New Mars Forums

Oldfart1939

Member

Registered: 2016-11-26

Posts: 2,445

Re: Air. Shelter. Water. Food.

Bearings can be made from "white metal" like the bearings for a crankshaft?  Okay, so you're going to modify the vacuum pump bearings and electric motor bearings on all the equipment on Mars so they get a constant supply of lubricating oil just so you can print these types of bearings with a 3D printer?

No modification of a Sargent-Welch vacuum pump to this style of bearing; that's how they are built at the factory

You can't see anyone printing ball or roller bearings?  The 3D printer could probably print the steel part but not apply the chrome coating.   

It might be possible to make oilite bearings?  It might.  I don't think they are better than needle bearings.

They don't have to be "better than needle bearings," they work fine as is.

Dook

Banned

From: USA

Registered: 2004-01-09

Posts: 1,409

Re: Air. Shelter. Water. Food.

If we ship powder and only use it to make tools when we need them we can make lots more of them or other things?  What if they need a screwdriver in space to open up the Moxie cover and splice in a new wire that shorted out?

No need as moxie is not on the space ship out going or return trips to fix..plus we are only talking about from first post....

It's fun to speculate on what technology we can bring to the surface of the Red Planet, but this is all about "first things first."

But to induged we would not be sending the 3 D printer for use of the space ship as that would have minimal tools onboard but the likely hood of a failure in a 6month trip is nearly none....

No one said we would have a continuing resupply of duplicates.

So you are landing at the same site each time?

What we would have is a continuing resupply of needed things that they can't make on Mars.

So when do you know you need it?
Can you survive until it gets there?
Whats the amount of backup when failure occurs, remembering that its a long time between resupplies?

The Moxie is not on the space ship out going or return trips?  A mini-Moxie will be on the outgoing Mars hab but, your right, it won't be powered until it gets to Mars.  The CAMRAS will be powered in flight. 

Are we landing at the same site each time?  Three exploration missions to different parts of Mars.  The first settlement over time becomes a base and all supplies land to the west of it, the crew drives a long range rover with a Marscart to go and get them.     

When do we need supplies?  I would expect a yearly food and spare parts shipment for the first and second year then, hopefully the settlement has perfected it's food growing so we would send another set of buried habitat components, then 4 more crew, then food.  Essentially, one rocket a year.   

Can they survive until supplies get there?  That depends, if both mini-Moxies quit and can't be rebuilt then no.  If the Mars Hab structure fails before they get a buried habitat built, then no.  Water can be recycled.  Urine can be boiled in a microwave inside the Mars Hab and then captured by a dehumidifier.  Food can be rationed and work cut back so less is needed. 

What is the amount of backup?  For oxygen, it's two mini-Moxies, an emergency air bottle, a small portable air bottle, and the Mars suits with rebreathers.  Once the buried shelter was finished the plants would provide some oxygen as well. 

For water the outer water sack radiation shield on the Mars Hab would have water storage.  Urine would be saved on the flight then boiled on Mars to become water vapor and captured by a dehumidifier.  Water would also come from the onboard fuel cell that takes in vented hydrogen and oxygen from the tanks.  On Mars the WAVAR unit would be started and it would fill the inner water sack radiation shield on the Mars Hab.

Food would come from on board supplies until the buried shelter is finished and the hydroponics, chickens, and tilapia fish tank gets going.  There would be a shipment of food some time after the first settlement lands and then maybe one more the next year.

Dook

Banned

From: USA

Registered: 2004-01-09

Posts: 1,409

Re: Air. Shelter. Water. Food.

Bearings can be made from "white metal" like the bearings for a crankshaft?  Okay, so you're going to modify the vacuum pump bearings and electric motor bearings on all the equipment on Mars so they get a constant supply of lubricating oil just so you can print these types of bearings with a 3D printer?

No modification of a Sargent-Welch vacuum pump to this style of bearing; that's how they are built at the factory

You can't see anyone printing ball or roller bearings?  The 3D printer could probably print the steel part but not apply the chrome coating.   

It might be possible to make oilite bearings?  It might.  I don't think they are better than needle bearings.

They don't have to be "better than needle bearings," they work fine as is.

I looked at the Sargent-Welch style vacuum pump, it uses a belt drive instead of having the electric motor attached directly to the vacuum pump.  The rubber belt would shrink and warm up from Mars temperature extremes.  And the rubber belt would have to be replaced periodically.  Those belts have thread in them for strength, how are you going to make that with a 3D printer?     

The oilite bearings work fine as is?  For certain applications.  All bearings are not equal.

Oldfart1939

Member

Registered: 2016-11-26

Posts: 2,445

Re: Air. Shelter. Water. Food.

I've also used similar, direct drive pumps, made by Edwards. The Sargent Welch pumps use rubber drive belts (suitably reinforced) simply because they're cheap and easily replaced. Switching one over to direct drive could be done before shipment to Mars. A small gearbox would be required in order to obtain the correct RPM for the pump to operate efficiently and not prematurely wear out the bearings. But--as I mentioned in an earlier post--newer technology utilizes a diaphragm pump. I have a high capacity air compressor her on the ranch that is a diaphragm design; I use it for pumping up my tractor tires and any other use that requires compressed air.

kbd512

Administrator

Registered: 2015-01-02

Posts: 7,812

Re: Air. Shelter. Water. Food.

WAVAR is the most power-intensive way to get the least amount of water possible.  It would literally take years to fill a water tank with any appreciable shielding capability unless a lot more power is devoted to it to move a lot more atmosphere through the zeolite bed every day.  The WAVAR documentation stated what the power requirements were, which is basically 8kW+ all the way up to 12kW continuous, as in 24/7.  There are no RTG systems that produce that kind of power and there never have been.

