OEM 101

Question 1

What kind of Orbits are the most commonly used orbital regime?

Answer 1

LEO Orbits

Question 2

What is the period and altitude of LEO?

Period: time it takes for one orbit

Answer 2

A period of 90 to 120 minutes and an altitude of < 2000 km

Question 3

What does LEO stand for?

Answer 3

Low earth orbit

Question 4

What type of missions are LEO orbits involved with?

Answer 4

SATCOM: iridium and star link
Earth observation
Weather/earth sensing/ISR

Question 5

What does MEO stand for?

Answer 5

Medium earth orbit

Question 6

MEO has a period of what?

Answer 6

Milo has a period of greater than 120 minutes in less than 24 hours.

Question 7

What missions does MEO support?

Answer 7

Position, navigation, timing (PNT)
SATCOM
Persistent earth, observation

Question 8

What is the period of a geosynchronous orbit (Geo)?

Period: time it takes for one orbit

Answer 8

24 hours, matches the rotational speed of the earth.

Question 9

MEO orbit with a period at about 12 hours is called what?

Answer 9

Semi synchronous orbit

Question 10

What is the altitude of Geo?

Answer 10

35,786 km

Question 11

What missions are covered in Geo?

Answer 11

SATCOM Dash DSCS, MILSTAR, WGS
Weather – GOES
Missile warning, Dash SBIRS GEO, DSP

Question 12

Three satellites in GEO can give ________ coverage with the exception of the polar regions.

Answer 12

Global

Question 13

what GEO orbit has an inclination and eccentricity that both equal zero?

Answer 13

Geo-stationary orbit

Question 14

What special orbit is it near the polar inclination, and is in Leo orbit with a retrograde motion?

Answer 14

Sun-synchronous orbit

Question 15

What orbits primarily support the mission of SATCOM and missile warning?

Answer 15

Highly-elliptical orbits (HEO)

Question 16

What is the field of regard?

Answer 16

It is the portion of the Earth surface that is geometrically visible from the satellites position in space.

Question 17

What is the field of view?

Answer 17

It is the instantaneous coverage area capable of being seen by the payload.

Question 18

The length of time a satellite has line of sight to a point on earth is called what?

Answer 18

Dwell time

Question 19

Which orbit is highly eccentric, it’s orbit creates Longville times, covers the gap left by the GEO constellation and it is normally over northern latitudes mission requirements?

Answer 19

Highly elliptical orbit (HEO)

Question 20

Give two examples of highly elliptical orbits (HEO)? By name.

Answer 20

Molniya orbit
Tundra orbit

Question 21

A Satellite at a _______ altitude will be moving _______ Intend to have a shorter dwelltime.

Answer 21

Lower, faster

Question 22

What reference frame is used to describe orbits, define classical orbital elements, and is considered non-rotating?

Answer 22

The ecliptic reference frame

Question 23

What reference frame is used to describe ground tracks, the path, a satellite travels, relative to the Earth surface and is considered rotating with earth?

Answer 23

ECEF reference

Question 24

What angle do we used to determine when to do a lunch, in order to launch any specific are R a a N?

Answer 24

Sidereal angles

Question 25

What describes were defines the size of an orbit?

Answer 25

Semi major axis

Question 26

Define eccentricity.

Answer 26

The shape of an orbit.

Question 27

What is the apogee?

Answer 27

The furthest point from the Earth.

Question 28

What is the perigee?

Answer 28

The closest point to the Earth.

Question 29

Are the inclination describes the _____ of the orbit.

Answer 29

Tilt

Question 30

The inclination of a satellite orbiting earth is measured off of the ___________.

Answer 30

Equatorial plane

Question 31

Eccentricity in their corresponding shapes.

Answer 31

Take minute to study! E = 0 circle 0 < e < 1 ellipse e= 1 parabola e > 1 hyperbola

Question 32

What is the corresponding shape to the eccentricity e = 0

Answer 32

Circle

Question 33

What is the corresponding shape to the eccentricity e >1?

Answer 33

Hyperbola

Question 34

What is the corresponding shape to the eccentricity 0 < e < 1?

Answer 34

Ellipse

Question 35

What is the corresponding shape to the eccentricity e= 1?

Answer 35

Parabola

Question 36

The inclination is measured from the __________ to the _________.

Answer 36

The inclination is measured from the equatorial plane to the orbital plane.

Question 37

True anomaly defines the satellites ________.

Answer 37

Location

Question 38

Right ascension of the sending no defines the ______ of the orbit

Answer 38

Twist

Question 39

The right ascension of the sending node ( RAAN) is measured from the ________ to the _______.

Answer 39

Vernal equinox, ascending node

Question 40

Types of orbits and their degrees.

Answer 40

Take a minute to study! i = 0°, 180° : equatorial i = 90° : polar 0° < i < 90° : prograde 90° < i < 180° : retrograde

Question 41

Name the type of orbit : i = 0°, 180°

Answer 41

equatorial

Question 42

Name the type of orbit : i = 90°

Answer 42

Polar

Question 43

Name the type of orbit : 90° < i < 180°

Answer 43

Retrograde

Question 44

Name the type of orbit: 0° < i < 90°

Answer 44

Prograde

Question 45

The argument of perigee is measured from the _________ to __________.

Answer 45

Ascending node to the perigee

Question 46

_________ describes orientation of an orbit with in the orbital plane.

Answer 46

Argument of perigee

Question 47

The true anomaly describes the ______ of a satellite within the orbit.

Answer 47

Location

Question 48

True anomaly is measured from the_______ to the _________ _________.

Answer 48

Perigee, satellite location

Question 49

How long is the period of a satellite and Leo ?

