Although the Solar Probe Plus science objectives remain the same as those established for Solar Probe 2005, the new mission design differs dramatically from the 2005 design (as well as from all previous Solar Probe mission designs since the 1970s). The 2005 and earlier missions involved one or two flybys of the Sun at a perihelion distance of 4 R_S by a spacecraft placed into a solar polar orbit by means of a Jupiter gravity assist. In contrast, Solar Probe Plus remains nearly in the ecliptic plane and makes many near-Sun passes at increasingly lower perihelia.

The baseline mission provides for 24 perihelion passes inside 0.16 AU (35 R_S), with 19 passes occurring within 20 R_S of the Sun. The first near-Sun pass occurs 3 months after launch, at a
heliocentric distance of 35 R_S. Over the next several years successive Venus gravity assist (VGA) maneuvers gradually lower the perihelia to ~9.5 R_S, by far the closest any spacecraft has ever come to the Sun. The spacecraft completes it nominal mission with three passes, separated by 88 days, at this distance.