The Mote in God's Eye by Larry Niven, Jerry Pournelle Page A

initiate hostilities it must be assumed that nonhuman sentient creatures may be hostile. Section Three—’“
    Whitbread was cut off by the final acceleration warning.
    Blaine nodded acknowledgment to the middle and settled back in his couch. The regulations weren’t likely to be much use anyway. They mostly dealt with initial contact without prior warning, and here Fleet command pretty well knew MacArthur was going out to intercept an alien vessel.
    Ship’s gravity edged upward, slowly enough to give the crew time to adjust, a full minute to rise to three gravities.
    Blaine felt two hundred sixty kilos settling into his acceleration couch. Throughout the ship men would be moving with the wary attention one gives to lifting weights, but it was not a crippling acceleration. Not for a young man. For Bury it would be rough, but the Trader would be all right if he stayed in his gee bed.
    Blaine felt very much at ease in his contoured armchair. It had headrest and fingertip controls, lapboard, power swiveling so that the entire bridge was in view without effort, even a personal relief tube. Warships are designed for long periods of high gravity.
    Blaine fiddled with his screen controls to produce a 3-d graph overhead. He cut in the privacy switch to hide his doodles from the rest of the crew. Around him the bridge officers attended to their duties, Cargill and Sailing Master Renner huddled together near the astrogation station, Midshipman Staley settled next to the helmsman ready to assist if needed but mostly there to learn how to handle the ship. Blaine’s long fingers moved over the screen controls.
    A long green velocity line, a short lavender vector pointing in the opposite direction — with a small white ball between. So. The intruder had come straight from the direction of the Mote and was decelerating directly into the New Cal system . . . and it was somewhat bigger than Earth’s Moon. A ship-sized object would have been a dimensionless point.
    A good thing Whitbread hadn’t noticed that. There’d be gossip, tales to the crew, panic among the new hands... Blaine felt the metallic taste of fear himself. My God, it was big .
    “But they’d have to have something that big,” Rod muttered. Thirty-five light years, through normal space! There never had been a human civilization that could manage such a thing. Still — how did the Admiralty expect him to “investigate” it? Much less “intercept” it? Land on it with Marines?
    What in Hannigan’s Hell was a light sail?
    “Course to Brigit, sir,” Sailing Master Renner announced.
    Blaine snapped up from his reverie and touched his screen controls again. The ship’s course appeared on his screen as a pictorial diagram below tables of figures. Rod spoke with effort. “Approved.” Then he went back to the impossibly large object on his view screen. Suddenly he took out his pocket computer and scribbled madly across its face. Words and numbers flowed across the surface, and he nodded.
    Of course light pressure could be used for propulsion.
    In fact MacArthur did exactly that, using hydrogen fusion to generate photons and emitting them in an enormous spreading cone of light. A reflecting mirror could use outside light as propulsion and get twice the efficiency. Naturally the mirror should be as large as possible, and as light, and ideally it should reflect all the light that fell on it.
    Blaine grinned to himself. He had been nerving himself to attack a space-going planet with his half-repaired battle cruiser! Naturally the computer had pictured an object that size as a globe. In reality it was probably a sheet of silvered fabric thousands of kilometers across, attached by adjustable shrouds to the mass that would be the ship proper.
    In fact, with an albedo of one— Blaine sketched rapidly.
    The light sail would need about eight million square kilometers of area. If circular, it would be about three thousand klicks across.
    It was using light for thrust,