The two spacecraft hung in orbit above the Earth. One was a truncated cone, with the 'Stars and Bars' displayed prominently on its flank; the other was a misshapen cylinder covered in antennae and solar panels. This one had a red square with a golden hammer and sickle on its side. The distance between them was physically small, but significant. The plan was that the two spacecraft would dock and their crews exchange gifts and greetings. It would be a symbolic gesture of friendship between two great powers.

"Ready to begin final approach." The transmission crackled on the speaker in the Soviet capsule. "Confirm we are on track."

The Soviet mission commander shifted in his seat and pulled himself towards a periscope. The reticle was centred on the docking target on the module carried by the American craft. He keyed his microphone. "Everything is ah-chin oh-gay. You may commence approach."

"Roger. Initiating RCS."

The Soviet commander kept his face pressed against the rubber eyepiece of the periscope, watching intently. He remembered the admonishments from the politruk. "This mission is important to the Secretary, comrade commander. Nothing must go wrong on our part - nothing? Pan'i mayu? Of course, if something could be blamed on the imperialists ... ." Then the politruk smiled. "But nothing will go wrong, of course."

"Steady. Steady." The image of the quartered circle of the docking target grew larger in the periscope. "Almost there."

There was a jarring as the two craft made contact. The speaker crackled into life again. "Cutting RCS. Do you have our docking probe?"

The Soviet commander looked down at his engineer. "Do we?"

The engineer shook his head. "No. We don't."

"We should do. What has happened?"

There was a trembling in the engineer's voice. "I don't know. The indicator doesn't show the latches engaged."

The Soviet commander considered swearing, but he knew that his superiors back in Moscow would be listening. While they would probably appreciate the sentiment - and were probably saying the same things amongst themselves - it wouldn't be politically correct for him to give vent to his feelings. And if the American press was to get hold of it? No. It was better to keep calm.

"Very well." The Soviet commander sent a message to his American counterpart. "Docking latches have not engaged. Do you think you might back up and try again?"

"What?" The radio could not hide the American's astonishment. "Alright. Stand by to disengage."

Of course, there was an inquiry. Engineers from both countries were despatched to examine the blueprints and mockups. Hundreds of hours of investigation were presented in thick reports, with the cause of the incident elaborated on. But, with his usual lack of grace, the Soviet Chief Designer summed it up best.

"What do you expect if they won't use the metric system?"