Pu238 costs $8M/kg and we think (we've thought a lot of things about cost that never happened) we can eventually get that cost down to $4M/kg.  7.6kg of Pu238 produces 300We, so you need 26.67kg (EDIT: 202.692kg, not 26.67kg) to produce 8kWe.  That's $1.62B just for the Pu238 at current costs or $810M if we get it down to $4M/kg.  We can only produce so much every year, too, because we make Pu238 by irradiating Np237 in breeder reactors.

U235, on the other hand, costs a few thousand dollars per kg and is a commercial product for use in current light water reactors, which is why NASA and DOE are working on small fission reactors (Kilopower) that have one moving part, even simpler than SAFE-400 which uses rotating control drums to turn the reactor on and off, minus the electric generators.  The power output is far in excess of what's feasible in a RTG and the output does not scale linearly with reactor size.  SAFE-400's 512kg core is 12" diameter compared to a 55 gallon drum's 24" diameter and 20" tall to the 55 gallon drum's 35".  Multiply SAFE-400's dimension by about 2 for the shielding and multiply the height by 3 for the radiators and electric generators on top.  That's 100kWe continuous output and we can easily run a WAVAR that produces meaningful output in a meaningful amount of time.  NASA wants to send multiple small (55 gallon drum size with full shielding) but properly shielded fission reactors.  I don't give a crap about irradiating the regolith, so I would just send SAFE-400 with shadow shielding on top.  If the colonists aren't busy mining near the reactor, it won't be a problem.

The Marscat or Centaur 2 robot can move a 2,000kg (760kg on Mars) SAFE-400 like it's a toy.  Robonaut 2 or Valkyrie connected to Centaur 2 can dig a hole to put the reactor in using a shovel because both robots have human hands.  Solar panels will easily provide enough power to recharge Robonaut 2 or Valkyrie and Centaur 2.  RTG's or batteries of some kind must provide power for life support before the reactor is online.  If you're that concerned about minimizing batteries, then 3 RTG's ($182.4M for the Pu238) provide enough output for minimal life support limited to CAMRAS, IWP, and thermal management systems.  I still think solar and batteries provide a lot more power for a lot less cost.  Centaur 2's batteries could supplement battery power available for life support equipment.

No EVA is required to emplace the fission reactor, but you can send someone to watch the robot work if you want to.  They're going a couple hundred meters away from the habitat module at most, which is well within walking distance for Apollo era space suits.

The batteries required to store tens of kilowatts of power are very heavy, even if we use Lithium-ion, and more than twice as heavy if we use Lead-acid.  In real life, the Lead-acid batteries will require more frequent replacement than Lithium-ion as a function of duty cycle, so quadruple the weight of Lithium-ion batteries with equivalent amp-hour rating and that's pretty close to what a Lead-acid solution would weigh.

120,000W / 900W = 133.3 Lead-acid batteries

133 * 51.8 = 6,889lbs / 3,131kg / 3.131t

Lead-acid will last about a year on Mars with the kind of duty cycle and temperatures we'd subject them to:

6,889 * 2 = 13,778lbs

120,000W / 3,120W = 38.5 Lithium-ion batteries

38 * 80 = 3,040lbs / 1,382kg / 1.382t

Just a check to see how much 4 times as many Lithium-ion batteries would weigh:

3,040 * 4 = 12,160lbs

So, my previous supposition that you'd about quadruple the weight for Lead-acid is pretty accurate.

These are just realistic masses for the batteries that WAVAR would require, BTW, and we've not included the masses of the batteries for electrical power fed to the life support equipment or the solar panels to recharge the batteries.

Let's multiply WAVAR's output by a factor of 8 using a more powerful motor and a 100kWe nuclear fission reactor to supply the electrical power required.

These are the estimated masses of the wear parts inside WAVAR from the document:

Dust filter - 10kg
10kW fan motor - 30kg
Bed rotation motors (2) - 10kg
Microwave emitters (2) - 40kg
Active control system - 10kg

That's 100kg and pretty similar to what I budgeted for a 3D print solution, not including the robot since we're using the robot to check and maintain the life support equipment (with human input, of course) so the colonists can focus on construction tasks.

About boiling urine in a microwave...

Paragon's IWP takes care of water purification with minimal power consumption (23.7kWh over 18 days, so 54.86We per hour) and weight is very reasonable 47.4kg (Direct Transfer; 3 systems) for the first year and 18.9kg (Direct Transfer; 3 systems) for every year thereafter.  The chassis is another one of those aluminum alloy boxes that aerospace loves so much.  The demonstrated water recovery is 98% and they think they can improve that to 99%.  The product still smells like ammonia afterwards, but it's drinkable.  A single stage reverse osmosis filter takes care of what very little ammonia (no urine smell) and dissolved solids (product is already within standards for potable water) are left.

I'd stick with a Direct Transfer system over the lighter single or two cycle systems because resupply mass is more than double that of Direct Transfer and no electric pump or transfer tank is required, as would be the case with the cycle-based systems.  Volumetrically, per system, it's 2.9ft^3 for direct transfer, vs 2.4ft^3 for single cycle or 3.3ft^3 for two cycle.  The subsequent resupplies are $2.835M for Direct Transfer and more than double that for either of the cycle-based systems.  The cycle-based systems would make more sense with more people.

Last edited by kbd512 (2017-05-08 15:22:44)

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,428

Re: Air. Shelter. Water. Food.

So rather than a pulley and belt drive use a sprocket and chain.

We currently are in this mode since the Dragon used for Mars is just a small 2mT payloads and the image gives you an idea of just how many landers that it would take on a one way mission let alone coming back home...

The Earth / mars alignment cycle is 2 yrs 7 weeks with a window depending of fuels of a couple months either side of it. The travel out time was fuel and mass dependant is 6 to 8 months. There can be no yearly launch from earth to mars as mars is on the oposite side of the sun when earth is at the same point in space that you mission is launched in. So in short no resupply...

Changing landing sites while its going to give more science and exploration will kill the program really quick as there is no reason to keep continuing, just like in apollo as once the bills start coming in and we see what we are getting for the investment its curtains for the program....

