There was a pause, and then the figures started coming over. Preston jotted them down on a scratch-pad.
"Okay, I've got them. Now sit tight and wait." He glanced contemptuously at the three mail-pouches behind him, grinned, and started setting up the orbit.
Mailman, am I? I'll show them!
He brought the Postal Ship down with all the skill of his years in the Patrol, spiralling in around the big satellite of Jupiter as cautiously and as precisely as if he were zeroing in on a pirate lair in the asteroid belt. In its own way, this was as dangerous, perhaps even more so.
Preston guided the ship into an ever-narrowing orbit, which he stabilized about a hundred miles over the surface of Ganymede. As his ship swung around the moon's poles in its tight orbit, he began to figure some fuel computations.
His scratch-pad began to fill with notations.
Fuel storage—
Escape velocity—
Margin of error—