"Hey, I--"

"Shut up, Weil," Hamilton growled on a private circuit.  Openly, she said, "He wouldn't be here if the company didn't have full confidence in his technical skills."

"I'm sure there's never been any question--" Sakai began.  He lapsed into silence as Hamilton's words belatedly reached him.

"There's a device on the hopper," Izmailova said to Gunther.  "Go pick it up."

He obeyed, reconfiguring Siegfried for a small, dense load.  The unit bent low over the hopper, wrapping large, sensitive hands about the device.  Gunther applied gentle pressure.  Nothing happened.  Heavy little bugger.   Slowly, carefully, he upped the power.  Siegfried straightened.

"Up the road, then down inside."

The reactor was unrecognizable, melted, twisted and folded in upon itself, a mound of slag with twisting pipes sprouting from the edges.  There had been a coolant explosion early in the incident, and one wall of the crater was bright with sprayed metal.  "Where is the radioactive material?" Sakai asked.  Even though he was a third of a million kilometers away, he sounded tense and apprehensive.

"It's all radioactive," Izmailova said.

They waited.  "I mean, you know.  The fuel rods?"

"Right now, your fuel rods are probably three hundred meters down and still going.  We are talking about fissionable material that has achieved critical mass.  Very early in the process the rods will have all melted together in a sort of superhot puddle, capable of burning its way through rock.  Picture it as a dense, heavy blob of wax, slowly working its way toward the lunar core."

"God, I love physics," Gunther said.

Izmailova's helmet turned toward him, abruptly blank.  After a long pause, it switched on again and turned away.  "The road down is clear at least.  Take your unit all the way to the end.  There's an exploratory shaft to one side there.  Old one.  I want to see if it's still open."