“Done,” said Chang.

“I didn’t think you had it in you, Chang. Good work,” said Huan, the edge in his voice gone.

Chang resecured himself to the space station and made his way to the main hatch while Huan brought Tiangong-3’s weapons online. The station crew had realized they were moving to war footing twelve hours ago when Huan switched off the live viz feed of their activities. But it still felt slightly unreal.

Once the taikonauts were all inside the station, Huan powered up the weapons module. The chemical oxygen iodine laser, or COIL, design had originally been developed by the U.S. Air Force in the late 1970s. It had even been flown on a converted 747 jumbo jet so the laser’s ability to shoot down missiles in midair could be tested. But the Americans had ultimately decided that using chemicals in enclosed spaces to power lasers was too dangerous. The Directorate saw it differently. Two modules away from the crew, a toxic mix of hydrogen peroxide and potassium hydroxide was being blended with gaseous chlorine and molecular iodine.

This was really it, thought Chang as he watched the power indicators turn red. There was no turning back once the chemicals had been mixed and the excited oxygen began to transfer its energy to the weapon. They would have forty-five minutes to act and then the power would be spent.

The firing protocol for mankind’s first wartime shots in space was well rehearsed. The targets marked in the firing solution had been identified, prioritized, and tracked for well over a year in increasingly rigorous drills the crew eventually realized were not just to support war games down on Earth. The long hours spent in the lab would finally pay off.

“Ready to commence firing sequence,” said Huan. “Confirm?”

One by one, the other taikonauts checked in from their weapons stations. Chang touched the photo taped to the wall in front of him. His fingers lingered on the image of his beaming wife and their grinning eight-year-old son. The smiling Ming, missing his two front teeth, wore his father’s blue air force officer’s hat.

What the photo did not show was how upset his wife had been when he’d given Ming that hat the night before. She thought it made her son look like a prop in a Directorate propaganda piece.

He moved his hand away from the photo and began his part of the operation, monitoring the targeting sequence. He startled even Huan when he cried out, “Ready!”

For years, military planners had fretted about antisatellite threats from ground-launched missiles, because that was how both the Americans and the Soviets had intended to take down each other’s satellite networks during the Cold War. More recently, the Directorate had fed this fear by developing its own antisatellite missiles and then alternating between missile tests and arms-control negotiations that went nowhere, keeping the focus on the weapons based below. The Americans should have looked up.

Chang snuck another look at the photo and caught Huan pausing, his trigger finger lingering above the red firing button. He appeared to be savoring the moment. Then Huan gently pressed the button.

A quiet hum pervaded the module. No crash of cannon or screams of death. Only the steady purr of a pump signified that the station was now at war.

The first target was WGS-4, a U.S. Air Force wideband gapfiller satellite. Shaped like a box with two solar wings, the 7,600-pound satellite had entered space in 2012 on top of a Delta 4 rocket launched from Cape Canaveral.

Costing over three hundred million dollars, the satellite offered the U.S. military and its allies 4.875 GHz of instantaneous switchable bandwidth, allowing it to move massive amounts of data. Through it ran the communications for everything from U.S. Air Force satellites to U.S. Navy submarines. It was also a primary node for the U.S. Space Command. The Pentagon had planned to put up a whole constellation of these satellites to make the network less vulnerable to attack, but contractor cost overruns had kept the number down to just six.

The space station’s chemical-powered laser fired a burst of energy that, if it were visible light instead of infrared, would have been a hundred thousand times brighter than the sun. Five hundred and twenty kilometers away, the first burst hit the satellite with a power roughly equivalent to a welding torch’s. It melted a hole in WGS-4’s external atmospheric shielding and then burned into its electronic guts.

Chang watched as Huan clicked open a red pen and made a line on the wall next to him, much like a World War I ace decorating his biplane to mark a kill. The scripted moment had been ordered from below, a key scene for the documentary that would be made of the operation, a triumph that would be watched by billions.

“And there’s the one,” said Huan. “Chang, it is good for us all that you did not miss,” he said as he clicked the pen shut with a flourish.

“Indeed,” Chang said, and then, smiling, he ad-libbed, “I would save you the trouble and walk myself out the airlock. Resetting for target number two.”

Originally known as the X-37, USA-226 was the U.S. military’s unmanned space plane. About an eighth the size of the old space shuttle, the tiny plane was used by the American government in much the same way the shuttle had been, to carry out various chores and repair jobs in space. It could rendezvous with satellites and refuel them, replace failed solar arrays using a robotic arm, and perform many other satellite-upkeep tasks.

But the Tiangong’s crew, and the rest of the world’s militaries, knew the U.S. military also used USA-226 as a space-going spy plane. It repeatedly flew over the same spots at the same altitude, notably the height typically used by military surveillance satellites: Pakistan for several weeks at a time, then Yemen and Kenya, and, more recently, the Siberian border.

With its primary control communications link via the WGS-4 satellite now lost, the tiny American space plane shifted into autonomous mode, its computers searching in vain for other guidance signals. In this interim period, USA-226’s protocol was to cease acceleration and execute a standard orbit to avoid collisions. In effect, the robotic space plane stopped for its own safety, making it an easy target.

The taikonauts moved on down the list: the U.S. Geosynchronous Space Situational Awareness system was next. These were satellites that watched other satellites. The Americans’ communications were now down, but once these satellites were taken out, the United States would be blind in space even if it proved able to bring its networks back online. After that was the mere five satellites that made up the U.S. military’s Mobile User Objective System, akin to a global cellular phone provider for the military. Five pulses took out the narrowband communications network that linked all the American military’s aerial and maritime platforms, ground vehicles, and dismounted soldiers. Then came the U.S. Navy’s Ultra High Frequency Follow-On (UFO) system, which linked all of its ships. It was almost anticlimactic, the onboard targeting system moving the taikonauts through the attack’s algorithm step by step, slowing down only when a cluster of satellites sharing a common altitude needed to be dispatched one by one.

The last to be “serviced,” as Huan dryly put it, was a charged-particle detector satellite. The joint NASA and Energy Department system had been launched a few years after the Fukushima nuclear plant disaster as a way to detect radiation emissions. A volley of laser fire from Tiangong-3 exploded its fuel source.

When Huan finally put the pen back in his suit pocket, there were forty-seven marks on the wall.

They had been told that the ISS would be taken care of “by other means.” On the other side of the Earth, discarded booster rockets were coming to life after months of dormancy. The boosters-turned-kamikazes advanced on collision courses with nearby American government and commercial communications and imaging satellites. The American ground controllers helplessly watched the chaos overhead, unable to maneuver their precious assets out of the way.