A Fall of Moondust

Forty years ago, thought Lawrence , I was playing on a California beach with bucket and spade, making castles in the sand. Now here I am on the Moon—Chief Engineer, Earthside, no less—shoveling in even deadlier earnest, with the whole human race looking over my shoulder.

When the first load was hoisted up, he had exposed a considerable area of Selene's roof. The volume of dust trapped inside the coupling-tube was quite small, and two more bucketfuls disposed of it.

Before him now was the aluminized fabric of the sun shield, which had long ago crumpled under the pressure. Lawrence cut it away without difficulty—it was so fragile that he could tear it with his bare hands—and exposed the slightly roughened Fiberglas of the outer hull. To cut through that with a small power saw would be easy; it would also be fatal.

For by this time Selene's double hull had lost its integrity; when the roof had been damaged, the dust would have flooded into the space between the two walls. It would be waiting there, under pressure, to come spurting out as soon as he made his first incision. Before he could enter Selene, that thin but deadly layer of dust would have to be immobilized.

Lawrence rapped briskly against the roof; as he had expected, the sound was muffled by the dust. What he did not expect was to receive an urgent, frantic tattoo in reply.

This, he could tell at once, was no reassuring “I'm O. K.” signal from inside the cruiser. Even before the men overhead could relay the news to him, Lawrence had guessed that the Sea of Thirst was making one final bid to keep its prey.

Because Karl Johanson was a nucleonics engineer, had a sensitive nose, and happened to be sitting at the rear of the bus, he was the one who spotted the approach of disaster. He remained quite still for a few seconds, nostrils twitching, then said “Excuse me” to his companion in the aisle seat, and strolled quietly to the washroom. He did not wish to cause alarm if there was no need, especially when rescue seemed so near. But in his professional lifetime he had learned, through more examples than he cared to remember, never to ignore the smell of burning insulation.

He was in the washroom for less than fifteen seconds. When he emerged he was walking quickly, but not quickly enough to cause panic. He went straight to Pat Harris, who was deep in conversation with Commodore Hansteen, and interrupted them without ceremony.

“Captain,” he said in a low, urgent voice, “we're on fire. Go and check in the toilet. I've not told anyone else.”

In a second, Pat was gone, and Hansteen with him. In space, as on the sea, no one stopped to argue when he heard the word “Fire.” And Johanson was not the sort of man to raise a false alarm; like Pat, he was a Lunar Administration tech, and had been one of those whom the Commodore had selected for his riot squad.

The toilet was typical of that on any small vehicle of land, sea, air, or space; one could touch every wall without changing position. But the rear wall, immediately above the washbowl, could no longer be touched at all. The Fiberglas was blistered with heat, and was buckling and bulging even while the horrified spectators looked at it.

“My God!” said the Commodore. “That will be through in a minute. What's causing it?”

But Pat had already gone. He was back a few seconds later, carrying the cabin's two small fire extinguishers under his arms.

“Commodore,” he said, “go and report to the raft. Tell them we may only have a few minutes. I'll stay here in case it breaks through.”

Hansteen did as he was told. A moment later Pat heard his voice calling the message into the microphone, and the sudden turmoil among the passengers that followed. Almost immediately the door opened again, and he was joined by McKenzie.

“Can I help?” asked the scientist.

“I don't think so,” Pat answered, holding the extinguisher at the ready. He felt a curious numbness, as if this was not really happening to him, but was all a dream from which he would soon awaken. Perhaps by now he had passed beyond fear; having surmounted one crisis after another, all emotion had been wrung out of him. He could still endure, but he could no longer react.

“What's causing it?” asked McKenzie, echoing the Commodore's unanswered question and immediately following it with another. “What's behind this bulkhead?”

“Our main power supply. Twenty heavy-duty cells.”

“How much energy in them?”

“Well, we started with five thousand kilowatt-hours. We probably still have half of it.”

“There's your answer. Something's shorting out our power supply. It's probably been burning up ever since the overhead wiring got ripped out.”

The explanation made sense, if only because there was no other source of energy aboard the cruiser. She was completely fireproof, so could not support an ordinary combustion. But there was enough electrical energy in her power cells to drive her at full speed for hours on end, and if this dissipated itself in raw heat the results would be catastrophic.