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Couple of points:
1. There are definitely higher grade iron ores on Mars than 20%.
2. "Economically viable" is meaningless on Mars, at least in the context of the early colony. It is also economically unviable to drill out ice from glaciers, transport it in tracked vehicles for use in domestic premises - but that is what we will likely do on Mars.
3. You're not really saying Mars is made entirely of iron are you!? So we will find lot of other usable mineral deposits. Basalt is an obvious one.
1 - Completely unsubstantiated, the existence of small nodules of higher purity is not what matters, it's macro rock fraction iron which matters and we have no indication of high grade ore, but we can be confident of low grade. The highest purity and first resource to exploit is likely to be iron meteorites scattered on the surface but we would not call that an ore.
2 - Economic viability always exists no matter when or where you are, it just varies based on your technology, the logistical difficulty in accessing the site, the scale of the mining operation and what your competitors are mining, a new technology or new deposit can render another deposit not economically viable anymore. Describing an iron ore deposit as low grade is not to say it can not be economically mined, it would be no grade in that case so I think you've misunderstood what grade means here. Obviously over time we would develop a benchmark for what constitutes economically viable on mars for any ore type and this is likely to depend on many factors beyond just the richness of the ore.
3 - I don't understand how you drew that meaning, I said I would be confident that Iron exists in at least earth standard low grade deposits on any terrestrial planet because iron is one of the most common elements in the universe and will always be a significant fraction of any rocky planetoid along with things like silicon, magnesium and aluminum. The fusion process of stars guarantees these elements are the most common heavy elements. But irons super abundance and it's low affinity to bond with silicon means it's basically guaranteed to be found enriched in some rocks up to the low grade level.
MGS had a thermal emission spectrometer. It not only observed spectra, but also thermal momentum. That means how quickly minerals warmed up at dawn, and cooled after dusk. Geologists used this data to determine surface minerals. They found two predominant surface types. Type 2 included 9.2% Fe-smectite (probably nontronite), and 2.2% illite. Type 1 included 9.9% illite, and 2.4% kaolinite! These are types of clay. Kaolinite is white clay, used to make porcelain; it's the end product of a long series of weather steps. They are formed by moving water, cannot be formed at the bottom of a lake or sea or ocean. Kaolinite takes at least 10 million years to form on Earth. It's presence means there were flowing rivers and streams, not just "brief floods". For millions of years. The theory is Mars was warm and wet for a billion years.
That's a low grade iron ore by Earth standards, high grade ore is near 70 percent Iron, the absolute bottom of the economically viable range is 20 percent. So your basically confirming exactly what I said about Iron ore. Iron is the only metal I'd be confident in obtaining on Mars or any other rocky planet for that matter.
Some other sulfide and evaporite type minerals may exist in usable deposits that might be sources of Aluminum, Calcium and Magnesium
Kaolinite needs any water, not flowing water to form and are believed to form in place underground through groundwater action, also it is irrelevant to gold deposits as their would never have been any native gold to erode out into these streams to form a placer deposit.
I think you haven't got the right perspective on Mars mining. There is no reason why on Mars there shouldn't be precious metals at or near the surface. We're not talking about deep mining. If a vein of gold ore is found it can simply be drilled out by hand or a mining robot and then the ore can be processed by flame before being shipped back to Earth.
As someone with a basic understanding of geology I can assure you their are LOTS of reasons to to expect no ores beyond perhaps some low grade iron. Mars dose not appear to have ever had plate tectonics or intrusive granitic rock formations which create nearly all out ore bodies on Earth, gold in particular requires hydro-thermal activity which deposits quartz veins in a parent rock, and placer surface deposits require flowing streams, not brief floods as have been theorized for Mars but slow grinding down of mountains followed by low energy separation of the sediment.
