Vanguard SLV-1, the first production Vanguard Satellite Launch Vehicle, attempted to orbit a 10 kg Lyman-alpha ultraviolet Earth-science satellite from Cape Canaveral on 28 May 1958. A second-stage attitude-control failure put the third stage on the wrong trajectory and the payload never reached orbit.
- Outcome
- Failure
- Orbit
- LEO
- Low Earth orbit
- Payload to orbit
- Did not reach orbit
- Flight
- 5th
- of 11 Vanguard flights