4 ms·

The Hohmann transfer is formally the most fuel efficient two-burn transfer. Bi-elliptic transfers require three burns.

• bell-cot 2y ago
  Which is an issue because re-starting a good-sized* rocket engine in 0g is non-trivial, and the penalty for failure tends to be "mission failed, vehicle lost". *Meaning "large enough for major orbital maneuvers".
  • GlenTheMachine 2y ago
    Correct. On the other hand, neither one is guaranteed to be optimal for continuous thrust maneuvers, which with electric prop are increasingly common.
  • jgsteven 2y ago
    For Earth orbiting satellites using their own on-board propulsion with storable propellant, hardly anyone actually does these transfer orbit maneuver sequences in just two-burns. (edit: For example, for geosynchronous transfer orbit) the delta-V is almost always broken up into 4 to 6 maneuvers of decreasing size (to improve targeting accuracy at the end). The launch vehicle upper stage usually does the first burn to go from the low circular orbit to the elliptical transfer orbit. For these onboard main engines, number of starts is not a concern. Back when some geosynchronous satellites used solid motors there would be one huge maneuver at apogee to get nearly all the way to GEO (e.g. the Hughes/Boeing 376 spinners). The uncertainty in performance on these maneuvers was quite large so correction maneuvers were always planned afterwards.