Louis' Solar Power Strategy

louis · 2017-05-25 19:18:52

Any cargo lander is going to be a tiny, tiny space! Enough to grow a lettuce every other day perhaps!

I think any farming effort has to be in dedicated farm habs, initially imported from Mars but after a few years being the product of ISRU.

SpaceNut wrote:

No need to carry inflateable green house on first mission as any empty cargo lander can serve as the space to grow food in.
In fact the second mission we can make use of all of the empty units if we are really going to grow food all that is needed then is supplemental power, lighting via colored LED, additional water, soil and other forms of trays to grow the plants with in and more seeds....
So where are we will daily intake of water for consumption and washing for the crew of 6? Keeping in mind that we know that we can always do with less water in the end. So we can add in the recycling masses later and efficiency rates to consider lowering the base level amount especially on the second mission onward.

RobertDyck · 2017-05-26 05:32:31

SpaceNut wrote:

No need to carry inflateable green house on first mission as any empty cargo lander can serve as the space to grow food in.
...colored LED...

I have also posted before that on a planet that doesn't have a breathable atmosphere we need reliable, robust life support. I have described life support that uses multiple principles and components that can be mixed-and-matched in various configurations. However, power is a single point of failure. The only life support that works during power failure is an ambient light greenhouse. Stored oxygen and stored whole air will only last a very short time. If the reactor fails, it could take weeks to repair. Extended time without power could be fatal. Only an ambient light greenhouse provides life support with absolutely no power.

And as Louis pointed out, cargo landers are tiny.

I found a reference: NASA Mars Rovers Braving Severe Dust Storms July 20, 2007

For nearly a month, a series of severe Martian summer dust storms has affected the rover Opportunity and, to a lesser extent, its companion, Spirit. The dust in the Martian atmosphere over Opportunity has blocked 99 percent of direct sunlight to the rover, leaving only the limited diffuse sky light to power it. Scientists fear the storms might continue for several days, if not weeks.
...
Before the dust storms began blocking sunlight last month, Opportunity's solar panels had been producing about 700 watt hours of electricity per day, enough to light a 100-watt bulb for seven hours. When dust in the air reduced the panels' daily output to less than 400 watt hours, the rover team suspended driving and most observations, including use of the robotic arm, cameras and spectrometers to study the site where Opportunity is located.
On Tuesday, July 17, the output from Opportunity's solar panels dropped to 148 watt hours, the lowest point for either rover. On Wednesday, Opportunity's solar-panel output dropped even lower, to 128 watt hours.

Dropping solar power from 700 watt-hours per day to 128 watt-hours leaves 128/700=18.2857% power output. The article says Spirit was affected as severely as Opportunity, but this was the most severe case since those rovers landed in 2004. Any human mission will have to prepare for the worst case. Yes, greenhouses will require artificial light during a dust storm. But an ambient light greenhouse will provide life support (oxygen and water) when there isn't a dust storm, even during power failure.

Spirit Rests During Dust Storm Jan 04, 2007'

The southern hemisphere dust storm lowered power levels to 267 watt-hours on Spirit's 1,061st sol, or Martian day, of exploring Mars (Dec. 27, 2006).

That's 267/700=38.142857% power. Not as bad. So some dust storms allow enough light through. Mars receives 43.0726% as much sun as Earth, so 38.142857% of that would be 16.429% as much Earth. That compares to Earth at the equator in a desert with absolutely no cloud or haze. Crops that grow in shade would still grow in an ambient light greenhouse with that much light. And again, that's using light levels that Spirit experienced during a dust storm. Crops that like shade:

Salad Greens, such as leaf lettuce, arugula, endive, and cress.
Broccoli
Cauliflower
Peas
Beets
Brussels Sprouts
Radishes
Swiss Chard
Leafy Greens, such as collards, mustard greens, spinach, and kale
Beans

Crops that require full sun: wheat, peppers, tomatoes, eggplants, corn, and squashes

Terraformer · 2017-05-26 07:13:38

If we can't store enough oxygen for people to breathe, how do you expect to store enough oxygen for rockets to use? Humans use less than a kilogram of oxygen each day, so we're talking about using ~400 kg per person per year. Such figures are dwarfed by the storage needed for rocketry. There is no problem at all with storing food - and even if you don't store oxygen, storing food and using electrolysis to get oxygen (3 kWh/person-day?) is going to take much less energy than keeping the plants alive.

