Main Topic 6: Orbital Maneuvers

orbital maneuver

• change the orbit or position

• velocity and direction

• altitude, inclination, or orbital period

An ____________ is a planned action taken to ____________ of a spacecraft in space, usually achieved by firing onboard thrusters or engines to adjust its _______ and ________, allowing it to move to a different ________, __________ or _______ as needed for its mission objectives.

• orbit altitude

• rendezvous

• correct errors

• avoid collision

• deorbit safely

Why do we perform orbital maneuvers?

• To change __________ (e.g., go from Low Earth Orbit to GEO)

• To _________ and dock with another spacecraft

• To ________ after launch

• To ________ (space debris or satellites)

• To ___________ at end of mission

• burn

Engine burn

In orbital mechanics, a “_______” is a period when a spacecraft’s engines are fired to change its motion—specifically its velocity (Δv), which then changes its orbit.

• Prograde burn

• Radial burn

• Retrograde burn

• Normal/antinormal burn

• __________________

  • Performed in the direction of motion, increasing velocity and raising the orbit.

• __________________

  • Directed inward or outward from Earth, altering the orbit’s shape or orientation.

• __________________

  • Performed opposite the direction of motion, decreasing velocity and lowering the orbit.

• ___________________

  • Executed perpendicular to the orbital plane, changing the orbit’s inclination.

• orbital transfer

  • parking orbit

  • transfer orbit

    • Double-checking

    • small corrections

    • controlled and precise

An _______________ is a specific type of orbital maneuver where an object moves from one orbit to another in a planned and controlled way. It can be from a lower orbit to a higher orbit or vice versa.

Why transfer orbits?

• Instead of going directly to its final orbit, the rocket first places the satellite into a low Earth orbit (LEO), called a _________.

• From this stable orbit, the spacecraft performs a burn to enter a ________.

• ________________________________________________________

Why transfer orbits?

• ____________________

• Allows ________ before final orbit

• Makes the transfer to the final orbit more _______ and _______

• Artemis I

  • 1.4-million-mile

  • Nov.16

  • Dec. 11, 2022.

_____________________________________________________________

• Artemis II

  • Space Launch System

    • Crewed lunar flyby

    • April 1, 2026

    • 10 days

_____________________________________________________________

• 2027

• first Artemis lunar landing

• SLS (Space Launch System)

______________

• It was an uncrewed flight test launching the Orion spacecraft on a _________ mile journey beyond the Moon and back. It was launched last ___________, 2022 and ended later on _________________

____________________________________________________________

• The ____________ test flight will be NASA’s first mission with crew aboard the SLS (___________________) rocket and Orion spacecraft.

  • MISSION TYPE:___________

  • LAUNCH DATE:_________

  • CREW SIZE: 4

  • MISSION DURATION:________

_____________________________________________________________

• Artemis III:

  • Scheduled for ______ this new demonstration mission in low Earth orbit will test one or both commercial landers from SpaceX and Blue Origin, respectively.

• Artemis IV:

  • NASA continues to target early 2028 for the ___________. After reaching lunar orbit, the crew will transfer from Orion to a commercial lunar lander for their descent to the Moon’s surface.

• Artemis V:

  • Using the standard __________________ rocket configuration, NASA expects to launch this lunar surface mission by late 2028, with subsequent missions planned roughly once per year.

James Webb space telescope

• On December 25, 2021, James Webb Space Telescope was launched through Arian 5. Its target Lagrange Point was on Sun–Earth L 2 It was inserted into a transfer trajectory and was intentionally under-speed to avoids risk of overshooting.

_____________________________________________________________

• MCC-1a (Major Course Correction)

  • 12 hours after launch, early in transfer trajectory

  • Corrects most of the launch injection error

  • Sets the correct overall path toward L2

  • First critical double-check point before proceeding further

_____________________________________________________________

• MCC-1b

  • 2.5 days after launch, midway along the Earth–L 2 transfer path

  • Refines trajectory after MCC-1a

  • Adjusts small residual errors

  • Confirms spacecraft is still on the correct long-range path

_____________________________________________________________

• MCC-2

  • 29 days after launch, near Sun–Earth L 2

  • Final fine-tuning before orbit insertion

  • Achieves very high precision (cm/s level)

  • Ensures proper entry into halo orbit around L2

Types of orbital maneuvers

• Impulsive maneuver

  • An impulsive maneuver is a quick burst of thrust that changes the velocity of a spacecraft. This maneuver is used to change the orbit of the spacecraft.

• Phasing Maneuver

  • A phasing maneuver is used to adjust a spacecraft’s position along its orbit by changing its orbital period. By moving to a slightly higher or lower orbit, the spacecraft can speed up or slow down relative to a target. This is commonly used to align with a space station before rendezvous.

• Chase Maneuver

  • A chase maneuver involves actively guiding a spacecraft to intercept and rendezvous with another object in orbit. It combines multiple burns to match orbit and reduce relative distance and velocity. This is used in missions where spacecraft dock with the International Space Station.

• Hohmann Transfer orbit

  • A Hohmann transfer orbit is a fuel- efficient method for moving between two circular orbits using two burns. The first burn places the spacecraft into an elliptical transfer orbit, and the second circularizes it at the target altitude. It is widely used for transferring satellites from low Earth orbit to higher orbits like GEO.