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ASCBC PHASE 1 AND 2 > PHASE 1 > Flashcards

PHASE 1 Flashcards

1
Q

Identify the primary goals of the following space programs: J

  1. MERCURY
  2. GEMINI
  3. APOLLO
A
  1. effects of space flight on humans
  2. skills necessary for eventually going to the moon
  3. landing a man on the mood and returning him
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2
Q

HOW ARE SATELLITES TRAVELING AROUND THE EARTH?

A

THEY ARE FALLING TO EARTH

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3
Q

DEFINE ORBIT SIZE:

A

SEMI MAJOR AXIS (A)

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4
Q

DEFINE ORBIT SHAPE

A

Eccentricity (e)
Perfect Circle e=0
elliptical orbit 0

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5
Q

define orbit tilt

A

inclination: i

the tilt or angle of the orbital plane w/ respect to the equatorial plane.

also, determines your max latitude of your ground trace

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6
Q

define orbit twist

A

right ascension of the ascending node

the ascending node is defined as the point where the orbit intersects the equatorial plane

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7
Q

define apogee

A

the point when an object is at the LEAST velocity (slowest) and the Farthest (away) from the body it orbits…in this case the earth.

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8
Q

define perigee

A

the point when an object is at the GREATEST velocity (fastest) and the CLOSEST to the body it orbits.

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9
Q

define prograde

A

rotational movement that is WITH the Earths rotation

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10
Q

define retrograde

A

rotational movement AGAINST the earths rotation

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11
Q

What is EM spectrum

A

Range of frequencies

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12
Q

EM energy that is emitted and/ or reflected off an object from a natural source, such as the sun is called?

A

Passive collection

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13
Q

EM energy that is reflected off an object from a transmitting source is known as?

A

active collection

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14
Q

list 3 characteristics of EM radiation

A
  • streams of photons
  • travels in a wavelike pattern
  • moves at speed of light
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15
Q

describe the relationship between wavelength and frequency

A

Low frequency is a long wavelength

it is inversely proportionate

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16
Q

describe computing bandwidth and how it relates to EM

A

amount of data (symbols) carried from one point to the other

Bandwidth: the range of frequencies (that is, the difference between the lowest and highest frequencies carried) that make up a signal is called a bandwidth.

google: informit.com Telecommunications Technology Fundamentals

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17
Q

what is the relationship between spectrum and bandwidth

A

more bandwidth = more data

the spectrum of a signal is the range of frequencies contained in the signal. the bandwidth is the difference between the lowest and highest frequency in the spectrum.

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18
Q

T/F?

The radio frequency portion of the EM spectrum is uncrowded and has room for growth?

A

false

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19
Q

Which portion of the EM spectrum is used for satellite communications?

A

microwave

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20
Q

which type of radar is dependent on alerting and cueing systems in order to be effective?

A

track radar “soda straw beam”

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21
Q

what factor determines radar discrimination performance?

A

frequency

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22
Q

When transmitting a signal, in order for it to be received the signal must be ___ than the strength of the background noise

A

greater

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23
Q

which radar has a broad area search beam that is continuously searching?

A

surveillance radar

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24
Q

Which portion of the EM spectrum can penetrate the Earth’s atmosphere?

A

Radio/ Microwave, IR, Visible, and UV

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25
Q

What is Solar Wind?

A

Charged particles continuously emitted from the sun

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26
Q

Space weather results from what 2 types of Solar Emissions?

A
  • Charged particles

- Electromagnetic radiation

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27
Q

What military systems can be degraded by space weather?

A

GPS, Intel Collection, HF Communications, SATCOM (UHF/ SHF), Radar Systems, SATCOM operations in orbit and on ground

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28
Q

What is the length of a typical solar cycle?

A

11 years

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29
Q

What are the greatest effects on LEO spacecraft during a period of increased solar activity?

A

atmospheric drag

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30
Q

Describe the Van Allen Belts

A
  • Charged particles emitted from the sun and trapped by the earths magnetic field
  • expand and contract based on the suns activity
  • potentially harmful to satellites due to the radiation

google it for an image.

-charged and energized particles that are captured by and held around a planet (by the magentosphere) Earth has two such belts, and others may temporarily be created.