Oldfart1939 · 2017-05-26 07:30:44

Just a quick poll here: How many posters here have ever raised vegetables in a big garden? How many have ever engaged in farm scale agriculture?

Oh, and on Robert's list, several of the crops require bees for pollination (peas and beans).

Oldfart1939: yes, and yes.

Antius · 2017-05-26 07:39:11

Terraformer wrote:

If we can't store enough oxygen for people to breathe, how do you expect to store enough oxygen for rockets to use? Humans use less than a kilogram of oxygen each day, so we're talking about using ~400 kg per person per year. Such figures are dwarfed by the storage needed for rocketry. There is no problem at all with storing food - and even if you don't store oxygen, storing food and using electrolysis to get oxygen (3 kWh/person-day?) is going to take much less energy than keeping the plants alive.

Quite correct I think. I agree with Robert that a naturally illuminated greenhouse will always be a more desirable means of producing food and oxygen from a systems reliability point of view. The problem is that it would appear to be very difficult to keep it warm without a supplementary heat source for much of the Martian year. The average temperature on Mars is about -55C. If concentrated solar power is used to harvest extra heat, that has reliability issues and costs of its own. If nuclear waste heat is used, that has reliability issues too and the greenhouse needs to be close to the reactor in order for piped heat to be feasible. That complicates reactor shielding. Less of an issue for a long-term base, but not a feasible solution for an expedition.

For early missions, enough stored food should be taken to cover the entire mission. The oxygen needed for the surface stay and return trips should be stored before the crew even arrive. For a long term base, the siting of the base should be chosen to allow natural food production at least in the summer. At high/low latitudes outside of summer, natural illumination may not provide enough heat to keep the greenhouse above freezing. Some modelling needs to be done to understand what the achievable growing season would be at different locations on Mars. One good thing about food - it can be easily stored for years if need be at ambient Martian temperatures. I think the problem with air is not so much providing additional oxygen, but removing excess CO2. If you can't use plants to do this, it must be scrubbed out of the air using an electrically driven fan and chemical reactants.

Last edited by Antius (2017-05-26 07:50:39)

Antius · 2017-05-26 07:41:50

Oldfart1939 wrote:

Just a quick poll here: How many posters here have ever raised vegetables in a big garden? How many have ever engaged in farm scale agriculture?
Oh, and on Robert's list, several of the crops require bees for pollination (peas and beans).
Oldfart1939: yes, and yes.

Yes (to the gardening), no to farming.

Antius · 2017-05-26 08:07:45

louis wrote:

Personally I think propellant manufacture for Mision One is unnecessary and a diversion. Of course, I believe in a minimalist Apollo style
lander/ascender, so we won't need to land too much fuel/propellant for the ascent. Last time I looked, I think maybe 5 tonnes of fuel/propellant should do it. NASA seems to overdesign for this sort of thing.

If you are using printed organic solar cells as your principal power source, ISPP is essential because the high UV environment of the Martian surface will degrade the cells within months. If you are stuck on the Martian surface for 2.5 years that leaves you with a bit of a problem. If the propellant plant and power supply are deliberately oversized, then sufficient propellant can be produced to power surface stay before the cells degrade.

The system will be significantly heavier than an SP-100 reactor when power transmission, over-size propellant plant and storage are factored in. But it avoids the bureaucratic issues of having to build, test and launch a space nuclear reactor. When that is done, you could power the mission by burning the paperwork needed to commission the reactor!

RobertDyck · 2017-05-26 09:08:17

Oldfart1939 wrote:

Just a quick poll here: How many posters here have ever raised vegetables in a big garden? How many have ever engaged in farm scale agriculture?

