You are not logged in.
The greenhouse humidity could be reduced with dehumidifiers so the zeolite or regolith can outgas as much water vapor as possible.
The regolith brought inside to get it's water out would have to be moved outside afterwards.
Also, it's easy for an ATV to get a bucket of loose sand but if you are digging into the ground you need a pulled blade that only digs in a little bit, or it will stop the ATV, then you can go back and use the bucket on the front to get the loose material.
Once this material had it's water vapor removed it would have to be moved outside and it would take some time before that material would absorb moisture so you could use it again. So you would be going farther and farther from the base each day.
This idea would require going through the greenhouse airlock many times, or you could just completely depressurize the greenhouse while you are moving in regolith and leave the airlock doors open. The moved regolith would take up space inside the greenhouse where plants would not be grown.
It's almost like we need a greenhouse just to harvest water.
Offline
Dook,
You need some sort of small airlock to enable the rover to simply slide the entire regolith container inside the greenhouse. With a fresnel lens mounted over the containers, the water boils, and it boils at a lower temperature at the lower partial pressure in the greenhouse.
The regolith container itself could be a removable stainless steel bin; not water or gas tight, just a way to keep excessive regolith residue off the airlock seals. You've seen those cash bins at the gas stations that the clerks use at night to keep from getting robbed, right? Same concept, except the dirt box goes into the cash bin and the cash bin is an airlock. No greenhouse depressurization or greenhouse regolith storage required.
Use a tiller to break up the regolith as the rover drives over it and then scoop that up, instead of trying to push a blade over it. That should also assist the outgassing process. If the ATV drives in concentric circles around the base, then it'll be a long time before it's even 2km away.
The ATV could do this with different attachments instead of having two different robots and use a larger box containing more regolith.
Offline
I just realized we can't pressurize a greenhouse.
A 100 foot wide domed greenhouse pressurized to only 2 psi would apply an upward force of about 2,304 lbs to each panel. If the greenhouse has 550 panels the total force applied to the inside of the greenhouse would be about 1.2 million pounds while the total downward force applied by Mars atmosphere would only be about 60,000 lbs. The internal pressure would lift the greenhouse and the pressure would escape.
We are going to have to use buried habitats for growing all the food.
After digging, building, and burying a series of habitat/hydroponics shelters we could build a greenhouse over the top to provide heat but we could never pressurize it.
Offline
You just now figured that out?
That's why many of the greenhouse designs presented here have built-in floors, and they would be inflated something like balloons, No lifting force whatsoever. The regolith fill would cover the sewn in floors, making agriculture possible.
P.S. That's also the reason many of the proposed structures are very heavy. Also explains why everything can't be brought from Earth.
Last edited by Oldfart1939 (2017-04-28 09:23:30)
Offline
You just now figured that out?
That's why many of the greenhouse designs presented here have built-in floors, and they would be inflated something like balloons, No lifting force whatsoever. The regolith fill would cover the sewn in floors, making agriculture possible.
P.S. That's also the reason many of the proposed structures are very heavy. Also explains why everything can't be brought from Earth.
Unlike you, I don't have to be "Mr. I know everything" on here.
A balloon greenhouse wouldn't last more than a year or two before it would have to be replaced.
Many of the proposed structures are very heavy? If the structure is a whole unit, floor and wall and ceiling all connected together, then it becomes a pressure vessel and doesn't have to be heavy, it just has to be very strong.
No one said everything could or should be brought from the Earth.
Offline
14.7psi is no joke. Every square yard of pressure vessel has 19,051.2lbs or 8.66t of force pushing outward. That's why, for the most part, there are no square pressure vessels. If there is any slight weakness in the welds when that kind of force is applied, there will be serious structural integrity issues. The force applied to the weld itself is minor, but the force applied to the joined pieces can be massive if the pressure vessel is of any significant size.
Imagine trying to design the tuna can to take the tension load from pressurization, the compression load from sufficient regolith to provide adequate radiation shielding on Mars, and trying to make it light enough to deliver to Mars. Any engineer who makes that work should get free beer for life.
There's a construction principle I'm learning from building my own aircraft. The individual pieces are built as strong as they have to be to withstand the loads applied to them and no stronger. It's not a question of whether or not it could be built stronger, because it could. It's a question of how well it would fly if it was built stronger than it had to be and was heavier than it needed to be as a result. The more extreme the performance requirement for an aerospace vehicle becomes, the more applicable this principle becomes.
Offline
One of the first considerations that arose when I was making some comments on one of the Crops, or Greenhouse threads was a calculation of the upward force exerted by the pressurized structure. I was initially appalled by the sheer magnitude of the resulting number and hence, refined my design to include an integral floor that would be covered up by several deep layers of regolith. This is also another reason to build from substantial materials and as Dook pointed out, the fragility of an inflated polymeric film/cloth/dome is a major concern. We don't really want to have a structure fail in a matter of a Martian year.
Offline
A greenhouse that is not clear might as well be made from a can or a bigelow habitat module as we must limit mass to mars. Something that would be needed is the air lock for a bigelow design. Modify a cygnus for multiport design with the pumps required for use and couple a bigelow inflateable on the ground to it once we lay the cygnus horizonatally on the ground.
As far as the z.. panel cart I would look at the solar hot air panels for how to design the units for outside mars design with venting holes to blow the outside air through with closure valves for night time to day time use. The moisture vents would circuilate a loop of air from a condensor unit to the return at the bottom of the panel while the exit at the top would go to the condensing unit to capture the moisture.
Offline
The habitat has to be buried, either below the surface or above ground. It should have multiple circular habitats for growing hydroponics and vegetables in tubs full of regolith.
