Why is a space probe spinning around its own axes, when flying through space?

[Bjarne]

Why is a space probe spinning around its own axes, when flying through space?

 

[madmike159]

If one side was facing the sun all the time it would get very hot and sensitive components could get damaged. Also it could be usful so the probe could take readings etc in different directions.

 

[Bjarne]

So fare I know, also probes flying out of the solar system is also spinning
Why ?

 

[madmike159]

Probably to move their telescopes etc it face different positions, it might be something to do with their propulsion system.

 

[Bjarne]

This was also what I was thinking, - but resistance is almost zero.
I mean we can not compare the liogic with a spinnng bullet ?

 

[arildno]

Hmm..I'd said it is due to the gyroscopic effect:

An object that spins around its axis of motion will be more STABLE in its motion along that axis.

That means it will keep its intended motion more easily.

 

[Andy Resnick]

Here are a few reasons:

Heh... I thought the answer would be obvious, until I tried to find a website.

Even for deep-space probes, space is not a perfect vacuum, so rotation makes sense for aerodynamic (is that term still applicable?) reasons. Yes, the density is very low but the flight duration is very long.

Also, in low Earth orbit, the effect of the gravity gradient is sufficient to apply a torque to non-spherical satellites, which require rotation as a stabilizing mechanism.

Solar panels cause a torque to be exerted from radiation pressure, and in terms of thermal management, it makes sense to rotate the satellite to prevent a hot spot from occurring.

That said, there are plenty of satellites that don't rotate: Hubble, the ISS, WMAP, etc.