 SOLRAD 4B reserve satellite (similar to SOLRAD 4) | |
| Names | GRAB 5 SOLar RADiation 4B SR 4B GREB 5 |
|---|---|
| Mission type | Solar X-rays |
| Operator | United States Naval Research Laboratory (USNRL) |
| COSPAR ID | 1962-F03 (SRAD4B) |
| Mission duration | Failed to orbit |
| Spacecraft properties | |
| Spacecraft type | SOLRAD |
| Manufacturer | Naval Research Laboratory (NRL) |
| Launch mass | 25 kg (55 lb) |
| Dimensions | 51 cm (20 in) |
| Start of mission | |
| Launch date | 24 April 1962, 10:49 GMT |
| Rocket | Scout X-2 |
| Launch site | Vandenberg Air Force Base, Western Test Range[1] |
| Contractor | Douglas Aircraft Company |
| End of mission | |
| Decay date | Failed to orbit |
| Orbital parameters | |
| Reference system | Geocentric orbit (planned) |
| Regime | Low Earth orbit |
| Perigee altitude | 930 km |
| Apogee altitude | 930 km |
| Inclination | 66.80° |
| Period | 103.00 minutes |
SOLRAD (SOLar RADiation) 4B was a solar X-ray, ultraviolet, and electronic surveillance satellite. Developed by the United States Navy's United States Naval Research Laboratory, it was the fifth in both the SOLRAD and the GRAB (Galactic Radiation And Background) programs.
This satellite was the only SOLRAD to be launched from Vandenberg Air Force Base, to be launched via Scout rocket, and to be launched unaccompanied by any other satellites. Launched on 26 April 1962, a fourth stage failure resulted in payload impact at 225 nautical miles of the downrange. SOLRAD 4B was the last of the SOLRAD/GRAB missions, future SOLRADs being launched with the National Reconnaissance Office's (NRO) next-generation POPPY satellites.