My paternal grandparents had a wheat farm in Saskatchewan. It was several quarter sections. The house had a 3 acre vegetable garden. I didn't do a lot of work on the farm, but did help a little when I was a child. The house where I grew up had a substantial vegetable garden. The house I rented in Toronto in 1989/90 had a garden, 14 fruit trees, 6 grape vines (Italian wine grapes), rosemary, a few varieties of rose, and some flowers. My house today has a small vegetable garden, one mature apple tree (Goodland), 2 grape vines (Valiant), and a berry bush (Chokeberry).

Oldfart1939 wrote:

Oh, and on Robert's list, several of the crops require bees for pollination (peas and beans).

Insect pollinators and their relative abundance on pea (pisum sativum) at Peshawar
Several flies, butterflies, lady bug.

Oldfart1939 · 2017-05-26 09:50:19

I'm simply asking this question for relevance of the posts made by members; i.e., are they speaking from strength of knowledge or simply blowing it out the wazoo?

I've ranched ( as a part-time avocation) for 20+ years, and harvested 77 acres of grass hay annually. Have berry bushes (Red and Black Currants, Gooseberries, and Red Raspberries). Have in the past done some gardening with my late wife, who was a true "homesteader-type" woman. Raised both red and white (Russet) potatoes, tomatoes, Swiss Chard, Bell peppers, and various hot peppers, Eggplant, yellow straightneck and crookneck squash, and that everybody's favorite--zucchini. Also raised beets, radishes, and Red Kuri winter squash, along with acorn squash. Just establishing my "credentials" in order to comment here.

Last edited by Oldfart1939 (2017-05-26 09:50:40)

elderflower · 2017-05-26 14:00:20

I grew up on and around farmsteads. First drove a tractor at age 6.
Later my wife and I had a large garden with vegetable patch, fruit trees and bushes in which we grew 3 kids.
Sold it and moved to a place with a tiny garden as gardening is not compatible with prolonged sailing trips.

louis · 2017-05-26 16:26:52

That's a bit silly. I am not a rocket scientist. But I had for many years suspected the Space Shuttle strategy was stupid. And so it proved.

For what it's worth my Uncle was a farmer and I do have a range of fruit trees and a vine, and we harvest mint and borage. Most people I know who have attempted to grow things in their gardens end up being severely disappointed. Tiny carrot syndrome.

If you go on the internet you will find discussions of the minimal area of land required to provide enough food for one person over one year in the temperate zone. People have various estimates but they are normally at least 10,000 square metres [Edit: Please ignore - an error on my part. The figure is closer to 2000 sq. metres...but still a lot of energy required - see discussion below] . That is a hell of a lot of energy required. You don't need to be a farmer to know that. For a six person mission it will be a bridge too far for Mission One. Even providing 10% of the requirement would in my view impose unnecessarily burdens on the pioneers.

Oldfart1939 wrote:

I'm simply asking this question for relevance of the posts made by members; i.e., are they speaking from strength of knowledge or simply blowing it out the wazoo?
I've ranched ( as a part-time avocation) for 20+ years, and harvested 77 acres of grass hay annually. Have berry bushes (Red and Black Currants, Gooseberries, and Red Raspberries). Have in the past done some gardening with my late wife, who was a true "homesteader-type" woman. Raised both red and white (Russet) potatoes, tomatoes, Swiss Chard, Bell peppers, and various hot peppers, Eggplant, yellow straightneck and crookneck squash, and that everybody's favorite--zucchini. Also raised beets, radishes, and Red Kuri winter squash, along with acorn squash. Just establishing my "credentials" in order to comment here.

