Design
| Enviro |
Astro | Propulsion
| Power | Thermal
| Structures | AD&C
| CDHS |
Test
Spacecraft
are required to maneuver
for
mission accomplishment. Examples include parking
to final orbit boosts and a Space Shuttle rendezvous
with the International Space Station.
Maneuvering
Perigee
is the point in a satellite's orbit closest to the
Earth.
Apogee
is the point in a satellite's orbit farthest from
the Earth.
DV
(delta V) is an instantaneous spacecraft velocity
change tangent to the orbit. Total DV is used to
determine the amount of propellant required to complete
a mission throughout the life of a spacecraft. Total
DV requirements drive the propulsion system design.
A
transfer orbit is
the trajectory between one orbit to another. Often,
transfer orbits are used to raise a satellite from
parking orbit (~300 km) to geosynchronous orbit
(~35,7890 km).
Hohmann
transfer
is
the most fuel-efficient method to move satellites
from parking orbit to a coplanar final mission orbit.
It uses an elliptical transfer orbit tangent to
the initial and final orbits.
Plane
changes
come in two varieties: a simple plane change, where
only the direction changes; or a combined plane
change, where both the direction and magnitude change.
In terms of DV, these are most efficient when executed
at apogee of the elliptical transfer orbit, where
satellite velocity is slowest. Plane changes in
general are the most costly maneuver in the DV budget.
