"The primitive hydrogen bomb tested at Eniwetok laid the groundwork for the storage of vast amounts of nuclear power in blast compartments a few inches square," Melvin said pridefully. "We can now power a very small rocket designed for space flight with the equivalent of fifty million tons of TNT."
"You left out one vital consideration, Melvin," Elwood said. "The automatic-control factor."
"Pop's right," Melvin said, confronting his sister almost accusingly. "The power won't be released all at once."
"It will be released in successive stages," Elwood corroborated. "We hope eventually to regulate the stages—or steps, as they are called—in such a way that other rockets, identical in design, will build up velocities approaching the speed of light."
Elwood picked up an odd-looking instrument from the work-bench against which he had been leaning. As he fingered it idly he enjoyed his daughter's stunned acceptance of his accomplishment, realising more than ever what an important contribution he had made to man's eventual conquest of the stars.
That conquest would come in good time. Even now enough atomic potential had been stored in the rocket to carry it to Alpha Centauri—and back. The blast mechanism had to have an overload to function at all. But only a tiny fraction of the potential would be needed to make the moon flight an accomplished fact.
The rocket wouldn't be traveling at anything like the speed of light. But just as soon as a few more complicated technical details had been worked out....
Elwood felt suddenly very tired. His back ached with stiffness and his eyelids throbbed. Fortunately he knew the reason for his weariness and refused to become alarmed. He had simply been driving himself too hard. But with the rocket so near completion he couldn't afford to let even a draft of cold wind blow upon him and increase his chances of becoming really ill.
"If it's all right with you, kiddies," he said, "I'm going upstairs to bed. I'm practically out on my feet."