An anonymous reader shares a report: In the days before Harvey hit Texas, flight controllers at NASA's Johnson Space Center outside of Houston had a decision to make: should they evacuate or ride out the storm at the agency's Mission Control Center? The dilemma wasn't just about the safety of the flight controllers. These personnel are tasked with flying the International Space Station -- a round-the-clock job that can't be done just anywhere. If there's a gap in ground communication, it could put the astronauts in danger. [...] On August 22nd, three days before the storm hit, the mission team was briefed by the National Oceanic and Atmospheric Administration, and decided the best plan was to stay put. They realized that whatever hit Texas would likely hit Round Rock, too, which is located outside of Austin. Plus, Harvey's real danger looked to be the water rather than the winds. The building containing the Mission Control Center is designed to withstand flooding incredibly well. But the team also knew they had to prepare. "Where you don't want to find yourself is just a single flight controller in any position who can't leave because there's no one to replace them," says Scoville. So the flight controllers were told to come into work early and to make sure they had a way to both enter and leave the center safely. Many showed up Friday night with "big, monstrous climbing backpacks," says Scoville. Meanwhile, cots were set up in a nearby room and in a building that serves as an astronaut quarantine facility, where astronauts quarantine before launch to avoid getting sick in space. "We have training rooms that are a mere copy of the flight control room," says Scoville. "They have the same consoles and same screens, but we turned off the lights and put some cots in there. It was interesting to see these rooms usually lit up with all these screens blacked out for people to sleep." Throughout the weekend, Mission Control operated with the bare minimum essential personnel needed to keep the ISS working safely. Normally, flight controller teams work in nine-hour shifts, swapping out three times a day. During the storm, only about six flight controllers worked each shift, and some stretched their shifts to 12 hours. Because the flooding made the roads impassable, everyone had to spend a couple of nights at NASA.