Thrust is provided by streaming liquid hydrogen through a solidcore nuclear reactor. The H is heated to more than 2,500C and escapes through the rocket nozzle at high speed. In 1972, an engine achieved an ISP of 850s, burnt continuously for 90 minutes, and generated 250,000 pounds of thrust!

Gas Core Nuclear Fusion Engine ( GCNR)

Lots of design problems:
Can a stable vortex of hot uranium plasma be maintained?
Heat load on engine chamber: 100 million Watts/m2

Ion Engine

Developed in the 1950s
Uses electrical fields rather than heat to eject the propellant. Gaseous fuel, such as cesium or xenon, flows into a chamber and is ionized by
an electron gun. The voltage on a pair of metal grids accelerates the positively charged ions so that they shoot through the grid and out into
space.

Solar Sails

Use SOLAR radiation to provide thrust.
A photon has momentum as well energy. By reflecting photons
momentum is provided to the reflector & hence payload.

VASIMR

Variable Specific Impulse Magnetoplasma Rocket


Two thrust options.


By regulating the manner of heating and adjusting a magnetic choke,
the pilot can control the exhaust rate.
Low gear:
High thrust, low exhaust speed.
Used to climb out of Earth Orbit
High gear
Low thrust, BUT high exhaust speed.
Used for interplanetary cruise.

Matter—Antimatter Rockets

Dream at present!
Matter–antimatter annihilation:
p+ + p- → 2γ rays + other particles.
1,000 times more energy than nuclear fission

Solar Wind Propulsion

Create a magnetic bubble around a spacecraft.


Solar wind would push on bubble, accelerating the spacecraft.


Acceleration independent of distance from the Sun!

Space Elevators

Need:
Tall Tower (50km!) on Earth. A large mass orbiting the Earth. A cable (140,000 km long!) that connects the tower to the weight. Might be feasible to make the cable out of lightweight carbon nanotubes which are 100 times stronger than steel, A spacecraft would ride the cable into orbit.

Buckyballs & Nanotubes

New form of carbon: discovered in 1985.
Prior to 1985, only two forms of carbon known: graphite and diamond.

Transit Method

Brightness of the star is reduced as planet passes (transits) in front of the
star. Change in brightness illustrated above is exaggerated --- change in
brightness << 1% (Simulation).

Doppler Method

Spectral lines in the stellar spectrum move periodically about their laboratory
wavelength. From the wavelength shift the velocity of the star can be estimated, and
hence the mass of the companion star (using Kepler’s Laws) can be estimated

The Anthropic Principle

What we see must be restricted by the conditions necessary for the existence of observers. Conditions on Earth are (finely) tuned for life. The Anthropic Principle states that this obviously has to be so, otherwise we wouldn't exist. Life requires C, O etc for its existence. Thus for life to evolve, enough time must have passed for massive stars to eject material back into the interstellar medium so that the 2nd (& 3rd) generations of stars can form. Conversely the Universe can not be too old, otherwise all the stars would have burnt out. Thus the very existence of life requires that the age of the Universe fall within certain limits.

The Gaia Hypothesis

Life alters the environment to make it more hospitable.

Habitable Zone

Region about a star in which an Earth-like planet has a
temperature between the freezing and the boiling point of
water.

Drake Equation

What is the number, N, of technologically advanced
civilizations present in our galaxy?


N = r! fp ne fl fi fc L

The Average Distance between Civilizations

Assuming N=1000, and R=40,000 ly gives
r=8000 ly
i.e., if civilizations exist, they may all be very
far from us.

The Murchison meteorite

Fell in Australia, 1969
Carbonaceous chondrite
Contains many of the amino acids found in living cells
Indicates that limited chemical evolution has occurred other
than on Earth.

Life in hostile environments.

Sites of undersea volcanic activity.
Hydrothermal vents expel boiling water.
They are sulfur rich, but oxygen poor water. Feeds extremeophilic life by a process known as chemosynthesis. Chemosynthesis is analogous to photosynthesis, but operates in total darkness.