No amount of gold, precious rocks are going to keep nasa funding science missions....

kbd512

Administrator

Registered: 2015-01-02

Posts: 7,812

Re: Air. Shelter. Water. Food.

When do we need supplies?  I would expect a yearly food and spare parts shipment for the first and second year then, hopefully the settlement has perfected it's food growing so we would send another set of buried habitat components, then 4 more crew, then food.  Essentially, one rocket a year.

Launch opportunities only occur every two years unless EMDrive becomes available.

For water the outer water sack radiation shield on the Mars Hab would have water storage.  Urine would be saved on the flight then boiled on Mars to become water vapor and captured by a dehumidifier.  Water would also come from the onboard fuel cell that takes in vented hydrogen and oxygen from the tanks.  On Mars the WAVAR unit would be started and it would fill the inner water sack radiation shield on the Mars Hab.

Urine can be reprocessed in-flight or on Mars using IWP, as long as we can spare 54We.  Microwaves typically require hundreds of watts.

Food would come from on board supplies until the buried shelter is finished and the hydroponics, chickens, and tilapia fish tank gets going.  There would be a shipment of food some time after the first settlement lands and then maybe one more the next year.

An egg laying hen requires about .25lbs of feed per day or 91.25lbs per year, so 182.5lbs of feed per chicken per launch opportunity or about $9.075M for the chicken feed at current prices.

How many chickens would you have?

Dook

Banned

From: USA

Registered: 2004-01-09

Posts: 1,409

Re: Air. Shelter. Water. Food.

WAVAR is the most power-intensive way to get the least amount of water possible.  It would literally take years to fill a water tank with any appreciable shielding capability unless a lot more power is devoted to it to move a lot more atmosphere through the zeolite bed every day.  The WAVAR documentation stated what the power requirements were, which is basically 8kW+ all the way up to 12kW continuous, as in 24/7.  There are no RTG systems that produce that kind of power and there never have been.

Pu238 costs $8M/kg and we think (we've thought a lot of things about cost that never happened) we can eventually get that cost down to $4M/kg.  7.6kg of Pu238 produces 300We, so you need 26.67kg (EDIT: 202.692kg, not 26.67kg) to produce 8kWe.  That's $1.62B just for the Pu238 at current costs or $810M if we get it down to $4M/kg.  We can only produce so much every year, too, because we make Pu238 by irradiating Np237 in breeder reactors.

U235, on the other hand, costs a few thousand dollars per kg and is a commercial product for use in current light water reactors, which is why NASA and DOE are working on small fission reactors (Kilopower) that have one moving part, even simpler than SAFE-400 which uses rotating control drums to turn the reactor on and off, minus the electric generators.  The power output is far in excess of what's feasible in a RTG and the output does not scale linearly with reactor size.  SAFE-400's 512kg core is 12" diameter compared to a 55 gallon drum's 24" diameter and 20" tall to the 55 gallon drum's 35".  Multiply SAFE-400's dimension by about 2 for the shielding and multiply the height by 3 for the radiators and electric generators on top.  That's 100kWe continuous output and we can easily run a WAVAR that produces meaningful output in a meaningful amount of time.  NASA wants to send multiple small (55 gallon drum size with full shielding) but properly shielded fission reactors.  I don't give a crap about irradiating the regolith, so I would just send SAFE-400 with shadow shielding on top.  If the colonists aren't busy mining near the reactor, it won't be a problem.

The Marscat or Centaur 2 robot can move a 2,000kg (760kg on Mars) SAFE-400 like it's a toy.  Robonaut 2 or Valkyrie connected to Centaur 2 can dig a hole to put the reactor in using a shovel because both robots have human hands.  Solar panels will easily provide enough power to recharge Robonaut 2 or Valkyrie and Centaur 2.  RTG's or batteries of some kind must provide power for life support before the reactor is online.  If you're that concerned about minimizing batteries, then 3 RTG's ($182.4M for the Pu238) provide enough output for minimal life support limited to CAMRAS, IWP, and thermal management systems.  I still think solar and batteries provide a lot more power for a lot less cost.  Centaur 2's batteries could supplement battery power available for life support equipment.

No EVA is required to emplace the fission reactor, but you can send someone to watch the robot work if you want to.  They're going a couple hundred meters away from the habitat module at most, which is well within walking distance for Apollo era space suits.

The batteries required to store tens of kilowatts of power are very heavy, even if we use Lithium-ion, and more than twice as heavy if we use Lead-acid.  In real life, the Lead-acid batteries will require more frequent replacement than Lithium-ion as a function of duty cycle, so quadruple the weight of Lithium-ion batteries with equivalent amp-hour rating and that's pretty close to what a Lead-acid solution would weigh.

120,000W / 900W = 133.3 Lead-acid batteries

133 * 51.8 = 6,889lbs / 3,131kg / 3.131t

Lead-acid will last about a year on Mars with the kind of duty cycle and temperatures we'd subject them to:

6,889 * 2 = 13,778lbs

120,000W / 3,120W = 38.5 Lithium-ion batteries

38 * 80 = 3,040lbs / 1,382kg / 1.382t

Just a check to see how much 4 times as many Lithium-ion batteries would weigh:

3,040 * 4 = 12,160lbs

So, my previous supposition that you'd about quadruple the weight for Lead-acid is pretty accurate.

These are just realistic masses for the batteries that WAVAR would require, BTW, and we've not included the masses of the batteries for electrical power fed to the life support equipment or the solar panels to recharge the batteries.

Let's multiply WAVAR's output by a factor of 8 using a more powerful motor and a 100kWe nuclear fission reactor to supply the electrical power required.

These are the estimated masses of the wear parts inside WAVAR from the document:

Dust filter - 10kg
10kW fan motor - 30kg
Bed rotation motors (2) - 10kg
Microwave emitters (2) - 40kg
Active control system - 10kg

That's 100kg and pretty similar to what I budgeted for a 3D print solution, not including the robot since we're using the robot to check and maintain the life support equipment (with human input, of course) so the colonists can focus on construction tasks.