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31
Q

Describe the harmful effects of space weather on satellites

A
  • Atmospheric Drag
  • Computer logic errors
  • radiations damage
  • spacecraft charging
  • scintillation
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32
Q

Define Solar conjunction

A

Sun appears directly behind a GEO COMSTAT as viewed by the ground receiver

33
Q

how are satellites traveling around the earth

A

falling due to gravity

34
Q

define basic terms that describe an orbit

A
  • period: how long the satellite takes to orbit the earth one time
  • apogee: point of orbit that’s furthest away from earth
  • perigee: point of orbit that’s closest to earth
  • prograde: rotates with the earth rotation
  • retrograde: rotates against the earth’s natural rotation
35
Q

what are the takeaways from Keplers 3 laws?

A
  • Law of Orbits: orbits of the planets are ellipses with the sun at a focus (distance from foci to point on ellipse is constant)
  • Law of Areas: orbits of the planets sweep out equal areas in equal time (apogee-slow/ perigee-fast)
  • law of periods: square of the orbit period is proportional to the cube of the average distance to the Sun (Larger orbits have longer periods)
36
Q

describe LEO:

A
  • Lower earth orbit
  • Typically, circular orbit
  • 200-900 miles above earths surface
  • 90-120 minute period
37
Q

sub-categories of LEO

A
  • Polar

- Sun-Synchronous

38
Q

Missions of LEO

A
  • Imagery
  • Weather
  • Manned (ISS)
39
Q

Describe MEO

A
  • Medium Earth Orbit
  • Typically, Circular Orbit
  • ~12,500 miles above earths surface
  • 12 hour period
40
Q

Sub-category of MEO

A

Semi-Synchronous

41
Q

Missions of MEO

A

GPS

42
Q

Missions of GEO

A

SATCOM

Missile Warning

43
Q

Describe GEO

A
  • Geosynchronous Earth Orbit
  • Typically, circular orbit
  • ~22,300 Miles above earth’s surface
  • 24-hour period
44
Q

Describe HEO

A
  • Highly Elliptical Orbit
  • High eccentricity (not circular)
  • Long dwell time over one of the poles
  • ~200 and ~24,000 miles above earth’s surface
  • 12 hour period
45
Q

Sub-category of HEO

A

Molniya

46
Q

Missions of HEO

A

High-Latitude Comms

Missile Warning

47
Q

How does a satellites orbit inclination relate to its ground trace?

A

Inclination of the orbit determines the maximum latitude the ground trace will reach. both above and below the equator. (45degrees N/ 45degrees S)

48
Q

What is a sun-synchronous orbit and why is it special for imagery satellites?

A

It is a polar orbit where the satellite passes over the same part of the Earth at roughly the same local time each day (i.e. the surface illumination angle will be nearly the same every time) allows for shadow analysis (to measure / track changes of items)

49
Q

A _______ sensor collects naturally occurring EM energy that is emitted by and / or reflected off an object. Think telescopes

A

passive

50
Q

A _________ sensor provides its own EM energy source for collection, which is reflected off an object and collected back by the transmitting source (think radar)

A

active

51
Q

list the 3 characteristics of EM radiation

A
  1. Stream of photons
  2. Travels in a wavelike patter (talking wavelengths here)
  3. moves at the speed of light
52
Q

describe the relationship between wavelengths and frequencies

A

it is inversely proportional.

the higher the frequency the smaller the wavelength (think xrays or gamma rays). the lower the frequency the larger the wavelength (think radio waves)

53
Q

Define the EM spectrum bandwidth and computing bandwidth.

how are they related

A

EM Spectrum: the range of frequencies that make up a signal (in hertz)…gHz, mHz…(difference between lowest and highest)

Computing Bandwidth: the amount of data carried from one point to another

the relationship: the higher the frequency, the more cycles per second and more cycles equal more data

54
Q

which portion of the EM spectrum is utilized for satellite communications?

A

microwaves

55
Q

Which type of radar is dependent on cueing systems in order to be effective?

A

Track Radar

56
Q

what is the primary factor that determines RADAR performance?

