Free Saturn by Ben Bova

essential."
    "I didn't mean to be disrespectful, Mal — I mean, Dr. Eberly."
    "You can continue to call me Malcolm when we're alone. But when there is a third person present, it would be better if you observed the formalities."
    "Sure," Holly said. "No prob."
    "Good. Now, we'd both better be getting back to work."
    He turned and started for the door that led back inside the building. Holly scampered after him.
    "About Dr. Cardenas," she said.
    "Yes?" Without turning or slowing his pace.
    "She's agreed to work under our guidelines. She'll be joining us at our closest approach to Ceres. It's all set."
    "Good," Eberly said, unsmiling. "Now we need to draw up the guidelines that will regulate her work."
    "We'll need Professor Wilmot's approval for that, won't we?"
    He grimaced. "Yes, we will. Unless..."
    Holly waited for him to finish the thought. Instead, Eberly yanked open the door and started down the metal stairs toward his office.

    Two days later, Eberly sat behind his bare desk studying the face of Hal Jaansen, head of the habitat's engineering department.
    Ruth Morgenthau sat beside Jaansen, looking worried. She wore one of her colorful tunics and enough jewelry, Eberly thought, to tilt the entire habitat in her direction. She's paying absolutely no attention to the dress codes, he said to himself. She's flaunting her independence, making me look like a fool. But he kept the distaste off his face as he watched Jaansen.
    The man doesn't look like an engineer, Eberly thought. Jaansen was one of those pale blond Norsemen; even his eyelashes were so light that they were practically invisible. He had a clean, pink, well-scrubbed look, and instead of the engineer's coveralls that Eberly had expected, Jaansen wore a crisply starched old-fashioned shirt with an open collar and neatly creased chocolate brown trousers. The only clue to his profession that Eberly could see was the square black palm-sized digital information processor that rested on his thigh, balanced there precariously. Jaansen touched it every now and then with the fingers of his left hand, as though to reassure himself that it was still there.
    "Nanotechnology is a two-edged sword," he was saying, somewhat pompously, Eberly thought. "It can be used for a tremendous variety of purposes, but it also poses grave dangers."
    "The gray goo problem," Morgenthau murmured.
    Jaansen nodded. His face was square-cut, stolid. Eberly decided that the man had very little imagination; he was a walking bundle of facts and information, but beyond his technical expertise he had no interests, no knowledge, no ambitions. Good! Eberly said to himself.
    "Gray goo is one thing," Jaansen replied. "Nanobugs have also been deliberately programmed to destroy proteins. Take them apart, molecule by molecule."
    "So I've been told," said Eberly.
    "We're made of proteins. Nanobugs can be designed to be killers. That's a real danger in a closed ecology like this habitat. They could wipe out everybody in less than a day."
    Morgenthau gasped a disbelieving, "No! Less than a day?"
    Jaansen shrugged his slim shoulders. "They can reproduce themselves out of the materials around them in milliseconds and multiply faster than plague microbes. That's why they're usually programmed to be de-functioned by near UV."
    "De-functioned?" asked Eberly.
    "Near UV?" Morgenthau inquired.
    "De-functioned, deactivated, broken up, killed, stopped. Near ultraviolet light is softer — er, not so energetic — as ultraviolet light of shorter wavelength. So you can use near UV to stop nanobugs without causing damage to people." He broke into a toothy grin as he added, "Except maybe they get a suntan."
    Eberly steepled his fingers. "So nanomachines can be controlled."
    "If you're verrry careful," Jaansen replied.
    "But the risks are frightening," Morgenthau said.
    Jaansen shrugged again. "Perhaps. But take the EVA we had to do on the solar mirrors a few days ago. Nanomachines could have been inserted into the mirror motors