I have a simple implementation of a delta-V calculator for bielliptic transfers here if you want a quick look at the underlying math: https://github.com/daeken/

I have a simple implementation of a delta-V calculator for bielliptic transfers here if you want a quick look at the underlying math: https://github.com/daeken/OrbitalRingsBook/blob/main/space-travel.ipynb https://github.com/daeken/OrbitalRingsBook/blob/main/space-t... -- the DeltaVForBiEllipticTransfer function. (The calculator widget in the book doesn't use it, but I was primarily using it for getting high orbits in an effort to minimize plane change delta-V for another calculation and this code inherited it. Also, you can actually play with the widget in action here, though again it's only using Hohmann transfers due to the low fuel requirements in play: https://ors.daeken.dev/space-travel.html https://ors.daeken.dev/space-travel.html) Happy to explain the math in more detail, but the code is -- I think -- pretty self-explanatory. Edit to add: this function doesn't calculate the initial lift to the higher orbit; that'd be the difference between the speed of your circular orbit and the perigee speed at the higher orbit.