Trip to Mars on hypergolics

[lobe]

Thanks for the link.

[fredinno]

1 hour ago, lobe said:

Thank you for posting this, it helped me find an error. I said 9 launchs, that was because I read 310000 kg instead of lbs, so this made it twice as practical. In reality, it takes 18 Saturn-V launches, or 12 Saturn-V25(S)B launches. I was wondering why the SuperSaturn was weaker than the Saturn.

As for aerobraking, I omitted any need of that with my propellant calculations. If Mars where completely devoid of atmosphere, my spacecraft would still be able to complete its mission.

Except Mars has an atmosphere, and you should use it. The ballutes would be pretty enormous, though. 

BTW, you can reduce HAB mass by removing the O2 tank, which is going to be unused on a Skylab. You need more solar array for Mars though, so you should account for that.

[lobe]

Isn't the O₂  tank already removed? There is a huge tank in the bottom, the waste tank, is that what you mean?

I didn't use aerocapture because it would require aerodynamic calculations which I don't feel like doing. As well as what some other people have brought up, in the end I am landing a 190 ton spacecraft in a period where the most we have landed on Mars is a half ton or less. May be parachutes on the lander, but the entire 2546 ton to under go aerobraking would be a nightmare, and I am assuming my tanks are on the light side of sheilding.

Edited March 14, 2016 by lobe
Air sucks

[DBowman]

9 minutes ago, fredinno said:

Except Mars has an atmosphere, and you should use it.

I agree, but on the other hand current NASA DRA 5 still plans to not aerocapture the crew vehicle.

[DerekL1963]

2 hours ago, fredinno said:

Yes, ISRU was considered risky at that time- NASA would not consider their proposal until Zubrin experimentally proved ISRU worked.

In the lab - which is a very long way from reliable, flyable hardware.

[kerbiloid]

"ISRU-produced Methane" is a synonym for "Unknown colorless volatile cryogenic liquid found in a canister lying by the side of the road".

Just imagine how many laboratory tests and acts of delivery and acceptance will be made before even a certified fuel would fill a rocketship or an airplane tank.

No high-ranking official will risk with the expedition failure, crew lives, personal career just to test: whether this liquid is indeed methane, enough pure to be used in the engine.

Edited March 14, 2016 by kerbiloid

[AngelLestat]

9 hours ago, lobe said:

The lander is still two stage. The ascent stage I based off of the dry mass of the Apollo CSM, at about 12 tons, adding another 1.2 tons for supplies of a 3 crew for 30 days on the ground, coming to 13.2 tons. Fuelled mass is 45.4 tons. The descent stage takes that number and adds 10 tons, when this is fuelled there is a total lander weight of 190.4 tons. Yes, AngelLestat, this does and my previous calculations include the the total 7.6 km/s it takes to land and depart Mars, because aerobraking is for wimps. Also, this is tech pretty much from Apollo that I am using, and the end date for the tech I can use is up to 1980, the launch doesn't need to be in that time frame. By 1980 we already landed 2 probes on Mars (Viking 1 and 2, 1976), so I assume that the development program they used could be scaled up. 

Ok, but even if you plan to kills all your deltav with propulsion, you have to know that this is not as easy as the moon, due the supersonic co2 flow that is trying to extinguish your burn.
Maybe is not a problem, maybe it is..  we just try it with modern engines at lower speeds and with a mix of nitrogen and oxygen.  The mars case would be much worst.

9 hours ago, lobe said:

Skylab weighed about 68 tons, adding 24.5 to that gives us 92.5 tons. This is added to the lander, and will assume that the tank Skylab is attached to is 25 tons. This brings the unfuelled mass to 307.9 tons, fuelled 740.4 tons. Since we are now moving something with the fuelled mass over the Proton rocket (693.8 tons) the tank and the amount of engines are going to be pretty massive, so I assumed another 50 tons for this departure stage. This now makes the rocket 2,546 tons fuelled. To put this in perspective, this is about 3 and 2/3 Proton rockets, or about 85% of a Saturn V. It would take 18(actually 18.1, but you aren't going to launch 0.1 of a rocket) Saturn V launches to complete this single spacecraft.