A

Frequency

the higher the frequency, the more details, affects the discrimination performance and design of a radar…i.e. X band…ada

57
Q

What are two types of solar emissions that are continuously emitted from the sun and are the cause of space weather impacts on earth?

A

Solar Wind (Charged particles)

EM Radiation (energy)

58
Q

Describe Solar Wind

A

the continuous flow of charged particles from the sun

59
Q

what is the typical length of a solar cycle?

A

11 years, solar activity occurs on an 11 year cycle

60
Q

what are the greatest effects on LEO spacecraft during a period of increased solar activity?

A

Atmospheric Drag-mostly effects LEO, can cause them to deorbit quicker

61
Q

what are some of the harmful effects of space weather? (4)

A
  1. atmospheric drag
  2. spacecreaft charging (highly charged electrical current discharges internally and can damage components)
  3. computer logic error (0s become 1s and vice versa)
  4. electromagnetic discharge (zing)
62
Q

A collection of _______ gathered in place by earths magnetic field. they can ____ and ____ in response to incoming energy from the sun, and are particularly harmful to satellite in ____ due to damaging radiation…this is from particles trapped in Van Allen Belts.

A
  1. charged particles
  2. expand and contract
  3. HEO (because HEO spends a lot of time at the poles
63
Q

Define Solar conjunction

A

When a GEO COMSTAT satellite is in front of the sun…with the sun behind it as seen from the view point of the control on ground…think eyeball sees light…with sun behind it, we are unable to fully pinpoint the traffic light because we are focusing on the sun

64
Q

what effect does a solar conjunction have on military systems?

A

Auto tracking: antenna assemblies lock onto sun

data-loss: likely to occur while aperture is aligned with the sun

65
Q

what are some mitigation techniques used in the case of a solar conjunction?

A
  • disable auto-tracking
  • shift to an alternate comms path

this is all easy to do because it is pretty predictable of knowing where a satellite will be at any given time

66
Q

describe scintillation

A

scintillation is caused by an increased presence of charged particles (emanated from the sun). this can cause the ionosphere to snap back to earth from the earth’s magneto-tail when they touch on the ‘dark side’ of earth

67
Q

what causes scintillation

A

geomagnetic storms

68
Q

scinillation happens at what time of day and where?

A

scintillation happens at night and happens along the +/- 20 degrees North or South of the equator (latitude) … the lines that follow parallel to the equator…longitude is up and down

69
Q

What military systems can be degraded by space weather?

A

UHF, SHF, SATCOM, GPS, ISR Systems, RADAR systems

70
Q

Define the 6 classical orbital elements: Orbit SIZE

A

-orbit size: (semi-major axis) how big an orbit is

71
Q

Describe the six classical orbits: ORBIT SHAPE

A

-orbit space: (eccentiricty) how round or stretched out an orbit is…

0=CIRCULAR
MORE THAN 0 = ELLIPTICAL

72
Q

Describe the 6 classical orbits: ORBIT TILT

A

-orbit tilt (inclination): tilt/ angle of the orbital plane with respect to the equatorial plane

73
Q

Describe the 6 classical orbits: ORBIT TWIST

A

-orbit twist (right ascension of the ascending node): the orbital planes orientation with respect to an inertial reference point

74
Q

Describe the 6 classical orbits: ORBIT ROTATION

A

-orbit rotation (argument of perigee): angle measured along the orbital path between the ascending node and perigee

75
Q

Describe the 6 classical orbits: SATELLITE POSITION

A

-Satellite position (True anomaly): spacecrafts actual position within the orbit, measured in the direction of spacecraft motion

76
Q

What are Keplers 3 laws?

A
  • Law of Orbit
  • Law of Area
  • Law of periods
77
Q

Keplers three Laws: Law of Orbit

A

Law of Orbit that the distance from a foci point on ellipse is constant

78
Q

Keplers three Laws: Law of Areas

A

Apogee: - slow

Perigee: -fast

79
Q

Keplers three Laws: Law of Periods

A

the larger the orbit, the longer orbit time will be…think sun with pluto, its way out there, orbit will take hundreds of years to go around the sun.

ASCBC PHASE 1 AND 2 (9 decks)

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