softly.

The thin fabric of the space cloth was enough to protect them from the
direct rays of the sun, but offered very little protection against the
heat. Soon the inside of the tent was boiling under the relentless sun.

They sat far apart, their knees pulled up, heads bowed. Once when the
heat seemed unbearable, Tom opened one side of the cloth in a desperate
hope that it might be a little cooler outside. A blast of hot air
entered the makeshift tent and he quickly closed the opening.

About three o'clock Roger suddenly slipped backward and lay sprawled on
the sand.

Tom opened one of the containers of water and dipped his shirttail into
it. Astro watched him moisten Roger's lips and wipe his temples. In a
few moments the cadet stirred and opened his eyes.

"I--I--don't know what happened," he said slowly. "Everything started
swimming and then went black."

"You fainted," said Tom simply.

"What time is it?" asked Astro.

"Sun should be dropping soon now, in another couple of hours."

They were silent again. The sun continued its journey across the sky and
at last began to slip behind the horizon. When the last red rays
stretched across the sandy desert, the three cadets folded back the
space-cloth covering and stood up. A soft evening breeze sprang up,
refreshing them a little, and though none of them was hungry, each boy
ate a light meal.

Tom opened the container of water again and measured out about an ounce
apiece.

"Moisten your tongue, and sip it slowly," ordered Tom.

Roger and Astro took their share of the water and dipped fingers in it,
wiping their lips and eyelids. They continued to do this until finally,
no longer able to resist, they took the precious water and swished it
around in their mouths before swallowing it.

They folded the space cloth, shouldered their packs, and after Tom had
checked the compass, started their long march toward their plotted
destination.

They had survived their first twenty-four hours in the barren wastes of
the New Sahara, with each boy acutely aware that there was at least a
week more of the same in front of them. The sky blackened, and soon
after Deimos rose and started climbing across the dark sky.

CHAPTER 21

"How much water left?" asked Astro thickly.

"Enough for one more drink apiece," Tom replied.

"And then what happens?" mumbled Roger through his cracked lips.

"You know what will happen, Roger--you know and I know and Tom knows,