About boiling urine in a microwave...

Paragon's IWP takes care of water purification with minimal power consumption (23.7kWh over 18 days, so 54.86We per hour) and weight is very reasonable 47.4kg (Direct Transfer; 3 systems) for the first year and 18.9kg (Direct Transfer; 3 systems) for every year thereafter.  The chassis is another one of those aluminum alloy boxes that aerospace loves so much.  The demonstrated water recovery is 98% and they think they can improve that to 99%.  The product still smells like ammonia afterwards, but it's drinkable.  A single stage reverse osmosis filter takes care of what very little ammonia (no urine smell) and dissolved solids (product is already within standards for potable water) are left.

I'd stick with a Direct Transfer system over the lighter single or two cycle systems because resupply mass is more than double that of Direct Transfer and no electric pump or transfer tank is required, as would be the case with the cycle-based systems.  Volumetrically, per system, it's 2.9ft^3 for direct transfer, vs 2.4ft^3 for single cycle or 3.3ft^3 for two cycle.  The subsequent resupplies are $2.835M for Direct Transfer and more than double that for either of the cycle-based systems.  The cycle-based systems would make more sense with more people.

The U of Washington WAVAR design uses a lot of power.  I still don't believe it uses 8kw of constant power.  Other than the bed rotation motors and two microwave units which only operate when needed the large fan is the main power user.  It's 6 feet across and spins at 500 rpm.  A 30" fan only uses about 250 watts of power so something isn't adding up.

Anyway, there are other WAVAR designs.  I don't like the rack and pinion set up.  The zeolite panels should be fixed already inside a large microwave and Mars atmosphere should be pulled through.

The Centaur is way over designed, typical of NASA.  I like that it's remote controlled so it could be driven from the Mars Hab but that's about it.

I'm not concerned about minimizing batteries.  The Mars Hab will need a dependable battery bank.  I'm not sure exactly how many.  On Mars they would have constant power from the RTG and additional power from the solar array in daytime. 

Lead-acid batteries will last a year on Mars?  They should last the normal 8-10 years.  The batteries in the Mars Hab should be the same temperature as the inside of the hab.  The batteries in the Long Range Rover and Marscat would have small battery heaters under them.  No battery would be discharged for more than 1 or 2 hours except in an emergency.

Let's multiply WAVAR by a factor of 8 to increase it's output?  The main thing that controls how much water you get is the amount of Mars atmosphere you move through the zeolite.  So, just increasing the fan and motor alone would give you more water.

You say the increased WAVAR size would equal the weight of a 3D printer?  But the WAVAR makes water.  The 3D printer doesn't.  One is life support, the other is not. 

Paragon has a water purification system?  I'll have to check it out.

Dook

Banned

From: USA

Registered: 2004-01-09

Posts: 1,409

Re: Air. Shelter. Water. Food.

So rather than a pulley and belt drive use a sprocket and chain.

http://cdn.mars-one.com/images/uploads/roadmap2023.jpg

We currently are in this mode since the Dragon used for Mars is just a small 2mT payloads and the image gives you an idea of just how many landers that it would take on a one way mission let alone coming back home...

The Earth / mars alignment cycle is 2 yrs 7 weeks with a window depending of fuels of a couple months either side of it. The travel out time was fuel and mass dependant is 6 to 8 months. There can be no yearly launch from earth to mars as mars is on the oposite side of the sun when earth is at the same point in space that you mission is launched in. So in short no resupply...

Changing landing sites while its going to give more science and exploration will kill the program really quick as there is no reason to keep continuing, just like in apollo as once the bills start coming in and we see what we are getting for the investment its curtains for the program....

No amount of gold, precious rocks are going to keep nasa funding science missions....

We would launch the crew when Mars is closest so the crew spends the least amount of time in space.  Mars doesn't just immediately zoom away, it takes years.  So the supply shipments would take a little longer to get to Mars but so what, they're supplies, not humans who use oxygen, water, and food.   

Changing landing sites would kill the program?  We've sent rovers to different sites on Mars, that hasn't killed the Mars exploration program.  The different landing sites would be just for the first three exploration missions.  The settlement would be one location. 

Once the bills start coming in it curtails the program?  When did NASA cease operations?

Dook

Banned

From: USA

Registered: 2004-01-09

Posts: 1,409

Re: Air. Shelter. Water. Food.

When do we need supplies?  I would expect a yearly food and spare parts shipment for the first and second year then, hopefully the settlement has perfected it's food growing so we would send another set of buried habitat components, then 4 more crew, then food.  Essentially, one rocket a year.

Launch opportunities only occur every two years unless EMDrive becomes available.

For water the outer water sack radiation shield on the Mars Hab would have water storage.  Urine would be saved on the flight then boiled on Mars to become water vapor and captured by a dehumidifier.  Water would also come from the onboard fuel cell that takes in vented hydrogen and oxygen from the tanks.  On Mars the WAVAR unit would be started and it would fill the inner water sack radiation shield on the Mars Hab.

Urine can be reprocessed in-flight or on Mars using IWP, as long as we can spare 54We.  Microwaves typically require hundreds of watts.

Food would come from on board supplies until the buried shelter is finished and the hydroponics, chickens, and tilapia fish tank gets going.  There would be a shipment of food some time after the first settlement lands and then maybe one more the next year.

An egg laying hen requires about .25lbs of feed per day or 91.25lbs per year, so 182.5lbs of feed per chicken per launch opportunity or about $9.075M for the chicken feed at current prices.

How many chickens would you have?

Launch opportunities occur every two years?  No, the distance from the Earth to Mars goes from closest to maximum then back to closest again over about a 15-16 year time frame.  So, we launch a crew of 4 when they are closest.  We launch supply missions each year for the next year or two, then we prepare for the next closest approach to launch another crew of 4.   

