NASA scrapped 1973 Venus flyby mission due to cost

NASA once planned to send astronauts on a daring Venus flyby mission in the 1960s and 70s, a plan that would have seen humans travel closer to the sun than ever before. The concept, known as the Manned Venus Flyby, was part of NASA’s Apollo-era ambitions to push the boundaries of human spaceflight. Had it launched, the mission would have seen a crewed spacecraft swing past Venus in 1973 or 1974, using the planet’s gravity to slingshot back toward Earth. The plan was eventually shelved, but it remains one of the most ambitious "what if" ideas in space exploration history.

The Venus flyby idea emerged as NASA raced to beat the Soviet Union during the Cold War space race. After the success of Apollo 11 in 1969, NASA explored even bolder missions, including sending astronauts to Mars and Venus. A Venus flyby was seen as a stepping stone—it required less propulsion than landing and could be done with Apollo-era technology. Scientists also hoped to study Venus up close, collecting data on its thick, toxic atmosphere and extreme surface conditions. But as the Apollo program wound down and priorities shifted, the mission was canceled in 1971 due to budget cuts and the realization that a Venus flyby offered fewer scientific returns than a Mars landing.

The plan was ambitious but risky. A crew would have spent nearly a year in space, enduring high radiation levels outside Earth’s protective magnetosphere. Communications would have been delayed by minutes due to Venus’s distance from Earth, making real-time problem-solving impossible. NASA estimated the mission would cost around $7 billion in today’s dollars—about half the price of the Apollo program. Some scientists argued the mission could have advanced our understanding of planetary formation and solar system dynamics. Others saw it as a distraction from more practical goals like building space stations.

Today, Venus is back in the spotlight—not for crewed missions, but for robotic exploration. NASA’s DAVINCI and VERITAS missions, launching later this decade, aim to study Venus’s atmosphere and geology. The European Space Agency’s EnVision mission will also map the planet. These efforts could reveal clues about Earth’s runaway greenhouse effect and whether Venus ever hosted habitable conditions. While the idea of sending humans to Venus remains science fiction, the renewed interest shows how far we’ve come—and how much we still have to learn.