Apollo 7's Service Propulsion System engine, with 20,000 pounds of thrust, fired eight times without a hitch during the mission.
Notes on verification
Multiple independent sources including NASA and Astronautix confirm eight successful SPS engine firings during Apollo 7; thrust figure of 20,000 lbs is within commonly cited range though slight variation exists across sources. [tier=gold indep_score=0.867 clusters=3 claim_tier=notable]
Sources
- The Flight (and Fights) of Apollo 7 - Smithsonian Magazine (seed:science_and_space)
- https://www.nasa.gov/history/50-years-ago-apollo-7-ends-101-successful (corroboration)
- https://www.nasa.gov/missions/apollo/apollo-7/apollo-7-launched-as-race-to-moon-reached-final-stretch/ (corroboration)
- http://www.astronautix.com/a/apollo7.html (corroboration)
- https://www.spaceline.org/united-states-manned-space-flight/apollo-mission-program-facts-sheet-index/apollo-7-fact-sheet/ (corroboration)