answer.

It was always night on Martha, but Mark broke up his time into mornings,
afternoons and evenings. Their life followed a simple routine.
Breakfast, from vegetables and Mark's canned store. Then the robot would
work in the fields, and the plants grew used to his touch. Mark would
repair the pump, check the water supply, and straighten up the
immaculate shack. Lunch, and the robot's chores were usually finished.

* * * * *

The two would sit on the packing case and watch the stars. They would
talk until supper, and sometimes late into the endless night.

In time, Mark built more complicated conversations into Charles. He
couldn't give the robot free choice, of course, but he managed a pretty
close approximation of it. Slowly, Charles' personality emerged. But it
was strikingly different from Mark's.

Where Mark was querulous, Charles was calm. Mark was sardonic, Charles
was naive. Mark was a cynic, Charles was an idealist. Mark was often
sad; Charles was forever content.

And in time, Mark forgot he had built the answers into Charles. He
accepted the robot as a friend, of about his own age. A friend of long
years' standing.

"The thing I don't understand," Mark would say, "is why a man like you
wants to live here. I mean, it's all right for me. No one cares about
me, and I never gave much of a damn about anyone. But why you?"

"Here I have a whole world," Charles would reply, "where on Earth I had
to share with billions. I have the stars, bigger and brighter than on
Earth. I have all space around me, close, like still waters. And I have
you, Mark."

"Now, don't go getting sentimental on me--"

"I'm not. Friendship counts. Love was lost long ago, Mark. The love of a
girl named Martha, whom neither of us ever met. And that's a pity. But
friendship remains, and the eternal night."

"You're a bloody poet," Mark would say, half admiringly. "A poor poet."

* * * * *

Time passed unnoticed by the stars, and the air pump hissed and clanked
and leaked. Mark was fixing it constantly, but the air of Martha became
increasingly rare. Although Charles labored in the fields, the crops,
deprived of sufficient air, died.

Mark was tired now, and barely able to crawl around, even without the
grip of gravity. He stayed in his bunk most of the time. Charles fed him
as best he could, moving on rusty, creaking limbs.

"What do you think of girls?"

"I nev