Thrust implies that you're pushing off of something. For a propeller say on a helicopter, you're pushing off a column of air that "sits" on the ground. In space

Thrust implies that you're pushing off of something. For a propeller say on a helicopter, you're pushing off a column of air that "sits" on the ground. In space, thrust typically means you're pushing against gas you're providing in the form of burnt fuel. I have no clue how solar energy could create true thrust in a vacuum.