[amsat-bb] Re: 9 cubesats on board Vega

Bruce Robertson ve9qrp at gmail.com
Thu Dec 8 09:51:37 PST 2011

On Thu, Dec 8, 2011 at 12:47 PM, Andy Kellner <hawat1 at yahoo.com> wrote:
> Well my point exactly. Somebody a while back jokingly put the concept out to tape 2 woxoun ht's together, mount 2 antennas on some solar panels and throw the thing out the window ...
> I mean just think about it for a second: : take a 2 U cubesat frame, put the guts of 2 HT's in there, together with a battery and some charging electronics, mount antennas and of you go ?
> Do we really _need_ remote command capability ? Or telemetry and all the software ? Onboard scheduling ? Or would a simple homebrew-repeater-in-space do ? I think the only intelligence you really need is
> in the battery charger. Ok, it might become unpredictable if and when the thing is switched on, based on low battery levels .. so what ? If its there I work it, otherwise I wait for the next pass. Just make sure
> it is smart enough to bridge batteries with a short.

Andy --

I appreciate your 'straw man' argument above. Let me respond to the
challenge it makes in what I hope you will take as a friendly manner.

First, I do believe there are international obligations to make any
satellite respond to commands, most importantly to switch 'off'.
Second, since the earliest, most basic, satellites only entailed
telemetry (and today's most basic satellites do the same), I don't
think one can claim that transmitting telemetry is the burden of
complexity that you suggest.

The largest part of your argument suggest that there are off-the-shelf
opportunities that we are not exploiting. But remember that space is a
very different environment than that for which woxoun engineers their
HTs. How would the final amplifier in that HT keep cool without any
air to draw away heat? How would the entire PCB act in a vacuum? Would
it survive the shaking that takes place during launch? Would it
consume power so excessively that two of them would never be sustained
by the solar power available? And then there is all the circuitry that
you would have to develop to ensure that the batteries are charged in
such a manner as to ensure a long life. It, too, would have to be
tested in the manner I described above.

Your argument also sneaks in a bit of a twist: perhaps because you
know that the HTs will be a tight fit, you stipulate a 2U cubesat
design. Fox is 1U. This matters greatly due to the current economics
of spaceflight. The bad news is, we no longer seem to get a free
lunch. The good news is that, if we can be satisfied with a very, very
small volume and weight, for the first time in history, we can buy a
launch for that very small volume and weight, on the order of $100,000
for 10cm^3 and 1kg. But since we aren't getting anything for free, the
next 10cm^3, your 2U bird, has a launch cost of on the order of

What we need, then, is some sort of miracle of miniaturization,
whereby a transponder (perferably not just FM, but SSB/CW, too) could
be shrunk and made to sip power far more abstemiously than ever
before. Behold: the software defined transponder. A huge step in this
field, and darn it all if OUR ORGANIZATION hasn't made it happen.
Listen to ARISSAT1's downlink: FM, transponded SSB/CW and telemetry
all generated by one SDX module. If you are lucky enough to hear your
own signal or make a short QSO, well, you've taken part in history.

> I mean the concepts of Fox & friends and great. But I think we are at the 'less is more' point. I think many of us would prefer a simple-and-dirty fm repeating sat which is actually flying, rather then all the great plans and concepts
> which take years and many many dollars to complete. ARISSAT was great, that the antenna was missing not our fault. Cant we put another ARISSAT in cubesat format together rather quickly, instead of re-inventing the wheel over and over again ? Its a bit like letting a kid starve to death because you don't have the resources to cook a gourmet meal. Guess what, a simple ham-and-cheese sandwich will do.

Here's the great news, Andy. Fox1 basically *is* ARISSAT in 1U format,
with respect to the tricky stuff that you have concerns about. As an
amateur organization, we have cracked the SDX nut, and up there, right
now, is a bird with essentially the firmware necessary for Fox1 to
work. You advocate off-the-shelf components; in a sense, FOX1 and 2
will be built from them, but it will be our own shelf, with our own
components, ready to go.

Moreover, with this know-how we now can partner with other cubesat
projects of which there are likely to be many in the future, perhaps
providing our know-how in exchange for a transponder function once the
bird finishes its primary mission. (For now, due to ITAR, this would
be within the US, but perhaps ITAR will be made more reasonable in the
coming years.)

To my mind, AMSAT has a very exciting and achievable set of goals that
will involve launching amateur communication satellites that are
innovative, (relatively) inexpensive, replaceable, and potentially
reconfigurable. The fun is just starting!

73, Bruce

> Andreas - VK4HHH
> ________________________________
>  From: Thomas Doyle <tomdoyle1948 at gmail.com>
> To: Andy Kellner <hawat1 at yahoo.com>
> Sent: Friday, 9 December 2011 1:25 AM
> Subject: Re: [amsat-bb] 9 cubesats on board Vega
> How many cubesats does the Amateur Radio community have ready for launch - not talking, planning or thinking about about building but actually ready to go ?
> 73 W9KE tom ...
> On Thu, Dec 8, 2011 at 8:28 AM, Andy Kellner <hawat1 at yahoo.com> wrote:
> I'll be darned. 9 (nine!) cubesats on board of this launch vehicle and the whole world wide amateur radio community has major problems finding somebody to launch 1 every 5 years ?
>>Whats wrong with this picture ? I would like to find out why ESA for example has no problems launching the cubesats by the dozend  (for free i bet you),
>>but refuse to carry just one for us. Does somebody has ESA's email address ?  :) Is it really all about the educational aspect of things ? We can use that sales pitch, too.
>>Andreas - VK4HHH
>> From: Trevor . <m5aka at yahoo.co.uk>
>>To: amsat-bb at amsat.org
>>Sent: Thursday, 8 December 2011 9:56 PM
>>Subject: [amsat-bb] Re: LARES To Test Einstein's Theory
>>--- On Thu, 8/12/11, Bob- W7LRD <w7lrd at comcast.net> wrote:
>>> can't we squeeze a little bird in there?
>>They'll be some CubeSat's on the launch I believe going into a 1500 by 300 km orbit see
>>73 Trevor M5AKA
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> --
> Sent from my computer.
> tom ...
> _______________________________________________
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