of the table pg30, which has the lander mass its for 6 crewmen for a 40mT lander, 4 crewmen are in a 20mT with of course anything small thought of as being to small...
pg33 shows the payload down mass and fuel requirements for the lander sizes
The use of beam and cygnus can make for a smaller mass without sacrificing
a 2 person crew needs
Crew Consumables 2610 kg
Science 480 kg
Robotic Rovers 200 kg
Drill 250 kg
Unpressurized Rover 200 kg
wish list
Pressurized Rover 7500 kg
mass may be zero or small depending on options taken
LOX Transfer Cart 400 kg
Habitat 19870 kg
Stationary Power System 7800 kg
ISRU Plant 1230 kg
We need to excavate regolith soil to process for water and its got to fit into current technology landings and power requirements of that down mass payload limitations.
Pioneering Space Requires Living Off the Land in the Solar System
RASSOR 2.0, the Regolith Advanced Surface Systems Operations Robot. RASSOR excavated regolith and delivered sand and gravel to a hopper and mock oven. Making about two pounds of fuel on Mars saves about 500 pounds launching it from Earth to get it to the Red Planet.
So a reduction of launch mass of 250 lb per that we can do insitu on mars by delivering a smart sized payload of a 1 mT package.
This is something that a Falcon heavy launch cost can do now...
So for the remaining of the marco polo lander is the processing to methane all within that landers capability.
You still have 250 tons left. For Mission One habs, we might be talking about two or three habs. I doubt they'd weigh in more than 5 tons a piece as units themselves. The double air locks might add a couple of tons (they don't need to be so robust as the rest of the structure, as they don't have to support permanent radiation protection). So if we had three hab spaces, maybe it would be 5 x 3 plus 2 x 3 = 21 tons.
So, even on that basis you'd have at least 225 tons remaining. Of course I think for Mission One a lot of that will be emergency food supplies, water, medicines and medical equipment.
Regarding hab mass, the only thing I can find to go on are the Bigelow units.
https://en.wikipedia.org/wiki/Bigelow_E … ity_Module
1.4 tons for 16 cubic metres of space.
I think a hab unit for 6 people might occupy 7 x 7 x 3 metres = 147 cubic metres.
Scaling up that gives you 12.9 tons but -
1. I think as you scale up the ratio of tonnage to cubic interior reduces...maybe someone who knows about these things can confirm (it's the elephant principle, they are big which means they can contain more than a smaller animal, proportionally per skin area unit). So if I am right then the 12.9 tons figure would go lower.
2. Bigelow are building for space, not planetary surfaces. On Mars we can reduce the hab mass and load on regolith to give the radiation protection.
My mass figure for a hab - 5 tons might be too low but I doubt it will be above 10 tons. Even if it was 50% more, that's still only 28.5 tons in total, I don't think the double air locks would mass any more.
Happy to have my guesstimates critiqued!
Every watt for a power source or sources, mass gram to metric ton of deliverables to mars matters for survival.
So whats the mass of the safe entrance garage?
Whats the mass and energy needs to make the garage port?
What is the total add ons for a safe habitat to rover connection egress unit?
What is the EVA mass and portable energy needs for operation for the rover for clean entrance system?For a construction or foundary module its only going to a contaminant while in operation, so we close the connecting hatch and give safe haven with in the module for if a mishap occurs. So when the shift is done the equipment is turned of and the atmosphere is check to validate it before opening the connecting hatch.
sending 6 units
with finally human crew of four in 2024
Granted I think we can do better than a ton or two but the landings will be no dragon or skycrane as they are.
The skycrane is a set of canted engines like as the red dragon or crewed version. As I indicated cargo will not need the heavy pressure vessel.
The goal is to use in-situ resource utilization to create more fuel. The teams would take water and carbon dioxide to make liquid oxygen and methane. The carbon dioxide would come from the atmosphere, and the water would come from ice reserves. The team uses electrolysis to split water into oxygen and hydrogen, and uses the Sabatier process to take carbon dioxide and hydrogen and create water and methane.