Those 2500 tons is the why NASA is trying to search other alternatives to reduce the deltav, managing such huge rocket with so many stages and trying to land such heavy vehicle on mars surface is not the way to improve safety, in fact increase the risk, each kg you save in your final stage it has a huge impact in your first stage.  In those cases ISRU, high isp fuel and even hard aerobrake techniques are welcome.

1 hour ago, kerbiloid said:

"ISRU-produced Methane" is a synonym for "Unknown colorless volatile cryogenic liquid found in a canister lying by the side of the road".

Just imagine how many laboratory tests and acts of delivery and acceptance will be made before even a certified fuel would fill a rocketship or an airplane tank.

No high-ranking official will risk with the expedition failure, crew lives, personal career just to test: whether this liquid is indeed methane, enough pure to be used in the engine.

You can have sensors to measure the quality of the fuel before you sent people there, those kind of sensors are super lightweight and you can add redundancy.
You can even test engine firing, hover and landing before you send someone. This will complete the test that your engines work and the fuel is fine.
In the other way, if you sent someone there carrying your return fuel from here, you dont know if the engines will work when you need them, plus the risk to land heavier payloads and how much that impact in your amount of required launchers from earth.

[kerbiloid]

1 hour ago, AngelLestat said:

You can have sensors to measure the quality of the fuel before you sent people there, those kind of sensors are super lightweight and you can add redundancy.
You can even test engine firing, hover and landing before you send someone. This will complete the test that your engines work and the fuel is fine.

Rocketship needs dozens of tonnes of methane, and absolutely pure (less than 1%) because otherwise you just kill your engine with water and CO2 ice and unpredictable pollutions.

Raw material for the Mars Sabatier are CO2 mudded with other gases, water ice mudded with hydrates, perchlorates, carbonates, sulphates, etc.
Sabatier reaction does not give pure methane, it gives a mix of methane, CO, CO2, H2O, H2, etc. Enough to show in laboratory, but requiring a big and massive cryogenic separator, adsorbtion plant, etc - just to filter out all this mud.

So, until you build a nice and large methane fabric, with dozens of columns, reactors, adsorbers and regenerators, all this ISRU methane is just a canister of unknown petrol-looking liquid found near the road which you are trying to pour into your Ferrari tank. With the same probable result.

[fredinno]

10 hours ago, lobe said:

Isn't the O₂  tank already removed? There is a huge tank in the bottom, the waste tank, is that what you mean?

I didn't use aerocapture because it would require aerodynamic calculations which I don't feel like doing. As well as what some other people have brought up, in the end I am landing a 190 ton spacecraft in a period where the most we have landed on Mars is a half ton or less. May be parachutes on the lander, but the entire 2546 ton to under go aerobraking would be a nightmare, and I am assuming my tanks are on the light side of sheilding.

The O2 tank is the waste tank yes. You might need it to use it to store waste in until MAV ejection, but probably isn't necessary.

Another option to reduce mass is the use of a Saturn IB to launch a S-IVB to LEO, with solar panels, radiators and a SM. Another Saturn IB would launch supplies to retrofit the module. One last one would carry an airlock and a CSM to LEO. The 3 would dock in LEO (thankfully, Saturn IB has 5 possible pads to use, so you can launch a lot at once) and would use the S-IVB as a "wet workshop" to make a HAB out of. This HAB would be lived in for a year or two, with resupply and crew turnover, to be used as a science base and to ensure it is safe for the journey to Mars (of course, at least one other similar HAB would be made to test this too). Then, the crew would leave, and the rest of the stack would be docked to it.  This was a serious consideration for Apollo Applications, and can shave off a bit more mass.

Another is the use of a Venus flyby trajectory to do a short duration Mars mission.

You can also carry the mars mission in pieces- allowing the cargo to use aerobraking, while the more fragile crewed segment uses propulsive insertion.

4 hours ago, kerbiloid said:

"ISRU-produced Methane" is a synonym for "Unknown colorless volatile cryogenic liquid found in a canister lying by the side of the road".

Just imagine how many laboratory tests and acts of delivery and acceptance will be made before even a certified fuel would fill a rocketship or an airplane tank.

No high-ranking official will risk with the expedition failure, crew lives, personal career just to test: whether this liquid is indeed methane, enough pure to be used in the engine.

Which is why we need a large precursor robotic program to test these tech before depending human lives on it.

