he ship save a
heliographed warning to keep clear.

But how came a rocket-flier here, in the perilous swarms of the meteor
belt? Many a vessel had been destroyed by collision with an asteroid,
in the days before charted lanes were cleared of drifting metal.

The lanes more frequently used, between Earth, Mars, Venus and
Mercury, were of course far inside the orbits of the asteroids. And
the few ships running to Jupiter's moons avoided them by crossing
millions of miles above their plane.

Could it be that legendary green ship, said once to have mysteriously
appeared, sliced up and drawn within her hull several of the primitive
ships of that day, and then disappeared forever after in the remote
wastes of space? Absurd, of course: he dismissed the idle fancy and
examined the ship still more closely.

Then he saw that it was turning, end over end, very slowly. That meant
that its gyros were stopped; that it was helpless, drifting, disabled,
powerless to avoid hurtling meteoric stones. Had it blundered unawares
into the belt of swarms--been struck before the danger was realized?
Was it a derelict, with all dead upon it?

* * * * *

Either the ship's machinery was completely wrecked, Thad knew, or
there was no one on watch. For the controls of a modern rocket-flier
are so simple and so nearly automatic that a single man at the bridge
can keep a vessel upon her course.

It might be, he thought, that a meteorite had ripped open the hull,
allowing the air to escape so quickly that the entire crew had been
asphyxiated before any repairs could be made. But that seemed
unlikely, since the ship must have been divided into several
compartments by air-tight bulkheads.

Could the vessel have been deserted for some reason? The crew might
have mutinied, and left her in the life-tubes. She might have been
robbed by pirates, and set adrift. But with the space lanes policed as
they were, piracy and successful mutiny were rare.

Thad saw that the flier's navigation lights were out.

He found the heliograph signal mirror at his side, sighted it upon the
ship, and worked the mirror rapidly. He waited, repeated the call.
There was no response.

The vessel was plainly a derelict. Could he board her, and take her to
Mars? By law, it was his duty to attempt to aid any helpless ship, or
at least to try to save any endangered lives upon her. And the salvage
award, if the ship should be deserted and he co