The new document replaces a 1996 space policy. It was approved by Bush on August 31 and was published quietly by the White House on October 6.
"United States national security is critically dependent upon space capabilities, and this dependence will grow," the strategic document says.
"The United States will preserve its rights, capabilities, and freedom of action in space ... and deny, if necessary, adversaries the use of space capabilities hostile to US national interests."
The text also rejects any treaties forbidding space weapons.
"The United States will oppose the development of new legal regimes or other restrictions that seek to prohibit or limit US access to or use of space."
The US government said the new policy document did not signify moves towards using weapons from space.
"It's not a shift in policy," Tony Snow, White House spokesman, said.
"The notion that you would do defence from space is different than the weaponisation of space."
Nonetheless, the policy document has surprised some.
"While this policy does not explicitly say we are not going to shoot satellites or we are going to put weapons in space, it does, it seems to me, open the door towards that," Theresa Hitchens, director of the Centre for Defence Information, said.
According to Hitchens, this view is confirmed by US army documents that clearly express an interest in space weapons.
Shift in direction
Hitchens noted the new policy also represents a significant shift from the previous policy document initiated under Bill Clinton, the previous US president.
"This is a much more unilateralist vision of space. The United States in this policy seeks to establish its rights but fails to acknowledge the rights of other countries in space, where the Clinton policy was very careful to acknowledge the rights of all nations in space," Hitchens said.
The US currently dominates space. Russia has lost most of its means and China is still in the development phase.
But the US supremacy in space faces threats from other countries. "The United States is in particular concerned about China," Hitchens said.
"While both China and Russia have been promoting a space weapons ban, it is clear to me that the Chinese at the same time are considering ways to do damage to US space assets."