[lobe]

16 hours ago, DBowman said:

I used NASA 'Baseline Assumptions and Values' doc and derived a 1,400 kg for 500 man days.

Were you using table 3.3.6 and subtracting what ever water the crew used because it can be recycled (multiplied by 0.85), then added the CO₂ generated?

[AngelLestat]

10 hours ago, kerbiloid said:

Rocketship needs dozens of tonnes of methane, and absolutely pure (less than 1%) because otherwise you just kill your engine with water and CO2 ice and unpredictable pollutions.

Raw material for the Mars Sabatier are CO2 mudded with other gases, water ice mudded with hydrates, perchlorates, carbonates, sulphates, etc.
Sabatier reaction does not give pure methane, it gives a mix of methane, CO, CO2, H2O, H2, etc. Enough to show in laboratory, but requiring a big and massive cryogenic separator, adsorbtion plant, etc - just to filter out all this mud.

So, until you build a nice and large methane fabric, with dozens of columns, reactors, adsorbers and regenerators, all this ISRU methane is just a canister of unknown petrol-looking liquid found near the road which you are trying to pour into your Ferrari tank. With the same probable result.

sabatier reaction is like a children play for chemist..  gas separation very easy using different frozen point temperatures, etc.
You can carry your h2 from earth or just get it from the water, (a way to get water on mars using ISRU will increase the survival chances of the mission.
ISRU= Lower risk
Also why you always said "massive" machine.. massive  filter,  massive  sabatier.. etc.  I understand, you want to make the point against ISRU, but these machines are way far from massive, in the worst of all cases, all your elements will weight 1000 kg, that is several times less than the fuel you need to carry in case you dont use ISRU.
Here is a NASA site speaking on ISRU:
http://nssdc.gsfc.nasa.gov/planetary/mars/marssurf.html

Here is another link but it seems too old:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120001775.pdf

9 hours ago, fredinno said:

Which is why we need a large precursor robotic program to test these tech before depending human lives on it.

Is not really need it, if you design 2 or 3 types of landers in which one of those is able to make methane and return to earth.
The other 2 will carry extra supplies, vehicles and other ISRU tools just in case (mostly for water).

You send them first..  you test methane production and quality with many sensors, you test the engine fire and thrust,  if something doesn´t work, you can fix the problem and launch another one in the next launch window, then you test again, if all works fine and they had full fuel, then you launch the human mission using the same design that also is ISRU capable in case something happen or that would stay and work for the next explorers, you can also exchange fuel between vehicles in case something happen and you need to launch using your arriving ship.

Why human lives are in "risk" if you are already test all this from earth?  And you have many contingencies solutions that you will no have with a no ISRU approach.
Is cheaper.. is more efficient..  and is more safe.
You are also sending the humans in a ship that already did all the trip and land in mars, because you use a copy of the one that already is there.

There is no point to sent a rover to test something so simple as the savatier process to mars, because it can be test it here simulating mars conditions.
You will be doing triple test for nothing, when in fact the most hard about mars is aerobraking and landing (and that risk increase proportional to your lander mass)

[DBowman]

7 hours ago, lobe said:

Were you using table 3.3.6 and subtracting what ever water the crew used because it can be recycled (multiplied by 0.85), then added the CO₂ generated?

I had used 3.3.6 ( & 4.1.1 to budget some hours a day at the high util for O2 exercise / buffer ). So for water: Metabolic Required = Potable Required - Vapor recovered - 0.84 * Urine - 0.06 * Urine Forward Osmosis Driver Solution (sugar water) = 0.065 i.e. a couple of shot glasses of H2O generated per man day - go wild with hygiene.

The CO2 just gets vented overboard using a machine to absorb the CO2 in 'beds', then expose the beds to vacuum to 'clean' them.

