Crile Fisher tried to suppress his excitement, tried to maintain the same calm expression that the others were wearing.

He didn't know where Tessa Wendel was at the moment. She couldn't be far, since the Superluminal was reasonably small - though broken up so that someone in one bay might well be out of sight to someone in another.

The other three crew members were just pairs of hands to Fisher. They each had something to do and they were doing it. Only Fisher himself had nothing specific to do, except perhaps to be careful to stay out of the way of the others.

He looked at the other three (two men and one woman) almost furtively. He knew them to talk to, and had talked to them frequently. They were all young. The oldest was Chao-Li Wu, who was thirty-eight and a hyperspacialist. Then there was Henry Jarlow, who was thirty-five, and Merry Blankowitz, the baby of the team, twenty-seven years old and with the ink still damp on her doctor's diploma.

Wendel, at fifty-five, was ancient by comparison, but she was the inventor, the designer, the demigoddess of the flight.

It was Fisher who was odd man out. He would be fifty on his next birthday, which was not so far off, and he had no specialized training. He had no right to be on the ship if either youth or knowledge were considered.

But he had been on Rotor once. That counted. And Wendel wanted him with her, and that counted even more. So did Tanayama and Koropatsky, which counted most of all.

The ship was making its way, lumbering through space. Fisher could tell that, even though there was no physical indication that this was so. He could feel it with the tendrils of his intestines - if they had any. He thought fiercely: I've been in space far longer than all the others put together, far more times on far more ships. I can tell there is nothing sleek about this ship just by the feel of it. They can't.

The Superluminal had to lack sleekness. The normal power sources that kept ordinary spaceships moving through the vacuum were cramped and cut down in the Superluminal . They had to be, for most of the ship was given over to the hyperspatial motors.

It was like a seabird that waddled clumsily on land because it was designed for the water.

Wendel suddenly appeared. Her hair was somewhat disheveled and she was perspiring a bit.

Fisher said, ‘Is everything all right, Tessa?’

‘Oh yes, perfectly.’ She rested her rear end against one of the convenient wall depressions (very useful, considering the light pseudo-grav maintained on the ship). ‘No problems.’

‘When do we make the move into hyperspace?’

‘In a few hours. We want to get into the proper coordinates with all appropriate gravitational sources twisting space precisely as calculated.’

‘So we can allow for it exactly?’

‘That's right.’

Fisher said, ‘That doesn't make hyperspatial flight sound very practical. What if you don't know where everything is? What if you're in a hurry and can't wait to calculate every gravitational twitch?’

Wendel looked up at Fisher with a sudden smile.

‘You've never asked anything like this before. Why do you ask it now?’

‘I've never actually been on a hyperspatial flight before. The question presents itself to me with greater urgency under these conditions, you see.’

‘This and many other such questions have presented themselves to me with the greatest possible urgency for years. Welcome to the club.’

‘But answer me.’

‘Gladly. In the first place, there are devices that measure overall gravitational intensity, in both scalar and tensor aspects, at any point in space, whether you know the neighborhood or not. The result is not quite as accurate as it would be if you painstakingly measured each gravitational source and added them together, but it is close enough - if time is precious. And if time is still more precious and you have to push the hyperspatial button, so to speak, and trust to good fortune that gravitation is not very significant and should happen to be slightly wrong, then the transition would be accompanied by something roughly equivalent to a jar - like crossing a threshold and catching the toe of your shoe on the sill. If we can avoid that, fine, but if we don't it's not necessarily fatal. Naturally, in the first transition point, we would like it to be as smooth as possible for our psychological peace of mind - if nothing else.’

‘What if you're in a hurry, feel that gravitation is negligible, and it isn't?’

‘You have to hope that that doesn't happen.’

‘You talked about strains during transition. That means our very first transition might be fatal, even if gravity is allowed for.’

‘Might be, but the odds against a fatal accident at any given transmission are enormous.’

‘Even if it isn't fatal, might it not be unpleasant?’

‘That's harder to say because it requires a subjective judgement. Understand that there's no acceleration involved. In hyper-assistance, a ship has to work its way up to light speed, and even a little beyond at intervals, by use of a low-energy hyperspatial field. Efficiency is low, speeds are high, risks are great, and, frankly, I don't know what the discomforts may, or may not, be.

‘In our kind of superluminal flight, using a high-energy hyperspatial field, we make the transition at normal speeds. We may be at a speed of a thousand kilometers per second at one instant, and at the next we are going a thousand million kilometers per second without acceleration. And since there is no acceleration, we don't feel it.’

‘How can there be no acceleration when you increase the speed a millionfold in an instant?’

‘Because the transition is the mathematical equivalent of acceleration. However, whereas your body responds to acceleration, it does not to transition.’

‘But how can you tell?’

‘By sending animals through hyperspace from one point to another. They are in hyperspace for only a brief fraction of a microsecond, but it's the transition between space and hyperspace that we worry about, and there is one in either direction in even the briefest possible passage through hyperspace.’

‘And animals were sent?’

‘Of course. Once they had reached the reception point, they couldn't very well tell us how things were, but there they were, totally unhurt and calm. It was clear they hadn't been harmed in any way. We tried it on dozens of animals of all kinds. We even tried it on monkeys, all of which survived perfectly - except in one case.’

‘Ah. And what happened in that one case?’

‘The animal was dead, grotesquely mutilated, but that was caused by a mistake in the programming. It wasn't the transition at all. And something like that can happen to us. It's not likely, but it can. It would be equivalent to stepping over a threshold, catching the toe of your shoe on the sill, tripping, falling forward, and breaking your neck. Such things have, indeed, happened, but we don't expect it to happen every time we cross a threshold. All right?’

‘I guess I don't have a choice,’ said Fisher grimly. ‘All right.’

Two hours and twenty-seven minutes later, the ship crossed safely into hyperspace, with no sensation whatever for anyone on board, and the first superluminal flight at speeds far beyond that of light took place.

The transition, by Earth Standard time, was at 9.20 p.m., 15 January 2237.