Last edited by louis (2017-05-27 07:31:54)

RobertDyck · 2017-05-26 17:40:55

Another point is energy of the greenhouse. Starting with calculations when there isn't a dust storm, and assuming a location near the equator. Some individuals here in Canada assume a greenhouse would have to be partially buried. That's actually not correct for Mars. Here in Canada, winter can get cold, but several feet below ground remains above freezing. But Mars has the opposite. Mars Curiosity Rover weather for sol 1703 (2017 May 21), maximum ground temperature +8, minimum -78°C. Below ground will be the mean not just during a single sol, but the mean over the Martian year. That's still very cold. While Mars atmosphere at Curiosity that same day is mean 830 Pa (8.30 mbar). That makes the air very thin, very little heat loss to the atmosphere. While heat loss to ground will be great. Ideal is to heat a greenhouse via passive solar. That means collect and trap heat inside. Using spectrally selective coating to reflect more long wave IR from warm things like the floor, and reflect less (transmit more) short wave IR from extremely hot things like the surface of the Sun. One question is whether we also need an aluminized Mylar curtain to cover the ceiling during night? With the spectrally selective coating, the curtain may not be required. Or it may only be required during a dust storm. Or may be required every night, depending on heat balance. We have also talked about a double pane window; for Mission One that will be two layers of polymer film with a gap between. The gap will be pressurized more than Mars ambient, but less than greenhouse interior. That allows pressure and hold-down straps to hold the shape, no ribs. Pressure in the gap can be monitored to detect a leak: if gap pressure drops, there's a leak in the outer layer. If gap pressure rises there's a leak in the inner layer. That gap can be filled with argon gas, which is less thermally conductive than air (oxygen and nitrogen). And the floor of the greenhouse will have the be insulated from ground. Will this be enough? Will passive solar alone warm the greenhouse?

One project the Mars Society could do itself is calculate heat conduction to answer this question. Using weather data from Mars landers and rovers, calculate heat balance.

I have described long-narrow greenhouses with mirrors on either side as tall as the greenhouse roof. This will provide as much illumination from the mirrors as direct illumination. That doubles illumination to keep crops healthy. This is only necessary for crops that require full sun, such as wheat or corn or tomatoes. Crops that don't require full sun can simply use Mars ambient light, so no mirrors. But how will mirrors change the heat balance? Again the goal is to maintain growing temperature using solar thermal heat alone, preferably passive solar.

SpaceNut · 2017-05-26 19:01:54

I am looking at the early times when we did not bring a greenhouse as to what can be done with what we have to make use of with the sugested use of the landers. The dragon is 25 m^3 internal volume and if we are growing fast growing plant crops we can space shelfs just a few feet appart inside with just enough soild for the crop we are planting in them.

I think that many are jumping to this level of food production Inside the World's Largest Indoor Farm a Q&A session
81667.adapt.768.1.jpg

With others at this level Living off the land: How much land? with lots of good data on the sites page.

CROP YIELD VERIFICATION is 10,642 pounds per one acre of land. Therefore, the yield for 1/4 acre is 1/4 of that, or 2660 pounds.

With early on crop growth is more like this Urban farming is booming, but what does it really yield? Which is enough to give food.

only mars would need to correct materials...

louis · 2017-05-27 06:49:01

I like the mirrors idea.

Have you ever considered the possibility of using thermogenic plants to keep a greenhouse warm at night?

https://en.wikipedia.org/wiki/Thermogenic_plant

A system of hot water pipes might help - so have solar reflectors outside heating a water system that then lets off heat at night.

The problem though with all direct light/heating systems is the dust storm problem. That means you either live with crop failure or have back up energy (in which case you might as well use that energy anyway in an arificially light and heat system).

RobertDyck wrote:

