'Historic' Box on Mars Making Oxygen at the Rate of One Tree
https://www.cnet.com/science/space/hist … -one-tree/
Elon Musk tells Chinese state media he wants to build ‘self-sustaining’ city on Mars
https://www.independent.co.uk/space/elo … 45690.html
The Cost of Space Flight Before and After SpaceX
https://www.visualcapitalist.com/the-co … ce-flight/
MarsDirect, chemical rockets in general, cannot be scaled up to provide more than a few small crew rotations and <100 tons of payload every two years... paltry even for a serious science mission. Even using ISPP to produce TEI fuel will be prohibitive because of the size of lander/launcher involved, nor does it solve the travel time/window problem... And no, nobody ever HAS done aerobraking on a 25+ ton vehicle into Martian orbit from TMI velocity, which is vastly different from aerobraking a little few hundred kilo space satelite.
Conventional NTR engines are also roughly "held hostage" to the similar limitations since they are not sufficently more powerful and likly can't use ISPP fuel. Ion engines, too slow. Vasimr, not going to happen any time soon (if ever). Orion? Ummm no... so what is there left? GCNR...
To go to Mars, to really go and to stay, will require somthing better than chemical and MarsDirect... there are no other options except exotic fission engines. No, I still contend that MarsDirect, and lesser powerd vehicles in general, cannot be improved to reach sufficent performance for a real settlement. It can get our boots red, but beyond that it has NO room for growth. If you want to call that "belitting" MarsDirect, then yeah I guess you could say that, because that is what MarsDirect is - Little - The two year window alone is enough to scuttle a true settlement.
And settlement is what we want, right? Science is a peripheral goal, going and living is what we really want... A tiny base with a crew rotation of a dozen or so people and a hundred tons of cargo that can be sent using lesser technologies every two years is all that can be managed best-case and is only justifiable for the science goal, hence, MarsDirect is inherintly a detour to developing technology that is powerful enough. Unless you intend to build the Sea Dragon ultrarocket or somthing, the inherint limitations of conventional technology will prevent larger and faster Mars vehicles from being built. So, a month or a dollar spent on chemical/NTR is a month and a dollar delaying the real mission to Mars... which at the moment, the only technology that is remotely viable for this mission is GCNR.
And this is all assuming that i'm wrong, and Mars doesn't become Antarctica 2.0, where we are content to let little groups of scientists go and risk their necks to "do neat things," which doesn't get colony ships built. And there won't be, either, because the startup investment is too great unless the government pays it, and that means telling Nasa to build a colony, not a Martian McMurdro... No, we wait until we are ready to go to stay, technologicly and politicly.
]]>Another way to get the whole thing paid for is to involve more than one country. If we could get the ESA, the Russian Space Agency, JAXA, and maybe China to pay for some of the cost it would be much more manageable. It would be important to look at good examples of international cooperation, such as the Concorde, not bad examples, like the ISS, as a referance.
Of course, a problem you run into under that setup is that every country wants representation on the mission. That's fine untill you consider that when you have ten (?) people from four different countries speaking as many different languages, you hit a psychological wall. That problem is furthur compounded even if everyone is from only two countries, ie the US and Russia. Then you get people splitting into two sides, in a worse-case scinerio splitting up entirely like the Lenonov and Discovery in the movie 2010. Still, it's not a bad idea for financing.
]]>*I went back through chapters 3 and 4 of _The Case for Mars_; perhaps I overlooked something, but I didn't see information on approximately how many people will be required as Support Staff for a Mars Direct mission. Of course any mission needs round-the-clock monitoring, and I suppose the beginning (launch) and ending (landing) -- either way -- will require the most intense focus. So, I'm wondering what number of personnel will be required to act as Support back on Earth during a mission? Also, can anyone provide an estimate of payroll costs in that regard?
Bill White: "I wonder whether MarsDirect would be better received if Geoffrey Landis took the advocacy lead rather than Robert Zubrin?"
*Aw, poor Dr. Z. I'm not familiar with Geoffrey Landis. Does he have a lot of public speaking and media experience? Not implying Dr. Z doesn't, btw. I have no idea and really can't offer an opinion in this regard.
--Cindy
]]>You would still need to pay people to operate the mission support, and the support costs will probably outweigh the manufacturing costs for the new spacecraft.
*Bill White wrote: "Zubrin may be the most vocal proponent of Mars Direct yet there are many other scientists who agree with much of his plan."
Thanks for pointing that out, Bill. It's good to be reminded that there is support for MD in the scientific community -- by scientists. Also Buzz Aldrin, Carl Sagan and Arthur C. Clarke all gave public "thumbs up" for MD; Clarke wrote a Forward to _The Case for Mars_ as well. That's definitely a nice "nod"! Those names are respected, and carry a lot of clout. Nice to have them in your corner, so to speak. Too bad Sagan's not still with us...I miss his big toothy grin.
