From: Terry Kok To: Dean Calahan, FoB Subject: digest6 Date: Monday, April 03, 2000 1:00 PM

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Howdy everyone:

Terry Kok has expressed some concerns regarding life support system design. I just want to take a few lines to clarify what is going on.

The life support group is designing a high fidelity system of unique design that is intended as a prototype of actual flight ready hardware. Thats why it is being run by the TTF. If the result can be used at Devon Island and benefit can be obtained, we will consider its integration into the hab. The systems currently under design are an immediate solution to water / waste issues at Devon. It is not a final solution. The bidding process is closed in that sensitive proprietory issues are included in the packages. At present I have 12 weeks to purchase and install the plumbing and need to do that as quickly as possible. The design of this plumbing system will enable connection to your system, or others that may be made available (we may also wish to test physicochemical / mech. systems). Since I believe most of these issues have been discussed during the telecons, I urge all team members to particpate in future telecons, if at all possible. If anyone would like to talk further regarding this, it is perhaps best that we talk by phone. Please call 303.980.9947 or send an e-mail with your phone number.

Thanks Kurt

--- Alexey Morozov wrote:

> I have some experience in developing software for > embedded temperature > and vacuum controllers (although for very small > control volumes -- > measured in cubic inches). I've done some > distributed processing on > PC's as well. All in all, I'd be glad to volunteer > some of my time. > As Joshua mentioned, what are the specs for the > monitoring/control > system? >> Cheers, > Alex Morozov. > morozov@ava.obu.edu

Alex and Joshua,

I'm not a computer/sensor person but I have a good idea of the perimeters we need sensors on. Here are the basics:

HAB ATMOSPHERE: H20 vapor (humidity), temperature, CO2 levels, O2 levels, CO levels, hydrogen sulphide, methane

CELSS ATMOSPHERE: (same as above)

CELSS WaTeRS (Waste Treatment and Resource Recovery module): PH, BOD (biological oxygen demand)

CELSS V-GES (Vegetable Growth Environment System): PH, BOD, nitrate/nitrite levels, sodium levels, E-coli count

CELSS POTABLE H20: (same as above)

We need a system in which alarms sound when levels fall outside our set perimeters, with the ability for the system to be able to trigger appropriate shifts in fans, pumps, etc. It would also be nice to have a track record of the levels over time. Both the HAB and the CELSS need light intensity meters and thermometers as well. Thanks you for asking!

- Terry R. Kok at biostar_a@yahoo.com

--- Joshua Lamorie wrote: > Thanks for the updates, perhaps we can start putting > together a simple 'data > monitoring' spec/design for the system. >> Data monitoring for analysis is simple. Generating > alarms from specific > readings from sensors is also simple. Creating a > feedback control system for > the overall setup is not. It sounds like you have > most of these systems > (closed loop etc.) in your funky RV. Do you also > have a closed loop control > system for your electro-mechanical systems?

I don't have an RV. I live in a 3584 sq.ft. testbed for CELSS-style technologies called BIOSTAR-A. I have no monitoring/sensors in BIOSTAR-A. I wish I could afford them. The closed loop water/waste system is passive, gravity feed. There is a 12VDC pressure pump at the clean water "end" of the system which pumps the water to the sinks, shower, toilet. I also have an ozonator in the system which I haven't been using for about 6 months now (no need). No other power is needed to ensure proper recycling. The biology does the job. >> The design of this control system should be an > integral part of the overall > system, and not thrown together at the end. I've > been too busy to keep fully > up-to-date with the Life-Support groups work, but do > they have initial plans > for the dynamics (and control) of the Life > Support/Waste Loop design?

I haven't seen or heard any details (or basics) on anything yet. >> I just want to emphasize that data acquisition and > monitoring (which includes > tripping alarms) is trivial. Controlling a dynamic > system is not, and > requires design. I recommend that, unless required > by the design, that > dynamic control is delayed until after the initial > version. The data > acquisition from the first version will help > establish the type of data and > it's bandwidth, and allow the remainder of the > system to be debugged (without > worrying about debugging the control loops).

Data aquisition (with alarms) is all we really need at this time. >> However, I've not made a closed waste processing > loop before, and I'm just an > apprentice control systems engineer, so this could > well have been assumed > already within the Life-Support groups design. >> So, if no one else has started to think about > dynamic control, perhaps we can > postpone that until after the DAQ and monitoring? >> Joshua Lamorie > MarSoc Montréal/Ottawa

Thanks Joshua! I wish we had more from the other life support team members on their plans for FMARS but I guess we will have to wait a bit longer. I'm moving ahead to designing and building my own version (2 people) which will be wo-man-rated and well documented so that the Mars Society and/or other interested parties will have a working CELSS module available when in need. I need the sensor system we're talking about for this CELSS as well as for FMARS (potentially).

PS - The sensor system should work off a 486 laptop if possible. Is that possible?