Another point is energy of the greenhouse. Starting with calculations when there isn't a dust storm, and assuming a location near the equator. Some individuals here in Canada assume a greenhouse would have to be partially buried. That's actually not correct for Mars. Here in Canada, winter can get cold, but several feet below ground remains above freezing. But Mars has the opposite. Mars Curiosity Rover weather for sol 1703 (2017 May 21), maximum ground temperature +8, minimum -78°C. Below ground will be the mean not just during a single sol, but the mean over the Martian year. That's still very cold. While Mars atmosphere at Curiosity that same day is mean 830 Pa (8.30 mbar). That makes the air very thin, very little heat loss to the atmosphere. While heat loss to ground will be great. Ideal is to heat a greenhouse via passive solar. That means collect and trap heat inside. Using spectrally selective coating to reflect more long wave IR from warm things like the floor, and reflect less (transmit more) short wave IR from extremely hot things like the surface of the Sun. One question is whether we also need an aluminized Mylar curtain to cover the ceiling during night? With the spectrally selective coating, the curtain may not be required. Or it may only be required during a dust storm. Or may be required every night, depending on heat balance. We have also talked about a double pane window; for Mission One that will be two layers of polymer film with a gap between. The gap will be pressurized more than Mars ambient, but less than greenhouse interior. That allows pressure and hold-down straps to hold the shape, no ribs. Pressure in the gap can be monitored to detect a leak: if gap pressure drops, there's a leak in the outer layer. If gap pressure rises there's a leak in the inner layer. That gap can be filled with argon gas, which is less thermally conductive than air (oxygen and nitrogen). And the floor of the greenhouse will have the be insulated from ground. Will this be enough? Will passive solar alone warm the greenhouse?
One project the Mars Society could do itself is calculate heat conduction to answer this question. Using weather data from Mars landers and rovers, calculate heat balance.
I have described long-narrow greenhouses with mirrors on either side as tall as the greenhouse roof. This will provide as much illumination from the mirrors as direct illumination. That doubles illumination to keep crops healthy. This is only necessary for crops that require full sun, such as wheat or corn or tomatoes. Crops that don't require full sun can simply use Mars ambient light, so no mirrors. But how will mirrors change the heat balance? Again the goal is to maintain growing temperature using solar thermal heat alone, preferably passive solar.

louis · 2017-05-27 07:29:44

So, I may have misremembered re the area required to feed one person - my apologies. Your links suggest something more like 0.2 hectares (2000 sq, metres) should suffice with intensive farming. That's 44x44 metres.

So your 25 m3 would maybe equate to a growing area of about (I am using an average tray height partition of 40 cms) about 69 sq metres. Enough to feed one person for about 12 days if all goes well or 2 days for a crew of six. I really doubt it would be worth going to all that effort of converting a lander to that use (not going to be easy I imagine), rather than just pre-landing an inflatable farm hab.

I am as keen as anyone to get going with farming on Mars but I think for Mission One, a pre-landed mostly automated (just add water) small farm hab producing a few lettuces, tomatoes and other salad items would be the best approach.

SpaceNut wrote:

I am looking at the early times when we did not bring a greenhouse as to what can be done with what we have to make use of with the sugested use of the landers. The dragon is 25 m^3 internal volume and if we are growing fast growing plant crops we can space shelfs just a few feet appart inside with just enough soild for the crop we are planting in them.
I think that many are jumping to this level of food production Inside the World's Largest Indoor Farm a Q&A session
http://news.nationalgeographic.com/cont … .768.1.jpg
With others at this level Living off the land: How much land? with lots of good data on the sites page.
CROP YIELD VERIFICATION is 10,642 pounds per one acre of land. Therefore, the yield for 1/4 acre is 1/4 of that, or 2660 pounds.
With early on crop growth is more like this Urban farming is booming, but what does it really yield? Which is enough to give food.
https://ensia.com/wp-content/uploads/20 … 60x378.jpg
only mars would need to correct materials...

Last edited by louis (2017-05-27 07:32:55)

Oldfart1939 · 2017-05-27 09:13:34

The numbers being stated here are somewhat misleading, since what should be considered is calories per acre, which is the reason for this drill in the first place. Yes, salad greens are attractive, but hardly worth the effort if calories are considered. Turnips, potatoes, yams, and squashes are the best caloric return for the effort expended. Add in carrots and parsnips, if you will. Collard greens are much higher in caloric content than lettuce; ditto Swiss chard. For beans and squash, however, we need pollinators (bees, butterflies, lady bugs, etc.). Turnips and cabbage formed the diet in Germany during the W.W. I British blockade.

louis · 2017-05-27 11:21:26

A man, or a woman, doesn't live by calories alone. I think Space Nut's link (Living off the land) gives the best idea of what is required. A lot of Germans were suffering severe malnutrition by 1918.

