Volume IX · Orbit軌道
Circles, ellipses, Hohmann, the expensive plane change, escape.
Once you have Δv, you spend it on a shape: circle, ellipse, a Hohmann climb, a plane, or escape. Named orbits are just jobs at altitudes.
In English
After the rocket, the question is the shape of the path. Circles, ellipses, two-burn climbs, turning the plane, or leaving altogether. This volume is that menu.
- Try this
- Start with Circle so LEO looks as low as it is. Then Hohmann.
- Keep this
- Orbits are shapes you buy with Δv. Named parks are jobs.
The stack · click a layer
What this is
LEO drawn as the thin ring it is, an ellipse with Earth at a focus, a two-burn climb, named parks, a plane-change bill, and escape as √2.
What this is not
Not STK. Numbers use μ and R for a spherical Earth. Inclination and J2 are mentioned, not modelled, except the plane-change formula.
- 01 · ShapesCircle圓軌道Raise altitude. Period stretches. Speed falls.Higher = slower = longer day. LEO is skimming, not visiting another country.
- 02 · ShapesEllipse橢圓Stretch apoapsis. Slide along the track.Fast at periapsis. Burn there to raise apoapsis.
- 03 · TransfersHohmann霍曼Pick a target. Pay two burns.Hohmann = two burns + half an ellipse. Usually cheapest.
- 04 · TransfersParks停泊Click a named orbit. Read the job.Named orbits are altitudes (and tilts) with jobs.
- 05 · ExpensivePlane軌道面Turn the orbit. Watch the bill.Plane changes cost $2 v \sin(\theta/2)$. Launch onto the plane you want.
- 06 · ExpensiveEscape逃逸Compare circular, escape, the extra.Escape = $\sqrt{2}\times$ circular. LEO extra ~3.2 km/s.