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Re: cube sat



    I second the idea of a SSTV payload.  Almost every computer in use 
today can easily decode SSTV images in real time using the soundcard and 
free/almost free software.  I can imagine a very large number of users 
who would enjoy seeing a "live" image of earth from LEO.  Also, the 
technical challenges of such a payload are not all that difficult.  I 
have a feeling that a lowish resolution (the sstv mode is limiting 
resolution anyway) digital camera sensor, like the ones used in webcams 
could be queryed directly by the spacecraft computer and that the 
onboard microprocessor could directly generate the SSTV audio using a 
resistor network and 8 or so digital outputs.  Another benefit to this 
payload is that the power budget is very predictable.  The images are 
transmitted at a known interval (possibly dynamically adjustable 
depending on battery voltage) and thus a target power budget is easily 
obtained.
    Some interesting work could be done in the development of a "digital 
SSTV" mode where the compressed images are transmitted via packet, but 
there really is something to say for the fault tolerance and established 
user base of good ol' analog SSTV.

73s and good luck,
David Carr
KD5QGR

Brian wrote:

>>-----Original Message-----
>>From: nick pugh [mailto:quadpugh@bellsouth.net]
>>Sent: Wednesday, March 24, 2004 9:19 AM
>>To: amsat-bb@AMSAT.Org
>>Subject: [amsat-bb] cube sat
>>
>>
>>All
>>A School in my area is thinking about building a cube sat . This is a
>>satellite that is 4 inches cube weighting < 2 pounds. The size and weight
>>constraints implies a power budget of < 4 watt-hours per orbit max. The
>>questions for the group is what kind of pay load could you suggest to fly?
>>    
>>
>
>A camara pointed at earth and a sstv/fax transmitter?
>Maybe with a sstv simplex relay.
>
>Or a ATV transmitter with a camara pointed at earth, but that might
>be a tuff one, and would take up alot of space on the satellite freqs, so
>it would need to be on a high band, like maybe 1.2GHz, then people could
>use a old analog satellite box to view the video :-)
>
>Could be fun with some new stuff beside aprs/packet and voice.
>
>  
>
>>nick
>>    
>>
>
>Regards
>Brian
>OZ1SKY.
>
>
>----
>Sent via amsat-bb@amsat.org. Opinions expressed are those of the author.
>Not an AMSAT member? Join now to support the amateur satellite program!
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>
>  
>

----
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