Why does Explorer 1 satellite spinning on launchpad?

[Pawelk198604]

Does this was stabilization mechanism or so?

 

[Jaelommiss]

Quoth Wikipedia regarding Juno I (the vehicle that launched Explorer I) , "The Juno I consisted of a Jupiter-C rocket with a fourth stage mounted on top of the "tub" of the third stage, and fired after third-stage burnout to boost the payload and fourth stage to an orbital velocity of 8 kilometres per second (29,000 km/h; 18,000 mph). The tub along with the fourth stage were set spinning while the rocket was on the launch pad to provide gyroscopic force in lieu of a guidance system that would have required vanes, gimbals, or vernier motors."

[Pawelk198604]

22 minutes ago, Jaelommiss said:

Quoth Wikipedia regarding Juno I (the vehicle that launched Explorer I) , "The Juno I consisted of a Jupiter-C rocket with a fourth stage mounted on top of the "tub" of the third stage, and fired after third-stage burnout to boost the payload and fourth stage to an orbital velocity of 8 kilometres per second (29,000 km/h; 18,000 mph). The tub along with the fourth stage were set spinning while the rocket was on the launch pad to provide gyroscopic force in lieu of a guidance system that would have required vanes, gimbals, or vernier motors."

Thanks 

[IncongruousGoat]

28 minutes ago, Jaelommiss said:

The Juno I consisted of a Jupiter-C rocket with a fourth stage mounted on top of the "tub" of the third stage

History time! The original design in the chain that lead to the Jupiter-C included that fourth stage - it was part of a 1955 proposal called Project Orbiter, concocted by von Braun and the Huntsville Arsenal in 1955 as a proposal for the IGY (International Geophysical Year) goal of launching a satellite, to study the radiation environment in near Earth space. When the NRL's Project Vanguard was selected over Project Orbiter for the IGY, von Braun re-tooled the proposal as a test bed for IRBM re-entry vehicles, removing the fourth stage in the process. The hope there was that, eventually, the Eisenhower administration would see reason and greenlight Project Orbiter. Which they did, but only after the launch of Sputnik and several failed Vanguard launch attempts.

Interestingly, the first tests of the Jupiter-C in 1956 included a dummy fourth stage that was very specifically filled with sand in order to prevent it from achieving orbit. There were all kinds of concerns about satellite overflight rights at the time, and it was seen as imperative that the first satellite launched be a civilian one.

EDIT: And it's a mis-nomer to say that Juno I was a Jupiter-C with an additional first stage. The Jupiter-C was a Jupiter-A vehicle with the fourth stage and a different first stage fuel. Juno I is just another name for Jupiter-C. Making things more confusing is the fact that the Jupiter-A and Jupiter-C are both derived from Redstone, and are unrelated to the Jupiter IRBM. It's not surprising that the Wikipedia article got things wrong.

Edited May 7, 2019 by IncongruousGoat