Oldfart1939 wrote:

The numbers being stated here are somewhat misleading, since what should be considered is calories per acre, which is the reason for this drill in the first place. Yes, salad greens are attractive, but hardly worth the effort if calories are considered. Turnips, potatoes, yams, and squashes are the best caloric return for the effort expended. Add in carrots and parsnips, if you will. Collard greens are much higher in caloric content than lettuce; ditto Swiss chard. For beans and squash, however, we need pollinators (bees, butterflies, lady bugs, etc.). Turnips and cabbage formed the diet in Germany during the W.W. I British blockade.

RobertDyck · 2017-05-27 12:36:02

louis wrote:

The problem though with all direct light/heating systems is the dust storm problem. That means you either live with crop failure or have back up energy (in which case you might as well use that energy anyway in an artificially light and heat system).

During a dust storm, use energy normally used for industrial or science work. Which means no mining, ore processing, smelting, refining, manufacturing, or construction during a major dust storm. And using figures from the storm Spirit endured in December 2006 / January 2007, crops that thrive in shade should survive the storm without artificial light.

Oldfart1939 · 2017-05-27 12:48:56

My late wife was a "survival gardener" in an experimental manner. She actually researched the most efficient and nutritional crops to grow, and then did experimental plantings in order to test the palatability of them. She was also a chemical professional with her degree from Case Institute of Technology, with a very strong background in microbiology. Her experiments and literature studies showed that Turnips (yuck) were one of the most efficient crops to grow for overall nutrition. The root portion is high in carbohydrates and minerals, whereas the greens could also be eaten with the additional vitamins being furnished. Collard greens were the most nutritional of the leafy green crops, followed by Swiss chard. If we ever get to the point of raising meat animals, there is a beet variety known as a Mangel. All of the plant. root and tops, can be consumed by either beef or swine--to their enormous benefit. Chickens also do well on a Mangel diet. They grow huge! They also grow fast. Probably the #1 energy producing crop possible.

louis · 2017-05-27 13:18:44

That's one option but the energy requirement for feeding six people would be about 790 Kwe constant - which is a lot, as I am sure you appreciate. Is it really sensible to prioritise food in that way for Mission One? Or even the first three missions, say...

I would prioritise exploration, mining, habitat construction and industrial infrastructure over agriculture - all of them over agriculture.

RobertDyck wrote:

louis wrote:
The problem though with all direct light/heating systems is the dust storm problem. That means you either live with crop failure or have back up energy (in which case you might as well use that energy anyway in an artificially light and heat system).
During a dust storm, use energy normally used for industrial or science work. Which means no mining, ore processing, smelting, refining, manufacturing, or construction during a major dust storm. And using figures from the storm Spirit endured in December 2006 / January 2007, crops that thrive in shade should survive the storm without artificial light.

RobertDyck · 2017-05-27 14:01:27

louis wrote:

That's one option but the energy requirement for feeding six people would be about 790 Kwe constant - which is a lot, as I am sure you appreciate. Is it really sensible to prioritise food in that way for Mission One? Or even the first three missions, say...
I would prioritise exploration, mining, habitat construction and industrial infrastructure over agriculture - all of them over agriculture.

We are talking about only during a dust storm. Other than a dust storm, power would be used for all the stuff you said you would prioritize. Also realize during a dust storm you won't be able to see far. During a minor dust storm like Spirit encountered, it would be as bad as depicted on the National Geographic mini-series "Mars". Remember when the episode when one guy had to go outside to fix a power relay during the storm? He walked past the rover so couldn't see back? I haven't found a YouTube clip of that, but here is the clip from that series where real NASA scientists talk about Mars dust storms. Video is 1 minute and 43 seconds.