We can ship thin (1/4") fiberglass floor panels that are 25' wide circles and 25' circular fiberglass honeycomb composite panels maybe 4-6" thick for ceiling panels. They would have pre-assembled wall sections that lock into the floor and ceiling panels, maybe with lego style tabs. The ends of the curved wall sections would have to fit together, maybe with tongue and groove. All pieces would be sealed before assembly. We should be able to make 5-7 buried units all connected.
There's good and bad about it. No natural sunlight. No natural heating. And you have to do a lot of digging and might hit rock. The good is that you would have a lot of radiation shielding and the internal air pressure would balance the weight of the regolith above so there would be less stress on the structure. Another bad thing is you wouldn't be able to just get away and go for a walk.
Offline
A possible solution to the domed greenhouse pressurization problem might be to use upside down "T" shaped foundation pieces that are buried 11 feet deep.
The upside down "T" shaped foundation panels would be set 11 feet deep, so, for every foot of greenhouse circumference there would be 11 inner and 11 outer feet of regolith on the buried foundation panel.
Each upside down "T" panel has a base width of 2' that would have regolith piled on top. The stem of the upside down "T" panel would point up and be 11' tall to be equal with the surface and it would have steel bolts built in that extend upwards 2 inches that the bottom row of greenhouse panels can bolt to.
The foundation panels base would be buried 11 feet down. Each upside down "T" panel would be 10' feet long. So, every ten foot long buried foundation panel would have 440 cubic feet of regolith on it. Regolith is about 92 lbs per cubic foot, multiply that by the circumference of the dome which is 314 feet, and we get 1.2 million pounds which should be more than the total upward force of 1.1 million pounds caused by pressurizing the greenhouse to 2 psi. To some degree the pressure in the greenhouse would help keep the regolith down, which keeps the foundation panels down.
Each buried ten foot foundation panel will have an upwards force of 32,352 lbs of force applied by the dome pressurization. That same section will have 40,480 lbs of regolith weight.
I don't know what to make them out of. Fiberglass or aluminum just doesn't seem to be strong enough and steel would be very heavy. Possibly carbon composite?
If we dug out a large circular area to build a series of circular habitats that we are going to bury we could also position these upside down "T" foundation panels in a large circle and cover them and the habitats with regolith at the same time.
Last edited by Dook (2017-05-03 20:55:53)
Offline
Elon Musk being allowed to ‘make the rules’ in space, ESA chief warns
https://www.ft.com/content/7d561078-37c … 7b81a26241
The head of the European Space Agency has urged the continent’s leaders to stop facilitating Elon Musk’s ambition to dominate the new space economy, warning that the lack of co-ordinated action meant the US billionaire was “making the rules” himself.
Josef Aschbacher, the new director-general of ESA, said that Europe’s readiness to help the rapid expansion of Musk’s Starlink satellite internet service risked hindering the region’s own companies from realising the potential of commercial space.
“Space will be much more restrictive [in terms of] frequencies and orbital slots,” he said in an interview with the Financial Times. “The governments of Europe collectively should have an interest to . . . give European providers equal opportunities to play on a fair market.”
Germany has recently applied to the International Telecommunications Union, which coordinates the use of wireless frequencies for carrying data, to grant Starlink spectrum for roughly 40,000 satellites. Musk has already won approval for more than 30,000 satellites through US regulators.
Earlier this year, Musk said SpaceX, his private rocket company, was prepared to spend up to $30bn to expand Starlink.
Aschbacher said Musk’s Starlink was already so big that it was difficult for regulators or rivals to catch up. “You have one person owning half of the active satellites in the world. That’s quite amazing. De facto, he is making the rules. The rest of the world including Europe . . . is just not responding quick enough.”
Starlink and the UK government-backed OneWeb are leading a rush to create mega-constellations of hundreds and even thousands of satellites in low earth orbit, or LEO, to provide broadband to places hard to reach by cable.
The Chinese government and Amazon’s Project Kuiper both plan to launch their own LEO constellations.
A new generation of space companies, driven by falling launch costs and cheaper satellites, is also aiming to deliver commercial services from LEO such as earth observation.
The rush to tap the potential of commercial space — made possible by falling launch costs and cheaper, smaller satellites — has fuelled concern over the absence of a global space traffic management system for low earth orbit, a region of up to 2000 kms above the earth where most new commercial services are targeted.
Last year the Satellite Industry Association estimated there could be more than 100,000 commercial spacecraft in orbit by 2029.
Aschbacher’s concerns were echoed by Franz Fayot, Luxembourg’s economy minister, who said new rules were needed to ensure the safe use of space.
Last edited by Mars_B4_Moon (2021-12-05 14:27:55)
Offline
Elon must really be making these clowns look bad. If the powers that be were getting the job done, then he would've focused his attention elsewhere. Since they're not, someone has to make it happen, so it might as well be him.
Offline
Neil DeGrasse Tyson says nuclear weapons no longer have a “radiation problem.”
https://www.youtube.com/watch?v=XqJ1T6r-2WQ
Tom Cruise has a critic! World-famous scientist Neil deGrasse debunks the star's flight stunt from Top Gun: Maverick
https://www.dailymail.co.uk/tvshowbiz/a … stunt.html
Last edited by Mars_B4_Moon (2022-10-16 19:43:06)
Offline
Moronic gutter politics from deGrasse or maybe he's trying to be a new William Bill Nye science guy entertainer or maybe he's moving into controversy and comedy stand up like those Joe Rogan types
'Neil deGrasse Tyson Uses Science to Show Why Whites Resemble Monkeys More Than Blacks'
Offline