Final answer:
It is true that solar sail craft can be propelled by the particles within the solar wind, relying on the momentum of sunlight and the solar wind for thrust.
Step-by-step explanation:
The claim that solar sail craft can be propelled using just the particles within the solar wind is indeed true. Solar sails are a form of spacecraft propulsion that uses the radiation pressure exerted by the sunlight on large mirrors. Although photons lack mass, they have momentum, and when this momentum is transferred to the sail, it provides a small but continuous thrust. Over time, this can build up to allow the spacecraft to reach considerable speeds, making long-distance space travel feasible without the need for traditional fuel. The solar wind, which is a stream of charged particles emitted by the sun, also contributes to this effect, albeit to a lesser extent than the momentum of photons.