Ingrid’s nerves tingled with a strange sensation of alarm.

She returned to her machines and telescopes, again and again checked their readings as she mapped the unknown area. Everything was quiet but still Ingrid could not take her eyes off the malignant blackness ahead of the ship. Kay Bear noticed her anxiety and for a long time studied and listened to the instruments.

“I don’t see anything,” he said at last, “aren’t you imagining things?”

“I don’t know why, but that unusual blackness ahead of us bothers me. It seems to me that our ship is diving straight into a dark nebula.”

“There should be a dark cloud here,” Kay Bear agreed, “but we shall only scratch the edge of it. That’s what was calculated! The strength of the gravitational field is increasing slowly and regularly. On our way through this area we should pass close to some centre of gravity. What does it matter whether it’s light or dark?”

“That’s true enough,” admitted Ingrid, more calmly.

“We’ve got the finest commander and officers there are. We’re proceeding along a set course even faster than was computed. If there are no changes we’ll be out of our trouble and we’ll get safely to Triton despite our short supply of anameson.”

Even at the thought of the spaceship’s station on Triton, Neptune’s satellite on the fringe of the solar system, Ingrid felt much happier. To reach Triton would mean that they were home.

“I was hoping we’d be able to work on the symphony together but Lynn’s asleep. He’ll sleep six or seven hours so I’ll think over the orchestration of the coda of the second movement — you know, the place where we couldn’t find a means of expressing the integrated accession of the menace. This piece….” Kay sang a few notes.

“Tee-ee-e, tee-ee-e, ta-rara-ra,” came the immediate response from the very walls of the control tower. Ingrid started and looked round, but a moment later realized what it was. There had been an increase in the force of gravity and the instruments had responded by changing the melody of the artificial gravitation apparatus.

“What an amusing coincidence,” laughed Ingrid, with an air of guilt.

“There is stronger gravitation, as there should be in a black cloud. Now you can calm yourself altogether and let Lynn sleep.”

Kay Bear left the control tower and entered the brightly-lit library where he sat down at a tiny electronic violin-piano. He was soon deeply immersed in his work and, no doubt, several hours must have passed before the hermetically sealed door of the library flew open and Ingrid appeared.

“Kay, please wake up Lynn.”

“What’s wrong?”

“The strength of the gravitation field is much more than was computed.”

“What is ahead of us?”

“The same blackness!” Ingrid went out.

Kay Bear woke the astronavigator, who jumped up and ran to the instruments in the control tower.

“There’s nothing especially dangerous. Only where does such a gravitational field come from in this area? It’s too strong for a black cloud and there are no stars here.” Lynn thought for a time and then pressed the knob to awaken the commander of the expedition and after another moment’s thought pressed the knob of Nisa Creel’s cabin as well.

“If nothing extraordinary happens they can simply take over their watch,” Lynn explained to the anxious Ingrid.

“And if something does happen? Erg Noor won’t return to normal for another five hours. What shall we do?”

“Wait quietly,” answered the astronavigator. “What can happen here in five hours when we are so far from all stellar systems?”

The tone of the measuring instruments grew lower and lower telling of the constantly changing conditions of the flight. The tense waiting dragged out endlessly. Two hours dragged by so slowly that they seemed like a whole watch. Outwardly Pel Lynn was still calm but Ingrid’s anxiety had already infected Kay Bear. He kept looking at the control-tower door expecting Erg Noor to appear with his usual rapid movements although he knew that the awakening from prolonged sleep is a lengthy process.

The long ringing of a bell caused them all to start. Ingrid grasped hold of Kay Bear.

Tantra was in danger! The gravitation was double the computed figure!

The astronavigator turned pale. The unexpected bad happened and an immediate decision was essential. The fate of the spaceship was in his hands. The steadily increasing gravitational pull made a reduction in speed necessary, both because of increasing weight in the ship and an apparent accumulation of solid matter in the ship’s path. But after reducing speed what would they use for further acceleration? Pel Lynn clenched his teeth and turned the lever that started the ion trigger motors used for braking. Gong-like sounds disturbed the melody of the measuring instruments and drowned the alarming ring of those recording the ratio of gravitational pull to velocity. The ringing ceased and the indicators showed that speed had been reduced to a safe level and was normal for the growing gravitation. But no sooner had Pel Lynn switched off the brake motors than the bells began ringing again. Obviously the spaceship was flying directly into a powerful gravitation centre which was slowing it down.

The astronavigator did not dare change the course that had been plotted with such great difficulty and absolute precision. He used the planetary motors to brake the ship again although it was already clear that there had been an error in plotting the course and that it lay through an unknown mass of matter.

“The gravitational field is very great,” said Ingrid softly, “perhaps….”

“We must slow down still more so as to be able h turn,” exclaimed the navigator, “but what can we accelerate with after that?…” There was a note of fatal hesitancy in his words.

“We have already passed the zone of outer vortices,” Ingrid told him, “gravitation is increasing rapidly all the time.’’

The frequent clatter of the planet motors resounded through the ship; the electronic ship’s pilot switched them on automatically as it felt a huge accumulation of solid matter in front of them. Tantra began to pitch and toss. No matter how much the ship’s speed was reduced the people in the control tower began to lose consciousness. Ingrid fell to her knees. Pel Lynn, sitting in his chair, tried to raise a head as heavy as lead. Kay Bear experienced a mixture of unreasoning brute fear and puerile hopelessness.

The thuds of the motors increased in frequency until they merged into a continual roar — the electronic brain had taken up the struggle in place of its semi-conscious masters; it was a powerful brain but it had its limits, it could not foretell all possible complications and find a way out of unusual situations.

The tossing abated. The indicators showed that the supply of ion charges for the motors was dropping with catastrophic rapidity. As Pel Lynn came to he realized that the strange increase of gravity was taking place so fast that urgent measures had to be taken to stop the ship and then make a complete change of course away from the black void.

Pel Lynn turned the handle switching on the anameson motors. Four tall cylinders of boron nitride that could be seen through a slit in the control desk were lit up from inside. A bright green flame beat inside them with lightning speed, it flowed and whirled in four tight spirals. Up forward, in the nose of the spaceship, a strong magnetic field enveloped the motor jets, saving them from instantaneous destruction.

The astronavigator moved the handle farther — through the whirling green wall of light a directing ray appeared, a greyish stream of K-particles[9].” Another movement and the grey stream was cut by a blinding flash of violet lightning, a signal that the anameson had begun its tempestuous emission. The huge bulk of the spaceship responded with an almost inaudible, unbearable, high-frequency vibration….