Edited March 15, 2016 by DBowman
oops fixed minor calc error

[fredinno]

30 minutes ago, AngelLestat said:

sabatier reaction is like a children play for chemist..  gas separation very easy using different frozen point temperatures, etc.
You can carry your h2 from earth or just get it from the water, (a way to get water on mars using ISRU will increase the survival chances of the mission.
ISRU= Lower risk
Also why you always said "massive" machine.. massive  filter,  massive  sabatier.. etc.  I understand, you want to make the point against ISRU, but these machines are way far from massive, in the worst of all cases, all your elements will weight 1000 kg, that is several times less than the fuel you need to carry in case you dont use ISRU.
Here is a NASA site speaking on ISRU:
http://nssdc.gsfc.nasa.gov/planetary/mars/marssurf.html

Here is another link but it seems too old:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120001775.pdf

Is not really need it, if you design 2 or 3 types of landers in which one of those is able to make methane and return to earth.
The other 2 will carry extra supplies, vehicles and other ISRU tools just in case (mostly for water).

You send them first..  you test methane production and quality with many sensors, you test the engine fire and thrust,  if something doesn´t work, you can fix the problem and launch another one in the next launch window, then you test again, if all works fine and they had full fuel, then you launch the human mission using the same design that also is ISRU capable in case something happen or that would stay and work for the next explorers, you can also exchange fuel between vehicles in case something happen and you need to launch using your arriving ship.

Why human lives are in "risk" if you are already test all this from earth?  And you have many contingencies solutions that you will no have with a no ISRU approach.
Is cheaper.. is more efficient..  and is more safe.
You are also sending the humans in a ship that already did all the trip and land in mars, because you use a copy of the one that already is there.

There is no point to sent a rover to test something so simple as the savatier process to mars, because it can be test it here simulating mars conditions.
You will be doing triple test for nothing, when in fact the most hard about mars is aerobraking and landing (and that risk increase proportional to your lander mass)

Mars is NOT EARTH< that's why you need to test this tech on Mars, IRL conditions are different. The martian atmoshpehere is not 100% CO2, for example, and there areother unseen factors that could destroy a potential Mars mission MAV and leave them stranded if not tested extensively enough (which is a lot).

[lobe]

1 hour ago, DBowman said:

I had used 3.3.6 ( & 4.1.1 to budget some hours a day at the high util for O2 exercise / buffer ). So for water: Metabolic Required = Potable Required - Vapor recovered - 0.84 * Urine - 0.06 Forward Osmosis Driver Solution (sugar water) = -0.012 i.e. half a shot glass of H2O generated per man day - go wild with hygiene.

The CO2 just gets vented overboard using a machine to absorb the CO2 in 'beds', then expose the beds to vacuum to 'clean' them.

Holy crap I am still having trouble getting your numbers. Through the method I described to you I got 2.8 kg/crew-day, which works out to 1371 kg for a 500 day trip for a solitary person, close enough to your original number. Through your latest method ditching the CO₂ and fully describing your water loss and recovery process, I got 1.4 kg/crew-day. In either case I guess I can revise the numbers and maybe this week I can complete the architecture of this massive and glorious project (hab and return stage delivery).

1 hour ago, fredinno said:

The martian atmoshpehere is not 100% CO2,

Mars's atmosphere is more CO₂ (95%) than our atmosphere is N₂ (78%), so I would expect the Sabatier process to work pretty well given a supply of hydrogen feed stock. However, for this discussion it does not matter because we are using Aerozine 50/N₂O₄ and is not producible in the Martian atmosphere.

 

2 hours ago, AngelLestat said:

Is cheaper.. is more efficient..  and is more safe.

I couldn't agree with you more but it is probably well outside of 1970-1980 tech and well outside of this thread. Though reading about boil off is slowly changing my opinion to one where a cryogenic mission with long term storage might be possible. I think the longest a cryogenic tank has been made to contain liquids is a month, and that was the Space Shuttle fuel cell reactant tanks, which probably where designed and tested in the late 70's.

[DBowman]

8 minutes ago, lobe said:

is not producible in the Martian atmosphere.

You probably don't want to go there but you could make the N2O4 by bringing just the N2 and extracting the O4 from Mars CO2 + H2O via Solid Oxide Electrolysis + Haber-Bosch + Ammonia Oxidization ( see Real ISRU mod ). You avoid the bringing O2 mass, but it's even more complex etc than CH4...

[lobe]

3 minutes ago, DBowman said:

You probably don't want to go there but you could make the N2O4 by bringing just the N2 and extracting the O4 from Mars CO2 + H2O via Solid Oxide Electrolysis + Haber-Bosch + Ammonia Oxidization ( see Real ISRU mod ). You avoid the bringing O2 mass, but it's even more complex etc than CH4...

