Yuri Gagarin's spaceflight preceded Alan Shepard's spaceflight by about three weeks.
Notes on verification
Well-documented dates from NASA, FAI, and multiple independent secondary sources consistently confirm a 23-day gap between the two flights. [cascade flags: wikipedia_dropped_other_sources_exist | tier=silver indep_score=0.917 clusters=3 claim_tier=everyday | kind=empirical eligibility=high]
Sources
- How Yuri Gagarin Was Picked to Be First in Space (seed:firsts_and_inventions)
- https://www.nasa.gov/image-article/trajectory-of-alan-shepards-historic-flight/ (corroboration)
- https://www.fai.org/news/60-years-alan-shepard-became-first-american-space (corroboration)
- https://www.space.com/11578-nasa-alan-shepard-space-race-human-spaceflight.html (corroboration)