US president Donald Trump recently announced the establishing of a “Space Force,” a new branch of the military to project US military might into outer space. In doing so, he followed up on his March 2018 statement that his administration “recognizes that space is a war-fighting domain, just like the land, air and sea.” While such ideas are neither wholly new nor exclusively held by president Trump, they seem to challenge the fundamental principle of outer space as a global commons, which was enshrined in the 1967 Outer Space Treaty. Questions of outer space security are not just important for …

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