“I like it,” Venkat said. “All he needs to do is notice one. And he’s sure to check out a bright green ribbon if he sees one outside.”

“Venk,” said Bruce. “If he takes the ‘Watneymobile’ to Ares 4, this’ll all be for nothing. I mean, we can land it at Ares 4 if that happens, but…”

“But he’ll be without a Hab. Yeah,” Venkat said. “One thing at a time. Let me know when you come up with a release mechanism for those ribbons.”

“Will do.”

After terminating the call, Venkat opened his laptop to get back to work. There was an e-mail from Mindy Park waiting for him. “Watney’s on the move again.”

• • •

“STILL GOING in a straight line,” Mindy said, pointing to her monitor.

“I see,” Venkat said. “He’s sure as hell not going to Ares 4. Unless he’s going around some natural obstacle.”

“There’s nothing for him to go around,” Mindy said. “It’s Acidalia Planitia.”

“Are those the solar cells?” Venkat asked, pointing to the screen.

“Yeah,” Mindy said. “He did the usual two-hour drive, EVA, two-hour drive. He’s one hundred and fifty-six kilometers from the Hab now.”

They both peered at the screen.

“Wait…,” Venkat said. “Wait, no way…”

“What?” Mindy asked.

Venkat grabbed a pad of Post-its and a pen. “Give me his location, and the location of the Hab.”

Mindy checked her screen. “He’s currently at… 28.9 degrees north, 29.6 degrees west.” With a few keystrokes, she brought up another file. “The Hab’s at 31.2 degrees north, 28.5 degrees west. What do you see?”

Venkat finished taking down the numbers. “Come with me,” he said, quickly walking out.

“Um,” Mindy stammered, following after. “Where are we going?”

“SatCon break room,” Venkat said. “You guys still have that map of Mars on the wall?”

“Sure,” Mindy said. “But it’s just a poster from the gift shop. I’ve got high-quality digital maps on my computer—”

“Nope. I can’t draw on those,” he said. Then, rounding the corner to the break room, he pointed to the Mars map on the wall. “I can draw on that.”

The break room was empty save for a computer technician sipping a cup of coffee. He looked up in alarm as Venkat and Mindy stormed in.

“Good, it has latitude and longitude lines,” Venkat said. Looking at his Post-it, then sliding his finger along the map, he drew an X. “That’s the Hab,” he said.

“Hey,” the technician said. “Are you drawing on our poster?”

“I’ll buy you a new one,” Venkat said without looking back. Then, he drew another X. “That’s his current location. Get me a ruler.”

Mindy looked left and right. Seeing no ruler, she grabbed the technician’s notebook.

“Hey!” the technician protested.

Using the notebook as a straight-edge, Venkat drew a line from the Hab to Mark’s location and beyond. Then took a step back.

“Yup! That’s where he’s going!” Venkat said excitedly.

“Oh!” Mindy said.

The line passed through the exact center of a bright yellow dot printed on the map.