Since the Cold War era, the world's spacefaring superpowers have abided by the 1967 U.N. Outer Space Treaty, which lays out some basic rules for how space can be used. Given the threats that existed at the time and the types of technology that did and did not exist, there were two main things the treaty covered: Not waging nuclear war from space, and not annexing other planets, moons, and celestial bodies.
Thus far, the treaty has achieved these two goals. But as a new article from Slate argues, the treaty is inadequate for the modern world, because with our new scientific knowledge and capabilities, it is possible to exploit outer space in ways that were never imagined when the treaty was first brokered.
For one thing, Slate argued, the legal status of private billionaires who want to colonize other planets, like Elon Musk and Jeff Bezos, is unclear, as the treaty was designed specifically with government actors in mind. There may, however, still be some leeway to regulate such projects, as the treaty makes signatories responsible for all of their "national activities in outer space," which could apply to private companies and individuals from those countries — which has led to debate over whether it is possible or not for such actors to "claim" land for an extraterrestrial colony.
For another, the 1967 treaty does not cover space conservation — which means that if private groups arrange missions to the Moon or Mars, there is theoretically nothing to stop them from polluting them, mining their resources, or bringing home rocks and dust. This has led to some advocacy to make the Moon a UNESCO World Heritage Site, which would offer some protection but would be a crude workaround.
Additionally, Slate points out, even though you cannot own bodies like asteroids, there is nothing to stop you from towing them to Earth. This could have massive implications for national security, as bringing an asteroid into the vicinity of Earth could disrupt satellites or even cause large-scale destruction if it collided with the planet.
As space travel becomes more sophisticated, powerful, and available, these problems will become more evident — and, Slate argues, a solution is needed sooner rather than later.