Course
Guided
250 XP4–5 hours

J₂ + Drag Orbit Decay Simulator

Add the real-world perturbations that make orbits drift, precess, and eventually re-enter.

Ideal two-body motion is a lie the universe tells beginners. In this guided build you will add the two dominant perturbations on a low orbit — J₂ oblateness and atmospheric drag — and watch a satellite’s altitude decay until re-entry.

J₂ oblateness & secular precessionAtmospheric drag & decayStation-keeping intuition
Milestones
0/4
J₂ is Earth’s equatorial bulge. Its acceleration depends on the z-component of position. • Use J2 = 1.08263e-3, R_E = 6378.137 km. • Add the standard J₂ acceleration vector to gravity. • Print the J₂ acceleration magnitude at r=[6778,0,0]; it should be ~1e-5 km/s² scale.
numpy
J₂ acceleration computed (~1e-5 scale)