[amsat-bb] Re: Model Rocket Booster Engine for Picosatellite

Ken Ernandes n2wwd at mindspring.com
Tue Jan 17 13:22:23 PST 2012

How would attitude be controlled so the thrust is in the correct direction?  Spin stabilization about the maximum moment off inertia axis is probably the best choice.  This would require a magnetic torquing system.

Another issue is the thrust needs to be directed through the spacecraft's center-of-mass or there will be stability problems.  How would a cluster be fired individually with each, in turn, directed through the center of mass?  That's a complex design problem.

One more issue is that when you carry multiple motors, the first must accelerate the mass of the unfired motors, so the early firing will be less effective.  The mass of the spent casings will need to be accelerated buy the subsequent motor firings.

You do have some work to do before you have a practical solution.

73, Ken N2WWD

Sent from my iPad

On Jan 17, 2012, at 3:44 PM, Joe Leikhim <rhyolite at nettally.com> wrote:

> David;
> There are some much bigger motors! Ask the Level-3 rocketry folks! Anyway a cluster of medium sized motors could be fired individually as required to raise altitude. I would think that SRB's would be more reliable and safer than hypergolic used on previous Oscars. There would of course be a lot of heat in the rocket casings that would need to be dissipated.
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