October 10

The Rules for a New Frontier

1967 — The Outer Space Treaty Enters into Force

Time not applicable

On October 10, 1967, an international treaty entered into force addressing a place where humanity had arrived only ten years earlier. Outer space. When Sputnik 1 launched on October 4, 1957, there was no comprehensive international legal framework specifically governing what nations could claim, place, build, or do beyond Earth. Now satellites circled the planet. Humans had traveled into orbit. Spacecraft had reached the Moon and Venus. The United States and Soviet Union were racing to land people on the Moon. And the same rockets capable of launching spacecraft were closely related to ballistic missiles capable of carrying nuclear weapons. The question was no longer whether humanity would operate in space. It was: What rules would apply when we did? The answer began to take shape through the United Nations. On January 27, 1967, the United States, Soviet Union, United Kingdom, and other nations began signing the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies. It became known much more simply as the Outer Space Treaty. On October 10, after the required ratifications had been deposited, the treaty entered into force. Its principles were remarkable. First, outer space was declared free for exploration and use by all nations. No country could claim the Moon, a planet, an asteroid, or another celestial body as sovereign national territory. Planting a flag would not create a new province. Landing first would not establish ownership. Occupation would not confer sovereignty. The treaty stated that outer space, including the Moon and other celestial bodies, was not subject to national appropriation. That principle became one of the foundations of space law. The treaty also addressed the military use of space. Nations agreed not to place nuclear weapons or other weapons of mass destruction in Earth orbit, station them in outer space, or install them on celestial bodies. The Moon and other celestial bodies were to be used exclusively for peaceful purposes. Military bases, weapons testing, and military maneuvers on celestial bodies were prohibited. The treaty did not completely demilitarize space. Military satellites, reconnaissance systems, communications spacecraft, and other national-security activities could still operate in Earth orbit. But the agreement established significant limits at a moment when the Cold War could easily have extended the nuclear arms race into another domain. The treaty also established responsibility. A nation could not avoid its international obligations simply because a space activity was conducted by a private company rather than directly by its government. States were made internationally responsible for their national activities in outer space, including those conducted by non-governmental entities. Private space activities therefore required governmental authorization and continuing supervision. That provision has become increasingly significant as commercial companies have assumed larger roles in launching satellites, carrying astronauts, exploring the Moon, and planning future activities beyond Earth. Another principle concerned astronauts. The treaty described them as “envoys of mankind” and called upon nations to assist astronauts in distress. Still another concerned damage. Launching states could be held internationally liable for damage caused by their space objects. And one provision has become especially important to planetary exploration. Article IX called upon nations to conduct exploration so as to avoid harmful contamination of the Moon and other celestial bodies, as well as harmful effects on Earth resulting from the introduction of extraterrestrial matter. This is one of the legal foundations underlying what is now called planetary protection. When spacecraft are sterilized or cleaned before traveling to potentially habitable environments, the concern is partly scientific. Scientists do not want terrestrial microorganisms contaminating a world such as Mars or an icy moon and confusing future searches for extraterrestrial life. When missions are deliberately ended to prevent an uncontrolled spacecraft from eventually striking a potentially habitable world, the same principle is involved. We have already encountered striking examples in this chronology. Galileo was deliberately sent into Jupiter in 2003 partly to eliminate any possibility that the spacecraft might eventually contaminate Europa. Cassini was deliberately plunged into Saturn in 2017 to protect Enceladus and Titan. Those decisions belong to a tradition of responsible exploration whose international legal framework reaches back to the Outer Space Treaty. The treaty was negotiated during the Cold War. Yet the United States and Soviet Union—competitors in an intense technological and ideological struggle—agreed that some principles should apply to everyone. That may be one of its most remarkable features. The treaty did not answer every future question. It did not anticipate reusable commercial launch systems, enormous satellite constellations, private lunar landers, asteroid-resource proposals, or permanent settlements on other worlds. Debates continue over how its principles should apply to those developments. But more than half a century after it entered into force, the Outer Space Treaty remains the foundation upon which much of international space law is built.

Why It Matters: The Outer Space Treaty established the fundamental international principles governing human activity beyond Earth. It rejected national sovereignty over celestial bodies, guaranteed freedom of exploration, prohibited nuclear weapons and other weapons of mass destruction from being stationed in space, established national responsibility for governmental and private activities, and required attention to harmful contamination. It transformed outer space from a technologically accessible frontier into a realm governed, however imperfectly, by international law.

