Free-Return Flyby Solver
CR3BP Earth–Moon rotating frame. Solves for
ẋ = 0
at
(1−μ + R
Moon
+ h, 0)
— exact symmetric free-return condition. Departure angle measured from
−x direction
(anti-Moon, 0–90°).
▶ Play
Reset View
Plot Center
Origin
Earth
Moon
L1
L2
L3
L4
L5
X Radius (GEO)
+ Add spacecraft
Remove
Color
Blue
Red
Green
Gray
Earth parking orbit altitude (km)
Target lunar flyby altitude (km)
Parking orbit inclination (deg)
ER3BP mode (elliptic Moon orbit)
TLI Moon phase
0° (Perigee)
▶ Solve & Plot
Solving…
Outbound
Return (toggle in controls)
Ready. Press "Solve & Plot".
Flyby altitude: —
Earth–Moon rotating frame ·
●
Earth (−μ,0)
●
Moon (1−μ,0)
●
L1–L5
●
SE-L1
●
SE-L2 (rotates with Play) · Drag to pan · Scroll to zoom
⬇ Download High-Res Image
⬇ Download High-Res Image
ER3BP Time-of-Flight Chart
Earth Alt (km)
Moon Alt (km)
Compute TOF Chart
Controls
☀ White Background
Time (days)
Speed
Steps
Show Lagrange L1–L5
L1
L2
L3
L4
L5
Show GEO orbit
Show Sun–Earth L1/L2 (rotating)
Show spacecraft marker
Show lunar orbit at flyby altitude
Show return path
Solid
Dashed
Show Jacobi contours
Jacobi C
3.100
Axis units
× GEO
km
Normalized