How many chickens would I have?  Hmm, don't know, maybe 2 hens and 1 rooster.  The hens should produce eggs (2 hens/1 egg a day) that could be hard boiled in the Mars Hab microwave to provide additional food for the crew.

Last edited by Dook (2017-05-08 16:56:37)

kbd512

Administrator

Registered: 2015-01-02

Posts: 7,812

Re: Air. Shelter. Water. Food.

The U of Washington WAVAR design uses a lot of power.  I still don't believe it uses 8kw of constant power.  Other than the bed rotation motors and two microwave units which only operate when needed the large fan is the main power user.  It's 6 feet across and spins at 500 rpm.  A 30" fan only uses about 250 watts of power so something isn't adding up.

It's a question of mass flow achievable at a given rotational speed.  Your 30" fan is not spinning as fast as WAVAR and it doesn't have a 2.4m diameter fan attached to it.  The 8kWe is not the peak power consumed, just the constant power required.  Their numbers are not mistakes.  It requires a lot of power.  It's not a problem if you have a lot of power.

About those bearings...

Coo Space bearings (Japanese company) has bearings that have about 10 times less rolling resistance (roll about 10 times longer than bearings in a retainer) and no bearing retainer, and thus last a long time.

Coo Space CO., Ltd.

There are no lubricants used in their bearing design, either.  The point is, they won't be replaced very often.  It's now a commercially available product and Coo Space makes custom bearings for paying customers.  I haven't seen too many companies turn NASA down, so it's a safe bet the agency could procure a source for their electric motors.

Anyway, there are other WAVAR designs.  I don't like the rack and pinion set up.  The zeolite panels should be fixed already inside a large microwave and Mars atmosphere should be pulled through.

What did you have in mind?

The Centaur is way over designed, typical of NASA.  I like that it's remote controlled so it could be driven from the Mars Hab but that's about it.

Its VR or autonomously operated.  It can go over large rocks, do a 360 in place, and move sideways.  It works with or without Robonaut 2 and can mount a bucket, blade, or drill on the other end.  It was built by GM for NASA.

I'm not concerned about minimizing batteries.  The Mars Hab will need a dependable battery bank.  I'm not sure exactly how many.  On Mars they would have constant power from the RTG and additional power from the solar array in daytime.

Do you want to send food and water or batteries?  I'd rather send food and water.

Start adding up the masses of everything you need to send.  See if SLS can deliver it.  If SLS can't deliver it, then it's probably not going.  We can only build one SLS per year.  SLS can TMI about 43t (94,600lbs) with the upper stage they have planned for it.  About 50% of that is lost to heat shield and retrorockets, no matter how creative JPL gets with the EDL tech, so 47,300lbs is what you have to work with.  We can afford two SLS flights per opportunity with current budgets.  You could get more with Falcon Heavy at far lower prices, but then you need orbital assembly and mass budgeted for the modularization-related stuff.  There won't be any 8.4m diameter habitat module with Falcon Heavy, though.  At some point, launch cadence will become more of an issue than cost.  There can only be so many launches in a given time period.

Lead-acid batteries will last a year on Mars?  They should last the normal 8-10 years.  The batteries in the Mars Hab should be the same temperature as the inside of the hab.  The batteries in the Long Range Rover and Marscat would have small battery heaters under them.  No battery would be discharged for more than 1 or 2 hours except in an emergency.

The Lead-acid battery in my truck doesn't last 10 years or 8 years, it lasts 2 years and it's capacity is greatly diminished after a year or so.  The capacity of Lead-acid batteries is even worse than Lithium-ion in low temperatures.  Go read the manufacturer's specs or talk to an auto mechanic and ask them how many Lead-acid batteries they've seen that lasted 8 years, never mind 10 years.  The gel cells are a different technology.  There are multiple Lead-acid technologies in commercial use.

Let's multiply WAVAR by a factor of 8 to increase it's output?  The main thing that controls how much water you get is the amount of Mars atmosphere you move through the zeolite.  So, just increasing the fan and motor alone would give you more water.

It's a question of mass flow.  You run more cycles per day using more power.  Increase the magnetron power, if required.

You say the increased WAVAR size would equal the weight of a 3D printer?  But the WAVAR makes water.  The 3D printer doesn't.  One is life support, the other is not.

I said the mass of the wear parts is equal to the mass of the 3D printing solution I planned to send to Mars.

Paragon has a water purification system?  I'll have to check it out.

Development of Ionomer-membrane Water Processor (IWP) technology for water recovery from urine

kbd512

Administrator

Registered: 2015-01-02

Posts: 7,812

Re: Air. Shelter. Water. Food.

Launch opportunities occur every two years?  No, the distance from the Earth to Mars goes from closest to maximum then back to closest again over about a 15-16 year time frame.  So, we launch a crew of 4 when they are closest.  We launch supply missions each year for the next year or two, then we prepare for the next closest approach to launch another crew of 4.

Go read up on how the mechanics of orbital transfers work with the alignments of Earth and Mars and when a vehicle would actually arrive at Mars.  You're launching every two years unless you have a warp drive.

Oldfart1939

Member

Registered: 2016-11-26

Posts: 2,445

Re: Air. Shelter. Water. Food.

We do NOT launch when Mars and Earth are at the closest approach, which is called an Opposition class mission. The Conjunction class mission provides a minimum energy expenditure Hohmann transfer trajectory. Conjunctions occur every 26 months.
Your comments indicate that you've been getting your information from  sources other than astrophysicists. Yes, there is a small variation in distance based on a 26 year cycle where the slightly elliptical planetary orbits may make a difference of maybe a million miles in the Earth to Mars distance, but insignificant in terms of ballistic trajectories. I have my astronomy books packed for moving, or I'd give a better answer.

RobertDyck

Moderator

From: Winnipeg, Canada

Registered: 2002-08-20

Posts: 7,924

Website

Re: Air. Shelter. Water. Food.