 

Also on This Day

1846 — William Lassell Discovers Triton

Observation time not established

On October 10, 1846, English astronomer William Lassell pointed his telescope toward a newly discovered planet. Only 17 days earlier, Johann Gottfried Galle and Heinrich Louis d'Arrest had identified Neptune from the Berlin Observatory, guided by mathematical predictions of its position. Now Lassell saw something near it. A moon. The object would eventually be named Triton. The speed of the discovery was extraordinary. Astronomers had spent years trying to understand irregularities in the orbit of Uranus. Mathematicians Urbain Le Verrier in France and John Couch Adams in Britain independently calculated that the gravitational pull of an unknown planet could explain those discrepancies. On September 23, 1846, Galle and d'Arrest found Neptune close to the position predicted by Le Verrier. News of the discovery spread quickly. Lassell, a successful brewer and accomplished amateur astronomer living near Liverpool, immediately turned his attention toward the new world. He possessed an important advantage. He built his own telescopes. Lassell had constructed a powerful 24-inch reflecting telescope, using a metal mirror he had ground and polished himself. With it, on October 10, he detected a faint companion to Neptune. Triton proved to be no ordinary moon. It is by far Neptune's largest satellite, with a diameter of approximately 2,700 kilometers. More surprisingly, Triton travels around Neptune in the opposite direction from the planet's rotation. This retrograde orbit is a powerful clue to its history. Large moons generally form from disks of material surrounding their planets and therefore orbit in the same general direction that their planets rotate. Triton probably did not form that way. Scientists now think it began as an independent world in the outer solar system—probably a Kuiper Belt object—and was later captured by Neptune's gravity. That capture would have profoundly disturbed Neptune's original satellite system. Triton's orbit eventually became nearly circular, but the process may have destroyed or ejected earlier moons and contributed to the formation of the irregular satellite system seen today. For more than a century after Lassell's discovery, Triton remained little more than a distant point of light. Then, in 1989, Voyager 2 flew past Neptune. Its cameras transformed Triton from a dot into a world. The surface was extraordinarily cold—about −235 degrees Celsius. Much of it was covered with frozen nitrogen and other ices. The terrain included broad plains, fractures, and unusual regions sometimes described as having a “cantaloupe” texture. Most surprising of all, Voyager saw active geyser-like plumes rising several kilometers above the surface. Even at the edge of the planetary system, on one of the coldest surfaces ever visited by a spacecraft, geological activity was occurring. Triton's strange orbit and Pluto-like characteristics have made it especially important to planetary scientists. Studying Triton may provide a way to examine a captured Kuiper Belt world without traveling all the way into the Kuiper Belt itself. Lassell could have known none of this. He saw only a faint point beside a newly discovered planet. But that point turned out to be one of the strangest large moons in the solar system.

Why It Matters: Triton's discovery, only 17 days after Neptune itself was found, quickly established that the newly discovered planet possessed a satellite system. Triton's retrograde orbit later revealed that it probably formed elsewhere and was captured by Neptune, while Voyager 2 showed it to be an unexpectedly active icy world and a likely relative of objects in the Kuiper Belt.

 

The Bigger Picture

October 10 brings together two very different kinds of discovery. In 1846, humanity was discovering what was out there. In 1967, humanity was beginning to decide how we should behave when we got there. The interval between those events tells an extraordinary story. Lassell could study Triton only as a distant point of light. One hundred and eleven years later, Sputnik crossed the boundary between observing space and entering it. Another decade passed. By October 1967, humans had orbited Earth, robotic spacecraft had landed on the Moon and Venus, and preparations were underway for people to travel to the Moon. The universe had not changed. Our relationship with it had. Once exploration became physically possible, astronomy encountered questions that astronomy alone could not answer. Who owns the Moon? Can a nation claim Mars? What responsibilities does a country have for a privately operated spacecraft? What happens if one nation's spacecraft damages another nation's property? Should terrestrial organisms be allowed to contaminate another world? What kinds of weapons should be permitted beyond Earth? These are questions of law, ethics, diplomacy, science, and politics as much as engineering. And they will become more important as exploration expands. Triton itself provides an interesting thought experiment. No spacecraft has landed there. No human has visited Neptune. But if someday explorers reach Triton, the principles established in 1967 would accompany them. No nation could legally declare Triton its sovereign territory under the treaty. Exploration would carry responsibilities as well as opportunities. And because Triton is an active world containing volatile ices and potentially scientifically sensitive environments, questions of contamination would matter greatly. This is the larger lesson of October 10. Discovery creates knowledge. Exploration creates capability. But capability creates responsibility. Humanity's journey into the universe is therefore not only the story of how far we can travel. It is also the continuing question of what we choose to do when we arrive.

At a Glance

1846 — Observation time not established — William Lassell discovers Triton, Neptune's largest moon, only 17 days after the discovery of Neptune itself.

1967 — Time not applicable — The Outer Space Treaty enters into force, establishing fundamental principles governing international activities in outer space, on the Moon, and on other celestial bodies.