Ad Astra, thanks for replying. I may have another question or two (not for you specifically; but of course you're welcome to reply), but need to do a little research first.
--Cindy
I wonder whether MarsDirect would be better received if Geoffrey Landis took the advocacy lead rather than Robert Zubrin?
]]>You would still need to pay people to operate the mission support, and the support costs will probably outweigh the manufacturing costs for the new spacecraft.
*Bill White wrote: "Zubrin may be the most vocal proponent of Mars Direct yet there are many other scientists who agree with much of his plan."
Thanks for pointing that out, Bill. It's good to be reminded that there is support for MD in the scientific community -- by scientists. Also Buzz Aldrin, Carl Sagan and Arthur C. Clarke all gave public "thumbs up" for MD; Clarke wrote a Forward to _The Case for Mars_ as well. That's definitely a nice "nod"! Those names are respected, and carry a lot of clout. Nice to have them in your corner, so to speak. Too bad Sagan's not still with us...I miss his big toothy grin.
Ad Astra, thanks for replying. I may have another question or two (not for you specifically; but of course you're welcome to reply), but need to do a little research first.
--Cindy
]]>In terms of the marginal cost to add more missions, it would be quite small compared to the original development program. You would still need to pay people to operate the mission support, and the support costs will probably outweigh the manufacturing costs for the new spacecraft.
Other opinions on this point?
]]>First, I haven't studied the plan in sufficient detail to come up with a price estimate. However, I do have friends who are working on the ERV design and I will ask them what their estimate is. Even without that knowledge, I'm willing to say that $50 billion is a reasonable estimate for the mission cost. If it was only Zubrin who produced this number, I'd be skeptical. However, NASA also verified this figure in 1993. In 2004 dollars, I'd be willing to say that even $ 70 billion is realistic due to inflation and the government's ability to underestimate costs and waste money.
Could $30 billion be realistic for MD? Possibly, but only if it was done by somebody like Kelly Johnson or Ben Rich, working in the "Skunk Works" and getting people to work in the most efficient way possible. Unfortunately, the Skunk Works under Lockheed Martin is a far cry from what it was under Johnson and Rich, and I doubt we will ever see men of their calibre again.
In terms of the marginal cost to add more missions, it would be quite small compared to the original development program. You would still need to pay people to operate the mission support, and the support costs will probably outweigh the manufacturing costs for the new spacecraft.
]]>Mason envisions membranes refreshing stale air aboard long human space missions, cleaning exhaust from smokestacks and removing CO2 from natural-gas pipelines.
GCNR - - if we skipped research into MarsDirect we never would have seen this potential pollution fighting technologies available for use right here on Earth. This $300,000 grant (issued with the primary goal of making MarsDirect feasible) may well prove a very valuable investment indeed.
The goal of "getting people to Mars" will motivate scientists to be creative and committed and focused and thinking outside the box in ways a paycheck and mere stature never will.
]]>I posted this on December 30th in the Reasons against Mars Direct thread. = IF = membranes work, can't we skip the freezer/wiper blade apparatus altogether, meaning big weight savings, no?
IMHO, Daniel Goldin spread tiny amounts of seed money in lots of right places, and much fruit is being born. Will the current administration do the same?
= = =
supercritical carbon dioxide is another potential "Swiss army knife" for Mars - - I just read a paper about using scCO2 as the working fluid in nuclear reactors. Given its greater density/weight, scCO2 allows the use of substantially smaller turbine blades to generate the same quantity of electricity from the same nuclear reactor.
Such a reactor probably wouldn't work for the unmanned ISPP - - a sealed helium heatpipe system (google David Poston or SAFE 400) may be the leading horse right now - - yet for a more permanent presence, sending a reactor without its working fluid to a manned facility will be waaay easier if its turbine blades are significantly smaller and lighter than needed for a water or helium turbine system.
Using google, I am increasingly satisfied that the pieces needed for MarsDirect are falling into place through the parallel efforts of scientists just about everywhere.
]]>The atmosphere of Mars is 95.32% carbon dioxide. That can be extracted and purified either with a reusable sorbent (absorb or adsorb), or cryogenic cooling. Since CO2 freezes to dry ice at -78.5?C it isn't much colder than Mars ambient at night. Other gasses liquefy at much colder temperatures, such as nitrogen at -195.8?C at 1.013 bar of pressure. This allows you to pressurize a chamber with Mars atmosphere, which will heat it a bit, then hold it and wait for it to cool to ambient temperature. When you reduce the pressure it will cool further; the idea is to cool it below -78.5?C so the CO2 will form dry ice snow. Then use a scraper that operates like a windshield wiper to scoop up the CO2 snow. Compact the CO2 snow with a plunger to squeeze out any air. Then allow it to warm a little to let some CO2 sublimate, and let some gas escape out the top. That should drive out any other gasses and leave pure CO2. Then seal the container and let it continue to warm to sublimate all the CO2, and pump it into a gas storage cylinder. I haven't read Robert Zubrin's paper yet, but it is: Mars Atmospheric Carbon Dioxide Freezer ? Robert Zubrin, Brian Frankie - Pioneer Astronautics
Once you have pure CO2, react it with hydrogen over a catalyst to convert it to water and carbon monoxide. The formula for the Reverse Water Gas Shift (RWGS) is H2 + CO2 -> H2O + CO. Water is condensed out, and unreacted gasses are separated with a membrane and recycled. Hydrogen is then combined with carbon monoxide over a catalyst to form methane: 3 H2 + CO -> CH4 + H2O. Methane (methanol) is condensed to a liquid, and the other products are separated with another membrane. H2 and CO2 are recycled back to the RWGS. CO is vented rather than recycled back to the Sabatier reactor to ensure enough oxygen is generated.
