The Curiosity rover is making its final descent to the Martian surface, and all eyes in the Jet Propulsion Laboratory's control room are glued to computer screens.
Except for Rob Manning's. The chief engineer for the rover mission is glancing at his watch, eager for his window of opportunity.
He sneaks out of the control room where the simulation is underway and heads down the street. There, in a cavernous building, an SUV-sized rover sits on a bed of sand.
Manning reaches for a radio connected to the rover and flips a switch.
Back in the control room, the signal cuts out. The flummoxed engineers sit in silence.
Manning congratulates himself on a job well done.
Regardless of whether the Curiosity rover lands safely on Mars on Sunday night, Manning can say, with a clear conscience, that he did his best to ruin it.
Manning heads a team of hundreds of engineers who design, test and operate the Mars Science Laboratory, as the rover mission is officially known. But for nine days, he becomes his own team's worst enemy.
The cheerful veteran of two previous rover missions devises horrible scenarios for the team to face. He throws solar flares at the rover and pokes holes in its fuel system.
You know Murphy's law, that anything that can go wrong will go wrong? "Well, I'm Murphy," Manning said.