2312

“Can you display your data in a 3-D model?” Wahram asked. Swan put her right hand against the table’s screen, and in the texture of the table appeared a glowing image of the Venus sunshield-a great circular sheet, spinning around the hub at its center point, somewhat like Saturn’s rings around Saturn. Red lines indicating the detected pebbles were coming in from many directions, looking like magnetic lines converging on a monopole. When massed together, they would tear through the thin concentric panels of the shield, and if the conglomerate was large enough, reach the hub and destroy the controls. The remainder of the giant thing would go Catherine-wheeling through the night, mirror banners twisting and knotting in the black vacuum. And Venus would be cooked.

“Has anyone alerted the Venusian defense system?” Wahram asked.

“Yes, Wang’s qube did that, and now Wang too, but the sunshield’s AI did not find that the data transmitted represented a hazard. We suspect something is wrong with it.”

“Did the sunshield AI explain itself?” Wahram asked. “I need to see that whole exchange, please. Display as text,” and then he was reading the table screen so intently that it seemed his exophthalmic eyes might pop out of his head entirely. Swan let him read and conducted her own quick conversation with Pauline.

“Pauline, say we can’t convince the sunshield’s AI to act, is there anything we could do from here?”

Pauline took a few seconds, then said, “A countermass arriving at the pebbles’ meeting point at the rendezvous moment and hitting the mass at a tangent would push the paired mass off to the side, thus missing the sunshield. After the impact, the sunshield’s security system would presumably react to any detritus flying its way. The countermass should have approximately an equivalent momentum to the pebble mob, to vector the paired mass away successfully.”

“How big is the pebble mob?”

“It looks like it will mass about the equivalent of ten ships of this size.”

“This ship? So… if this ship was moving ten times faster than the pebbles?”

“That would make a momentum equivalency, yes.”

“Can this ship get there in time, and going fast enough?”

By now Wahram was listening to them rather than reading.

“Yes,” Pauline said. “But only by accelerating at this ship’s maximum acceleration, and starting as soon as you can.”

Swan looked at Wahram. “We have to tell the ship’s crew about this. And everyone else too.”

“True,” he said, taking up his napkin and patting his mouth. He surged to his feet. “Let’s go up to the bridge.”

B y the time they got there, the officers of the ship were already gathered before their AI’s biggest screen and were looking into a graphic of the pebble array very similar to the one Wahram and Swan had been looking at.

“Oh good,” Wahram said when he saw it. He was huffing a bit from the run down hallways and up stairs. “You see the problem we have.”

The ship’s captain glanced at him and said, “I’m glad you’re here. Indeed a big problem!”

Wahram said, “Swan’s qube says our ship here can serve to ward off the attack, by colliding with the pebbles at their rendezvous point.”

The captain and everyone on the crew looked startled at this idea, but Wahram gave them little time to adjust: “If we decide to do this, are there enough lifeboats for everyone aboard?”

“ ‘Lifeboat’ is not the right word,” the captain said, “but yes. There are lots of small ferries and hoppers on board, and most of the passengers could be put in them. Also there are more than enough personal spacesuits to send everyone out on their own. There are supplies in the suits to last ten days, so in that sense they’re better than the ferries, which don’t carry that kind of emergency supply. Everyone would get picked up, either way. But…” The captain looked around at the ship’s officers. “I should think the Venusian defense system would take this kind of thing on. Are we sure they won’t? And”-gesturing at the screen-“is this image evidence enough for us to change course, accelerate, and abandon ship?”

Wahram said, “We have to trust our AIs here, I think. They’re issuing their warning because we programmed them to react to input like this.”

“But they set up this fine-grained detection system on their own, I’m being told.”

“Yes, but I guess you could say we asked for that too. Wang asked for better protection. So-we’ve already made the decision to trust them.”

The captain frowned. “I suppose you’re right. But I don’t like it that the sunshield security doesn’t recognize this as a problem. If it did we wouldn’t have to throw our ship into harm’s way.”

“That may be balkanization rearing its head again,” Inspector Genette said from the doorway. “The Venus sunshield isn’t connected to the warning system that saw these pebbles, and it’s heavily firewalled from influences just like Wang’s qube. So it may not be equipped to believe the input.”

“What do the Venusians say?” the captain asked.

“Let’s ask them and find out,” suggested Wahram.