KISS really sums up my approach to this whole project. Better to launch 5 extra Saturn-Vs than to develop new technologies which need extensive programs to develop.

[fredinno]

11 hours ago, lobe said:

Holy crap I am still having trouble getting your numbers. Through the method I described to you I got 2.8 kg/crew-day, which works out to 1371 kg for a 500 day trip for a solitary person, close enough to your original number. Through your latest method ditching the CO₂ and fully describing your water loss and recovery process, I got 1.4 kg/crew-day. In either case I guess I can revise the numbers and maybe this week I can complete the architecture of this massive and glorious project (hab and return stage delivery).

Mars's atmosphere is more CO₂ (95%) than our atmosphere is N₂ (78%), so I would expect the Sabatier process to work pretty well given a supply of hydrogen feed stock. However, for this discussion it does not matter because we are using Aerozine 50/N₂O₄ and is not producible in the Martian atmosphere.

 

I couldn't agree with you more but it is probably well outside of 1970-1980 tech and well outside of this thread. Though reading about boil off is slowly changing my opinion to one where a cryogenic mission with long term storage might be possible. I think the longest a cryogenic tank has been made to contain liquids is a month, and that was the Space Shuttle fuel cell reactant tanks, which probably where designed and tested in the late 70's.

Yeah, and guess what? For rocket engines, 95% is not pure enough and can destroy your MAV engines. Rocket fuel needs to be tightly controlled due to their nature.

[sgt_flyer]

@lobe

one quick question, if you simply want to use hypergolics for simplicity and to avoid boiloff and ISRU - what would prevent you to make the initial earth > mars transfer burn on lh2-lox ? granted, it won't reduce the mars braking stage and lander weight, but it still could save a good amount of weight , without having to worry much about boiloff & co (as all the cryogenic propellant would be used for the initial transfer).  

one second possibility to further reduce the weight of the manned mission would be to send the lander in advance, and park it in mars orbit. the manned mission would rendez-vous with the lander on arrival, and conduct their mission.

Edited March 15, 2016 by sgt_flyer

[fredinno]

Hey, here's a few more Saturn V upgrades you can use: http://www.friends-partners.org/partners/mwade/lvs/satv525s.htm

This would use Shuttle SRBs to augment the payload.

http://www.friends-partners.org/partners/mwade/lvs/satv523s.htm

This would need to be transported by barge due to the size of the SRB, but if aerojet makes it, it's still possible. It would also require new infrastructure to handle the massive SRBs at the pad. It also uses NERVA, so beware!

http://www.astronautix.com/lvs/satnv23l.htm

This is if you prefer LRBs. It has lower performance, though, than the previous one.

Edited March 15, 2016 by fredinno

[DerekL1963]

The big problem with those Saturn V upgrades is the crawler and the MLP...  Some of the configurations with strap-ons exceed the weight the crawler can support and those strap-ons have to be brought to the pad separately.   Almost all of them require extensive modification to the MLP that subsequently renders them useless for other configurations.  The LUT faces the same problem.

[fredinno]

23 minutes ago, DerekL1963 said:

The big problem with those Saturn V upgrades is the crawler and the MLP...  Some of the configurations with strap-ons exceed the weight the crawler can support and those strap-ons have to be brought to the pad separately.   Almost all of them require extensive modification to the MLP that subsequently renders them useless for other configurations.  The LUT faces the same problem.

Indeed, that's what I was warning about.

[lobe]

1 hour ago, sgt_flyer said:

one quick question, if you simply want to use hypergolics for simplicity and to avoid boiloff and ISRU - what would prevent you to make the initial earth > mars transfer burn on lh2-lox ? granted, it won't reduce the mars braking stage and lander weight, but it still could save a good amount of weight , without having to worry much about boiloff & co (as all the cryogenic propellant would be used for the initial transfer).  

one second possibility to further reduce the weight of the manned mission would be to send the lander in advance, and park it in mars orbit. the manned mission would rendez-vous with the lander on arrival, and conduct their mission.

Yes I could use hydrolox but I wanted to see how large a hypergolic rocket would be to deliver the payload+hab. For delivering the lander separately, I figure a simulation mode might be able to be rigged up so the crew can practice enroute.

