Sakharov Drive

The Sakharov Drive was the propulsion system used by the Cosmonaut Alexei Leonov featured in 2010: The Year We Make Contact.

Propulsion system
The Leonov was equipped with a "Sakharov Drive", a propulsion system that employed a pulsed thermonuclear reaction to heat while expelling propellant material. A variety of propellants could be used; the most efficient was hydrogen, but methane, ammonia, and water could also be used.

According to Lawrence Miller’s Spec Sheet 2, the propulsion system is accomplished using seven superheated chemical thrusters for interplanetary travel.

Aerobraking
In order to slow into Jovian orbit, the Leonov preformed aerobraking, by barely skirting the outer edges of the atmosphere, using the resultant drag force to slow them down into the proper orbit. This was the second time a manned spacecraft had been able to perform this maneuver, the first being the ill-fated Chinese spacecraft Tsein.

To prevent the spacecraft from burning up in Jupiter's thick atmosphere, Leonov deployed an inflatable low-density heat shield, made of an extremely durable, heat resistant material. The shield was discarded shortly after aerobraking.

The aerobraking procedure put Leonov into the Lagrange point between Io and Jupiter, the location of both the monolith and Discovery in 2010.

Andrei Sakharov
Arthur C. Clarke chose the name “Sakharov Drive”, to be named after Russian nuclear physist (1921—1989).