Reference: Mars Methanol In-Situ Propellant Production ? Robert Zubrin, Tomoko Kito, Brian Frankie - Pioneer Astronautics
Water is broken into hydrogen and oxygen via electrolysis. This can be done by running electricity through water with a catalyst dissolved, or the Hamilton Sundstrand built an electrolyser for ISS that uses a proton transport membrane (reverse of a fuel cell). Hydrogen is recycled, and oxygen is pressurized and cooled to liquefy it.
]]>http://www.nw.net/mars/docs/isrudemo.doc
Recommended Follow On Activities
The following activities are recommended to follow up the project reported on in this paper.
1. Further system optimization. In the limited time available for testing on the present system, conversion yields were increased from 68% to 94%. It is the belief of those involved in the project that with further adjustments, yields can be increased to better than 98%. In particular, increasing the amount of catalyst within the reactor vessel, inserting baffles within the vessel to reduce tunneling, modifying the heater system to give greater control over the temperature profile within the reactor, and increasing the reactor's operating pressure, all hold promise for increasing conversion yields. Installing an on-line system for real-time chemical analysis of the reactor output is possible, as the necessary equipment is available at Martin Marietta. Having such a capability would greatly accelerate the rate of system improvements.
2. Further system simplification, thermal optimization, and miniaturization. It is the belief of those involved in the project that significant simplifications and reductions in component masses and system size can be achieved with a moderate amount of additional work. The pressure differential gauge and the condenser coil can both be removed. If the pressure is increased, then the Sabatier reactor can be shrunk, possibly by as much as a factor of 10 in volume. The smaller Sabatier reactor would be a more intense heat source, allowing all supplemental reactor heating power during operation to be eliminated and possibly allowing the elimination of the insulating cover as well. Much smaller flow meters than those employed during this demonstration are also available. If all of these modifications are implemented, we believe that a miniaturized core Sabatier/Electrolysis unit could be built that would be fit inside a bread-box a have a mass of approximately 10 kg.
3. A long duration test needs to be done. Whether with the present or an improved unit, a long duration run needs to be done demonstrating continuous operation over a substantial period, perhaps more than 30 days. This is essential if the practicality of in-situ propellant production for a Mars Sample Return mission is to be demonstrated.
4. A propellant acquisition system needs to be added. The next step is to add a pump or other device capable of acquiring CO2 from a Mars like 8 mbar environment and pump it up to pressures suitable for input into the Sabatier reactor. The pump can then be placed in a Mars simulation chamber, used to acquire CO2 for a combined test with the SE system. Ultimately, such a combined pump/SE system should be subjected to a long duration test.
5. A propellant refrigeration system needs to be added. As a final step in completing an end to end pilot demonstration of a propellant production system capable of supporting an MSR mission, a refrigerator needs to be added to the combined pump/SE system demonstrated in programmatic step 4, above. The purpose of the refrigerator would be to liquefy the CH4 and O2 SE product gases, with all water, CO2, and other impurities removed prior to propellant liquefaction. Ultimately such a combined pump/SE/refrigerator system should be subjected to a long duration test.
6. Complete system optimization. The combined pump/SE/refrigerator system demonstrated in programmatic step 5 will need to be optimized and miniaturized to produce prototype flight hardware.
So now, my questions to my more scientificly gifted betters: We get weight estimations for the insitu production (10kg, breadbox size), what might the overall mass of the final device (pump and refrigerator).
I ask these questions simply becuase any MArs Direct Plan relies on insitu production for the return trip, and for cost savings. There is no Mars show unless we can get this there, and working, first. But not everyone understands things like this.
]]>As a footnote, I was part of a team that was designing and building the first demonstration of fuel production on Mars. The experiment was called MIP, "Mars ISPP Precursor" (where "ISPP" stands for "In-situ propellant production"), and was designed to produce oxygen by the electrolysis process.
Zubrin may be the most vocal proponent of Mars Direct yet there are many other scientists who agree with much of his plan. Tweaking? Of course.
]]>