The outermost two THEMIS spacecraft (Probes B and C) are on route to the Moon, where they will become the ARTEMIS mission's Probes 1 and 2 (red and green, respectively) , tasked with studying not only the tenuous cavity carved out by the Moon in the supersonic solar wind, but also reconnection, particle energization and turbulence in both the solar wind and the Earth's distant magnetotail at lunar distance. ARTEMIS stands for Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon's Interaction with the Sun.
Thanks to careful planning, sufficient fuel remained on both spacecraft at the successful completion of their primary mission to raise their apogees to lunar distance, where they could receive the multiple gravitational assists needed to fling the spacecraft first beyond the Moon and then assist them in entering in orbits that parallel that of the Moon at the L1 and L2 Lagrange points. Maneuvers in April 2011 enable the spacecraft to enter into prograde and retrograde lunar orbits (the 'braided' motion).
The direction of the Sun is indicated by the yellow arrow.