Also their is no such thing as 'flame processing' to extract gold from a raw ore, ore must be pulverized to nearly dust and then separated by a flotation process which requires huge quantities of water, power and chemicals here on Earth. The resulting product is far from pure and requires further processing, but the general rule of all mining is that the first processing steps are the most heavy and energy intensive and have to be located at the mine site and the later steps are less energy intensive and can be at a distance because so much less mass has to be moved.
This is why mining off Earth is so impractical, you need a massive scale at the site to have any hope of competing with production on Earth and the outbound transport to set up the mine will dominate the costs, the retrieved metals value density is nearly irrelevant.
How can private industry achieve remuneration for claim jumping, even if industry got together and created their own claim system and their own system to adjudicate infractions, both highly unlikely, they have no enforcement means. And no they can't do it with contract law, nothing forces a new entrant to the sector to sign up to the regime unless your still on the idea that a launch monopoly is going to be used to bar access, you would be in court immediately for restraint of trade. That's why a state comes in and has to be the one recording and granting claims as the whole point is that the state is on record that it will use force to protect the claim.
Musk's core premise that a colony will lead to transportation technology and then profitable business is ass backwards.
Profitable business opportunities lead to transport tech development, and once transport tech is cheap enough the famous voyages of discovery or colonization efforts are done with the standard run of the mill ship of the day, often RENTED as was the case for Columbus and the Pilgrims on the Mayflower. The existence of the transport technology was never dependent on getting large numbers of people to take risky voyages to discover or colonize a new land, the tech depended on routine freight activity that employed the vast majority of the transport capacity available.
In today's context space travel technology is supported by the routine launch of satellites, this is to our technology what hauling dried cod was to the caravel. That market has already driven the cost of space access down a huge amount and it is the 'forcing function' Musk wants but doesn't acknowledge already exists. We will see space colonized when the gradual improvement and growth of markets make the launch volumes high enough and costs low enough that vehicles like what Musk propose are normal and commercially sound and someone can just rent one for a few tens of millions to go where they want.
Impaler, I'm quite surprised you hold that opinion, given what we've worked on together outside of this forum. Maybe my explanation wasn't clear? By "outside of the international law framework" I mean "not explicitly governed by existing treaties," and NOT "illegal." Contractual agreements have weight irregardless of whether the the subject matter is explicitly regulated or not. E.g. SpaceX can mandate everyone they fly sign contracts entering themselves into a private industry regulatory regime which is able to use regular old contract law to extract remuninations from any signatories that do business with claim jumpers. You could still claim jump, but you'd be effectively cut off from all supply lines. Economic incentives keep this going, not the threat of criminal convictions.
Remember I'm as socialist not a libertarian, the idea that contracts can take the place of actual law is not something I subscribe too, and in fact I consider it a dangerous fantasy.
The situation you describe of SpaceX required some kind of resource extraction claim recognizing clause in order to be flown under the threat of embargo would never work. Presumably the US government not SpaceX is the body granting said claims as efforts are already underway to grant such claims though only US entities are bound to respect them. So this would essentially be a blatant attempt to use a launch monopoly to bind international companies to a unilateral US claims system.
No mining company foreign or domestic is going to invest if their claim is recognized only in the US and enforced only by a temporary launch monopoly from a US company. As soon as someone else gets launch capability, infringement on claims would begin immediately and all of the recognition contracts would be terminated. This idea is not something SpaceX would ever go for, though I can see Congressional Republicans being so stupid as to pass laws requiring that all US launch companies only do business with customers that recognize US claims, the blow-back from that would be incredible and quite crippling to the whole US launch sector.
The Outer Space Treaty prevents the direct application of existing mining claim laws, since those depend on states claiming sovereignty over the land itself. However this could be maneuvered around in either of two ways. First alternative, by pushing for new international treaties under the UN, in the same manner as the International Seabed Authority was created. This has a lot of downsides however, as shown with the ISA, in that it is likely to become politicized and the goals perverted in order get ratification from the major players. Second, direct contracts between launch and equipment providers could be used to bootstrap a mining claims registry that exists outside of the international law framework, but is effective nonetheless. It could later become international law untouched once its effectiveness is established.
