[Ground-station] Satellite program

Bruce Perens bruce at perens.com
Thu May 17 04:29:02 PDT 2018 

Thanks Doug. Wow. Was an ECC chip and extra bits considered less reliable?

On Thu, May 17, 2018 at 12:02 AM, Douglas Quagliana <dquagliana at gmail.com>
wrote:

> All,
>
> Here's more way more information than you wanted to know on a couple of
> the points that Bruce mentioned.
>
> Bruce writes:
> >They didn't always use rad-hard memory, just because they could not
> afford it,
> >but used error-correcting memory architectures and scrubbed the memory
> constantly
> >so that single-bit errors were corrected before they became large enough
> to be
> >uncorrectible.
>
> If I recall correctly, the memory scrubbing technique was used on the LEO
> Microsats and a three bank memory voting scheme was used on the IHU-2 on
> AO-40.  See
>
> http://www.amsat.org/amsat/articles/g3ruh/124.html
>
> *>EDAC memory:* 20 percent. The EDAC (Error Detecting And Correcting)
> memory scheme used requires the actual memory to be three times as large as
> the processor sees. This is necessary to allow a two-of-three vote for each
> bit.
> >This scheme results in a much faster memory system than the Hamming 12 to
> 8 EDAC system used on previous designs, in order to support the much faster
> processor.
>
>
> Bruce writes:
> >They have their own FORTH-like language, first written in the '70's,
> which
> >does concurrent but not parallel threads.  Most housekeeping is written
> >in this language.
>
> The language is IPS.  First described in 1979! The original reference is
>
> Meinzer K.; IPS, An Unorthodox High Level Language, BYTE, January 1979,
> pps 146-159.
>
> which, before you groan about ancient references to out-of-print paper
> magazines, is actually available online at
>
> https://archive.org/stream/byte-magazine-1979-01/1979_01_
> BYTE_04-01_Life_Algorithms#page/n147/mode/2up
>
> But...if you want to learn IPS then you probably want the IPS book that
> James Miller, G3RUH, first published in 1997.  Before you groan, again,
> about ancient references to out-of-print paper books, that book (actually
> the third edition of that book from 2016) is available online at
>
> http://www.jrmiller.demon.co.uk/IPS/IPS.pdf
>
> However, as you will quickly find out reading Miller's IPS book, the AO-13
> IPS flight code is written in a German variant of IPS, so a lot of that IPS
> code looks like this:
>
> : TRQ-ST Z-MARKE @
>     JA? E-FLAGS @ #14 UND >0  Z @
>         MZEITGRENZE @ = ODER
>         JA? 0 M-EIN !
>         DANN Z @B 32 + #FF UND 64 < M-EIN @
>              UND 1 UND MAGNET !B
>     DANN ;
>
> which to some people looks a lot like line noise but here "JA" is "YES"
> and "DANN" is "THEN" and so on in German (hint: There is an "English/German
> cheat sheet" in the IPS book on page 82).  If you wrote your own IPS code
> today you could use the English ones, but to read the old housekeeping code
> you need to be able to look up the equivalents in English AND understand
> the low level machine operations (such as byte addressing, a stack, bitwise
> operations...  remember this language was designed and meant to be run
> (originally) on an 1802 or an 8080 or a 6502 with maybe thirty-two
> KILObytes of memory.  Yes, KILO-bytes of memory.  Really.  I'm not making
> this up. Go read the IPS book.)
>
> Emulators/simulators for running IPS code (German and English) are on the
> AMSAT website if you want to start coding. See
>
> http://www.amsat.org/amsat-new/tools/softwareArchive.php#pc-ips
>
> Lastly, if you feel you must have a real 1802 CPU, well, there actually
> are 1802 CPU chips still around (well, regular ones not the SoS rad-hard
> ones), and there is even an entire 1802 computer that you can buy as a kit
> complete with toggle switches, LEDs, and up to 64K of RAM.  And it fits
> inside an Altoids tin!  No, I'm not making this up either. See
>
> http://www.sunrise-ev.com/membershipcard.htm
>
> Note that the membership card 1802 CPUs are not rad-hard and they can run
> TinyBasic not IPS. But, I'm sure AMSAT still has at least one rad-hard 1802
> CPU... somewhere. And, getting IPS to run on the 1802 membership card is
> left as an exercise to the reader.  If you're successful, I'd love to hear
> about it.
>
> 73,
> Douglas KA2UPW/5
