In the late twentieth century, science and technology facilitated exploration beyond the Solar System and extended human knowledge through messages comprised of pictures and mathematical symbols, transmitted from radio telescopes and inscribed on material artifacts attached to spacecraft. ‘Interstellar communication’ refers to collective efforts by scientists and co-workers to detect and transmit intelligible messages between humans and supposed extraterrestrial intelligence in remote star systems. Interstellar messages are designed to communicate universal knowledge without recourse to text, human linguistic systems or anthropomorphic content because it is assumed that recipients have no prior knowledge of humankind or the planet we inhabit. In addition to tracing and examining the history of interstellar communication during the period 1957-1977, I present an overview of scientific research on ‘interplanetary communication’ with the supposed inhabitants of Mars and other planets in the Solar System during the first half of the twentieth century. I show that it was not until the late 1950s that space exploration research provided the resources for humans to engage in systematic attempts to contact extraterrestrial civilizations in other star systems. My thesis focuses on two interstellar messages incorporated on specially designed material artifacts –NASA’s Pioneer plaque and Voyager Record—dispatched from Earth on board space probes during the 1970s. I critically examine how scientists designed and mobilized interstellar messages both to convey meaning and simultaneously support rhetorical claims about the universality of science and mathematics. I analyze how situated practices, craft skills and graphical technologies associated with scientific research on interstellar messages were deployed by scientists to produce and disseminate knowledge and support the claim that science and mathematics are universal. I examine the histories of technologies linked to space exploration including radio astronomy, television, communication satellites and space probes, tracing how knowledge practices and discourse associated with these technologies are enmeshed with the history of interstellar communication. In particular, I explain how and why television and other display technologies were appropriated by researchers working on interstellar communication to create visual representations of knowledge. I argue that televisual displays and radio telescopes constitute graphical technologies or ‘inscription devices’ deployed by scientists, media producers and others to translate natural objects, agency and culture into legible forms constituted in and through inscriptions, predominantly pictures and mathematical symbols, that convey knowledge within communication networks.