Design
| Enviro |
Astro | Propulsion
| Power | Thermal
| Structures | AD&C
| CDHS |
Test
Atmospheric
drag
provides a method of bleeding off energy from a
spacecraft without using propulsion. Spacecraft
thermal protection shields (TPS) insulate against
resultant high stagnation point heating temperatures.
Aeroassist maneuvers reduce spacecraft propellant
requirements, launch weight and launch vehicle expense.
Aeroassist
Precise
atmospheric density predictions are necessary for
all of these techniques. Mathematical atmospheric
models which produce these predictions are derived
from observations of orbiting satellites. For example,
Mars Global Surveyor (MGS) atmospheric reports were
used for Mars Odyssey aerobraking.
Re-entry
(Direct Entry) is the method employed by such missions
as Apollo and the Space Shuttle to slow down and
enter the atmosphere.
Aerobraking
uses the atmosphere over long periods of time to
slowly circularize elliptical orbits. Each revolution
the spacecraft dips a little into the atmosphere
until the final orbit is achieved. This process
could take months.
Aerocapture
very aggressively uses the atmosphere to slow spacecraft
from interplanetary trajectories into a final orbit.
Unlike aerobraking, penetration into the atmosphere
is much deeper and lasts only minutes. If the flight
path angle is too shallow, the spacecraft "bounces"
off the atmosphere into space; if the flight path
angle is too steep, the spacecraft will burn up.
Despite its high propellant savings, aerocapture
technology has not been demonstrated to date.