Yes that will save mass of launch for the outward journey bit also for what we can land that changes the ability to land on mars for a bfr starship.
https://www.inverse.com/article/60133-s … uel-depots
“Depends on total system efficiency & how long the propellant plant can run to refill Starship, so 1 to 10MW as a rough guess,”
Assuming an average of one megawatt over a day and night cycle, this would require a solar array measuring 40,000 square meters.
Error in wattage is what is not a day cycle...as that is the whr and that is not true for solar either as ther is the slow rise to high noon and then the slow fall until night. So no that does not calculate...
Depending on the solar panels in use, Zubrin estimates that an array may weigh around 4 kg per square meter. That would result in a mass of around 160 tons. Each Starship is estimated to carry around 150 tons of cargo, hence the need for multiple Starships.
Ya that is going to be the issue for packaging them into the cargo area as well as for selecting the efficiency of the panels as the mass does not go hand in hand with either material or efficiency as some require mass in framing to make them work as well as to align them.
I have given estimates for volume of just the panels less packaging to protect them.
Zubrin estimates that producing two tons of liquid oxygen and methane every day would need around one megawatt of power. The power figures cover carbon dioxide acquisition, electrolysis, and cryogenic liquefaction.
If the team requires 780 tons of fuel to return home, that means that it would take around 390 days to produce enough fuel to come home, or a year and a month.
Yup energy will go up for the shorter duration being used to manufacture the propellant but what he does not go into is the energys to gain co2, to harvest the ice or the heat required to make the water let alone the filtering of dust and minerals from the water.
Image details are:
5 million cubic km ice
https://www.aqua-calc.com/calculate/vol … lank-solid
1 cubic foot of Ice, solid weighs 57.3713 pounds [lbs] Ice, solid weighs 0.919 gram per cubic centimeter or 919 kilogram per cubic meter , i.e. density of ice, solid is equal to 919 kg/m³. In Imperial or US customary measurement system, the density is equal to 57.4 pound per cubic foot [lb/ft³], or 0.531 ounce per cubic inch [oz/inch³] .
https://www.convert-me.com/en/convert/v … ?u=km3&v=1
25 trillion metric tons co2
http://www.uigi.com/co2_conv.html
Of course none of this is a 1 mT or 2 mT for delivery and that is the issue for building up to a large vehicle.
]]>Musk has previously confirmed that in-house design work on a Sabatier reactor was "pretty far along" back in 2017.
https://www.teslarati.com/spacex-resear … g-on-mars/
Only words I know, but I think it's probably comments such as that which have led me to conclude Space X are probably making more progress on this than we we are necessarily aware of.
Louis,
Tell you what. If we can get a single successful LOX/LCH4 ISPP demonstrator mission under our belt, no matter how much we have to scale up the technology and power to do what SpaceX wants to do, then I'll call it good to go. As of right now, I don't see any mission that doesn't bring the propellant to get home as being a viable plan. At best, it's a crap shoot. SpaceX already has the rocket technology to test this on Mars. If they have the MOXIE, then just do it. Someone needs to stop talking a good game about ISPP and start demonstrating it on Mars. A lab demonstration won't do. We're not sending people to a lab somewhere on Earth. The first crew will be farther from home than anyone has ever been. Their lives are worth the due diligence through realistic testing. I can't think of a more realistic test environment than Mars. If there's not enough money in the R&D budget to do that, then there's nowhere near enough to actually send humans there.
