"It's a tough nut to crack," said Joe dourly.

It haunted him. Ships going up had to have crews. Crews had to come down
again because they had to leave supplies at the Platform, not consume
them there. Getting a ship up to orbit was easier than getting it down
again.

"The Navy's been working on light guided missiles," said Sally.

"No good," snapped Joe.

It wasn't. He'd been asked for advice. Could a space ship crew control
guided missiles and fight its way back to ground with them? The answer
was that it could. But guided missiles used to fight one's way down
would have to be carried up first. And they would weigh as much as all
the cargo a ship could carry. A ship that carried fighting rockets
couldn't carry cargo. Cargo at the Platform was the thing desired.

"All that's needed," said Sally, watching Joe's face, "is a slight touch
of genius. There's been genius before now. Burning your cabin free with
landing-rocket flames----"

"Haney's idea," growled Joe dispiritedly.

"And making more ships in a hurry with metal-concrete----"

"Mike did that," said Joe ruefully.

"But you made the garbage-screen for the Platform," insisted Sally.