Solar Fox was released by CBS Electronics in 1983.  The story behind the game is the Earth is about to go to war over control of the world's energy sources.  You can prevent war by collecting solar cells and bringing them back to Earth, thus providing an additional source of energy.

On each board, you fly your ship over around the screen collecting a matrix of solar cells.  Sentinels at the edge of the matrix shoot fireballs at you while you try to collect the solar cells.  You try to clear the matrix before time runs out.  Every 5th level is a challenge round where you are not shot at by the sentinels.  On the challenge round, you can score bonus points by clearing the matrix before you run out of time.  When you complete the challenge round, a letter comes up on the screen.  If you clear all 6 challenge rounds, you get 6 letters which spell out a secret word.