handed him a folder; he leafed through it.
"Actually it was a lot of fun, Malenfant."
"I'll bet. Gave you something real to do."
"For the first time in too long. First we looked at a continuous nuclear-fusion drive. Specific impulse in the millions of seconds. But we can't sustain a fusion reaction for long enough. Not even the Japanese have managed that yet."
"All right. What else?"
"Maybe photon propulsion. The speed of light -- the ultimate exhaust velocity, right? But the power plant weight and energy you'd need to get a practical thrust are staggering. Next we thought about a Bussard ramjet. But it's beyond us. You're looking at an electromagnetic scoop that would have to be a hundred kilometers across--"
"Cut to the chase, Sally," he said gently.
She paused for effect, like a kid doing a magic trick. Then she said, "Nuclear pulse propulsion. We think that's the answer, Malenfant. A series of microexplosions -- fusion of deuterium and helium-3 probably -- set off behind a pusher plate."
He nodded. "I've heard of this. Project Orion, back in the 1960s. Like putting a firecracker under a tin can."
She shaded her eyes from the Sun's glare. "Well, they proved the concept, back then. The Air Force actually ran a couple of test flights, in 1959 and 1960, with conventional explosives. And it's got the great advantage that we could put it together quickly."
"Let's do it."
"Of course we'd need access to helium-3."
"NASDA will supply that. I have some contacts... Maybe we should look at assembly in lunar orbit. How are you going to keep me alive?"
She smiled. "The ISS is still up there. I figure we can cannibalize a module for you. Have you decided what you want to call your ship?"
"The Commodore Perry," he said without hesitation.
"Uh-huh. Who -- ?"
"Perry was the guy who, in 1853, took the U.S. Navy to Japan and demanded they open up to international trade. Appropriate given the nature of my mission, don't you think?"
"It's your ship." She glanced about. "Anyhow, what are you doing out here?"
He nodded at the shuttle exhibit. "They've got my old EMU in there, on display. I'm negotiating to get it back."
"EMU?"
"My EVA mobility unit. My old pressure suit." He patted his gut, which was trim. "I figure I can still get inside it. I can't live with those modern Jap designs full of pond scum. And I want a maneuvering unit..."
She was looking at him oddly, as if still unable to believe he was serious.
"Not ours," Xenia whispered. "Nothing to do with Bruno."
Suddenly Maura found it difficult to breathe. This is it, she thought. This unprepossessing blanket: the first indubitably alien artifact, here in our Solar System. Who put the blanket there? What was its purpose? Why was it so crudely buried?
A robot arm reached forward from the probe, laden with sensors and a sample-grabbing claw. She wished that was her hand, that she could reach out too, and stroke that shining, unfamiliar material.
But the claw was driven by science, not curiosity; it passed over the blanket itself and dug a shallow groove into the regolith that lay over it, sampling the material.
Within a few minutes the results of the probe's analysis were coming in, and she could hear the speculation begin in Bootstrap's back rooms.
"These are fines, and they are ilmenite-rich. About forty percent, compared to twenty percent in the raw regolith." "And the agglutinate has been crushed." "It's as if it has been beneficiated. It's just what we'd do." "Not like this. So energy-intensive..."
She understood some of this. Ilmenite was a mineral -- a compound of iron, titanium, and oxygen -- that was common in long-exposed regolith on airless bodies like the Moon and the asteroids. Its importance was that it was a key source of volatiles: light and exotic compounds implanted there over billions of years by the solar wind, the thin, endless stream of particles that fled from the Sun. But ilmenite was difficult to concentrate, extract, and process; the