SpaceX's Starlink and Starshield satellite networks share much of the same technology but serve different purposes, with one providing commercial internet access and the other, developed for the Pentagon, supporting military and intelligence operations. The distinction has come into focus after Ukraine said restrictions on military-grade Starlink services had hampered its drone strike missions and air defences, raising fresh questions about SpaceX's role in modern warfare.

Ukraine said on Wednesday that Elon Musk's SpaceX had restricted "military-grade" Starlink services, hampering Ukrainian drone strike missions and air defences. The complaint has drawn renewed attention to the distinction between Starlink, SpaceX's commercial satellite internet service, and Starshield, a military version developed for the Pentagon.

While Musk has said the two systems are separate, in many cases they share the same underlying satellite technology. "Starshield systems are owned and controlled by the US government," Musk said on Wednesday in a post on X, adding that any limits on speed or usage are decided by the US military or the president.

"Starlink is a commercial service owned and controlled by SpaceX. Usage of Starlink is limited to civilian or defensive activities and cannot be used for offensive military action, as doing so would be inappropriate for a commercial company."

Starlink, the main profit engine of SpaceX, is a satellite internet network of more than 11,000 satellites that beam broadband service directly to user terminals about the size of a folded newspaper. Its roughly 13 million subscribers range from households and hikers to shipping companies and major airlines.

Since launching its first Starlink satellites in 2019 aboard reusable SpaceX rockets, the company has built a vast low-Earth-orbit constellation that blankets much of the planet, delivering faster connections than traditional communications satellites, which typically operate much farther from Earth and in far smaller numbers.

Starlink gave Ukraine a critical communications advantage early in the war, reshaping how militaries operate on the battlefield. But Musk has restricted Starlink for certain military uses while highlighting Starshield, a more secure network developed for government and military missions.

Starshield is a SpaceX business unit that develops military and intelligence satellite systems for the Pentagon. While its missions are separate from Starlink's commercial broadband service, the distinction is not always clear-cut: Starshield's secure communications services use enhanced encryption and dedicated terminals, but rely on the vast Starlink constellation as their backbone.

Starshield leverages the technology, engineering and operational experiences of Starlink, according to SpaceX. In addition to secure communications, the company says the militarised version can also provide users with Earth observation and the ability to integrate sensors or other payloads.

The Pentagon, Starshield's largest customer, has spent billions of dollars on both Starlink and Starshield services. It has also bought dedicated Starshield satellites, including communications spacecraft for missile-warning missions and a spy constellation for the National Reconnaissance Office.

Questions over the relationship between Starlink and Starshield have persisted since Russia threatened Western satellites supporting Ukraine in 2022.