Helios A . Booster stage contains Lox tanks only to take nuclear second stage to stratosphere. Nuclear sustainer takes payload to orbit or escape trajectory. Helios B . Booster stage contains Lox tanks only to take nuclear second stage to stratosphere.
Nuclear sustainer takes payload to orbit or escape trajectory.
Booster stage contains Lox tanks only to take nuclear second stage to stratosphere. Nuclear sustainer takes payload to orbit or escape trajectory. Nuclear, recoverable upper stage boosted above atmosphere by minimum chemical stage. Improved Specific Impulse chemical stage uses many engines feeding into single large nozzle. Nuclear, recoverable upper stage boosted above atmosphere by minimum chemical stage.