Tell you what. If we can get a single successful LOX/LCH4 ISPP demonstrator mission under our belt, no matter how much we have to scale up the technology and power to do what SpaceX wants to do, then I'll call it good to go. As of right now, I don't see any mission that doesn't bring the propellant to get home as being a viable plan. At best, it's a crap shoot. SpaceX already has the rocket technology to test this on Mars. If they have the MOXIE, then just do it. Someone needs to stop talking a good game about ISPP and start demonstrating it on Mars. A lab demonstration won't do. We're not sending people to a lab somewhere on Earth. The first crew will be farther from home than anyone has ever been. Their lives are worth the due diligence through realistic testing. I can't think of a more realistic test environment than Mars. If there's not enough money in the R&D budget to do that, then there's nowhere near enough to actually send humans there.
]]>The first jet engines wouldn't run for more than 25 hours before they were completely destroyed from the heat generated. There is no war on and getting to Mars before "the other guy" doesn't mean anything if you end up dying there or along the way from insufficient testing. Oddly enough, militaries that wage successful wars seem to be of the same opinion when it comes to using a battlefield as a test facility. In other words, you can think about, but don't do it. There's always some level of experimentation in war time, but betting your life on something working that's never been properly tested is just a really bad idea and an act of desperation, no matter when or where you do it. Furthermore, despite what you claim, cost is entirely relevant to this mission. That's another idea you've constructed in your head that doesn't even seem to agree with what Elon Musk has stated as it pertains to spending a reasonable amount of money to go to Mars.
Regarding timelines, who's timeline are we operating on, yours or the people doing all the development work?
It was about 30 years from the time the first jet engine was used in an aircraft until jet engines had TBO's comparable with the piston engines of the day. Gas turbines are significantly more powerful than piston engines for a given weight, but only at extreme operational cost. The TBO's for first generation jet engines, no matter who made them, were typically 50 hours or less, which meant you spent far more time tinkering with the engine than actually flying the aircraft. While those engines technically "worked", only militaries and major airliners could afford to operate them and catastrophic failures weren't unusual. Modern jet engines are amongst the most reliable power plants in existence, but that level of reliability required approximately a human lifetime to achieve- 70+ years from the first run until multiple technological generations later we had jet engines that would run for years with minimal maintenance (actually spends more time flying than being torn apart).
The V2, whilst being a notable technical achievement, was nowhere near as effective as bombing targets using the technology of the time, if casualties and destruction were any indication- and they were. I'm sure the V2 scared people, or maybe not since you'd never hear it or see it coming, and it even killed people and destroyed some buildings in London, yet had precisely zero practical effect on the outcome of the war. I don't think Hitler or his scientists had any idea about how to actually win against numerically superior forces. It seems more like they were just throwing ideas against the wall, hoping something would stick. That's a recurring theme with creative but disorganized people. If they had any clue about what worked well, they'd not waste a minute of their time on "vengeance weapons". Germany desperately needed effective surface to air missiles to shoot down incoming enemy bombers, which they didn't have because they squandered their limited braintrust / money / resources on ineffectual "wonder weapons", much to our good fortune. Even with as many bombers as we made during the war, there was no way we could match the economy of singular SAM's that could obliterate them. Our bombers were more than 10 times the cost of the few limited production SAM's that Germany did develop. If the enormous resource expenditures associated with the V1 and V2 programs were directed towards SAM's, it's highly probable that both the RAF and the 8th USAAF would've been forced to suspend the bombing campaign against Germany. That would've had a profound effect on the war.
I don't even want to think about what kind of living hell we would've faced if the Germans made half-way intelligent military technology development decisions regarding what tools, tactics, and strategies to spend the most time and effort on. WWII could easily have gone on for 10 years or more. Even nuclear weapons only work when you can deliver them to their targets. Between SAM's, only building survivable twin-engined aircraft, using cheap but very effective assault guns like the "Sturmgeschütz" vehicles, and assault rifles, I don't even think the Russians would've been able to stop them.
