>>11412465Yes, it would be illegal. According to Article VIII of the Outer Space Treaty of 1967, legal possession of any item placed in space is retained by the country that put it there. Voyager I remains the property of the United States government. Article VIII explicitly extends this ownership to space items that have been returned to Earth.
>A State Party to the Treaty on whose registry an object launched into outer space is carried shall retain jurisdiction and control over such object, and over any personnel thereof, while in outer space or on a celestial body. Ownership of objects launched into outer space, including objects landed or constructed on a celestial body, and of their component parts, is not affected by their presence in outer space or on a celestial body or by their return to the Earth. Such objects or component parts found beyond the limits of the State Party of the Treaty on whose registry they are carried shall be returned to that State Party, which shall, upon request, furnish identifying data prior to their return. If you are a citizen of any of the green or yellow countries, you, as members of a nation bound by the treaty, are also bound by the treaty. If you are a citizen of one of the red countries, the US government will ask your government to recover its property. If they refuse to do so, the United States will simply violate their sovereignty and get it from you.
