. Miles laughed and hurried to the control deck.

* * * * *

Astro got up on his knees slowly. Though the fall had been a hard one,
he had rolled quickly with the first impact, thus preventing any
injuries. He shook his head, regained his sense of direction, and then
rose to his feet, starting back to the ship in hope of helping Tom. He
tripped over something and fell to the ground. Groping around in the
thickening ammonia gas he felt the still form of a body. For a moment,
thinking it was Tom, his heart nearly stopped, and then he breathed a
silent prayer of thankfulness when he recognized Charley Brett. He felt
the man's heart. There was a faint beat.

Astro opened the valve on Brett's oxygen mask wide and waited until the
man was breathing normally. Then he began feeling his way back to the
ladder. Suddenly he heard a sound that made his blood run cold. It was
the unmistakable whine of the cooling pumps building for blast-off. And
he was directly underneath the exhaust tubes.

He scrambled away, heading back to the spot where Brett lay. The whining
of the pumps built to an agonizing scream. There were scant seconds left
to save himself. He could not wait to find Brett. He began running
wildly away from the ship, stumbling, failing, rising to his feet again
to plunge on, away from the deadly white-hot exhaust blast of the _Space
Knight_.

[Illustration]

There was a terrific explosion, and then Astro was lifted off his feet
and hurled through the mist, head over heels. He screamed and then
blacked out.

* * * * *

"We found him about a thousand yards away from the warehouse,
Commander," said the guardsman. "He looks pretty beat and his clothes
are burned a little. I think he must have been caught in the blast of
that ship we heard take off."

Walters looked down at Astro's big frame, sprawled on the ground, and
then at the medical corpsman who was giving him a quick examination. The
corpsman straightened up and turned to Walters and Captain Strong.
"He'll be all right as soon as he wakes up."

"Shock?" asked Strong.

"Yes. And complete fatigue. Look at his hands and knees. He's been doing
some pretty rough work." The corpsman indicated the big cadet's hands,
skinned and swollen from his labor in the mines.

"Wake him up!" growled Walters.

"Wake him up!" exclaimed the corpsman. "Why, sir, I couldn't allow--"

"Wake him up. And that's an or