OTD in 1960 NASA awarded Douglas Aircraft Company a contract to develop & build the 2nd stage (S-IV) of the Saturn 1 launch vehicle later modified as the S-IVB on the Saturn 1B & Saturn V. A total of 6 S-IV stages were flown on Saturn 1 vehicles during 1964 (SA-5)& 1965 (SA-10). pic.twitter.com/YiE6j9nEAk

— Astro Info Service (@aisoffice) April 26, 2020