The Outer Space Treaty, an agreement signed by more than one hundred countries that lays the basis for international space laws, became operational on this day in 1967. The laws, signed by the United States, England, China, and the Soviet Union, dictate the codes of conduct for space exploration and warfare, setting the stage for a new era in human exploration. The treaty dictates that weaponry stationed on the moon, along with all experiments and expeditions not benefiting the international community and instead only for the benefit of the nation be considered illegal. Only two years later, the United States landed men on the moon, one of the first cases in which the treaty’s contents were enforced. Yet another example of the Outer Space Treaty’s effect on space exploration is NASA’s rover, Curiosity, which is currently forbidden to go to the water reservoirs newly discovered on Mars, in fear of contaminating the rest of the planet, or even the rest of our solar system. Today’s signatory nations of the treaty include Canada, Western Europe, India, Pakistan, Australia, and much of South America.