mical burners. I was on a freighter called
the _Happy Spaceman_. A tube blew on us. Luckily we were close enough to
Phobos to make a touchdown, or the leak would have reached the main fuel
tanks and blown us clean out to another galaxy."

"What happened?" asked Roger.

"I had to go outside," said Astro. "I was junior rocketman in the crew,
so naturally I had to do all the dirty work."

Tom's warning call from the _Polaris_ control deck, tuned to the open
communicators of all the jet boats, broke through the loud-speaker.

"Attention! Attention! Corbett to Connel. One hour and twenty minutes to
blast-off time. One hour and twenty minutes to blast-off time."

The two cadets looked at each other as they heard Tom's voice, but
neither spoke. Finally Roger asked, "What happened on Phobos?"

"No one bothered to tell me," continued Astro, "that I had to protect
myself from the ultraviolet rays of the sun, since Phobos didn't have an
atmosphere. It was one of my first hops into space and I didn't know too
much. I went outside and began working on the tube. I did the job all
right, but for three weeks after, my face was swollen and I couldn't
open my eyes. I almost went blind."

Roger grunted and continued to line the clear plastic fish-bowl helmets
with the darker protective shields.

Connel's voice rang through the cabin over the communicator: "I guess
we'd better go down and get it over with. I don't see anything that will
give us any protection down there. Be sure your humidity control is
turned up all the way. As soon as you step outside the jet boat, you're
going to be hit by a temperature of four hundred degrees!"

"Aye, aye, sir," came Shinny's reply over the intercom. Roger flipped
the communicator on and acknowledged the order.

Astro and Shinny followed Connel's jet boat in a long sweeping dive to
the surface of the satellite. Stepping out of the air-cooled jet boat
onto the torrid unprotected surface of the flat plain was like stepping
into a furnace. Even with space suits as protection, the five Earthmen
were forced to work in relays in the digging of the hole for the reactor
unit.

"Attention! Attention! Corbett to Connel. One hour exactly to blast-off
time! One hour--sixty minutes--to blast-off time."

Tom flicked the teleceiver microphone off, and on the teleceiver screen,
watched his spacemates work under the broiling sun. They were ahead of
time. One hour to complete two more units. Tom allowed him