She pulled a hose out of the front of the commode; the hose would take her pee to a tank, for dumping in space later. The hose justified the Apollo-era nickname, “relief tube,” that the crews still used for the waste station. In a cupboard beside her there was a set of funnels, all color-coded to ensure they weren’t mixed up by the crew; hers, anyway, were of the distinctive female variety. The cupboard was already starting to stink a little, and the clear plastic of the funnels was turning yellow. Eighteen months of this.

She fitted the funnel to the hose, clamped it over her private parts, and opened the valve to the urine store.

There was a certain strategy to it, which involved aiming for the minimum of pain when using the device. If she opened the valve too soon, the suction would grab at her. And when it resealed itself it was liable to trap a little piece of her inside it. The way round that was to start pissing a split second before opening the valve. But there was a danger that the funnel would just slip off, and off would float her piss in little golden globules.

It took her a few seconds to be able to let go.

Now that she’d gotten set up there, she considered whether to try taking a dump. That was actually easier, mechanically, than peeing. She’d have to start up the slinger, a spinning drum under the commode. The shit would stick to the walls of the drum, and later she would turn a switch to expose the drum to vacuum, and the shit would be frozen and dried out.

But, though she felt a pressure in her lower gut, there was nothing doing; she suspected it was going to take her a few days to relax enough to unclench. And besides, there was no gravity to help her, as the guys had informed her with glee; she wasn’t looking forward to the experience.

She took a couple of wet wipes and cleaned out the inside of the funnel. The wipes might have come out of any drugstore back home, except for the strong stink of disinfectant about them.

She unlocked herself from the john seat. She pushed her hands into the washbasin, a plastic globe which sprayed water across her skin and out into a waste tank. One or two droplets escaped the basin and went oscillating around the john, but she swatted them out of the air easily. There was a row of towel holders on the wall, little color-coded rubber diaphragms: towels, their corners shoved into the holders, hung out in the air like flags. She dried her hands.

She heard a noise; she turned.

Ralph Gershon was in the wardroom, wearing a T-shirt and shorts. He was just floating, with a plastic can of Coke in one hand and a silver-gray lithium hydroxide canister in the other. The lith canisters were used to scrub carbon dioxide out of the recycled air, and they had to be checked and changed regularly. The familiar red-and-white Coke can was pretty much the normal size and shape, except for a baby-style microgravity dispenser at the top.

Gershon held a finger up to his lips — evidently Stone was still asleep — and he held the can out toward her.

She shook her head. “Too gassy.”

“Yeah,” he whispered back. “Coke paid a million bucks to get these cans on the Mission Module, but they just can’t get the damn mix right.” He started to juggle with the lith and Coke cans, sending them spinning and oscillating from hand to hand. York had already observed that microgravity was like a three-dimensional playground for the guys; as soon as they’d gotten into the Mission Module’s big workshop area Stone and Gershon had started doing cartwheels and loops and spins, throwing bits of gear to each other like Frisbees.

Gershon’s eyes kept straying to her chest.

She resisted the temptation to fold her arms across her T-shirt. Well, that’s it. She had a stock of sports bras, and in future she’d be wearing one every time she left her sleep cubicle. No significant relating on this damn mission.

Gershon looked away and sipped at his Coke.

“What’s with the lith cylinders?”

He shrugged. “You know me. I catnap. I’m not sleepy now; I figured I might as well get ahead of myself.” He cackled. “You know, I even got a little shut-eye during the docking.”

That was true. And, with York still unable to rest, there he was, drinking Coke and ogling her chest and getting ahead of his chores.

“You’re an asshole, Ralph,” she said with passion.

He grinned at her. “I know how you’re feeling, by the way.”

“You do?”

“Sure. Stuffy head, right?”

“I know what it is. Zero G. Blood gathering in my chest and my head—”

“Look, if it’s really bad, you should take a scop/Dex.”

“I’ll be okay.”

“Suit yourself. What else? You got a sore back, right?”

“Yeah.” She rubbed at her lower spine. “How did you know?”

“You want to know where that comes from? I’ll tell you. In your bag, you’re never perfectly stable. There’s always a little bit of movement. You drift this way and that. And you know what your body does in response?”

“Tell me.”

“Your toes clench. Right up, into tiny little balls.”

“Why?”

“Because here we are flying to Mars, but we’re still goddamn apes who think we’re going to fall out of a tree any minute. Anyhow, that’s where the back pains come from.”

“So what do I do?”

“Just unclench.” He grinned. “Chill out and unclench. And, Natalie. Use eye masks and earplugs if you have to. What the hell. I won’t tell.”

She went back to her closet. Maybe I’ll give up on trying to sleep and follow Gershon’s example. Get ahead of the day. But she climbed back into her sleeping bag, and it felt warm, and she turned off her overhead light and stretched out again.

She made a deliberate effort to uncurl her toes. Immediately, her back felt easier. Hey, what do you know? The asshole was right.

She closed her eyes.

The United States of America and the Union of Soviet Socialist Republics:

Considering the role which the U.S.A. and the U.S.S.R. play in the Exploration and Use of Outer Space for Peaceful Purposes;

Striving for a further expansion of cooperation between the U.S.A. and the U.S.S.R. in the Exploration and Use of Outer Space for Peaceful Purposes;

Noting the positive cooperation which the parties have already agreed to in this area;

Desiring to make the results of scientific research gained from the Exploration and Use of Outer Space for Peaceful Purposes available for the benefit of the peoples of the two countries and of all the peoples of the world;

Taking into consideration the provisions of the Treaty on Principles Governing the Activities in the Exploration and Use of Outer Space, including the Moon and other Celestial Bodies, as well as the Agreement on the Rescue of Astronauts, the Return of Astronauts, and the Return of Objects Launched into Outer Space;

In accordance with the agreement between the United States of America and the Union of Soviet Socialist Republics on Exchanges and Cooperation in Scientific, Technical, Educational, Cultural and other fields, signed 11 April 1972, and in order to develop further the principles of mutually beneficial cooperation between the two countries; Have agreed as follows…

ARTICLE 3 (of 6)

The parties have agreed to carry out projects for developing compatible rendezvous and docking systems of United States and Soviet manned spacecraft and stations in order to enhance the safety of manned flights in space and to provide the opportunity for conducting joint scientific experiments in the future. It is planned that the first experimental flight to test these systems be conducted during the second half of the decade, envisaging the docking of a United States Apollo-type spacecraft with a Soviet Salyut-type space station, and/or a Soviet Soyuz-type spacecraft with a United States Skylab-type space station, with visits of astronauts in each other’s spacecraft and stations. The implementation of these projects will be carried out on the basis of principles and procedures which will be developed in accordance with the summary of results of the meeting between representatives of the U.S. National Aeronautics and Space Administration and the U.S.S.R. Academy of Sciences on the question of developing compatible systems for rendezvous and docking of manned spacecraft and space stations of the U.S.A. and the U.S.S.R., dated 6 April 1972…