The cruiser moved away and we all surged gently out, then pulled ourselves back to the window with the grips, as our ship began to close in on Gateway.

"Looks like a case of smallpox," said somebody in the group.

It did; and some of the pockmarks were open. Those were the berths for ships that were out on mission. Some of them would stay open forever, because the ships wouldn't be coming back. But most of the pocks were covered with bulges that looked like mushroom caps.

Those caps were the ships themselves, what Gateway was all about.

The ships weren't easy to see. Neither was Gateway itself. It had a low albedo to begin with, and it wasn't very big: as I say, about ten kilometers on the long axis, half that through its equator of rotation. But it could have been detected. After that first tunnel rat led them to it, astronomers began asking each other why it hadn't been spotted a century earlier. Now that they know where to look, they find it. It sometimes gets as bright as seventeenth magnitude, as seen from Earth. That's easy. You would have thought it would have been picked up in a routine mapping program.

The thing is, there weren't that many routine mapping programs in that direction, and it seems Gateway wasn't where they were looking when they looked.

Stellar astronomy usually pointed away from the sun. Solar astronomy usually stayed in the plane of the ecliptic -- and Gateway has a right-angle orbit. So it fell through the cracks.

The piezophone clucked and said, "Docking in five minutes. Return to your bunks. Fasten webbing."

We were almost there.

Sheri Loffat reached out and held my hand through the webbing. I squeezed back. We had never been to bed together, never met until she turned up in the bunk next to mine on the ship, but the vibrations were practically sexual. As though we were about to make it in the biggest, best way there ever could be; but it wasn't sex, it was Gateway.

When men began to poke around the surface of Venus they found the Heechee diggings.

They didn't find any Heechees. Whoever the Heechees were, whenever they had been on Venus, they were gone. Not even a body was left in a burial pit to exhume and cut apart. All there was, was the tunnels, the caverns, the few piddling little artifacts, the technological wonders that human beings puzzled over and tried to reconstruct.

Then somebody found a Heechee map of the solar system. Jupiter was there with its moons, and Mars, and the outer planets, and the Earth-Moon pair. And Venus, which was marked in black on the shining blue surface of the Heechee-metal map. And Mercury, and one other thing, the only other thing marked in black besides Venus: an orbital body that came inside the perihelion of

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(Transcript of Q. & A., Professor Hegramet's lecture.)

Q. What did the Heechee look like?