>
>
> On Wed, May 16, 2018 at 9:08 PM, Bruce Perens via Ground-Station <
> ground-station at lists.openresearch.institute> wrote:
>
>> OK, I'm *sure *I'm going to get something wrong, so please, list folks,
>> feel free to jump in and correct me when I do. I still don't know much
>> about satellites.
>>
>> Keith,
>>
>> While silicon-on-insulator parts are a great way to go, there is at least
>> a $1000 cost differential for CPUs and then you get to memory... So,
>> cubesat folks have been creative in finding radiation-tolerant parts in
>> consumer or industrial grades. The main problem we're trying to avoid is
>> latch-up that actually damages the part. The second problem is bit errors.
>> I have heard that some FLASH gate-array-based CPUs do not suffer *damage
>> *from radiation induced latch-up and there are viable recovery
>> mechanisms, and their FLASH-based gate-array does not require configuration
>> memory and is resistant to single-element errors. I googled this:
>> https://digitalcommons.usu.edu/cgi/viewcontent.cgi?art
>> icle=3399&context=smallsat which discusses the Microsemi SmartFusion2
>> (which we used for our abortive Whitebox SDR, so Chris Testa knows it
>> well). No doubt you can find more.
>>
>> Others in the group have experience with other radiation-tolerant
>> consumer or industrial grade parts.
>>
>> The Cortex M0 is more than enough for housekeeping and might be enough
>> for some signal and image processing tasks. But the housekeeping CPU need
>> not be the signal-processing CPU as well.
>>
>> AMSAT has had some interesting strategies. First, they had a cache of SoS
>> 1802s which they used for 30 years or so. They used a lot of components
>> that were given to them from cancelled space projects. They didn't always
>> use rad-hard memory, just because they could not afford it, but used
>> error-correcting memory architectures and scrubbed the memory constantly so
>> that single-bit errors were corrected before they became large enough to be
>> uncorrectible. There was *no* ROM onboard, a hardware modem loaded
>> memory from the radio and then reset the CPU and set it running. Nobody's
>> told me, but if there was any cryptography on that it wasn't much more than
>> exclusive-OR of a secret word. They have their own FORTH-like language,
>> first written in the '70's, which does concurrent but not parallel threads.
>> Most housekeeping is written in this language.
>>
>> So, you can expect that some of an IHU project might be prospecting for
>> radiation-tolerant parts that don't cost so much. Others have left
>> breadcrumbs to follow.
>>
>> Even when you do have rad-hard parts, generally they have a consumer or
>> industrial grade pin-equivalent so that non-flight and LEO units don't have
>> to be made with the most expensive parts.
>>
>>     Thanks
>>
>>     Bruce
>>
>>
>>
>> On Wed, May 16, 2018 at 1:37 PM, Keith Wheeler <keith.m.wheeler at gmail.com
>> > wrote:
>>
>>> 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
>>>>>>
>>>>>>
>>>>>> ---------- Forwarded message ----------
>>>>>> From: ground-station-request at lists.openresearch.institute
>>>>>> To:
>>>>>> Cc:
>>>>>> Bcc:
>>>>>> Date: Wed, 16 May 2018 00:16:18 -0400
>>>>>> Subject: confirm db1d86455ef4eb7857a41676b75024137549ff1d
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>>>>>>
>>>>>
>>>>>
>>>> _______________________________________________
>>>> Ground-Station mailing list
>>>> Ground-Station at lists.openresearch.institute
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>>>>
>>>>
>>>
>>
>>
>> --
>> Bruce Perens K6BP - CEO, Legal Engineering
>> Standards committee chair, license review committee member, co-founder,
>> Open Source Initiative
>> President, Open Research Institute; Board Member, Fashion Freedom
>> Initiative.
>>
>> _______________________________________________
>> Ground-Station mailing list
>> Ground-Station at lists.openresearch.institute
>> http://lists.openresearch.institute/mailman/listinfo/ground-station
>>
>>
>


-- 
Bruce Perens K6BP - CEO, Legal Engineering
Standards committee chair, license review committee member, co-founder,
Open Source Initiative
President, Open Research Institute; Board Member, Fashion Freedom
Initiative.
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