It took a few minutes, but eventually he was alone and drifted over toward her. He said, “An excellent dinner, don’t you think?”

It was a neutral remark. He knew that tonight she had something unusual in mind, but neither his face nor his manner revealed that. He was making Jan take the initiative, not exactly playing hard-to-get but giving her full freedom to make suggestions.

Jan said, in just as calm and formal a voice, “Closest approach to Jupiter will happen in an hour or so.”

He glanced at his watch. “An hour and three minutes.”

“I’ve heard it said that the captain and the second in command of a ship like this have keys that will open or close any of the locks.” Jan was staring away across the room, as though the conversation might be a little boring to her. Inside, she was tingling. “Is that true?”

“Quite true. We have to be able to deal with any sort of emergency. That would be impossible if parts of the ship were inaccessible.” He glanced at Jan. “By the way, I should mention that there will be an engineer aft with the Diabelli Omnivores, if they happened to be somehow on your mind.”

“They weren’t.” She turned to face him. “Paul, there is an observation port right at the front of the ship. Do you know it?”

“Given my position on this ship, that’s almost an insult. Come on, Jan. Of course I know it. I’ve been there dozens of times.”

“How would you like to go there again — with me? I want you to lock the door, so that nobody else can get in.” She reached out her hand and placed it flat against his chest. The white uniform was cool to her touch, but she could feel the beat of his heart. “And then” — she was nervous, breathless — “I want us to stay there. I want to make love during the Jupiter swingby. I want to reach orgasm exactly when we are at the point of closest approach to the planet.”

“My God. You don’t ask for much, do you?” But his eyes were alive with speculation. “I was trained as an engineer. An engineer is always allowed some kind of operating tolerances. When you say exactly at swingby minimum distance — how close do we have to get?”

“You would know that better than me. But I want the bells in the ship and the bells inside me ringing at the same time.”

He stood for a moment, thoughtful. Then he nodded. “It might be possible. But before we start, I need five minutes to pay my respects to a couple of other passengers. Head forward, just as far as the bend in the corridor, and wait for me — and don’t get friendly with anyone else. We have a date in the forward observation chamber. If anyone asks what you will be doing, say it is a project of the highest priority.”

Jan nodded, stepped away from Paul as if she were bidding him a polite good evening, and walked toward the dining room exit. Her legs felt wobbly, which was ridiculous — that’s how your legs were supposed to feel after, not before.

She was almost out of the room when the fresh-faced young sailor approached her. He had traveled Earth’s southern oceans before deciding to try the Outer System, and they had spoken about the sea life several times. He had seemed interested in Jan, and now he was smiling.

“Great dinner, and I bet it’s going to be a great party. Are you lined up for anything special?”

“I’m afraid I am.” Jan pulled a face. “You know, Sebastian Birch and I will be going on to Saturn, to work on the Atlas weather station. I’ve been asked to study Jupiter’s cloud patterns as we are making our atmospheric entry and withdrawal, in preparation for what we’ll be doing at Saturn.”

“That’s a bit much, isn’t it? On a party night.” He looked disappointed, and said as he turned away, “But if it’s your job, I guess you have no choice but to do it.”

“I suppose I don’t.”

Jan made her escape as quickly as possible. As she went to wait at the bend in the corridor she had a new thought. Suppose the young sailor decided that she would like company during the cloud observations? He might come to the forward chamber, and discover that a quite different form of entry and withdrawal was taking place.

When Paul at last appeared, making a final farewell comment over his shoulder, her first words were, “When we’re in the observation chamber and the door is locked, no one else can get in. Can they?”

“Only the captain. And the chance that Eric Kondo will run the gauntlet from all the way aft to all the way forward, with a high-grade party going on everywhere in between, is a flat zero unless he thinks the ship is in danger. Why? Who else are you expecting?”

Jan explained about the sailor from Earth as they went forward. Paul laughed, and said, “You know what sailors are. They know there’s a port in every girl. But if he can enter the chamber when the door is locked, he will have earned anything he gets.”

It was clear why Paul was so confident as soon as they entered the observation chamber and he locked the door. Jan had taken no notice of locks before, but this one seemed substantial and complex.

“Proprietary experiments were performed in here a couple of times,” Paul said. “But so far as I know, it will be a first for this particular experiment.”

He switched off the chamber lights and turned Jan to face forward. “Before we become distracted by anything else, take a look. Have you ever seen anything like it?”

The cloud-torn face of Jupiter filled half of the all-around observation port. Jan moved to the window and stared out. She felt overwhelmed. It was twilight at this location on Jupiter. The Achilles was close to the top of the atmosphere, racing forward for its planetary rendezvous. The ship would penetrate only the tenuous upper layers before skipping out again, but Jan could already feel — or imagine — a change in her weight caused by the deceleration.

She watched, fascinated, as they sped across gigantic puffy white thunderheads, or stared down into dark gas chasms wide and deep enough to swallow any of the inner planets. She caught sunlit gleams of orange and purple, and once a far-off bolt of green lightning. For the first time in her life she had a faint comprehension of what clouds and cloud patterns might mean to Sebastian.

She stood and stared for a timeless period, until at last Paul tapped her on the shoulder. He said softly, “I don’t want you to feel that I am in any way rushing you, but it is less than twenty minutes to the point of closest approach. If you really want to ring your bell…”

“All my bells.” As they gently and carefully undressed each other, Jan looked around the interior of the observation chamber. She had not thought things through in enough detail. The floor of the room was cold, hard plastic. There were two chairs, but one of them was thin and angular and bolted down. The other chair was hinged, so that it would swing to follow the line of the ship’s acceleration. It was also padded and probably comfortable, but if either she or Paul sat down in it the geometry would be completely wrong for close body coo-tact.

Paul didn’t seem concerned with practical matters. His attention was wholly on Jan’s body, touching and kissing and nuzzling her. Finally she pushed herself away, held him by the shoulders, and said, “Paul, that feels wonderful. But, I mean, how?”

“How?” He sounded puzzled. “I was thinking the usual way, unless you have different ideas. We’ve done this before in free-fall.”

“But this won’t be free-fall. We’ll decelerate — we are already doing it. Don’t you hear the wind?”

Jupiter’s thin upper atmosphere, rushing past at many kilometers a second, was already producing a thin shrill whistle on the outer skin of the Achilla.

Paul shook his head. “It won’t quite be free-fall, but close to it. We’ll feel a weak force — a small fraction of a gee — pushing us toward the outer wall of the chamber. I was thinking that with me like this” — he drifted across to flatten his back against the broad curve of the observation window, pulling her with him — “and you facing me, with your legs around me, like this… if you think it won’t work, I’m ready to prove otherwise.”