The US military needs to better protect its satellites and strengthen its ability to use them as weapons as the uncharted battlefield of space becomes increasingly crowded and dangerous, Pentagon leaders have warned.
A new military strategy for space calls for greater cooperation with other nations on space-based programmes to improve America's ability to deter enemies.
"It's a domain, like air land and sea," said General Kevin Chilton, who headed US Strategic Command until he retired recently.
The US, he said, needs to make sure that it protects and maintains the battlefield capabilities it gets from space-based assets, including global positioning data, missile warning system information, and communications with fighters or unmanned drones.
As America and other countries depend more on their satellites for critical data, those assets become greater targets for enemies.
While the new military strategy stresses the peaceful use of space, it also underscores the importance of orbiting satellites in both waging and deterring war.
"We need to ensure that we can continue to utilise space to navigate with accuracy, to communicate with certainty, to strike with precision and to see the battlefield with clarity," said William Lynn, deputy defence secretary.
Mr Lynn and other Pentagon leaders say space has become more congested, competitive and contested, and the US needs to keep pace.
General James Cartwright, vice chairman of the Joint Chiefs of Staff, said the US and other nations must develop rules of the road for space that lay out what is acceptable behaviour and movement there.
At a forum put on by the Centre for Strategic and International Studies, General Cartwright said nations need to have guidelines that govern the approximately 22,000 man-made objects orbiting earth, including about 1,100 active satellites.