It was a real effort to grip the bar of the dumbbell through his stiffened gloves and to hold the packages away from him. After maybe thirty feet, he stopped and put the SEP down.

Bleeker laughed. “It’s only plywood, Phil.”

“Goddamn it,” Stone shouted at him, “do you have to walk so far?”

“You know I do.”

Of course, Bleeker was right; on Mars they would have to carry the SEPs far enough from their MEM, or from the Mars Rover, that they could be sure to find a piece of surface undisturbed by the dust kicked up by their vehicles.

He pulled off the gloves and threw them in the general direction of the MET; he didn’t bother to look where they’d gone.

Bleeker whistled. “Are you supposed to do that, skipper?”

“Sue me.”

He brought the SEP mock-up to Bleeker and set it down; together, they began to deploy the instruments.

Assembling the SEP was like setting up a home barbecue. Undo the bolts. Take the packages out of their Styrofoam blocks. Tamp down the dirt to make the ground flat — actually that wasn’t so easy here; the loess was gravelly and unforgiving — and set the instruments level. Make sure each instrument is pointed the right way, and is the right distance from the others. And don’t let them get coated in dirt, goddamn it.

When they’d finished, the SEP looked like an odd, multipointed star, with the radioisotope power package at the center, and the instruments set up on the ground all around it, connected by fine orange cables. The seismometer was that silvery paint tin. A little meteorology boom stuck up in the air — the SEPs would act as weather stations for the astronauts during their stay on Mars — and that spidery gold-leaf sculpture was a magnetometer. At the front of the assembly was a pair of tall, thin stereoscopic color cameras. And on top of the whole thing sat a delicate S-band antenna, pointing to an imaginary Earth.

The SEPs would be placed at a variety of sites, as the astronauts completed their traverses. There was every hope that the SEPs could send back data long after Stone and his crew had returned to Earth. It would be kind of a neat memorial to the mission; looking down at the installed balsa-and-card mock-up of the SEP, Stone felt a certain pride in his accomplishment, in a task done well.

“Okay, Natalie, the SEP’s installed,” he said. “What next?”

“Rog. According to our checklist, here, one of you should be setting up the CELSS, and the other taking samples.”

“It ain’t time for lunch yet?” Bleeker asked plaintively.

Stone laughed. “I’ll do you a favor, Adam. You set up the CELSS, and I’ll hike around for the goddamn samples.”

They trudged back to the MET, and Stone sucked a little more of the flat, tasteless Tang from the tube at his neck.