Launch opportunities occur every two years?  No, the distance from the Earth to Mars goes from closest to maximum then back to closest again over about a 15-16 year time frame.  So, we launch a crew of 4 when they are closest.  We launch supply missions each year for the next year or two, then we prepare for the next closest approach to launch another crew of 4.

Orbits of Earth and Mars around the Sun align once every 26 months.

::Edit:: This spirograph shows a harmonic relationship between the period of Earth's orbit and Mars. Earth has an orbital period of 365.2425 days, Mars has 686.971 days. The should work out to a fraction (integer / integer), but I don't see it. The spirograph implies the number 5 somehow; but again, I don't see it.

In the 1970s scientists noticed the near but not quite arithmetic progression in the orbital periods of the inner planets. They asked if that was a coincidence, or was there a reason? They said it would require additional data, planets around another star. Back then no extrasolar planets had been detected, and no one know how to do it. Then one individual realized we have a second system right here: the moons of Jupiter. They follow an arithmetic progression much more closely.

How many chickens would I have?  Hmm, don't know, maybe 2 hens and 1 rooster.  The hens should produce eggs (2 hens/1 egg a day) that could be hard boiled in the Mars Hab microwave to provide additional food for the crew.

How are you going to get them there? An express trajectory takes 6 months. That trajectory was used by Spirit and Opportunity. A Hohmann transfer orbit from Earth to Mars is about 8.5 months. Curiosity used that trajectory; it allows a little more payload mass for a launch vehicle of the same size. Fertilized chicken eggs can be stored in a refrigerator; not as cold as a kitchen fridge, but at the right temperature they will remain viable for at most 6 weeks. But again, an express trajectory is 6 months. Do you want live chickens in your spacecraft with you? As you go from high acceleration launch to Earth orbit, then zero-G, then spin-up rotation for artificial gravity, then cut the tether for zero-G again, then high acceleration during Mars atmospheric landing? Do you want panicked chickens in your spacecraft with you? How much chicken shit will float about during zero-G?

Last edited by RobertDyck (2017-05-08 19:09:28)

Oldfart1939

Member

Registered: 2016-11-26

Posts: 2,445

Re: Air. Shelter. Water. Food.

Somehow--this chicken issue is sounding familiar!

kbd512

Administrator

Registered: 2015-01-02

Posts: 7,812

Re: Air. Shelter. Water. Food.

I think I know what Dook is talking about here.  It's technically feasible, if never attempted.  As long as nothing perishable is sent, it should work.

Dook

Banned

From: USA

Registered: 2004-01-09

Posts: 1,409

Re: Air. Shelter. Water. Food.

The U of Washington WAVAR design uses a lot of power.  I still don't believe it uses 8kw of constant power.  Other than the bed rotation motors and two microwave units which only operate when needed the large fan is the main power user.  It's 6 feet across and spins at 500 rpm.  A 30" fan only uses about 250 watts of power so something isn't adding up.

It's a question of mass flow achievable at a given rotational speed.  Your 30" fan is not spinning as fast as WAVAR and it doesn't have a 2.4m diameter fan attached to it.  The 8kWe is not the peak power consumed, just the constant power required.  Their numbers are not mistakes.  It requires a lot of power.  It's not a problem if you have a lot of power.

About those bearings...

Coo Space bearings (Japanese company) has bearings that have about 10 times less rolling resistance (roll about 10 times longer than bearings in a retainer) and no bearing retainer, and thus last a long time.

Coo Space CO., Ltd.

There are no lubricants used in their bearing design, either.  The point is, they won't be replaced very often.  It's now a commercially available product and Coo Space makes custom bearings for paying customers.  I haven't seen too many companies turn NASA down, so it's a safe bet the agency could procure a source for their electric motors.

Anyway, there are other WAVAR designs.  I don't like the rack and pinion set up.  The zeolite panels should be fixed already inside a large microwave and Mars atmosphere should be pulled through.

What did you have in mind?

The Centaur is way over designed, typical of NASA.  I like that it's remote controlled so it could be driven from the Mars Hab but that's about it.

Its VR or autonomously operated.  It can go over large rocks, do a 360 in place, and move sideways.  It works with or without Robonaut 2 and can mount a bucket, blade, or drill on the other end.  It was built by GM for NASA.

I'm not concerned about minimizing batteries.  The Mars Hab will need a dependable battery bank.  I'm not sure exactly how many.  On Mars they would have constant power from the RTG and additional power from the solar array in daytime.

Do you want to send food and water or batteries?  I'd rather send food and water.

Start adding up the masses of everything you need to send.  See if SLS can deliver it.  If SLS can't deliver it, then it's probably not going.  We can only build one SLS per year.  SLS can TMI about 43t (94,600lbs) with the upper stage they have planned for it.  About 50% of that is lost to heat shield and retrorockets, no matter how creative JPL gets with the EDL tech, so 47,300lbs is what you have to work with.  We can afford two SLS flights per opportunity with current budgets.  You could get more with Falcon Heavy at far lower prices, but then you need orbital assembly and mass budgeted for the modularization-related stuff.  There won't be any 8.4m diameter habitat module with Falcon Heavy, though.  At some point, launch cadence will become more of an issue than cost.  There can only be so many launches in a given time period.

Lead-acid batteries will last a year on Mars?  They should last the normal 8-10 years.  The batteries in the Mars Hab should be the same temperature as the inside of the hab.  The batteries in the Long Range Rover and Marscat would have small battery heaters under them.  No battery would be discharged for more than 1 or 2 hours except in an emergency.

The Lead-acid battery in my truck doesn't last 10 years or 8 years, it lasts 2 years and it's capacity is greatly diminished after a year or so.  The capacity of Lead-acid batteries is even worse than Lithium-ion in low temperatures.  Go read the manufacturer's specs or talk to an auto mechanic and ask them how many Lead-acid batteries they've seen that lasted 8 years, never mind 10 years.  The gel cells are a different technology.  There are multiple Lead-acid technologies in commercial use.