This does not mean that I am bailing out of the FMARS gray water system project. I'm just waiting on the other part of the team to get something on line so we all can look at it and make comments and suggestions.

Terry R. Kok at biostar_a@yahoo.com 812-275-0694

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Pokchoy@aol.com wrote:

> Hello- I have used homeostatic control systems and monitor them with an AI or > 'expert system' I wrote. You will find that as the system becomes more > complex it is much easier and more accurate to use pro-active controls rather > than reactive. Any life support system that is integrated as you have been > describing must be considered VERY complex. I think limit based alarms will > end up a case of 'locking the barn door after the horse is gone'. >

Well, the system that has been described so far, has not really been that dynamic, and has relied on the natural biological processes. An integrated control system is a fundamental part of the design, and currently there is no dynamic electro-mechanical pieces to the system, therefore there is no control-system. The less computer/electronics etc. the better. As Kurt pointed out, NASA is spending lots of time and money on a heavy electro-mechanical dynamically controlled system. We have an opportunity to make something more simple (from a materiel point of view), so I think that we should limit the complexity (i.e. no AI or expert systems). Hopefully we won't need any more computing power than is in a modern car.

But, I might be missing something.

Joshua

The containment/nutrient-delivery/biofilter systems are simple. No pumps or valves are needed (only a few fans). The ecosystems which grow inside the provided containment are complex but that makes them very stable (unlike hydroponics). I've been living in BIOSTAR-A for over three years now. The ecosystems crashed once (in the first two months of occupancy) due to NUTRIENT OVERLOAD when everyone I know showed up to try the new bathroom (coupled with the fact that the building wasn't yet sealed and it got cold inside during a blizzard)! I also had made some mistakes with design. Over that year I gradually eliminated complexity (including the hydroponics) and played with different plants and now, after 2 more years of occupancy with an average of 6 people/day using the system, there has been no trouble at all with the ecology. I've tried to crash it by pouring chlorine bleach straight down the drain, letting sections dry out, flooding others, etc. So far it hasn't crashed. Of course, BIOSTAR-A is a crude experiment compared to the next, improved version: BIOSTAR-B. It will be far better. Hopefully, what I learn from B-B will apply to FMARS and beyond.

PS - The ecosystems I'm refering to are simple (by comparison) with John Todd's (Ocean Arks International - New Alchemy Institute) Living Machines. You can accomplish the same (or better) as a Living Machine without the complexity of equipment and/or ecology.

- Terry at biostar_a@yahoo.com

--- Salinay@aol.com wrote: > [ to Mars Society Arctic Base TF & discussion ] > [ from Salinay@aol.com ] > [ see end of message to unsubscribe ] >> The Martian atmosphere may be 3% nitrogen, but you > must remember that the atmosphere on Mars is at MOST > 8% as thick as the atmosphere on Earth, and that > Earth plants are used to 70% nitrogen in the > atmosphere...so all in all, we have about 0.3% as > much nitrogen as on Earth. I.e. not alot. > ----------

That's why I'm all for 100% recycling in the HAB-CELSS complex. We can count on what we bring with us until we can learn to extract that which is rare.

Terry at biostar_a@yahoo.com

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In a message dated 03/31/2000 04:44:33 PM, Salinay@aol.com writes:

<< the atmosphere on Mars is at MOST 8% as thick as the atmosphere on Earth >>

Daniel,

Actually, that's an order of magnitude too high. It varies between 1% during spring and fall, and 0.7% during winter or summer, when 30% of the carbon dioxide freezes out over one pole or the other.

The relative thickness will not matter. We can use compressors. Just an engineering problem.

Peter

From: Pokchoy@aol.com | Block address Date: Sat, 1 Apr 2000 08:27:31 EST Subject: Re: Mars_Arct/ ecosystem complexity/stability To: biostar_a@yahoo.com, Arctic-sig@lists.marssociety.org

Add Addresses

Hello- I think I should clear something up. I use homeostatic control. That means a self-regulating system without external intervention. Essentially it is 3 to 5 distinct biological cycles running simultaneously. While it uses hydrponic media, it is a bio-active, organic system. I htink I caused some confusion with mentioning the AI. I am developing that to aid inexperienced operators, or to accellerate the learning curve. The AI does not control the system. It analyses it and interprets it so the operator can make better decisions. such as how much he can harvest, etc.

RB

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Peter is right, I am an order of magnitude too high. The atmosphere on Mars is about 8 proMIL, not proCENT, the pressure of that on Earth. That gives Mars 0.03% as much nitrogen as Earth. Thank you for catching my error Peter.

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In a message dated 04/01/2000 03:01:01 PM, Salinay@aol.com writes:

<< That gives Mars 0.03% as much nitrogen as Earth. >>

We routinely extract noble gases from Earth's atmosphere: argon (1% - about as much argon in our atmosphere as all of Mars' atmosphere alltogether), but also lesser ingredients: helium, neon, krypton, xenon.

