Juno I
| Juno I awaiting launch with Explorer I | |
| Function | Orbital launch vehicle | 
|---|---|
| Manufacturer | Chrysler for the ABMA | 
| Country of origin | United States | 
| Size | |
| Height | 21.2 m (70 ft) | 
| Diameter | 1.78 m (5 ft 10 in) | 
| Mass | 29,060 kg (64,070 lb) | 
| Stages | 4 | 
| Capacity | |
| Payload to LEO | |
| Mass | 11 kg (24 lb) | 
| Launch history | |
| Status | Retired | 
| Launch sites | LC-5 and 26A, Cape Canaveral Missile Annex, Florida | 
| Total launches | 6 | 
| Success(es) | 3 | 
| Failure(s) | 3 | 
| First flight | 1 February 1958, 03:47:56 GMT | 
| Last flight | October 23, 1959 | 
| First stage – Redstone (stretched) | |
| Powered by | 1 Rocketdyne A-7 | 
| Maximum thrust | 42,439 kgf (416.18 kN; 93,560 lbf) | 
| Specific impulse | 235 s (2.30 km/s) | 
| Burn time | 155 seconds | 
| Propellant | Hydyne/LOX | 
| Second stage – Baby Sergeant cluster | |
| Powered by | 11 Solid | 
| Maximum thrust | 7,480 kgf (73.4 kN; 16,500 lbf) | 
| Specific impulse | 220 s (2.2 km/s) | 
| Burn time | 6 seconds | 
| Propellant | Polysulfide-aluminum and ammonium perchlorate (Solid) | 
| Third stage – Baby Sergeant cluster | |
| Powered by | 3 Solid | 
| Maximum thrust | 2,040 kgf (20.0 kN; 4,500 lbf) | 
| Specific impulse | 236 s (2.31 km/s) | 
| Burn time | 6 seconds | 
| Propellant | Polysulfide-aluminum and ammonium perchlorate (Solid) | 
| Fourth stage – Baby Sergeant | |
| Powered by | 1 Solid | 
| Maximum thrust | 680 kgf (6.7 kN; 1,500 lbf) | 
| Specific impulse | 249 s (2.44 km/s) | 
| Burn time | 6 seconds | 
| Propellant | Polysulfide-aluminum and ammonium perchlorate (Solid) | 
The Juno I was a four-stage American space launch vehicle, used to launch lightweight payloads into low Earth orbit. The launch vehicle was used between January 1958 to December 1959. The launch vehicle is a member of the Redstone launch vehicle family, and was derived from the Jupiter-C sounding rocket. It is commonly confused with the Juno II launch vehicle, which was derived from the PGM-19 Jupiter medium-range ballistic missile. In 1958, a Juno I launch vehicle was used to launch America's first satellite, Explorer 1.