The latter approach is my preference and it works today, thanks to the existence and market dominance of SpaceX. It was also a business model I was working on until recently, and would be happy to mentor anyone who wants to take it up.
Their is no such thing as 'exists outside of the international law framework' and 'is effective nonetheless', these are mutually exclusive terms.
The strategy of a Internationally recognized claim granting organization is the only feasible means to entice investment in resource extraction. The history of the ISA proves this beyond a doubt, the US tried to run it's own unilateral claims and without any international legitimacy it just stagnated the whole field, including the ISA claims being developed because industry didn't want to jump until it knew which claims regime was going to be the winner, in essence it was https://en.wikipedia.org/wiki/High-defi … format_war all over again.
No framework created unilaterally would be functional due to the OuterSpace Treaty, as signatories nations can't make or recognize any other nations claims so no set of reciprocal recognized claims between the leading space-fairing nations could be created, that was the point to prevent the super-powers from carving up the 'new world' between themselves and locking the rest of the world out.
Like it or not the rest of the world is going to get a say in how space resources are collected and distributed. SpaceX is not Americas ticket to do an end run around the OuterSpace Treaty, it would be bad for their business and I'm sure Musk would resist it. The very notion that treaties are to be dispensed with once one is in a position of power is an anathema to the very idea of the rule of law.
I'd say conventional chemical rockets are just 100% plain engineering now as we all the physics involved now, their was hardly any science in rocketry by the Apollo ere, though arguably their was still a lot of 'Art' in it then even that is largely gone.
One last thing anyone who loves NTR should read, this ENTIRE thread from NSF, http://forum.nasaspaceflight.com/index.php?topic=1139.0
Here he have a REAL NASA Nuclear Engineer who went from being an enthusiast for NTR to being highly skeptical after he looked at the numbers.
The specific impulse numbers that are achievable with SEP are achievable by accelerating V-E-R-Y S-L-O-W-L-Y. So slow that it extends the duration of a manned Mars mission to more than two years and provides for a stay of less than a year on Mars. These numbers come from NASA, Boeing, and every other proposal I've ever seen. Maybe they're all lying because it doesn't support your argument or maybe, just maybe they're trying to tell you something. When higher thrust is utilized to accelerate faster and reduce transit time, the specific impulse drops to numbers that are less than those that would be produced by an advanced NTR.
Are you completely incapable of understanding that duration is dependent on THRUST to MASS ratio, not ISP?? We can make a SEP thruster that is ~1.5 kg/kw and Solar is running 3 kg/kW right now (both easily cut in half with future improvement by the way), so for 4.5 kg and 1 kw you get 25-70 mN (5.5 mN/kg - 15.5 mN/kg) depending on ISP choice (remember HALL thrusters are variable now) variable from 1300s to 5000s. The ISP choice determines your propellent FRACTION. The ACCELERATION determines duration.
To get to Mars in 180 days from ESOI you only need ~1 mN per kg providing 1 mm/s acceleration rate and a total DeltaV of 15.5 km/s. Propellent mass fraction would range from 25% - 70% depending on the ISP, so we have PLENTY of room to pile on propellent and payload and still have the desired transit duration. The sweet spot looks to be at the higher end 5k ISP, 5.5 mN/kW, 1 mN/kg, ~25% propellent, ~18% propulsion hardware, 55% payload.
