In 1969, Apollo 10 astronauts set the fastest human speed record in space — here's why it still hasn't been broken

Apollo 10 astronauts still hold the fastest human spaceflight speed record. Their return journey from lunar orbit reached nearly 40,000 kilometers per hour. No crewed mission has traveled far enough from Earth to challenge this speed. Modern human spaceflight has not produced conditions needed to exceed Apollo 10's velocity. NASA's Artemis missions may potentially break this long-standing speed record.