Answer 49

90-120 minutes

Question 50

Which orbits inclination eccentricity both equal 0, is it GEO-stationary or Geo-synchronous?

Answer 50

Geo-stationary

Question 51

What orbit creates long do all times, normally over the northern latitudes permission requirements?

Answer 51

HEO or highly elliptical orbit

Question 52

What operational consideration describes a portion of the Earth surface that is geometrically visible from the satellites position in space?

Answer 52

Field of regard

Question 53

What operational consideration describes the instantaneous coverage area capable of being seen by the payload?

Answer 53

Field of view

Question 54

What operation consideration describes the length of time a satellite has line of sight to a point on earth?

Answer 54

Dwell time

Question 55

Semi major axis = _________ Range? Description?

Answer 55

=a Range : 0 to infinity Description : size of orbit

Question 56

Eccentricity =__________ Range? Description?

Answer 56

= e Range : 0 to 1 Description : shape of orbit

Question 57

Inclination = _________ Range? Description?

Answer 57

=i Range : 0 to 180° Description: tilt of orbit

Question 58

(RAAN) right ascension of the descending node = ________ Range? Description?

Answer 58

= “omega symbol” Range : 0 to 360° Description : twist of orbit

Question 59

Argument of perigee =_________ Range? Description?

Answer 59

=w Range : 0 to 360° Description : orientation of orbit

Question 60

True anomaly = _________ Range? Description?

Answer 60

= v Range : 0 to 360° Description : location of orbit

Question 61

Which of newtons laws states- to every action there is always an opposed and equal reaction?

Answer 61

Third law

Question 62

Which of newtons laws states - an object either remains at rest, or continues to move at a constant velocity, unless acted upon by an external force?

Answer 62

First Law

Question 63

Which of newtons laws state-any two bodies attract one another, with a Force, proportional to the product, their masses and inversely proportional to the square of the distance between them?

Answer 63

Law of Universal gravitation

Question 64

Which of newtons laws states - the rate of change of momentum is proportional to the Force impressed, and is in the same direction as the force?

Answer 64

Second law

Question 65

Which of Kepler’s laws states - the planets, orbit the sun in elliptical orbits, with the sun at one focus of the ellipse?

Answer 65

First law

Question 66

Which of Kepler’s laws states - the period of the orbit squared is proportional to the semi major axis cubed?

Answer 66

Third law

Question 67

How long is a sidereal day?

Answer 67

Approximately 23 hours 56 minutes in 04.09 seconds.

Question 68

What are the three fundamental plans?

Answer 68

Equatorial plane, ecliptic plane, orbital plane

Question 69

Equatorial plane

Answer 69

Passes through earths equator

Question 70

Ecliptic plane

Answer 70

Plane of earths orbit around the sun (separated from equatorial plane due to the tilt of earths axis)

Question 71

Which of Kepler’s laws states the orbiting body must be moving faster when it is closer and slower when it is farther away?

Answer 71

Second law

Question 72

What does ECI stand for?

Answer 72

Earth centered inertial frame

Question 73

And what is the principal direction of ECI?

Answer 73

Vernal equinox

Question 74

What is the origin of ECI?

Answer 74

Earth

Question 75

What is the fundamental plane of ECI?

Answer 75

Equatorial

Question 76

What does ECEF stand for?

Answer 76

Earth centered earth fixed frame

Question 77

What is the origin of ECEF?

Answer 77

Earth

Question 78

What is the fundamental plane of ECEF?

Answer 78

Equatorial

Question 79

What is the principal direction of (ECEF) earth centered earth fixed frame?

Answer 79

0° latitude, 0° longitude “rotating with the Earth”

Question 80

Is earth centered inertial rotating or non-rotating?

Answer 80

Non-rotating

Question 81

Is earth centered earth fixed rotating, or non-rotating?

Answer 81

Rotating

Question 82

The ECI in the ECEF reference frames utilize what as their fundamental plan?

Answer 82

Equatorial plane

Question 83

Define perifocal frame.

Answer 83

The perifocal frame is a frame of reference from an orbit. The frame is centered at the focus of the orbit ( the celestial body about which the orbit is centered)

Question 84

What does RIC stand for?

Answer 84

Radio in track cross track frame

Question 85

What is the origin of the perifocal plane?

Answer 85

Earth

Question 86

What is the fundamental plane of the perifocal plane?

Answer 86

Orbital

Question 87

What is the principal direction of the perifocal plane?

Answer 87

Eccentricity of vector (points towards perispsis)

Question 88

What is the origin of RIC (radical in track cross track frame) ?

Answer 88

Satellite

Question 89

What is the fundamental plane of RIC ( radical in track cross track frame) ?

Answer 89

Orbital

Question 90

What is the principal direction of RIC ( radical in track cross frame) ?

Answer 90

Radical (points, directly way from the Earth)

Question 91

I which reference frame uses a satellite as its origin?

Answer 91

( RIC) radical and track cross track

Question 92

What is the principal direction of the perifocal reference frame?

Answer 92

Eccentricity vector

Question 93

What is the principal direction of the RIC reference frame?

Answer 93

Radical

Question 94

We use the sidereal angle to determine ________ to do a launch.

Answer 94

When

Question 95

Sidereal time is measured as the angle between the_______ of the earths-inertial and ________ frames

Answer 95

principal axes, earth-fixed

Question 96

What does SSO stand for?

Answer 96

Sun -synchronous orbit

Question 97

How long is the period of a satellite and Leo?

Answer 97

90 to 120 minutes

Question 98

The same sun, angle or shadow every orbit is a characteristic of what orbit?

Answer 98

Sun-synchronous orbit (SSO)