Nimbus B

retired

Earth ObservationsuborbitalLaunched 5/18/1968

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Mission & Launch

Launch Mission: Launch 1968-F04
Launch Vehicle: Thorad SLV-2G Agena D
Launch Date: 5/18/1968
Last Contact: 5/18/1968

Orbit & Mass

Orbit Class: suborbital
Altitude: -3,140 km
Inclination: 100 deg
Dry Mass: 574 kg
Total Mass: 574 kg

Payload Classification

Mission Type: Earth Observation
Payload Category: MET
Payload Class: C

Organizations

Operator: NASA Goddard Space Flight Center
Manufacturer: Lockheed Martin

Registry

UN Registration: A/AC.105/INF.193

Track

Mentions

4

All verified mentions of this spacecraft in source documents.

On May 18, 1968, a Thorad-Agena rocket carrying the Nimbus B-1 Earth observation satellite lifted off from Vandenberg Air Force Base.

PlanGeneralValue 2.5Jun 1, 2026Lost and found on the Pacific floor: the Nimbus SNAP-19 nuclear generators

No radiation leakage was detected during the entire Nimbus B-1 recovery operation.

CapabilityGeneralValue 4.0Jun 1, 2026Lost and found on the Pacific floor: the Nimbus SNAP-19 nuclear generators

Two SNAP-19 radioisotope thermoelectric generators with plutonium fuel fell into the water north of San Miguel Island after the Nimbus B-1 launch accident.

GeneralValue 4.2Jun 1, 2026Lost and found on the Pacific floor: the Nimbus SNAP-19 nuclear generators

The Thorad-Agena rocket carrying Nimbus B-1 strayed off course within two minutes of launch and was destroyed by the flight safety officer over the Santa Barbara Channel.

PlanGeneralValue 2.5Jun 1, 2026Lost and found on the Pacific floor: the Nimbus SNAP-19 nuclear generators