Aerobraking

Aerobraking is a technique used by mission scientists to reduce the height of spacecraft orbits by allowing atmospheric drag to slow the spacecraft's velocity. Often the solar panels onboard orbiters can be used to maximize and control the amount of drag applied to the craft. This technique will ultimately minimize the requirement for the use of propellants (to slow the craft down), thereby optimizing cost effectiveness.

This technique was used to great effect on missions such as the Mars Reconnaissance Orbiter in 2006 and Mars Odyssey in 2001, and is standard practice when spacecraft are being inserted into orbit or when a reduction in velocity is required.