When was flown the first CMG ?

[Nicolas PILLET]

Hi everyone,

The first Soviet satellite using a Control Moment Gyro was Omega-1, aka Cosmos-14, launched in 1963.

But I wonder what was its US counter part ? When was flown the first US satellite using a CMG to orientate itself ?

Thank you very much !

[gpetrie]

Probably the best reference to Soviet Rocketry is Chertok's Memoirs which can be obtained from the NASA Library.

He was one of the GNC Gurus under Korolyev.

Note that the Soviet Astronauts did not control their spacecraft until after their third flight (the first three landed by parachute) and even then the first docks were automated!
Regards Glen

[Nicolas PILLET]

Probably the best reference to Soviet Rocketry is Chertok's Memoirs which can be obtained from the NASA Library.

He was one of the GNC Gurus under Korolyev.

Note that the Soviet Astronauts did not control their spacecraft until after their third flight (the first three landed by parachute) and even then the first docks were automated!
Regards Glen

No doubt about this, but my question is about American GNC

[Jim]

CMGs or reaction wheels?

[Nicolas PILLET]

CMGs or reaction wheels?

CMG.

[Jim]

CMGs or reaction wheels?

CMG.

Skylab

[Nicolas PILLET]

Really ? There was no test before on a 'random' satellite, less valuable than Skylab ?

This seems quite surprising to me.

[catdlr]

Really ? There was no test before on a 'random' satellite, less valuable than Skylab ?

This seems quite surprising to me.

I don't question Jim's knowledge with this; I was anticipating he would respond to this.

[Nicolas PILLET]

I don't question too !

I just feel surprised that the Soviets had this idea back in 1955 for the first Vostok protoyype (it was finally not used), actually flew it in 1963, whereas the Americans didn't fly it before 1973.

I wonder why it was considered useful on one side and useless on the other side, since physics laws are the same on both sides of the Pacific ocean.

[Nicolas PILLET]

I have a Russian source saying that Nimbus in 1964 was the first US spacecraft with CMG. I cannot find confirmation of this in US sources, but I've found this document with an extract that we could interprete as a confirmation...

[Nicolas PILLET]

I think this is a confirmation...

[Jim]

I think this is a confirmation...

No, reaction wheels.

[Nicolas PILLET]

Thank you, Jim.

So, actually I think I was wrong : Omega didn't have CMG, but reaction wheels.

So it means that :
- USSR launched its first reaction wheel-controlled satellite in 1963 (Omega-1), the US in 1964 (Nimbus 1)
- USSR launched its first CMG in April 1973 (Salyut-2), but the mission was a failure. The second attempt (Salyut-3) was a success in June 1974.
- The US launched its first CMG in May 1973 (Skylab).