US forces must prepare for conflict around Moon, top military adviser says

The US military must be ready for potential combat not only in Earth's orbit but also in the space between Earth and the Moon, Chairman of the Joint Chiefs of Staff Gen Dan Caine said on Wednesday.

Caine made the remarks at the Air, Space and Cyber Conference outside Washington, according to the Associated Press (AP), as US officials publicly disclosed that the military had deployed weapons in space.

The general said the US military needed to adapt to ensure it "is prepared to fight, endure and win ... from the seabed to cislunar space."

Lt Gen Gregory Gagnon, head of the US Space Force's Combat Forces Command, said the service was preparing for operations in space and around the Moon as human activity extended farther beyond Earth.

"Humanity is advancing deeper into space — the Space Force's job is to help be prepared to defend US interests," Gagnon told reporters.

US confirms deployment of space weapon in orbit

The comments came days after Air Force Secretary Troy Meink revealed at the same conference that the US had fielded "on-orbit space control weapons".

The disclosures have intensified concerns over the militarisation of outer space, which has traditionally been governed by international agreements stressing peaceful use.

Space Force warns of potential adversaries

Several countries, including the US, have demonstrated the ability to destroy satellites in Earth orbit. However, those tests were conducted from the ground against their own satellites.

Gagnon said the US intelligence community had warned that potential adversaries were seeking to expand warfare into space.

"Our potential adversaries such as the PRC are actively pursuing activities in the system, in parts of space," he said, referring to the People's Republic of China.

China established its own military space troops in 2024 to strengthen its ability to respond to space-related crises.

Asked about Washington's announcement on space-based weapons, Chinese Foreign Ministry spokesperson Guo Jiakun said on Tuesday, "China always upholds the peaceful use of outer space, maintains outer space security and opposes the weaponization, militarization and an arms race in outer space."

Guo also urged the US to "stop expanding its military preparations in outer space."

It remains unclear whether the deployment of weapons in space or possible plans for military operations around the Moon would violate international treaties.

Treaty calls for peaceful use of space

The 1967 Outer Space Treaty, signed by both the US and China, says celestial bodies such as the Moon must be used "exclusively for peaceful purposes". It also prohibits placing nuclear weapons in space and makes countries "liable for damage caused by their space objects."

Efforts to strengthen restrictions on weapons in space gained momentum at the United Nations after reports that Russia was developing a space-based weapon.

Russia vetoed a US-Japanese resolution calling on countries not to develop or deploy nuclear weapons or other weapons of mass destruction in space. A separate Russian proposal to ban all weapons in space "for all time" also failed.

Asked about the treaty and related obligations, Gagnon said the US Space Force "will continue to execute safe and responsible space operations in all the reaches of space."

He declined to clarify the Space Force's policy on using bullets or projectiles in space, referring questions to the Pentagon, which did not immediately respond to a request for comment.

Gagnon said the US plans to double the Space Force's size over the next five years to around 25,000 service members, with roughly two-thirds of the additional personnel assigned to the Combat Forces Command.

"We have capabilities in the military because we are preparing to defend the nation," Gagnon said. "The reason we have the capabilities is to help create deterrence."