Re: [amsat-bb] Re: Useless CubeSats

["William Leijenaar" <pe1rah@xxxxxxxxxxx>]

Hi AMSATs,

I like to give some comment on your reply:

>Now, come on...the big sat and the little sat have all the same things - 
>solar
>cells, batteries, control circuits, comm circuits, mission specific 
>circuits,
>attitude parts...and they work the same. Bill, the ICs are just the same, 
>the
>solar cells too. Same Teflon wire, Kapton tape, potting compound, machined
>aluminum...just less of it. And less is cheaper, easier to manage, test and
>design for some who have never done so.

Maybe I didn't explain to well why a CUBESAT can not be compaired with a 
real satellite.
Yes, they are both made of the same materials, but that doesn't mean they 
have the same problems. A cubesat has no high powers, not that much high 
temperature problems, no difficult propulsion systems. They have mostly 
simple tranceivers, only omni-antenna's etc etc...

With a bigger satellite you have real physical problems to solve, that can 
not only be fixed with a program. There you even have to think where to 
place components to get ride of the heat (e.g PA) or find ways to shield 
sensitive parts (like uProcessors), think out how to place antennas in a way 
they "light" the earth without interfering other radios on board.
Then you need to deal with high current/voltages that must be converted in 
other voltage levels, in an efficient way (not with simple regulators).
When the satellite is spin-stabalized, all the payloads have to be weight 
balanced.
>
> > Its like giving a truck-mechanic-student a small truck model to learn 
>how to
> > repair a truck engine.

>A good analogy - but to make it complete - the truck model runs, just like 
>a big
>truck. It doesn't haul as much, but it runs.

When you think that an electrical motor work equal to a diesel motor...
They are both made of metal, but never work the same...