[amsat-bb] Re: Model Rocket Booster Engine for Picosatellite (G0MRF at aol.com)

[Burns Fisher]

 Pretty cool idea!  Of course Aerotech sells much larger engines with
hundreds of newton-seconds of total impulse, and somewhere close to 100
pounds of instantaneous thrust when it is first lit!  And even if it stays
in LEO, this certainly prolongs its life...

What I wonder about is how the 3-axis stabilization on this bird works...I
don't see any additional nozzles in the picture and if they use a momentum
wheel, they have to unload it at some point.  I suppose you could spin it
instead of active stabilization, but then you can only use one engine (on
the spin axis).  As someone commented earlier in another thread, you need
two firings to go from one circular orbit to another one at a different
altitude.

Thanks for posting!

Burns


> Thanks Joe.
>
> What an exciting concept.
>
> Having got really enthusiastic, I thought I would roughly calculate how
> high one of these little rockets could raise the orbit.
>
> Given that one rocket reload pack has
>
> 40 Newtons of thrust
> and lasts for about one second
> We have 40 Newton seconds of specific impulse.
>
>
> The mass flow rate is 18.6g in one second or 0.0168kg/s
>
> So.....the ISP (a bit vague here) is around 219 seconds (ave thrust / mass
> flow rate / 9.81ms^2)
>
> Which should get a 3.7kg satellite's apogee about..... 40km  higher.
>
> So...Not enough for P3E then
>
> Oh well, not so exciting after all.  Time for a beer.
>
> 73  David  G0MRF
>
>
>
>
> In a message dated 17/01/2012 03:56:37 GMT Standard Time,
> rhyolite at nettally.com writes:
>
> Has  anyone seen this. I am surprised a shuttle mission permitted this
> type of  booster. From what I believed, safety concerns prevented most
> types of  boosters.
>
> http://www.rocketryplanet.com/content/view/3706/30/#axzz1jgQ85qx1
>
> --
> Joe Leikhim
>
> Leikhim and Associates
> Communications  Consultants
> Oviedo,  Florida
>
> www.Leikhim.com <http://www.leikhim.com/>
>
> JLeikhim at Leikhim.com
>
> 407-982-0446
>
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