Rip estimated the axis on which the asteroid was spinning and selected a crystal in the right position.[pg 215] He had to be careful, otherwise their counter-blast might do nothing more than start the gray planet wobbling.
He and Kemp ran ahead of the others. The Planeteers and their prisoners were running at a speed that kept them right in the middle of the dark area.
It was like running on a treadmill. The Planeteers were making good speed, but were actually staying in the same place relative to the sun's position, keeping the turning asteroid between them and the sun.
Rip and Kemp ran forward until they were right at the sun line. Then they slowed down, holding position and waiting for the crystal they had chosen to reach them. As it came across the sun line into darkness they stopped running and rode the crystal through the shadow until it reached the sun again. Then the two Planeteers ran back across the dark zone to meet the crystal as it came around again. There was only a few minutes' working time each revolution.
Kemp worked fast, and the first hole deepened. Rip helped as best he could by pushing away the chunks of thorium that Kemp cut free, but it was essentially a one-man job.
As Kemp neared the bottom of the first hole, Rip reviewed his plan and realized he had overlooked something. These weren't nuclear bombs; they were simple tubes of chemical fuel. The tubes wouldn't[pg 216] destroy the hole Kemp was cutting.
He reached a quick decision and called Koa to join them. Koa appeared as Kemp pulled his torch from the hole and started running again to avoid the sun. Rip and Koa ran right along with him, crossing the dark zone to meet the crystal as it came around again.
"There's no reason to drill three holes," Rip explained as they ran. "We'll use one hole for all three charges. They don't have to be fired all at once."
"How do we fire them?" Koa asked.
"Electrically. Who has the exploders and the hand dynamo?"