Does anyone know what the partial pressure of each of these is versus the partial pressure of nitrogen on Mars (0.008 ATM x3% = 0.0024 ATM) ?

As I mentioned, there is serious discussion of extracting water vapor from Mars' atmosphere and there is enormously much more nitrogen there than water vapor.

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All,

TK> HAB ATMOSPHERE: H20 vapor (humidity), temperature, CO2 TK> levels, O2 levels, CO levels, hydrogen sulphide, TK> methane TK> CELSS ATMOSPHERE: (same as above) TK> CELSS WaTeRS (Waste Treatment and Resource Recovery TK> module): PH, BOD (biological oxygen demand) TK> CELSS V-GES (Vegetable Growth Environment System): PH, TK> BOD, nitrate/nitrite levels, sodium levels, E-coli TK> count TK> CELSS POTABLE H20: (same as above) Temperature, humidity, and PH should be easy. My first place to look would be Omega Engineering, but they can get expensive. Does anybody know of a cheaper place? As far as various gas and chemical levels, can anyone suggest a place that sells those sensors/detectors -- I haven't dealt with those yet. All in all, it seems to me that the most expensive part of this monitoring system would be the sensors themselves. Does anyone have an idea of the budget? Also, what are the dimensions of the system -- how far will we have to transmit data?

TK> PS - The sensor system should work off a 486 laptop if TK> possible. Is that possible? I would say it is. However, to me laptop implies mobiliy, and if you are running a long-term data collection, you would want something that doesn't get unplugged from the sensor net and carried away. Joshua, correct me if I am heading in the wrong direction -- I am thinking of a network of simple data aquisition devices running off microcontrollers and a central computer that collects data and stores/monitores if for analysis/alarms/etc. You can use an old 386 running Linux for the later purpose. This brings up another issue. I assume the station will have a lab and computers. It would be nice to have an ability to integrate the sensor net with the rest of the station (computer) systems, if not run it on them. Does anyone have any idea what operating systems and network types will the station have?

JL> Something like Dallas' one-wire set of units would be good for very JL> low data rates, and very low power consumption. They can also be JL> arranged to have fairly good redundancy. Otherwise, there's always JL> old daisy chained 'raw' serial. Using some cheap PIC's/STAMPs etc is JL> a great way of doing it. Joshua, I have only dealt with RS-232 so far (besides heavy stuff like ethernet, etc). Can you give a name or a part number of the Dallas' units you have in mind, so I can look up the specs? Motorola has a nice 68HC12 with built-in Byte Data Link netwok that is used heavily in automotive industry and a standard UART, but those micros are about $15 a pop. Also, which PICs are you thinking about -- I'll look up datasheets. My own experience is limited to PIC14000 and Motorola's 68HC11 and 68HC12.

And the last question for now -- what kind of development time frame are we talking about?

Alex. morozov@ava.obu.edu ava.obu.edu/~morozov

--- Alexey Morozov wrote:

> Temperature, humidity, and PH should be easy. My > first place to look > would be Omega Engineering, but they can get > expensive. Does anybody > know of a cheaper place? As far as various gas and > chemical levels, > can anyone suggest a place that sells those > sensors/detectors -- I > haven't dealt with those yet. All in all, it seems > to me that the > most expensive part of this monitoring system would > be the sensors > themselves. Does anyone have an idea of the budget? > Also, what are > the dimensions of the system -- how far will we have > to transmit data?

I have no idea if we even have a budget for FMARS but I think we should shoot for a system which comes in under $2000 (American) for the prototype (not including the laptop). On a commercial level (for Earth-based CELSS which I want in MY backyard) we need a system which can hook up to any computer with a cost of $1000 or less for the sensor package. As far as distance - 30 meters maximum distance to the HAB ... >> TK> PS - The sensor system should work off a 486 > laptop if > TK> possible. Is that possible? > I would say it is. However, to me laptop implies > mobiliy, and if you > are running a long-term data collection, you would > want something that > doesn't get unplugged from the sensor net and > carried away.

I'm interested in saving power, not mobility. A flat screen (laptop style) is the key.

>> And the last question for now -- what kind of > development time frame > are we talking about?

I could use a system on BIOSTAR-B (a test bed I am currently designing and raising money for) by this time next year (2001) or maybe sooner.

Terry Ryan Kok at biostar_a@yahoo.com (812) 275-0694

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TK: >> PS - The sensor system should work off a 486 laptop if > possible. Is that possible? >

You can read about GPIB (DAQ) controllers for the PCMCIA slot of a laptop here (and I'm sure there must be more that just these folks): http://www.inesinc.com/gpibpcmc.htm

GPIB should be familiar to users of LabView, which is a popular data acquisistion package (or, at least I've heard of it, without being a hands-on lab guy myself...)

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