Vostok 1: First Human Orbit & Ballistic Reentry

On April 12, 1961, Yuri Gagarin became the first human in space aboard Vostok 1, completing one elliptical orbit of Earth — perigee 169 km, apogee 327 km, inclination 64.95° — before a 41-second retrorocket burn began the descent. This simulator propagates that real orbit with Kepler's equation and the vis-viva relation, then switches to a point-mass ballistic reentry model the instant you trigger retrofire, integrating drag through an exponential atmosphere to reproduce the steep, high-g descent a lifting-free spherical capsule actually flies — no parachute-softened lifting reentry like later spacecraft, just gravity and drag.