[AngelLestat]

17 hours ago, lobe said:

I couldn't agree with you more but it is probably well outside of 1970-1980 tech and well outside of this thread. Though reading about boil off is slowly changing my opinion to one where a cryogenic mission with long term storage might be possible. I think the longest a cryogenic tank has been made to contain liquids is a month, and that was the Space Shuttle fuel cell reactant tanks, which probably where designed and tested in the late 70's.

The shuttle tank was not really insulated to prevent boiling, it last a lot due its big volume, and we are talking about hydrogen which boiling temperature is 90 degree lower than methane, also the golden rule of volume..  you need a lot of propellent for a mars trip, this require huge tanks, each time you increase the tank radius in a 25%, you double the volume and your surface only increase a 60% (tank cost and surface leak), but other think happens, volume increase by cubic and surface square, so the volume/surface ratio increase a lot, each time you double the volume, the ratio increase like this: 8, 17, 33, 67, 133.    Why this is important?   because it tells you how much energy needs all that mass of fuel to rise few degrees its temperature, so if your tank volume is big, (5 to 10 times the shuttle tank) then it can last years, and hydrogen leak takes a lot of time too.

The missions that needs to be worry about leaks or cryo boling, are those who has small tanks (like sats or probes), or those who need to be orbiting in LEO a lot of time (because is harder to block the sunlight because you need to change always your angle and also by earth albedo)
Your huge mission with several tons of fuel does not enter in this category, and 450 isp is always welcome.
 

17 hours ago, lobe said:

KISS really sums up my approach to this whole project. Better to launch 5 extra Saturn-Vs than to develop new technologies which need extensive programs to develop.

Yeah hypergolics can be a better choice to leave mars and save the development time for a methane engine, active cooling and ISRU, but if it will be just for ISRU alone, then it makes a huge case to save (5 saturn V no reusable launches), because savatier is nothing of other world, it may take you few years, but the total cost is much lower because all your tanks and engine scale is also reduce, but the methane engine development may take some time.

Landing location?   Take a view on the benefits that a pole landing can provide for a first manned mars mission:
http://www.geoffreylandis.com/pole.html

Edited March 15, 2016 by AngelLestat

[fredinno]

48 minutes ago, AngelLestat said:

The shuttle tank was not really insulated to prevent boiling, it last a lot due its big volume, and we are talking about hydrogen which boiling temperature is 90 degree lower than methane, also the golden rule of volume..  you need a lot of propellent for a mars trip, this require huge tanks, each time you increase the tank radius in a 25%, you double the volume and your surface only increase a 60% (tank cost and surface leak), but other think happens, volume increase by cubic and surface square, so the volume/surface ratio increase a lot, each time you double the volume, the ratio increase like this: 8, 17, 33, 67, 133.    Why this is important?   because it tells you how much energy needs all that mass of fuel to rise few degrees its temperature, so if your tank volume is big, (5 to 10 times the shuttle tank) then it can last years, and hydrogen leak takes a lot of time too.

The missions that needs to be worry about leaks or cryo boling, are those who has small tanks (like sats or probes), or those who need to be orbiting in LEO a lot of time (because is harder to block the sunlight because you need to change always your angle and also by earth albedo)
Your huge mission with several tons of fuel does not enter in this category, and 450 isp is always welcome.
 

Yeah hypergolics can be a better choice to leave mars and save the development time for a methane engine, active cooling and ISRU, but if it will be just for ISRU alone, then it makes a huge case to save (5 saturn V no reusable launches), because savatier is nothing of other world, it may take you few years, but the total cost is much lower because all your tanks and engine scale is also reduce, but the methane engine development may take some time.

Landing location?   Take a view on the benefits that a pole landing can provide for a first manned mars mission:
http://www.geoffreylandis.com/pole.html

You're missing what he was talking about. The Shuttle ET is jettisoned before the Shuttle enters orbit- he's talking about the H2 O2 tanks IN THE SHUTTLE ORBITER to produce power from.

[AngelLestat]

1 hour ago, fredinno said:

You're missing what he was talking about. The Shuttle ET is jettisoned before the Shuttle enters orbit- he's talking about the H2 O2 tanks IN THE SHUTTLE ORBITER to produce power from.

ok. in that case those tank should be well insulated.  But my point for big tanks is still valid. You can find it in literature.