On Thu, Dec 8, 2011 at 12:47 PM, Andy Kellner <haw...@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 $200,000. 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 VE9QRP > > Andreas - VK4HHH > > > > ________________________________ > From: Thomas Doyle <tomdoyle1...@gmail.com> > To: Andy Kellner <haw...@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 <haw...@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 . <m5...@yahoo.co.uk> >>To: amsat-bb@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 <w7...@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 >> >>http://www.esa.int/esaMI/Education/SEM3N03MDAF_0.html >> >>73 Trevor M5AKA >> >> >>_______________________________________________ >>Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. >>Not an AMSAT-NA member? Join now to support the amateur satellite program! >>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb >>_______________________________________________ >>Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. >>Not an AMSAT-NA member? Join now to support the amateur satellite program! >>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb >> > > > -- > > Sent from my computer. > > tom ... > _______________________________________________ > Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb -- http://ve9qrp.blogspot.com _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! 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