Surrounded by rising floodwaters, a skeleton crew at NASA’s Johnson Space Center is keeping the lights on for the International Space Station.

About 125 people are riding out Harvey’s devastating flood on-site at Johnson Space Center, or JSC. Those on-site include the ISS Mission Control team, the support team for the James Webb Space Telescope (which is currently at JSC for testing), and the JSC Recovery Team, which has the task of dealing with the storm and its impacts.

“Current work focuses on supporting critical operations, riding out the storm, and addressing minor issues such as fixing leaks and keeping drains open, as they arise,” said a NASA representative in an e-mail while working from home due to the flooding.

No problem, Houston

Redundancy is pretty much an article of faith at NASA, so it’s no surprise that the agency has backup plans for ISS Mission Control—and backup plans for its backup plans. If it looks like conditions in Houston are going to get too rough, NASA can transfer Mission Control to the Marshall Space Flight Center in Huntsville, Alabama. It can even activate a Backup Advisory Team, or BAT, a skeleton flight control crew that connects to their Mission Control workstations through laptops from somewhere outside the storm’s path. When Ike hit the Houston area in 2008, for instance, the BAT ran mission control from outside Austin, Texas.

This time around, the Mission Control team stayed in Houston to ride out the storm, and they’ve been busy. As floodwaters rose around them on Sunday, Mission Control talked ISS astronauts through an orbital adjustment maneuver that got ISS into position to dock with a Soyuz spacecraft scheduled to arrive next month. A Progress cargo spacecraft currently docked to ISS fired its engines to boost the station into a slightly higher orbit, about a kilometer farther from the Earth’s surface.

And to give the locked-in JSC crew some perspective on their situation, the helpful astronauts aboard ISS have been sending home images of Harvey from space.

James Webb is keeping cool

The other critical mission at Johnson is one that won’t actually launch until 2018: the James Webb Space Telescope, or JWST. Its primary mirror arrived in Houston in May 2017 for a final round of cryogenic testing to make sure the mirror can actually withstand the cold of space. After months of separate testing, assembled components of JWST (everything but the sunshield and the spacecraft bus) started a hundred-day testing session in a vacuum chamber at JSC, where liquid nitrogen and cold helium gas will chill the telescope to minus 233 degrees Celsius.

Then came Harvey. Now it’s up to the JSC Recovery Team to keep the test running and, most importantly, prevent damage to NASA’s $10 billion space telescope. So far, all is well.

“The James Webb Space Telescope (JWST), at JSC for testing, is in good shape. All backup facility systems required to maintain the JWST have been checked and readied for use if necessary,” wrote the NASA representative.

NASA’s other facilities in the Houston area include Ellington Field, which is home to a fleet of T-38 jets used for astronaut flight training. Ellington formerly housed the infamous KC-135 “Vomit Comet,” which NASA decommissioned in 2004. “The NASA side of Ellington Field is doing fine and all aircraft are safe,” wrote the representative. Ellington is also home to a Texas Air National Guard unit, a Coast Guard air station, and a Civil Air Patrol squadron.

“Kind of surreal”

So what’s it like riding out a hurricane at Mission Control? Flight Director Royce Renfrew described it in a tweet shortly after he arrived to relieve another flight director on Sunday night as “kind of surreal with off duty folks crashed in the [flight control rooms].” Later in the day, he described JSC as an island surrounded by floodwaters.

Managed to make it in to relieve one of the other flight directors. MCC kind of surreal with off duty folks crashed in the B&WFCR. pic.twitter.com/3U43QMKxbe — Royce Renfrew (@Tungsten_Flight) August 28, 2017

Earlier in the evening, the @JSCSOS account observed that storm sewers at Johnson were “holding their own” against the downpour, despite the 31 inches of rain the center had received between Friday morning and late Monday. The center expects to have received another 3 to 5 inches of rain on Monday night and another 5 to 7 inches through the day on Tuesday.

Because this is NASA, the big challenge at the moment seems to be keeping employees from coming to work. A memo on JSC’s emergency communications website Monday night advised, “DO NOT REPORT IN UNLESS YOU HAVE BEEN ASKED TO DO SO! We will call you when we are ready for you.” JSC SOS has repeated that message several times since Friday, and the tone has grown steadily more emphatic. (JSC employees, if you’re reading this, please stop trying to go to work. It sounds like they mean it.)

Even with most employees unable to come to work, JSC is looking out for its own. “While the vast majority of our workforce is safe, many have experienced severe flood damage, are without power, and may need other assistance,” wrote JSC Director Ellen Ochoa in a message to Center employees on Monday night. At the time, nearly 90 percent of employees had checked in via JSC’s Emergency Notification System.

“We are anxious to hear from the rest,” Ochoa wrote. “We are putting together a system to gather needs and mobilize volunteer resources to help our JSC family.” And just as it did in 2008 in the wake of Hurricane Ike, JSC plans to open the Gilruth Recreation Center to give employees and their families access to showers, air conditioning, and computers during the recovery process.

When the coast is clear

With the rain still coming down, it’s not yet clear what the total final impact on JSC will be from a storm whose overall damage to the Houston area could top $40 billion. In 2008, the last time a major storm impacted the Houston area, more than 160 buildings at JSC sustained damage, mostly from heavy rains and flooding.

“The JSC Recovery Team hasn’t had a chance to do a full assessment of the storm’s effects on the center yet,” wrote the NASA representative. “The team has been handling issues as they come up and will conduct the full assessment when the storm threat subsides.”

That process will probably begin later in the week, before JSC reopens for normal operations. Harvey, now a tropical storm, is expected to make its second landfall east of Houston on Wednesday morning, putting the city—and the Space Center—on the relatively dry western side of the storm. That means rain should begin to taper off on Wednesday. As the floodwaters recede, it will be time to assess the damage, begin cleanup and repairs, and get on with the business of spaceflight.

“Our JSC recovery team has been doing just that,” wrote the NASA representative.

Meanwhile, Ochoa managed to find some humor in the situation. “Ironically had to cancel survival training for #NewAstronauts this week,” she tweeted at 4:17pm on Monday. “They'll get partial credit, onsite folks full credit and big thanks.”