Vanguard SLV-6 (Vanguard 3B), a Naval Research Laboratory satellite intended to study solar heating of Earth, launched from Cape Canaveral LC-18A on 22 June 1959. A second-stage helium valve failure led to helium-bottle rupture; the third stage drove the 10.8 kg sphere into the Atlantic.
- Outcome
- Failure
- Orbit
- LEO
- Low Earth orbit
- Payload to orbit
- Did not reach orbit
- Flight
- 10th
- of 11 Vanguard flights