After the USSR launched Sputnik 1 in 1957, the space race quickly gained momentum. A decade later, the first space probe that entered the atmosphere of another planet while still operational did so successfully — 55 years ago today, on October 18, 1967. Venera 4 arrived on Venus and began sending data about the planet’s atmosphere until it lost contact thereafter, also making it the first space probe to send data from inside the atmosphere of another planet.
