OEM 2 Flashcards
What is the movement of a satellite due to changing mission requirements?
Station Changing
What consists of small maneuvers that may be needed at regular intervals due to orbital perturbations that caused satellites to drift from their desired position/orbit?
Station Keeping
What boundary requires operators to fire thrusters to station keep?
Control Bound
What boundary causes satellites to naturally drift to station keep?
Turn Around Bound
Which maneuver is required when the threat of conjunction reaches user-defined threshold criteria?
Collision Avoidance
Where are satellites maneuvered when they reach end of life?
Disposal orbit or de-orbit into the Earth’s atmosphere
Maneuvers change which vector for the satellite?
Velocity
Which COEs do in-track maneuvers change?
Semi-major axis and eccentricity
Which COEs do radial maneuvers change?
Argument of Perigee and Eccentricity
Which COEs do cross-track maneuvers change?
Inclination and/or RAAN
Where must cross-track maneuvers be conducted to maintain RAAN?
Ascending or descending node
What maneuvers make up a Hohmann transfer?
Two in-track maneuvers
What is the time of flight for a Hohmann transfer?
Half the period of the transfer orbit
Which maneuver changes inclination or RAAN while keeping all other COEs the same?
Simple plane change
At GSO, how much does ∆V cost per degree change?
50 m/s
At LEO, how much does ∆V cost per degree change?
130 m/s
Which is less expensive: plane change maneuvers or non-plane change maneuvers?
Non-plane change maneuvers
Which is more efficient when conducted farther from Earth: plane change maneuvers or non-plane change maneuvers?
Plane change maneuvers
Where should the second burn of a Hohmann transfer (combined plane change) occur to save fuel?
Slowest point of the orbit (Apogee)
Where is a satellite maneuvered during rendezvous?
Close to another satellite or a point in space
What are 6 reasons for conducting rendezvous?
- Service an existing satellite
- Refuel a satellite
- Inspect a satellite
- Intercept a satellite
- Fill a constellation slot
- Fill a geostationary longitude slot
What two variables must be determined to conduct a rendezvous?
Burn (direction/magnitude/∆V) and Timing
What is the difference in two satellites’ mean motion relative to each other?
Drift Rate
Which rendezvous is used for two satellites in the same orbit, but different true anomalies?
Co-orbital
How does a chaser satellite speed up to catch an RSO in the same orbit?
Negative in-track burn to decrease orbit size
How does a chaser satellite slow down to catch an RSO in the same orbit?
Positive in-track burn to increase orbit size
What does a phasing orbit alter between two satellites?
Angular distance
Multiple phasing orbits saves fuel for which rendezvous: co-orbital or co-planar?
Co-orbital
Which should be used for co-planar rendezvous to save fuel: multiple phasing or Hohmann transfer?
Hohmann transfer
For co-planar rendezvous, which 2 COEs must be the same? Which one must be different?
Inclination and RAAN / Semi-major axis
What must be correct for a fuel-efficient co-planar rendezvous via Hohmann transfer?
Angle between the chaser and RSO
Plane-matching rendezvous are always required when launching satellites into which orbit?
Geostationary
When should a plane-matching rendezvous be conducted for fuel efficiency?
Apogee
