[Ground-station] Satellite program

Wed May 16 13:37:50 PDT 2018

Bruce,

I'm not familiar with the requirements for an IHU, but I've done a lot of
embedded firmware/hardware design.  With the desire for DX (above LEO), I'm
assuming rad-hard will be a requirement.  I was looking at a rad-hard ARM
Cortex M0.  What kind of horsepower would the IHU require?

-Keith Wheeler

On Wed, May 16, 2018 at 11:54 AM, Bruce Perens via Ground-Station <
ground-station at lists.openresearch.institute> wrote:

>
> Legal stuff first: Image credit: XKCD #1992: "SafetySat" at
> http://xkcd.com/1992/ Creative Commons Attr-NC 2.5 license.
>
> Yes, we should have a satellite program and do what AMSAT is not. Everyone
> I have heard from so far is asking for a "DX Satellite", "like AO-13" and
> not LEO.
>
> Mission should include digital communications using Michelle's design. I
> also have some blue-sky ideas that we can discuss at Hamvention, some of
> them might be good grant candidates. Think grant. Money is out there, we
> will start soliciting as soon as we have a mission plan.
>
> Build the satellite (and maybe P-pods) first, approach launch providers
> with flight hardware in hand and ready to go. Satellites are cheap,
> launches are not. Be prepared to take advantage of opportunities on very
> short schedules.
>
> I think we should fabricate extras of parts we design, and sell them as
> TAPR does to supplement their budget, but right off of Amazon Prime. Make
> them really easy and fast to buy, and someone else does the shipping. Aim
> at flight-quality but mostly going to classroom use rather than flight, to
> start. Nicer for the class than the PLA 3-D printer stuff that is so
> obviously non-flight that they are using now.
>
> Aim for 100% to 200% markup over cost, Amazon gets around 18% of the order
> and a warehouse fee and fulfills from their warehouse. Most of the
> commercial cubesat companies, like Pumpkin, are running 500% to 1000%
> markup in order to amortize R&D and operational costs and still make a
> profit, but most of them have flight heritage that we would not start out
> with. We use slave labor :-) and can mostly base our final cost on
> fabrication and sales costs.
>
> I have been looking at cubesat structures (because I feel competent enough
> to make one, at least with your help) and I really like Pumpkin's design.
> Almost all laser-cut 5000-class sheet aluminum, bent on a brake, anodized
> corners on the sheet, only the 8 corner pieces are machined, and that only
> simple shaping and drilling of bar stock into a simple rectilinear shape
> with specified-radius corners and edges and a place to put the springs and
> cutoff switch pins. Most other designers seemed to be more interested in
> showing their skill in CNC machining than making a practical structure. If
> you look at Pumpkin's stuff, it is clear that they put a lot of thought
> into mechanical engineering. And they actually engineered for cost and
> mass-production, while few others bothered. We will not ever directly copy
> anything (I am an intellectual property specialist, and will keep us
> legal), but we can and should learn from their work.
>
> Besides the structure, other non-mission-specific stuff we should be
> building would include an IHU (computer) and the other general bus
> components: lithium battery pack with heaters and per-cell management,
> magnetorquer, solar panels (what cells, from where?), maybe some heat
> distribution components like adiabatic heat pipes?
>
> Can we hear from volunteers for any of this?
>
> LIME mini might be a good flight candidate, besides Ettus and Rincon.
> Their CEO and Open Source guy are very friendly and their PCB design may
> already be licensed appropriately. No idea how the chip would take
> radiation.
>
> We should look into the Open Source finite element analysis and CFD
> programs. We should simulate as much as possible before going to thermal
> vacuum, vibration and shock, etc. And publish all input data so that it can
> be reused along with our part designs.
>
> I saw a really nice indium electronic thruster at Cal Poly. All
> proprietary, of course. Goes up with the fuel solid, gets heated in flight.
> No moving parts, works by wicking through a sintered tip. Probably very
> patented. But a source of ideas.
>
>     Thanks
>
>     Bruce
>
>
> On Wed, May 16, 2018, 09:23 Michelle Thompson <mountain.michelle at gmail.com>
> wrote:
>
>> Heh! The SDR really ties it all together in your sketch there.
>>
>> Yes, there's interest in building an open source satellite. The time is
>> right and we have the best chance of making it happen that I've seen in a
>> long time. There's a variety of forces at work in the industry, in
>> academia, and in open source culture and achievement that help make a
>> modern, innovative, amateur, open source payload possible.
>>
>> I don't know enough about MEO but I'm game for supporting any payload
>> that enables an enduring amateur community through reliable communications
>> in space. I'm very happy we get the chance to dig into this and I want to
>> enable and support it as much as possible.
>>
>> The Careful COTS of an Ettus USRP effort is one way to get a capable SDR
>> for space. This is a joint project between Phase 4 Space and GOLF to get
>> the E310 in play soon/now for GOLF and the E320 later for Phase 4 Space.
>> Business unit at Ettus is reviewing it. Systems engineering lead for GOLF
>> endorsed it as an open source effort. Meeting minutes were posted to the
>> list. Next steps depend on what IP from Ettus. We'll proceed with the E320
>> as far as it takes us regardless. I expect to make a lot more progress here
>> in late summer/early fall, especially at GNU Radio Conference 2018.
>>
>> The Rincon AstroSDR is another option, and Rincon has reached out with
>> questions and clarifications in response to the Kittens Weekly Report.
>> There will be more talks after Hamvention. Rincon will be a significant
>> presence at GNU Radio Conference 2018.
>>
>> Propulsion, attitude control, solar power, and a variety of antennas all
>> have open source flight-tested options at LEO. I don't know much about
>> navigation.
>>
>> I do know that we have a lot of support out there from like-minded
>> organizations and projects.
>>
>> I do know that a payload design is within the capabilities of people on
>> this list and within our extended Slack/GitHub/phone/email/club/conference
>> network. That does not mean it's easy by any stretch, and it means that our
>> economic development team will be tested. I think we are up to the
>> challenge.
>>
>> What's the first thing that you think we need to do?
>>
>> -Michelle W5NYV
>>
>>
>>>
>>> ---------- Forwarded message ----------
>>> From: Howie DeFelice <howied231 at hotmail.com>
>>> To: "ground-station at lists.openresearch.institute" <ground-station at lists.
>>> openresearch.institute>
>>> Cc:
>>> Bcc:
>>> Date: Wed, 16 May 2018 04:16:15 +0000
>>> Subject: Satellite Building
>>> Just wondering if there is interest in putting together a project to
>>> build a satellite. There is no particular launch in mind and no particular
>>> mission at this pint other than the generic Amateur Radio goal of
>>> furthering the art of communication. I think most will agree that the LAST
>>> thing we need another LEO. To simply exploit the microwave bands I think we
>>> want to consider orbits that allow hours of coverage at a time. A GEO would
>>> be great, a HEO would be really good. An overlooked orbit, at least in ham
>>> radio, is MEO. An orbit between 8000 and 10,000 Km would provide about 2
>>> hours of coverage and orbit the earth about twice a day. The problem is
>>> that not too many people fly there so we need another  strategy. If we
>>> aren't in a big hurry, maybe we can get there from LEO. This means we need
>>> propulsion, attitude control, navigation, lots of solar power and a really
>>> cool radio. Does this sound reasonable? How  long would this actually take
>>> with a milli-Newton thruster ? I have attached a sketch of my first ideas.
>>>
>>> - Howie AB2S
>>>
>>>
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>>> Date: Wed, 16 May 2018 00:16:18 -0400
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>>
>>
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