Let's multiply WAVAR by a factor of 8 to increase it's output?  The main thing that controls how much water you get is the amount of Mars atmosphere you move through the zeolite.  So, just increasing the fan and motor alone would give you more water.

It's a question of mass flow.  You run more cycles per day using more power.  Increase the magnetron power, if required.

You say the increased WAVAR size would equal the weight of a 3D printer?  But the WAVAR makes water.  The 3D printer doesn't.  One is life support, the other is not.

I said the mass of the wear parts is equal to the mass of the 3D printing solution I planned to send to Mars.

Paragon has a water purification system?  I'll have to check it out.

Development of Ionomer-membrane Water Processor (IWP) technology for water recovery from urine

Coo Space bearings has bearings that have about 10 times the rolling resistance?  Okay, can they be printed?

Their bearings would last a long time?  Cool, but they won't last forever.  What if Mars dust gets in them? 

Why don't we stop this round and round.  You think that it's more important for a first settlement to be able to print a rocket engine on Mars than have spare parts for life support equipment.  You can have your idea and I can have mine. 

What WAVAR did I have in mind?  The zeolite panels should be fixed already inside a large microwave, no rack and pinion set up. 

The Centaur is autonomously operated?  Suuuure it is.  It can go over large rocks, do a 360, and move sideways?  Great, the next time we decide to make a base in a giant rock field that thing will be useful.  What if we put the base in a place where the vehicles don't need all that?

Do I want to send food and water or batteries?  You're trying to make up a rule that is not a rule.  You have to have food, water, and batteries.  Unless you're going to use a 3D printer to make the food, water, and batteries?

You'd rather send food and water?  No, you want to send multiple 3D printers and multiple types of powder, and a robonaut. 

I should start adding up the masses for everything I want to send and see if SLS can deliver it?  It's called Mars Direct.  For settlement all of the science equipment would not be sent in a Mars Hab, which saves 500 lbs, the lab equipment won't go,saves 500 lbs, and the pressurized rover and two open rovers would be in the Rover Hanger which is launched on a separate SLS and the Mars Hab and Rover Hanger dock in space so that saves another 4,400 lbs.  Total saved so far of 5,400 lbs.     

I would add the WAVAR which is 1,947 lbs.  How's it lookin?

The lead-acid battery in your truck doesn't last 10 years, not even 8, it lasts 2 years?  I just replaced the one in my car after 11 years. 

The mass of life support wear parts is equal to the mass of the 3D printing solution you want to take?  I thought you wanted to take food and water?

Dook

Banned

From: USA

Registered: 2004-01-09

Posts: 1,409

Re: Air. Shelter. Water. Food.

We do NOT launch when Mars and Earth are at the closest approach, which is called an Opposition class mission. The Conjunction class mission provides a minimum energy expenditure Hohmann transfer trajectory. Conjunctions occur every 26 months.
Your comments indicate that you've been getting your information from  sources other than astrophysicists. Yes, there is a small variation in distance based on a 26 year cycle where the slightly elliptical planetary orbits may make a difference of maybe a million miles in the Earth to Mars distance, but insignificant in terms of ballistic trajectories. I have my astronomy books packed for moving, or I'd give a better answer.

Mars orbit and the Earth's orbit align every 2 years but Mars and the Earth are even CLOSER every 15-16 years. 

You can have your launch window and I can have mine.

Dook

Banned

From: USA

Registered: 2004-01-09

Posts: 1,409

Re: Air. Shelter. Water. Food.

Launch opportunities occur every two years?  No, the distance from the Earth to Mars goes from closest to maximum then back to closest again over about a 15-16 year time frame.  So, we launch a crew of 4 when they are closest.  We launch supply missions each year for the next year or two, then we prepare for the next closest approach to launch another crew of 4.

Orbits of Earth and Mars around the Sun align once every 26 months.
https://s-media-cache-ak0.pinimg.com/or … 8bf0a9.gif
::Edit:: This spirograph shows a harmonic relationship between the period of Earth's orbit and Mars. Earth has an orbital period of 365.2425 days, Mars has 686.971 days. The should work out to a fraction (integer / integer), but I don't see it. The spirograph implies the number 5 somehow; but again, I don't see it.

In the 1970s scientists noticed the near but not quite arithmetic progression in the orbital periods of the inner planets. They asked if that was a coincidence, or was there a reason? They said it would require additional data, planets around another star. Back then no extrasolar planets had been detected, and no one know how to do it. Then one individual realized we have a second system right here: the moons of Jupiter. They follow an arithmetic progression much more closely.

How many chickens would I have?  Hmm, don't know, maybe 2 hens and 1 rooster.  The hens should produce eggs (2 hens/1 egg a day) that could be hard boiled in the Mars Hab microwave to provide additional food for the crew.

How are you going to get them there? An express trajectory takes 6 months. That trajectory was used by Spirit and Opportunity. A Hohmann transfer orbit from Earth to Mars is about 8.5 months. Curiosity used that trajectory; it allows a little more payload mass for a launch vehicle of the same size. Fertilized chicken eggs can be stored in a refrigerator; not as cold as a kitchen fridge, but at the right temperature they will remain viable for at most 6 weeks. But again, an express trajectory is 6 months. Do you want live chickens in your spacecraft with you? As you go from high acceleration launch to Earth orbit, then zero-G, then spin-up rotation for artificial gravity, then cut the tether for zero-G again, then high acceleration during Mars atmospheric landing? Do you want panicked chickens in your spacecraft with you? How much chicken shit will float about during zero-G?

How am I going to get chickens to Mars?  In a plastic shipping container with tiny vent holes in it.  Their feet would be secured so they can't move.  They would have to be force fed daily and their mess cleaned up. 

The container would probably need a small computer fan on constantly to circulate air.

