NASA's Voyager probes have traveled through space for nearly 50 years. See the remarkable photos from their journeys.

NASA's Voyager 2 is now 49 years old. The probe is more than 13.2 billion miles from Earth, having crossed into interstellar space in 2018.
insider.si.edu

50 years of solar system exploration historical perspectives edited by Linda Billings

Introduction: NASA's solar system exploration paradigm : the first fifty years and a look at the next fifty / James L. Green and Kristen J. Erickson -- Part I. Overview. Exploring the Solar System : ...