That's during a mild storm. When Spirit still produced 38% as much power with solar panels. This image shows the sky when Opportunity experienced a severe dust storm, with only 18% power.

louis · 2017-05-27 14:19:31

We know dust storms can last for several months...we have to assume the worst. We must have a failsafe food supply. So it would appear you are advocating that on Mission One we (a) try and grow as much food as possible and (b) we take along a back up food supply in case there is a dust storm (which will mean we are doubling up on mass to achieve the same objective of feeding people). If you are not suggesting (b) then you are placing the pioneers' lives at risk aren't you?

RobertDyck wrote:

louis wrote:
That's one option but the energy requirement for feeding six people would be about 790 Kwe constant - which is a lot, as I am sure you appreciate. Is it really sensible to prioritise food in that way for Mission One? Or even the first three missions, say...
I would prioritise exploration, mining, habitat construction and industrial infrastructure over agriculture - all of them over agriculture.
We are talking about only during a dust storm. Other than a dust storm, power would be used for all the stuff you said you would prioritize. Also realize during a dust storm you won't be able to see far. During a minor dust storm like Spirit encountered, it would be as bad as depicted on the National Geographic mini-series "Mars". Remember when the episode when one guy had to go outside to fix a power relay during the storm? He walked past the rover so couldn't see back? I haven't found a YouTube clip of that, but here is the clip from that series where real NASA scientists talk about Mars dust storms. Video is 1 minute and 43 seconds.
https://i.ytimg.com/vi/JKBk_Kfucs4/hqdefault.jpg?custom=true&w=336&h=188&stc=true&jpg444=true&jpgq=90&sp=68&sigh=jnNpv2ih09kCkLXeOOFxY-B4ydE
That's during a mild storm. When Spirit still produced 38% as much power with solar panels. This image shows the sky when Opportunity experienced a severe dust storm, with only 18% power.
https://www.nasa.gov/images/content/182692main_mer-20070719-516.jpg

RobertDyck · 2017-05-27 14:43:32

louis wrote:

We know dust storms can last for several months...we have to assume the worst. We must have a failsafe food supply. So it would appear you are advocating that on Mission One we (a) try and grow as much food as possible and (b) we take along a back up food supply in case there is a dust storm (which will mean we are doubling up on mass to achieve the same objective of feeding people). If you are not suggesting (b) then you are placing the pioneers' lives at risk aren't you?

Again, but "Mission One" you mean the first ever human mission to Mars. I argue to carefully test everything. That means the first mission will got to Mars, and come home. It will include an inflatable greenhouse to grow food, and prove growing food will work. That mission will also demonstrate several In-Situ Resource Utilization techniques. And there will be science. Yes, that mission will bring enough stored food for the entire mission.

My mission plan is a modification of Mars Direct, with elements taken from NASA's Design Reference Mission (Semi-Direct), and more importantly elements taken from Apollo. Specifically, Apollo left the CSM parked in Lunar orbit. I would leave an Interplanetary Transit Vehicle parked in Mars orbit. Mars Direct used the surface hab as the transit vehicle, so it would have food for both the transit and surface stay. The ERV would have food for return. But in case Free-Return was necessary, the surface hab would require food for the return transit as well. My mission plan would pre-land an MAV. Astronauts would ride the ITV from Earth orbit to Mars orbit, with the lander / surface hab attached. The ITV would have food for both transits, the surface hab would have food for the surface stay. In case of Free-Return, the surface hab would still be attached, so they would have all that food during return. They would also have all the life support equipment in the surface hab as backup to the ITV. This adds additional safety, while reducing redundancy.

Again, I would like to see technologies demonstrated first. Then an unmanned full-up test all the way to Mars and back. Then the first human mission. Then a couple human missions. Then and only then do the first permanent setters go to stay.

louis · 2017-05-27 15:26:10

If you are saying there should be a food-producing farm unit as part of Mission One, I am with you on that. It just helps to define what you mean by that. I'd probably devote no more than 20 sq. metres to that and just focus on salad produce.

I agree with you on an Apollo style landing and leaving the ITV in Mars orbit. I would build in pre-landing of cargo, including food, so you can make the human lander really light in mass.

Not sure we need an unmanned test if we pre-landing supplies, as long as we do some extended testing with humans in Earth/Lunar orbit.

