He didn't really believe it. There would be plenty to worry about. Like detonating nuclear bombs and trying to figure their blast reaction. Like figuring out the course that would take them closest to the sun without pulling them into it. Like a thousand things—all of them up to him.

The chief analyst greeted them. "We got the orders to change course, Commander. That gave us the location of the asteroid. We're already working on it."

"Anything yet?"

"No, sir. We'll have the albedo measurement in a few minutes. It'll take longer to figure the mass."

The asteroid's efficiency in reflecting sunlight was its albedo. The efficiency depended on the material of which it was made. The albedo of pure metallic thorium was known. If the asteroid's albedo matched it, that would be one piece of evidence.

In the same way, the mass of thorium was known. The measurements of the asteroid were being taken. They would be compared with a chunk of thorium of the same size. If it worked out, that would be evidence enough.

Commander O'Brine motioned to chairs. "Might as well sit down while we're waiting, Foster." He took one of the chairs and looked closely at Rip. Suddenly he grinned. "I thought Planeteers never got nervous."

"Who's nervous?" Rip retorted, then answered his own question truthfully. "I am. You're right, sir. The closer we get, the more scared I get."

"That's a good sign," O'Brine replied. "It means you'll be careful. Got any real doubts about the job?"

Rip thought it over and didn't think so. "Not any real ones. I think we can do it. But I'm nervous just the same. Great Cosmos, Commander! This is my first assignment, and they give me a whole world to myself and tell me to bring it home. Maybe it isn't a very big world, but that doesn't change things much."