June 30 – The crew of the Soyuz 11 spacecraft are killed when their air supply leaks out through a faulty valve during re-entry preparations, the only human deaths to occur outside Earth's atmosphere.
July 26 – Apollo program: Launch of Apollo 15. On July 31 the Apollo 15 astronauts become the first to ride in a lunar rover a day after landing on the Moon's surface.
J. J. Stiffler publishes his book Theory of Synchronous Communications and edits a special issue of IEEE Transactions on Communication Technologyonerror correction codes.