Relate altitude to circular orbital velocity

Use prograde and retrograde burns to change orbital energy

Manage finite delta-v

Rendezvous by reducing both distance and relative velocity

Why does a prograde burn raise the orbit?

Adding velocity increases specific orbital energy and typically raises the opposite side of the orbit.

Why is matching position not enough for rescue?

Rendezvous also requires low relative velocity. Two spacecraft can pass very close while moving too differently to dock safely.

Is the orbit a predefined animation?

No. Position and trajectory are generated from Newtonian gravity and the player’s applied thrust.