[Ground-station] Satellite program

Tue May 29 10:22:17 PDT 2018

OK, I still don't know anything about satellites, so correct me if I get
something wrong:

The reason we *need *rad-hard for higher orbits is that conventional
processors may get a radiation-induced latch-up between some part of the
chip and the base silicon, and this latch-up can be soft, in that
everything's OK if we just reset the chip, or hard, in that an over-current
damages the chip through a gate rupture or other burnout, and no amount of
redundancy or watchdogs will help us after that. Silicon-on-insulator
fabrication prevents that sort of latch-up, but we still have to deal with
events that cause upsets (logic state changes) or transients.

    Thanks

    Bruce

On Tue, May 29, 2018 at 10:06 AM, Robert McGwier <rwmcgwier at gmail.com>
wrote:

> Looks like a good find.  Worse case ~0.4 watts at 135 ma on 3.3V supply
> (and this is the nonexistent worst case).  It is very hard.  Inside an
> aluminum box with tantalum slides it could be used for MEO!  For most
> applications it will idle most of the time, so power consumption would be
> very low.  I hate putting communications on IHU processors,  so that
> doesn't break my heart.
>
> The development board and software look more than usable.
>
> Bob
> N4HY
>
>
> On Mon, May 28, 2018 at 2:23 PM, Bruce Perens <bruce at perens.com> wrote:
>
>> Please take a look at the Vorago VA10820. We can afford it. A board
>> design we can copy exists in their tech notes and Open Source software
>> supports it. Rather than redundant CPUs,  it triples all registers. It runs
>> at only 50 MHz so maybe is not your communications processor.
>>
>> Thanks
>>
>> Bruce
>>
>>
>> On Mon, May 28, 2018, 09:03 Robert McGwier via Ground-Station
>> <ground-station at lists.openresearch.institute> wrote:
>>
>>> I'm always worried about seamless handover when one detects the lack of
>>> agreement and you swap to the other.
>>>
>>> So I want to say I strongly recommend that state be maintained in ECC
>>> memory and when fault is found the "other" processor pair is selected,
>>> "boots", and takes over after initializing and restoring saved state.
>>>
>>> This is allows handoff to be asynchronous rather than trying to maintain
>>> perfect synchrony.
>>>
>>> If there are unsafe activities possible then the highest priority is
>>> shutting those down in some priority order: propulsion,  attitude change,
>>> .......
>>>
>>> I can relate the tale that the strongest delivered proclamation I ever
>>> received from Karl Meinzer was to never attempt this at all.  He was
>>> adamantly opposed to multiple processors and handoffs in spacecraft.
>>>
>>> 73s
>>> Bob
>>> N4HY
>>>
>>> On Mon, May 28, 2018, 10:15 AM Jonathan Brandenburg via Ground-Station
>>> <ground-station at lists.openresearch.institute> wrote:
>>>
>>>> [I'm speaking a bit for Zach Metzinger, so I've copied him on this
>>>> email. I'm not sure if he's on this mailing list or not and want him to be
>>>> in a position to expand or correct my statements, or even disavow anything
>>>> I'm saying, if he desires.]
>>>>
>>>> A small team, primarily Zach Metzinger with the assistance of others
>>>> (Bill Reed, Jordan Trewitt, me), is designing an IHU based on the TI
>>>> Hercules safety-critical processor. While the Hercules is not necessarily
>>>> radiation-hardened, the processor is designed for operation in very noisy
>>>> environments. It's also designed to detect faults, by executing
>>>> instructions on two cores in lockstep, detect when the result differs, and
>>>> signal a failure. (I imagine there are other features, but this is a high
>>>> point.)
>>>>
>>>> So, we've been designing an IHU with two Hercules processors and two
>>>> digital transceivers configured in a fail-over configuration along with
>>>> redundant power circuits. There's still work to be done, but Zach has begun
>>>> laying out this board in a 1U footprint.
>>>>
>>>> [This is the part where I'm speaking for Zach...] I believe Zach is
>>>> committed to ensuring this design is open and available. As a result, I
>>>> expect we'll be quickly publishing this work (by ITAR/EAR definitions) as
>>>> we achieve milestones. This IHU work was begun before the AMSAT Golf
>>>> program was kicked off and is now being integrated into Golf. I don't know
>>>> of any reason this work couldn't be leveraged and used in other satellites.
>>>>
>>>> Thus, I submit this IHU-in-progress for our consideration...
>>>>
>>>> Jonathan Brandenburg
>>>>
>>>> On 5/16/2018 1:54 PM, Bruce Perens via Ground-Station 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>
>>>>>> <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
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>>>>>>
>>>>>
>>>>>
>>>>
>>>> _______________________________________________
>>>> Ground-Station mailing listGround-Station at lists.openresearch.institutehttp://lists.openresearch.institute/mailman/listinfo/ground-station
>>>>
>>>>
>>>> --
>>>> Jonathan Brandenburg
>>>> 1-214-213-1066jonathan at jonathanbrandenburg.com
>>>> -----------------------
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>>>>
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>>
>
>
> --
> Bob McGwier
> Founder, Federated Wireless, Inc
> Founder and Technical Advisor, HawkEye 360, Inc
> Research Professor Virginia Tech
> Chief Scientist:  The Ted and Karyn Hume Center for National Security and
> Technology
> Senior Member IEEE, Facebook: N4HYBob, ARS: N4HY
> Faculty Advisor Virginia Tech Amateur Radio Assn, Trustee K4KDJ
> Member of PVRC (Roanoke-Blacksburg), TAPR,  life member of ARRL and AMSAT,
> NRVR.ORG (Rocketry)
>

-- 
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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