Unit 2.4 COE Flashcards
(11 cards)
𝑎
Semi major axis Describes - size of the orbit Range - 0 to infinity Measured from: Perigee To: halfway to apogee
𝑒
Eccentricity Describes - Shape of the orbit Range - 0 to infinity 𝑒=0: Circular Orbit 01: Hyperbolic Orbit
𝑖
Inclination Describes - tilt of the orbit Range - 0 to 180 Measured from: K vector/equatorial plane To: H vector/orbital plane Equatorial: 0, 180 Polar Orbit: 90 Prograde Orbit: 0 - 90 Retrograde Orbit:90 - 180
Ω
Right Ascension of the Ascending Node (RAAN) Describes: Twist of the orbit Range - 0 to 360 Measured from: Vernal Equinox To: Ascending node
𝜔
Argument of Perigee Describes: orbit rotation Range - 0 - 360 Measured from: Ascending Node To: Perigee
𝜈
True Anomaly Describes - satellite location Range - 0 - 360 Measured from: Perigee To: Satellite
When 𝑒=0
There is no perigee, thus 𝜔 and 𝜈 are undefined
Use argument of latitude, 𝑢, measured from ascending node to spacecraft’s position vector, 𝑟⃗, in the direction of the spacecraft’s motion
When 𝑖=0
There is no ascending node, thus Ω, and 𝜔 are undefined
Use Longitude of perigee, Π, measured from the principal direction, 𝐼̂, to perigee, 𝑒⃗, in the direction of the spacecraft’s motion
When 𝑒=0 and 𝑖=0
There is no perigee or ascending node, thus Ω, 𝜔, and 𝜈 are undefined
Use True longitude, 𝑙, measured from the principal direction, 𝐼̂, to the spacecraft’s position vector, 𝑟⃗, in the direction of the spacecraft’s motion
TLE
Two-Line Element. Used to quantify satellite position, velocity, orbital perturbations showing all 6 orbital elements (mean anomaly instead of true anomaly) and values quantifying expected drag of a satellite
Orbital Propagation
Prediction of the orbital characteristics of a satellite at some future date given the current orbital characteristics
