Astronomy

An orbit that turns

Tilt an Earth orbit. Watch its orbital plane precess and compare the node drift with the special polar case.

Actual application image

The model and its limits

Secular first-order J2 nodal and apsidal precession around an oblate Earth; no short-period perturbations. Oblateness in the scene is enlarged.

Equations used in the module

Equations
Ωdot = -(3/2)J₂ n(R/a)² cos i; ωdot = (3/4)J₂ n(R/a)²(5cos²i-1)

Astronomy

Track a surface meridian over two eccentric orbits. Change the spin ratio and see why Mercury presents alternating faces at successive perihelia.

Astronomy

Lower a spacecraft’s periapsis into a thin atmosphere. Compare drag energy loss and peak heating along an idealized grazing pass.

Astronomy

Change the mass ratio. Both stars orbit their common centre of mass; compare their speeds and see the brighter star’s reflex motion.