A satellite on a science mission to Mars aims for a low-altitude orbit, but the lower the orbit, the more propellant is required to enter orbit when arriving from Earth. To save propellant, a technique called aerobraking uses a small propulsive maneuver for orbit insertion to enter a large orbit; the satellite then makes many passes through the upper atmosphere, using drag on the solar panels to reduce the size of the orbit a little bit each pass until the orbit is the desired size for science operations. This aerobraking technique requires three to six months to complete and requires near-constant supervision by a ground team on Earth.
Click here for original story, New automatic control technique uses spacecraft solar panels to reach desired orbit at Mars
Source: Phys.org