Aero-braking assisted ascending node plane changes using differential J2 precession
AssigneeAtomos Nuclear and Space Corporation
InventorKieran Wilson
Life of this patent
Estimating the term…
Abstract
A method of moving a spacecraft from an initial orbit to a final orbit includes providing a spacecraft with thrusters traveling in an initial orbit that has a first RAAN. Thrusters are activated to move the spacecraft into a transfer orbit having more eccentricity than the initial orbit. A RAAN of the transfer orbit changes over time toward a target RAAN. The spacecraft enters an aerobraking orbit wherein the spacecraft is exposed to increased atmospheric drag to reduce orbit energy and reduce an apoapsis radius. Thrusters may be activated to increase the periapsis radius of the aerobraking orbit and cause the spacecraft to move into the final orbit, the final orbit having a final RAAN different from the first RAAN.
Claims20
A method of moving a spacecraft from an initial orbit to a final orbit, the method comprising:
- providing a spacecraft with thrusters traveling in an initial orbit, wherein the initial orbit has an initial semimajor axis and an initial right ascension of the ascending node (“RAAN”);
- defining a target RAAN, a target apoapsis radius, and a target periapsis radius for a final orbit;
- activating the thrusters such that the spacecraft moves from the initial orbit to a transfer orbit, wherein the transfer orbit comprises:
- a transfer orbit semimajor axis with more eccentricity than the initial semimajor axis;
- a transfer orbit periapsis region having a transfer orbit periapsis radius;
- and
- a transfer orbit RAAN, wherein the transfer orbit RAAN changes with each revolution in the transfer orbit due to earth's oblateness;
- propagating the spacecraft in the transfer orbit until the second RAAN is substantially equal to the target RAAN;
- activating thrusters when the spacecraft is in the transfer orbit apoapsis region to reduce the transfer orbit periapsis radius such that the spacecraft moves from the transfer orbit to an aerobraking orbit, wherein the aerobraking orbit comprises:
- an aerobraking orbit apoapsis radius;
- and
- an aerobraking orbit periapsis region having an aerobraking orbit periapsis radius;
- reducing an orbit energy of the spacecraft by exposing the spacecraft to atmospheric drag;
- and
- propagating the spacecraft in the aerobraking orbit until the aerobraking orbit apoapsis radius is substantially equal to the target apoapsis radius;
- and
- activating the thrusters over one or more orbits to increase the aerobraking orbit periapsis radius such that the spacecraft travels in a final orbit, the final orbit comprising:
- a final RAAN substantially equal to the target RAAN;
- a final apoapsis radius substantially equal to the target apoapsis radius;
- and
- a final periapsis radius substantially equal to the target periapsis radius.
A method of moving a spacecraft from an initial orbit to a final orbit, the method comprising:
- providing a spacecraft with thrusters traveling in an initial orbit, wherein the initial orbit has an initial semimajor axis and an initial right ascension of the ascending node (“RAAN”);
- defining a target RAAN, a target apoapsis radius, and a target periapsis radius for a final orbit;
- activating the thrusters such that the spacecraft moves from the initial orbit to a transfer orbit, wherein the transfer orbit comprises eccentricity greater than zero and wherein a transfer orbit RAAN approaches the target RAAN;
- activating thrusters when the spacecraft is in a first region of the transfer orbit such that the spacecraft moves from the transfer orbit to an aerobraking orbit;
- reducing an orbit energy of the spacecraft by exposing the spacecraft to atmospheric drag;
- and
- propagating the spacecraft in the aerobraking orbit until an aerobraking orbit apoapsis radius is substantially equal to the target apoapsis radius;
- and
- activating the thrusters such that an aerobraking orbit periapsis radius is substantially equal to the target periapsis radius;
- and
- propagating the spacecraft in the final orbit, the final orbit comprising:
- a final RAAN substantially equal to the target RAAN;
- a final apoapsis radius substantially equal to the target apoapsis radius;
- and
- a final periapsis radius substantially equal to the target periapsis radius.
Dependencies are inferred from the claim text.