OEM FINAL Flashcards
_______orbits are the most commonly used orbital regime.
LEO
Leo has a period of _______ to ______minutes and a altitude of _______kms or less.
90-120 minutes
2,000kms
MEO has a period of greater than _______120 minutes and less than _____hours.
120 minutes
24 hours
MEO supports the missions of ______,_______, and ___________.
PNT,SATCOM and Persistent Earth Observation.
_________ is a MEO orbit with a period of about 12 hours.
Semi-Synchronous Orbit
_______orbits have a period of about 24 hours and an altitude of __________kms.
GEO
35786kns
Three satellites in GEO can give ________coverage with the exception of the polar regions.
global
_________is a GEO orbit where inclination and eccentricity both equal 0.
Geo Stationary Orbit
_________ is a special, near-polar inclination, LEO orbit with a retrograde motion.
Sun-Synchronous orbit (SSO)
HEO orbits allow max coverage at higher latitudes, covering the gap left by _______orbits.
GEO
________orbits primarily support the missions of SATCOM and missel warning.
HEO
Field of ________is the portion of Earths surface that is geometrically visible from the satellites position in space.
regard
Field of ______ is the instantaneous coverage area capable of being seen by the payload.
view
The length of time at satellite has line of sight to a point on the Earth is called _________.
Dwell Time
The _______refrence frme is used to describe orbits, define classical orbital elements and is considered “non-rotating”
ECI
The ECEF reference frame is used to describe ground tracks, the path a satellite travels relative to the earth’s surface and is considered “___________” with earth.
rotating
The _________ reference frame is best used to describe motion from an individual satellite’s perspective.
RIC
Radial intrack cross track
we use _______angles to determine when to do a launch, in order to launch at a specific RAAN.
Sidereal
_________describes the size of an orbit.
Semi-major axis
The greater the energy of an orbit, the larger the _________.
size
Eccentricity describes the _______of an orbit.
shape
E=0
circle
0<e<1
elipse
e=1
parabola
e>1
hyperbola
Inclination describes the _______ of the orbit.
tilt
The inclination of a satillite orbiting earth is mesured off of the _______plane.
equitorial plane
i=0 degrees 180 degrees
equitorial
i=90 degrees
Polar
0 degrees < i < 90 degrees
Prograde
90 degrees < i < 180 degrees
retrograde
____________describes the TWIST in the orbit.
RAAN
Right accension of the accending node
RAAN is measured from _______ to _________.
vernal equinox, ascending node
__________ describes the ORIENTATION of an orbit with the orbital plane.
argument of perigee
Argument of perigee is measured from _________to _________.
ascending node, perigee
True anomaly describes the _______ of a satellite within the orbit.
location
________ is measured from perigee to the satellite location.
true anomaly
how long is the period of a satellite in LEO?
90-120 minutes
what statement is true about GEO orbits?
a.) Geo-stationary i=0 e=0
b.) Geo-synchronous i=0 e=0
a
The same sun angle or shadow every orbit is a characteristics of what orbit?
(SSO) Sun-synchronous orbit
What orbit creates long dwell times, normally over the northern latitudes for mission requirements?
a.) LEO b.)MEO c.)HEO d.)GEO
c
What operational consideration describes the portion of earths surface that is geometrically visible from the satellite’s position in space?
a.) field of regard b.) field of view c.)dwell time
a
What operational consideration describes the instantaneous coverage area capable of being seen by the payload?
a.) field of regard b.)field of view c.) dwell time
b
