he outer wall of the
hub-shielding tank, where he grasped another line, quickly transferred
his safety line, and began working his way toward the observatory.

As the intersection of the rim where Mike had been passed into
darkness, another figure moved and jumped up the same line he had
taken. But this Mike did not notice.

Reaching the bulge at the end of the shielding tank and crawling up
over it, Mike made his way up, at an odd reversed angle, through the
netting; and into the observatory dome through its open shutter.

Making his way about in the open vacuum in free-fall conditions of the
observatory, Mike carefully checked the lock at the main axis to make
sure that he could get into it without arousing an alarm for any
guards that might be nearby.

The lock showed vacant, and empty. Just as he was about to enter it,
he saw another figure in a spacesuit come drifting through the open
shutter where he had entered.

Mike stepped into the lock, closed the door behind him as though he
had not noticed, and cycled the lock. But he did not remove his suit
and did not leave.

As the lock showed clear, the observatory door opened again, and the
two spacesuited figures stood face to face. Mike with needle gun
raised checked himself in surprise. Then he motioned the other figure
into the lock.

"And just what are you doing here?" he inquired as the air around them
became sufficient to carry his voice.

"You might have needed help," answered Dr. Millie Williams in a small,
scared voice as she took off her helmet and shook out her long hair.

"And just _what_," Mike inquired, "were you planning to do about it
besides having me shoot you by mistake?"

Millie held up an oversize pair of calipers. "The Security people,"
she said, "are not the only ones with weapons. I borrowed this from
the machine shop."

Mike stared down at the odd-looking "weapon."

"It's hard," Millie continued, "to look at more than one thing at a
time through a spacesuit helmet. I could've got 'em in the air hose
while you held their attention."

Mike's chuckle was just a trifle ragged, and his mutter about
blood-thirsty panthers didn't really go unheard as he began shucking
his spacesuit.

This was the most dangerous point, Mike knew. The axis tube went from
the observatory straight through to the south polar lock, with nothing
to block sight or sound from traveling its length. They'd have to
simply chance it. The spacesuits shucked, he