RobertDyck

Moderator

From: Winnipeg, Canada

Registered: 2002-08-20

Posts: 7,924

Website

Re: Air. Shelter. Water. Food.

Because the orbit of Mars is eliptical, the exact distance between the planets varies. If the 26 month close point happens to coincide with Mars perihelion, then the distance will be shorter. If it happens to coincide with Mars aphelion then it will be farther. But that difference is insignificant compared to the distance from Earth to Mars. Mars was closed to Earth in 2003, the closest it has been in 60,00 years. It won't be that close again until 2287. Did you spot that? The next is not 60,000 years away, it's only 284 years. The planets align for a close approach every 15 to 17 years. But are you really going to wait 17 years just to shave off a couple days transit time?

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,428

Re: Air. Shelter. Water. Food.

Earth and Mars at launch

The Hohmann Transfer Orbit

Mars and Earth at the start and end of the transfer orbit return

Mars and Earth at the start of the return trip

Oldfart1939

Member

Registered: 2016-11-26

Posts: 2,445

Re: Air. Shelter. Water. Food.

Dook has never been around chickens. That is the most absurd suggestion he's made so far: "feet secured so they cannot move." They would all be dead in a matter of days. They would peck their own feet off.

Here's a potential timeline and methodology for the transport of chickens: Refrigerated eggs: 6 weeks; incubation of eggs: 3-3 1/2 weeks; baby chicks (no feathers): 6 weeks; poults fledging feathers: 6 weeks; young adult chickens to Mars touchdown: 12.5 to 15 weeks (depends on chosen Hohmann trajectory). How do we get rid of the mess? Answer: shop vac removes all the chickenshit and excess food; done every 6 hours for smell and airborne feathers, down, and miscellaneous shit. If we have centripetal acceleration induced artificial gravity, the problems will be minimal. In a way, there might be some psychological benefit; chickens can be very sociable critters. For the first 12-15 weeks of the transit, they will not be a significant issue.

Dook

Banned

From: USA

Registered: 2004-01-09

Posts: 1,409

Re: Air. Shelter. Water. Food.

Because the orbit of Mars is eliptical, the exact distance between the planets varies. If the 26 month close point happens to coincide with Mars perihelion, then the distance will be shorter. If it happens to coincide with Mars aphelion then it will be farther. But that difference is insignificant compared to the distance from Earth to Mars. Mars was closed to Earth in 2003, the closest it has been in 60,00 years. It won't be that close again until 2287. Did you spot that? The next is not 60,000 years away, it's only 284 years. The planets align for a close approach every 15 to 17 years. But are you really going to wait 17 years just to shave off a couple days transit time?
https://mars.nasa.gov/imgs/2016/05/May-Mars2016-2018.jpg

https://mars.nasa.gov/images/mep/allaboutmars/closeapproach/mars-apparent-size-2016.gif?new

Am I willing to wait 17 years between crewed launches to Mars?  Yes.  I'm not the one who is in a hurry.  Could we send humans sooner than that?  Sure, but necessary supplies and spare parts for the first crew takes priority.

Dook

Banned

From: USA

Registered: 2004-01-09

Posts: 1,409

Re: Air. Shelter. Water. Food.

Dook has never been around chickens. That is the most absurd suggestion he's made so far: "feet secured so they cannot move." They would all be dead in a matter of days. They would peck their own feet off.

Here's a potential timeline and methodology for the transport of chickens: Refrigerated eggs: 6 weeks; incubation of eggs: 3-3 1/2 weeks; baby chicks (no feathers): 6 weeks; poults fledging feathers: 6 weeks; young adult chickens to Mars touchdown: 12.5 to 15 weeks (depends on chosen Hohmann trajectory). How do we get rid of the mess? Answer: shop vac removes all the chickenshit and excess food; done every 6 hours for smell and airborne feathers, down, and miscellaneous shit. If we have centripetal acceleration induced artificial gravity, the problems will be minimal. In a way, there might be some psychological benefit; chickens can be very sociable critters. For the first 12-15 weeks of the transit, they will not be a significant issue.

I've never been around chickens?  I've been around lots of chickens.  I drive by KFC all the time. 

The chickens would peck their own feet off?  Not if they don't have their peckers anymore.  But I guess that would violate some PETA laws or something.  And when we get to Mars they wouldn't be able to eat without their peckers. 

I guess we could put thin metal guards around their legs or something.

Last edited by Dook (2017-05-08 20:03:04)

SpaceNut

Administrator

From: New Hampshire

Registered: 2004-07-22

Posts: 29,428

Re: Air. Shelter. Water. Food.

Because the orbit of Mars is eliptical, the exact distance between the planets varies. If the 26 month close point happens to coincide with Mars perihelion, then the distance will be shorter. If it happens to coincide with Mars aphelion then it will be farther. But that difference is insignificant compared to the distance from Earth to Mars. Mars was closed to Earth in 2003, the closest it has been in 60,00 years. It won't be that close again until 2287. Did you spot that? The next is not 60,000 years away, it's only 284 years. The planets align for a close approach every 15 to 17 years. But are you really going to wait 17 years just to shave off a couple days transit time?
https://mars.nasa.gov/imgs/2016/05/May-Mars2016-2018.jpg

https://mars.nasa.gov/images/mep/allaboutmars/closeapproach/mars-apparent-size-2016.gif?new

Am I willing to wait 17 years between crewed launches to Mars?  Yes.  I'm not the one who is in a hurry.  Could we send humans sooner than that?  Sure, but necessary supplies and spare parts for the first crew takes priority.

Congress passes NASA funding bill, Mars mission date set A trip to Mars by 2033 is among the several long-term NASA goals included in a bill Congress just passed to fund the aerospace agency. The bill asks for a human mission “near or on the surface of Mars in the 2030s,” and specifically asks for a study to be conducted on the feasibility of a human spaceflight mission to be launched in 2033.

NASA Transition Authorization Act of 2017

https://www.nasa.gov/pdf/649377main_PL_111-267.pdf