Every spring, the top people in America’s space industry—scientists, researchers, military officers and executives—gather for a four-day conference at the century-old Broodmoor Hotel nestled at the base of Cheyenne Mountain in Colorado Springs.

They talk, they plan, they eat and drink. It’s equal parts professional confab and party.

Not for Bob Work. In April 2015, the avuncular former Marine artilleryman was just one year into his new job as deputy defense secretary. He was worried. And he was on a mission.

Work found John Hyten, the square-jawed four-star general in charge of Air Force Space Command, the organization that oversees the production of America’s military spacecraft and sensors. “I like what you’re doing in space,” Work said, according to Hyten.

“But you’re not ready,” Work added.

Specifically, Work said, Hyten and his command weren’t ready “to do space operations in a conflict that extends into space.”

For a career military officer such as Hyten, those words surely stung. Work was telling Hyten that, yes, the general was a great manager. But his team wasn’t prepared to wage a war that extended into space.

Five months later came the proof. A mock attack on U.S. military satellites showed America’s space forces getting their clocks cleaned.

The simulated space battle, which is only now being discussed in public, showed the general and his team realized that, when it came to preparing for orbital warfare, they had to do better.

It was all part of the beginning of a new era for the world’s leading space power. Just a few months after Hyten’s 2015 conversation with Work, the United States’ national-security space agencies—the Air Force, Army and Navy; Strategic Command, which owns America’s nukes; the spy satellite-operating National Reconnaissance Office; the eavesdropping National Security Agency; and the ground-mapping National Geospatial Intelligence Agency among others—had, for the first time, teamed up.

Occupying an unused command center at Schriever Air Force Base, not far from the Broadmoor in Colorado Springs, the 30 space officials began writing battle plans for a possible war in space. Their advice would drive far-reaching reforms in the U.S. space community.

In classic government fashion, the Pentagon gave the group a vague, awkward and forgettable name—the Joint Interagency Combined Space Operations Center, officially and weirdly abbreviated “JICSpOC,” pronounced “jick-spock.”

The collective kick in the ass that Work aimed at the U.S. space community came at a critical time. The United States possesses by far the largest fleet of satellites—military, government-owned, and private—and the most extensive network of ground-based sensors for peering into space, as well as the world’s biggest and most sophisticated space industry.

The military depends on satellites for navigation, communication and surveillance. American civilians count on space, too—for all the same functions plus entertainment and even banking. See how long your car, smart phone and T.V. work without a strong link to a satellite.

But the hundreds of U.S. satellites and sensors and the electronic links that connect them to their human operators are all, well, fragile. The spacecraft are lightly built. The rockets that boost them into orbit are so massively expensive—$100 million apiece or more—that the military and commercial operators can’t afford to launch new satellites very often.

The electronic command-and-control network underlying the space infrastructure is vulnerable to hacking and jamming. Equally worrying, the thousands of men and women who actually monitor and control U.S. spacecraft aren’t trained to respond to direct attacks—from laser blasts, ramming, computer hacking or electronic jamming—on their pricey hardware.

Everyone in the space industry knew all this, had known it for years, but Work was determined to actually do something about it. America can’t assume any longer that space is a safe “sanctuary” for American hardware, Work said at this year’s Broadmoor confab. “Even regional powers like North Korea or Iran have the ability to take out our space assets.”

And its the major powers that are the most threatening. “Both Russia and China have been vocal… about their ambitions to counter our access to space,” Adm. Cecil Haney, the head of Strategic Command, told The Daily Beast.

Russia is recovering from its long, post-Cold War funk and is now rebuilding its armed forces. China has been binging on new technology for more than a new decade. Both countries have jealously eyed America’s dominant position in space—and have determined to undermine it.

Moscow has deployed several small, maneuverable “inspection satellites” that could sneak up on other sats—and hijack, disable, or destroy them. Beijing has sats like that, too, and has also tested ground-based rockets designed to wipe out low-orbiting satellites.

Washington possesses all the same kind of offensive space weaponry, of course. But America’s space defenses are practically nonexistent. And that makes Work nervous. “People are more likely to attack if they see you as weak or vulnerable,” he said.

The first thing the JICSpOC did after setting up shop at Schriever in September 2015 was, apparently, stage a mock attack… on its own satellites. One enemy spacecraft, perhaps modeled on Russia and China’s dangerous inspection-sats, targeted one U.S. spacecraft in a computer simulation.

It was Hyten’s idea—and it didn’t go over well, at first. Some of the old space veterans in the room didn’t think the orbital war game was complex or challenging enough to be worth their time. “We got calls from everywhere saying, ‘What are you doing?’” Hyten recalled.

“I said, ‘I don’t think you understand. This first one is going to be hard.”

And it was. The space officials assumed that, once they put their minds to it, they could handle a simple orbital attack. Butthey quickly discovered, among other flaws, that America’s various spacecraft, sensors, and control systems can’t talk to each other. If, for example, one satellite comes under attack, other spacecraft and sensors should be able to come to its aid—alerting the craft to enemy movements or even directly intervening by going after the attacking sat.

That’s only possible if the hardware and software are compatible and the various operators on the ground can quickly team up. Lacking a single command system or any way to display all the spacecraft data on one set of screens, some of the three dozen increasingly harried members of the JICSpOC actually ran out to Office Depot and bought a bunch of white boards and erasable markers.

To do what Hyten called “integration,” the JICSpOC officials had to read data off of separate command systems then manually combine the figures on the white boards. In ink. As soon as it could, the JICSpOC brought in coders to write a new program capable of combining all the disparate data.

But Hyten—and, indirectly, Work—had made his point. It’s a new world. America can’t take its space advantage for granted. And it’s time for U.S. space operators to start thinking like warriors.

The changes since then have been dramatic. The Obama administration added $5 billion to the military space program for the years 2016 to 2020, including an extra $2 billion just for new defensive systems. The Air Force organized new satellite crews and put them on a rotating shift. While one crew is operating a satellite in shifts, a duplicate crew is off at some school learning new orbital tactics. Every few months, they switch.

Commanders expect these crews to be aggressive. Before, when a satellite malfunctioned, it was standard Air Force procedure to put the sat in “safe mode”—basically, hitting pause—then call a technician. “But that assumes no active threat,” Hyten explained. You can’t very well wait around for the tech guy when some Russian spacecraft is clawing at your GPS satellite.

So Hyten and other commanders changed the procedure. Now, if a spacecraft is on the fritz or suffers damage during an attack, the Air Force expects operators to adapt, figure out some technical work-around—and keep fighting. They must be “steely-eyed space warriors,” Work said.

New hardware and software are also in development, including small so-called “situational awareness” satellites that can maneuver and keep tabs on potentially hostile spacecraft—and can travel into space atop smaller, cheaper rockets.

Other new systems are classified, but they apparently include space vehicles or ground-based system that can destroy spacecraft threatening America’s own orbital hardware. “We are not going to talk about offensive capabilities, but we will develop and continue to operate capabilities to defend ourselves,” Hyten said at the same 2015 conference where Work spurred him into action.

Transforming America’s space operators into space warriors will take longer than one year. But the process has begun. And by government standards, it’s moving fast. “The stand up was done quickly,” Haney, the head of Strategic Command, said of the JICSpOC. “We’re still working on capability.”

For a country whose military prowess utterly depends on space, the stakes are enormous. America has staked out the orbital high ground. Now it needs to appreciate that advantage—and defend it. “Space has allowed us to project power,” Work said. “We want to keep it that way.”