WASHINGTON >> What would it mean if Russia used nuclear warheads to destroy U.S. satellites? Your home’s electrical and water systems could fail. Aviation, rail and car traffic could come to a halt. Your cellphone could stop working.

These are among the reasons why there was alarm this week over reports that Russia may be pursuing nuclear weapons in space.

The White House has said the danger isn’t imminent. But reports of the new anti-satellite weapon build on longstanding worries about space threats from Russia and China. So much of the country’s infrastructure is now dependent on U.S. satellite communications — and those satellites have become increasingly vulnerable.

It would also not be the first time a nuclear warhead has been detonated in space, or the only capability China and Russia are pursuing to disable or destroy a U.S. satellite.

Here’s a look at what’s happened in the past, why Russia may be pursuing a nuclear weapon for space now, and what the U.S. is doing about all the space threats it faces.

THE PAST: STARFISH PRIME AND PROJECT K

Both Russia and the U.S. have detonated nuclear warheads in space. In the 1960s, little was known about how the relatively new weapons of mass destruction would act in the Earth’s atmosphere. Both countries experimented to find out. The Soviet tests were called Project K and took place from 1961 to 1962. The U.S. conducted 11 tests of its own, and the largest, and first successful, test was known as Starfish Prime, said Stephen Schwartz, a non-resident senior fellow at the Bulletin of Atomic Scientists.

Starfish Prime launched in July 1962, when the U.S. sent up a 1.4-megaton thermonuclear warhead on a Thor missile and detonated it about 250 miles (400 kilometers) above the Earth.

The missile was launched about 800 miles (1,300 kilometers) from Hawaii but the effects from the tests were seen around the equator.

“The large amount of enerqy released at such a high altitude by the detonation caused widespread auroras throughout the Pacific,” according to a 1982 Department of Defense report on the tests.

The blast disabled several satellites, including a British one named Ariel, as radioactive particles from the burst came in contact with them. Radio systems and the electrical grid on Hawaii were temporarily knocked out, said Hans Kristensen, director of the Nuclear Information Project at the Federation of American Scientists. The debris left satellites in its path malfunctioning “along the lines of the old Saturday matinee one-reeler,” the 1982 report said.

When the former Soviet Union conducted its own test as part of Project K, it did so at a slightly lower orbit and “fried systems on the ground, including underground cables and a power plant,” Kristensen said.

The U.S. and the Soviet Union signed a nuclear test ban treaty a year later, in 1963, which prohibited further testing of nuclear weapons in space.

White House national security spokesman John Kirby declined to say today whether the emerging Russian weapon is nuclear capable, noting only that it would violate an international treaty that prohibits the deployment of “nuclear weapons or any other kinds of weapons of mass destruction” in orbit.

SATELLITE ATTACKS TODAY

It’s the ability to do that kind of damage that makes it logical that the Russians would want to put a warhead in space, especially if they see their military and economy weakened after fighting a U.S.-backed Ukraine for the past two years, said John Ferrari, a nonresident senior fellow at the American Enterprise Institute.

A space-based weapon that could cripple U.S. communications and the U.S. economy could be an intimidating equalizer, and would just be the latest development from both Russia’s and China’s efforts to weaponize space, he said.

In the past few years China has tested a satellite with a robotic arm that can maneuver to a system, grab it, and move it out of orbit.

Russia has developed a “nesting doll” satellite that opens up to reveal a smaller satellite, and then that one opens to reveal a projectile capable of destroying nearby satellites. In 2019, the Russians maneuvered a nesting doll near a U.S. satellite.

When one of those nesting doll systems “parks next to one of our high-value NRO capabilities, they are now holding that asset at risk,” the deputy chief of space operations of the U.S. Space Force, Lt. Gen. DeAnna Burt, said at a 2022 space conference. NRO is the National Reconnaissance Office.

Russia also generated headlines around the world when it conducted a more traditional anti-satellite test in 2021, where it shot down one of its own systems. As with the Starfish test, the impact created a large cloud of orbiting debris that even put the International Space Station at risk for awhile.

THE NEW SPACE FORCE

The quickly evolving threat in space was one of the main drivers behind establishing the U.S. Space Force, Pentagon spokesman Maj. Gen. Pat Ryder said at a briefing today. In the years since its 2019 creation, the service has focused on developing a curriculum to train its service members, called Guardians, on detecting threats from space and wargaming scenarios on what conflict in space would look like.

The creation of the Space Force elevated spending on satellite systems and defenses. Previously, when space needs were spread among the military services, spending on a new satellite would have to compete for funding with ships or fighter jets — and the services had a more immediate need for the aircraft and vessels, Ferrari said.

But there’s more work to be done, and the revelation that Russia may be pursuing a nuclear weapon for space raises critical questions for Congress and the Defense Department, Ferrari said. If Russia uses a nuclear weapon to take out satellites and that cripples the U.S. economy, does that justify the U.S. bombing Russian cities in return?

“How do you respond to that? You have no good option,” Ferrari said. “So now it’s a question of, ‘What is the deterrence theory for this?’ ”