RobertDyck wrote:

louis wrote:
We know dust storms can last for several months...we have to assume the worst. We must have a failsafe food supply. So it would appear you are advocating that on Mission One we (a) try and grow as much food as possible and (b) we take along a back up food supply in case there is a dust storm (which will mean we are doubling up on mass to achieve the same objective of feeding people). If you are not suggesting (b) then you are placing the pioneers' lives at risk aren't you?
Again, but "Mission One" you mean the first ever human mission to Mars. I argue to carefully test everything. That means the first mission will got to Mars, and come home. It will include an inflatable greenhouse to grow food, and prove growing food will work. That mission will also demonstrate several In-Situ Resource Utilization techniques. And there will be science. Yes, that mission will bring enough stored food for the entire mission.
My mission plan is a modification of Mars Direct, with elements taken from NASA's Design Reference Mission (Semi-Direct), and more importantly elements taken from Apollo. Specifically, Apollo left the CSM parked in Lunar orbit. I would leave an Interplanetary Transit Vehicle parked in Mars orbit. Mars Direct used the surface hab as the transit vehicle, so it would have food for both the transit and surface stay. The ERV would have food for return. But in case Free-Return was necessary, the surface hab would require food for the return transit as well. My mission plan would pre-land an MAV. Astronauts would ride the ITV from Earth orbit to Mars orbit, with the lander / surface hab attached. The ITV would have food for both transits, the surface hab would have food for the surface stay. In case of Free-Return, the surface hab would still be attached, so they would have all that food during return. They would also have all the life support equipment in the surface hab as backup to the ITV. This adds additional safety, while reducing redundancy.
Again, I would like to see technologies demonstrated first. Then an unmanned full-up test all the way to Mars and back. Then the first human mission. Then a couple human missions. Then and only then do the first permanent setters go to stay.

RobertDyck · 2017-05-27 16:15:06

louis wrote:

If you are saying there should be a food-producing farm unit as part of Mission One, I am with you on that. It just helps to define what you mean by that. I'd probably devote no more than 20 sq. metres to that and just focus on salad produce.
I agree with you on an Apollo style landing and leaving the ITV in Mars orbit. I would build in pre-landing of cargo, including food, so you can make the human lander really light in mass.
Not sure we need an unmanned test if we pre-landing supplies, as long as we do some extended testing with humans in Earth/Lunar orbit.

I was a pre-schooler through the Moon race, from the last 2 mission of Mercury through Apollo 11 and beyond. For me Apollo 11 was the summer between grade 1 and 2. Every Apollo mission had something go wrong, every mission except Apollo 17. Even Apollo missions to Skylab and Apollo-Soyuz had something go wrong. We have to be paranoid. As it was, Apollo 13 almost killed crew. Mars is harder than the Moon. A human mission will be the largest spacecraft to enter Mars atmosphere, and an affordable mission has to use aerocapture. That will have to be tested. First with a technology demonstrator, then one full-size unmanned test.

I keep thinking of Mars Direct. My mission plan is a modification of that. It included an inflatable greenhouse the same width as a double-car garage, and twice the length. That's between 80 and 100 square metres. Just for the inflatable transparent greenhouse. When Boris Yeltsin was president of Russia, many in the Mars Society argued to use the launch vehicle Energia. Robert Zubrin himself was the first to propose that in his book, published 1997 (one year before the founding of the Mars Society). Energia had roughly 2/3 lift capacity of Saturn V. Actually, Energia once lifted a 88 tonne satellite to 200km orbit, so more like 75% of Saturn V. Anyway, MD would take 3 launches. I had to make mine fit, so pre-land the MAV, and pre-land an inflatable laboratory with greenhouse and pressurized rover. If we use SLS block 2B, it breaks up differently. If we use Falcon Heavy, different again.

To make the greenhouse light-weight, use two layers of PCTFE film. For shape, hold-down straps secured with tent pegs. And I mean equivalent to pegs for an event tent (equivalent size). Light plastic soil trays, and a shovel. Mars regolith would be processed to form soil.

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