The point behind that shallow dive through part of the history of a period of rapid technological advancement is pointing out the logical fallacies that so many people hold towards newer technology, what actually matters, and what doesn't. Reliable transportation matters. Reliable energy sources matter. The advantage conferred by "better" technology is typically limited to how fast or easily something can be accomplished. No revolutionary new technology will be forthcoming in the fanciful world of "tomorrow", especially if defined as the next 5 years, even though future technology improvements could make existing problems easier to solve.
Even though we've known about the Sabatier reaction for more than a century now, we're just now developing the technology at sufficient scale to use it for this particular use case. That normally means there's not much of a practical application for the technology. I certainly hope you're right about normal commercial considerations not governing the technology developed for Mars missions, but thus far I only see governments and civilian corporations to achieve this goal and funding still appears to be as much of an issue as it ever was.
I spent so much time on Lemvig because you keep throwing out "what-if" ideas as though there aren't any practical impediments between the ideas in your head and actualization of those ideas through real engineering. You're the one who brought up Lemvig as if something they're doing is relevant to a Mars ISPP plant. I keep going wherever you want to go, but I also point out all the problems and you keep ignoring them. The V2 is toy compared to what SpaceX is trying to build, so what relevance does a war time program implemented by a country that lost the war have to do with development of the technology required for Starship to work as envisioned? They went to the moon in 10 years, so they should be able to go to Mars in 10 years. That seems to be the "visionary" logic. Then current technological reality rears its ugly head.
It took a decade of development to get Falcon 9 to where it is now and far longer to get Falcon Heavy operational than even Elon Musk thought it would take. Why? In the world of real engineering, it wasn't as simple as putting a banding strap on 3 Falcon 9 boosters and calling it a day. They ended up completely redesigning the rocket's core booster stage. They never thought about strapping 3 booster cores together when they designed it. Oops.
They played with CFRP until they figured out that there was no way for them to meet the cost and timeline targets using a technology that none of them were familiar with- precisely why they hired an independent firm to fabricate and test the giant propellant tank test article. Now they're playing with stainless steel, which once again, they clearly have little idea about how to use. Why? It's certainly not because they're not smart or capable. It's that "operational art" that GW always talks about that you studiously ignore because it's not telling you what you want to hear. Aerospace welding is almost an art form and what you'd do is very nearly as situationally-dependent as it is procedural. There's more than one "right way" to do it, but at least as many "wrong ways" as well. Unfortunately, the only way you begin to understand stuff like that is through experience that you only get after you need it.
In closing, I'm not trying to "divert" to anywhere. I simply stated what would actually be required if we actually wanted to get the ships back because, as Elon Musk has repeatedly pointed out, these things aren't exactly cheap and it's a shame to throw away perfectly good rockets after a few minutes of use.
Could we ever discuss any of these plans in a way that at least acknowledges that current technological reality matters in some small way?
]]>I fully accept the lab scale > proof-of-concept > sub-scale > full scale pattern but I don't accept the overlong timeline.
The Germans developed a jet engine in four years from first proposal. The A4/V2 rocket went from drawing board to effective weapon within 7 years. The Apollo mission to land a man on the Moon took about 7 years from the drawing board. The Hovercraft went from design to commercial service in about 4 years.
These things are really much more fluid than GW's dogmatic 15-20 years. The Sabatier reaction concept has been around for over 100 years. We knew how to build a Fax machine over 100 years ago but it took about 70 years before it came into general usage.
Mission One to Mars won't be governed by commercial considerations. It will be governed by the Mission aims and architecture: there will be plenty of funding available to get it right.
The main processes of the Lemvig project (biogas production) are irrelevant to Mission One on Mars so not sure why you spent so much time discussing them! Rest assured, Space X won't be relying on manure to get to Mars!!
I am happy to stick with an estimate of 1 MWe average continuous power to produce enough fuel-propellant to return one Starship to Earth. Space X are not proposing to return all 6 Starships to Earth - so your diversion there doesn't work.
