"That lithium hemisphere we built isn't a shield. It's a sail."
"But there's no wind—there's no air—"
"The wind that blows between the worlds," said Carrel solemnly. "Solar radiation. Its pressure will move a ship if you provide a sail that's big enough and light enough—and that's what we did."
"It's impossible," muttered Albrekt, crouching back against the automatic pilot.
"Not impossible, just extremely unusual this far out," said Carrel. "If they ever let you out of prison, Albrekt, I think a trip to Venus would be worth your while. I think you'd find the annual space regatta particularly interesting."