File:USAF ICBM and NASA Launch Vehicle Flight Test Successes and Failures (highlighted).png

English: A 1965 graph showing by month, the cumulative number of USAF ICBM and NASA launch vehicle flight tests, marking successes and failures, along with future scheduled launches planned by NASA. Launches of boosters with less than intercontinental range (ie, Redstone IRBMs) are not shown.

Failures are highlighted in Pink. NASA use of Atlas and Titan ICBM boosters for Projects Mercury and Gemini is highlighted in Blue.

The human spaceflight program was a highly visible means of demonstrating ICBM booster reliability, translating directly to national defense implications, during a period when the new developing technology had an extremely high failure rate. At the time of the first Mercury-Atlas orbital astronaut flight by John Glenn, more than 100 Atlas's had been launched with a track record of nearly half failures (48). Exactly half of the first 22 Titan missile launches failed (11). NASA acquired their boosters straight from the same manufacturing source that the Air Force procured their nuclear weapon boosters from, with the NASA rockets even being delivered with Air Force serial numbers. (See Serial Number list from 1958 and 1961/62 for Atlas and Titan procurement, respectively.)

By the time of the NASA Gemini-Titan astronaut launches, reliability had been firmly established with an unbroken string of successful launches that carried through Apollo-Saturn dominance and the Moon landings (projected on this 1965 chart).