2001 A Space Odyssey

Chapter 37 - The Sentinel
"The air in the ship is getting quite foul, and I have a headache most of the time. There's still plenty of oxygen, but the purifiers never really cleaned up all the messes after the liquids aboard started boiling into vacuum. When things get too bad, I go down into the garage and bleed off some pure oxygen from the pods.

"There's been no reaction to any of my signals, and because of my orbital inclination, I'm getting slowly farther and farther away from TMA-2. Incidentally, the name you've given it is doubly inappropriate - there's still no trace of a magnetic field.

"At the moment my closest approach is sixty miles; it will increase to about a hundred as Japetus rotates beneath me, then drop back to zero. I'll pass directly over the thing in thirty days - but that's too long to wait, and then it will be in darkness, anyway.

"Even now, it's only in sight for a few minutes before it falls below the horizon again. It's damn frustrating - I can't make any serious observations.

"So I'd like your approval of this plan. The space pods have ample delta vee for a touchdown and a return to the ship. I want to go extravehicular and make a close survey of the object. If it appears safe, I'll land beside it - or even on top of it.

"The ship will still be above my horizon while I'm going down, so I won't be out of touch for more than ninety minutes.

'Tm convinced that this is the only thing to do. I've come a billion miles - I don't want to be stopped by the last sixty."

For weeks, as it stared forever Sunward with its strange senses, the Star Gate had watched the approaching ship. Its makers had prepared it for many things, and this was one of them. It recognized what was climbing up toward it from the warm heart of the Solar System.

If it had been alive, it would have felt excitement, but such an emotion was wholly beyond its powers. Even if the ship had passed it by, it would not have known the slightest trace of disappointment. It had waited three million years; it was prepared to wait for eternity.

It observed, and noted, and took no action, as the visitor checked its speed with jets of incandescent gas. Presently it felt the gentle touch of radiations, trying to probe its secrets. And still it did nothing.

Now the ship was in orbit, circling low above the surface of this strangely piebald moon. It began to speak, with blasts of radio waves, counting out the prime numbers from 1 to 11, over and over again. Soon these gave way to more complex signals, at many frequencies-ultraviolet, infrared, X rays. The Star Gate made no reply; it had nothing to say.

There was a long pause, then, before it observed that something was falling down toward it from the orbiting ship. It searched its memories, and the logic circuits made their decisions, according to the orders given them long ago.

Beneath the cold light of Saturn, the Star Gate awakened its slumbering powers.