“Here we go again,” she called. “Brace for impact.”

“Pilot, Engineer. I got it. Locking down systems.” That was her engineer, Cabel: very young, very intense.

Torec called, “Navigator? What about you?” When there was no reply, she snapped, “Three. Lethe, girl, wake up.”

Tili Three called back, “Uh—Pilot, Navigator. I’m sorry—”

“Don’t be sorry. Just do your job.” She glanced at her displays. “Impact in thirty. Twenty-nine . . .”

Cabel, seventeen years old, was very able, and had completed his training for this flight in days. He was one of Pirius Blue’s “baby rats,” as Pirius Red put it a bit sourly, rescued by Pirius’s older self from the lethal servitude of Quin. Having worked with Cabel intensely, Torec backed Blue’s judgment.

Tili Three was another baby rat—but she was different. If anything, she was intrinsically smarter than Cabel. Though she had come into the squadron without having completed her basic navigator training, Pirius Blue had insisted on pushing her into Exultant, and now she had wound up in Torec’s crew. Torec had no doubt about her basic ability, in the classroom. But on these training runs—Lethe, even in the sims—she just couldn’t cut it. And so it seemed to be now.

The ripples washed down the tunnel at her. They were intense pulses of gravity waves. Torec saw the lead ships thrown from side to side, like bits of dirt on turbulent water. She braced.

The spacetime wash hit. The stars frothed around her. The ship pitched so violently she could feel it in her gut, even through the inertial shielding. She struggled to hold her line.

The trouble was, the grav shield was fundamentally unstable. No, worse than that, it actually was an instability, a fizzing, nonlinear flaw in spacetime. That was why it propagated in the first place, like a breaking wave. So having set it off, if you let it run by itself, it would push up to lightspeed and then disperse in a spectacular, bone-shaking explosion—or else it would collapse back into sublight, dissipating its energy. The propagating grav shield was an edge-of-chaos phenomenon, and had to be tweaked continually by the shield-master if it was to hang together.

But even here, in the calm, flat spacetime around Arches Base, it was all but impossible to hold everything together. Sailing along behind the shield was a constant strain, even when things went well. If the shield so much as wobbled, the little ships in its wake bobbed like motes of dust.

The ships handled badly, too. In theory, the prototype stage had passed, and they were into flight development, and these ships, fitted with the project’s new technologies, were the configuration they were supposed to fly into the center of the Galaxy. But it was only ten days since the first of them had come out of Enduring Hope’s workshops; they were lash-ups, and they flew like it.