Design
| Enviro |
Astro | Propulsion
| Power | Thermal
| Structures | AD&C
| CDHS |
Test
Interplanetary
transfer considerations
drive
the launch window, propellant requirements, launch
vehicle, type of orbital entry maneuver and often
the financial budget. Mission design teams at NASA/Caltech
JPL rely on interplanetary transfer mathematical
predictions to develop trajectories for travel from
Earth to other planets.
Interplanetary
Transfer
Patched-conic
approximation separates the interplanetary trajectory
into distinct regions: the departure, where the
spacecraft's planetocentric trajectory is in the
Earth's gravitational sphere of influence (SOI);
the transit, where the now heliocentric trajectory
is within the Sun's SOI; and finally the arrival,
where the trajectory is again planetocentric and
the target planet's gravitational force dominates.
Solving this series of two-body problems in order
and patching their results together gives an solution
for the complete transfer.
Gravity-assist
is a method of conserving propellant by leveraging
the gravity of planets in our solar system to "sling
shot" spacecraft on their trajectory to a target
planet. The spacecraft velocity is increased with
each planetary encounter without expending propellant.