Louis,
I couldn't help but notice that the target date Lemvig Biogas has set for a 25MW installation of their technology runs into 2035. I can only presume that that's because this is an area of active development for the company. Notice that just as NASA does when they develop a fundamentally new technology, Lemvig started with a lab scale demonstrator, progressed to a proof-of-concept installation, and the next item on the agenda is a sub-scale pilot plant to demonstrate commercial / industrial operation. Additionally, note how the optimal conditions for CH4 production differed somewhat from what the literature stated about what was ideal. That little bit of reality also flies in the face of the assertion that you can learn how to do something just from reading about it. Even a "well understood" reaction such as the Sabatier reaction clearly doesn't blindly follow the "theory" of how it's supposed to work. They still have no clue about how long the catalyst will last in their reactor, either. They also have 2% CO2 in the CH4 output as well, which isn't going to work at all in a rocket when you already have at least that much unusable propellant left in the tanks (knocking 2% off your available fuel is meaningful, hence propellant densification here on Earth) and, you know, that tiny little problem with having chunks of frozen CO2 in your LCH4 tank. All of that stuff is kinda important, even if all you have to do is guarantee a single return trip.
Could SpaceX develop their own Sabatier reactor in-house?
They certainly could, but along the way they're going to discover all these "gotchas" that dictate the actual rate of progress made in complex technology development programs. Lemvig's program spans decades, for example.
Remember what GW said about practical implementations of a fundamentally new technology always being around 15 to 20 years down the road?
Yeah... That. Seems to apply equally to both Lemvig and NASA, despite wildly different technological paths, requirements, and budgets.
So... When NASA says a crewed mission to Mars using ISRU / ISPP is destined for the mid-2030's, I think that figure is based upon TRL of required technologies under active development, not simply the agency dragging their feet. Everything has to work well, failure modes have to be well characterized, and fixes have to be practical and comparatively easy / fast to accomplish.
Everyone,
I want everyone here to take a good look at Lemvig's 2.5MW biogas plant:
Note that tiny looking big rig delivering manure for scale in the lower right hand corner of the picture labeled "Reception Hall".
I want one of our smart guys here tell me how much we have to scale this facility down to even fit inside a Starship, no matter what it weighs. With that, maybe some of you who are not having religious experiences when incredulous plans are offered up as solutions can begin to understand the scale of the problem. One of those steel cans labeled "primary digester" probably weighs more than a fully fueled Starship. Lemvig's "little" facility produces ~2.5MW of power using ~362t of manure slurry and ~75t of compost material per day. Over the course of a year it produces nearly 3,000t of biogas (CH4).
In terms of propellant, 1 Starship requires 1,100t of LOX/LCH4 to make 1 flight back to Earth. Thankfully, only 240t is LCH4. NASA's 1/36h scale propellant requirement demands 52kW of continuous input power, 17kW of which is devoted to regolith mining and drying. In order to actually send all Starships back to Earth to continue generating revenue for SpaceX or sending people and equipment to Mars, we'd need to produce at least 1,200t of CH4 over the course of 2 years. I suppose we might want to keep a spare Starship on Mars, provided we have the tools to use the parts to repair another Starship, but we're talking about constructing something with 1/6th of the production capacity of Lemvig, which remains one of the largest biogas plants in the world 30 years after it was built, for SpaceX to get all of their ships back.
Since we can't source hundred tons of manure everyday to feed into Lemvig's process to produce that methane, nor do we have the rocket technology to ship a 1/6th scale Lemvig to Mars even if we did, that means we'll need to scale the technology down to something that fits on a single Starship and virtually all of the input power and resources for the process must come from whatever technology we bring with us and whatever we can find on the surface of Mars. Incidentally, Lemvig also operates 24/7, not just whenever the Sun is shining or the wind is blowing.
Lemvig Biogas Plant YouTube Video
Most of these biogas plants are at least the size of a city block. The technology does work and it does produce useful if meager output, but the scale of the inputs required is staggering. In Lemvig's case, that equates to 159,505t of waste products per year.