“It’s supposed to have a useful life of seventy-two hours, operating automatically for a few minutes every half hour,” the captain said, “but the battery may have lost a lot of its power in storage. I think it would be a good idea to check it. It has a test meter on it, Isaac.”

“I’ll go out and check it, Captain,” Isaac said.

When he had pulled on one of the space suits, Isaac checked the air and pressure and went outside.

Garry and Patch watched him move in a light-footed gliding motion toward the spot where the antenna had been set up. He spent several minutes with the rig and then came back into the flier.

As he lifted his helmet off, he said with a shake of his head, “It’s quit sending, Captain. You were right. The battery must have been in bad shape to start with.”

“Not sending,” Captain Eaton muttered to himself, a dark worried frown on his face. “That means that if our SOS was not picked up earlier, it never will be, and no one will know where we are.”

Garry’s heart chilled at hearing this. What the captain really meant, but did not say, was that they were doomed to a slow death as their heat and air were depleted and they froze in the moon’s incredible cold. That would happen long before their food and water gave out.

Captain Eaton placed a fatherly arm around each of the boys and said, “Fellows, I wish there were something I could do. Believe me, if I could give my life to save you two, as Ben did, I would gladly do it. Do you believe that?”

“Yes, Sir, I do believe it,” Garry answered sincerely. “But can’t we really do something—anything at all? It—it’s better than waiting, isn’t it?”

“You’re trembling, both of you,” the captain said, “and I can’t blame you. If it’s any comfort to you, I think you’re the bravest two boys I ever knew. I would have been proud to have had a couple of sons like you.”