Stone became alert when they crossed the orbit of the outer most planet of the system. He kept his eyes open, searching space outside his craft, but there was nothing for him to see. None of the instruments that radiated were turned on. Everything was in the passive mode. If the enemy was searching, using instruments like those in Stone's ship, his computer would be able to detect that. It would tell them where the enemy was because he had been foolish enough to turn on his instruments. If the enemy didn't, and Stone didn't see them through his tiny window, then the two forces could pass with neither seeing the other.
But everything remained quiet. If the enemy was out there, he was as blind as Stone and his people. The HUD showed nothing other than the positions of the other fighters in the attack flight.
They continued on, flying closer to the fourth planet. They didn't use the radios, didn't use the navigation lights. They just held their position in the formation as they flew on toward the fourth planet.
Then, over shielded radio communication, Stone heard, "Let's go active."
Stone turned on the various search and acquisition radars and sensors and then studied the HUD. Nothing had changed on it. There were no enemy spacecraft around him. No enemy pickets to be seen. Just empty space except the invasion force.
"Let's slow it up and give the slicks time to catch up," said the flight leader.
Stone watched the HUD closely, adjusting his thrusters so that he stayed in the same position relative to the flight leader.
They coasted for several minutes. The fourth planet was in the center of the HUD, a small, glowing ball. Along one side were a series of numbers giving the distance and the time to the planet based on the current speed.
When they were still more than a hundred thousand miles out, flight lead ordered, "Let's clean it up and arm the weapons. You are cleared to fire if fired on. Do not initiate the action. They get the first shot. But they only get the one."
Stone laughed then. It seemed that the rules of engagement always gave the bad guys the first shot. Of course, in this situation, that kept the fighters from announcing their presence with an ill-advised shot. If the enemy took the first shot, it meant that the enemy already knew they were there.