Most SEP designs are going to go either very slow or very fast, because people fall into two camps, "slow-and-lots-of-payload" or "fast-light-avoid-the-radiation" we don't know which solution is the right one yet. SEP can go slow or fast depending on how you size the system so people who are in the slow camp who hope/assume radiation is no problem will go as slow as human factors allow. But if your in the fast camp then you just use a lot of juice and go super fast with SEP, at 10 mm/s acceleration you can go to Mars in 50 days, current systems only barely have that kind of acceleration even without propellent or payload so these uses of SEP are far more speculative. They ARE the fair comparison case to NTR considering that both would need further development of already mid TRL level tech. Their is simply no comparison with GCNTR as it is so much lower TRL.
louis: You said you want to maximize ISRU, but your also calling for just landing on any random flat piece of ground. This is contradictory, if you want highest utilization of local resource you must prospect for them.
The 'any flat ground' is the kind of landing site that a mission without ISRU would be aiming for, that was basically what Buzz was looking for on the moon, a spot to land the vehicle everything else be damned, they did not stay long.
Basically the longer you intend to stay the more investment you should be making in picking the spot. I think lots of people *cough* MarsOne *cough* are so impatient to 'colonize' that they neglect the due diligence necessary to make such a thing happen.
Also with respect to our robotic missions having acted as scouts, they have barely scratched the surface when it comes to identifying resources needed for colonists, nor have they tested the effectiveness of resource gathering technology on specific sites. We will need to establish both that a resource exists at a site AND that our technology can effectively extract it before we would commit to colonizing that site.
Ideal location: flat ground, low altitude (more atmosphere overhead for radiation shielding), close to equator (warm), plentiful water, iron (hematite is easitest to smelt), aluminum (bytownite is common), white sand (for glass, the only deposit found so far is a cup-full), thorium (nuclear fuel), and potassium salts (greenhouse fertilizer). That's a lot of stuff, and conflicting. The best location so far is Elysium Planetia; it has everything but thorium. Thorium appears to be at high altitude, dry locations.
Actually 15 degrees north of the Martian Equator is the optimum solar latitude, the total solar irradiance over the Martian year is highest AND the most constant, basically all the features we associate with the equatorial sun zone on Earth are moved ~15 degrees North on Mars due to the eccentricity of it's orbit. As we know Mars is wettest at the North pole and dryer towards the equator we would likely compromise somewhere between the pole and the 15 latitude to balance warmth/wetness, but we would never go south of 15 degrees.
If I'm a nuclear ideologue then you're most certainly a solar ideologue. Most of your posts in this thread have started with how stupid I am or how wrong I am, but then fail to provide evidence about why what I proposed won't work or how it's inferior to solar electric technology. If you have any cogent arguments about why what I've proposed won't work, I'd love to know. Apart from lots of adolescent insults, which may be all that you have to offer, you've proven spectacularly incapable of providing anything approaching a technical argument about why nuclear technology is inferior to solar electric technology.
Every single post I've made has pounded you into the ground on technical details, we have been over Specific Impulse, power density of solar panels, payload mass fractions, initial mass in LEO. To say I haven't provided any technical argument is THE BIGGEST LIE YET from you.
I'm not advocating for the replacement of your favorite technology, just the development of a complementary technology that doesn't require an external energy source to function. Wouldn't the fact that I kept writing about development funding for SEP tugs for Mars bound cargo indicate this, or did you ignore those parts of what I wrote because it doesn't support your sophomoric argument about my bias against solar technology?
Your arguing for a massive multi-billion dollar research effort that will replace the current NASA program whole-sale. You need to justify that kind of expenditure by showing that it is superior to any alternative and I've shown that it is markedly inferior instead. Thus your arguing for money to be thrown down a rat-hole and I'm going to oppose that no matter who's backside the money is coming out of.
Van Impe, my solevangelist friend, your repeated attempts to ignore what Boeing has in their presentations is what's blatantly dishonest.
The transit times are in Boeing's presentation and are transit times from/to EML2, not LEO.
Boeing wants to put a 130t SEP tug into LEO. There is no launch vehicle capable of putting something that massive into LEO and short of using liquid boosters (redesigning SLS and redesigning the launch facility accommodations) or addition of another RS-25 to SLS (redesigning SLS), there won't be one in the next 10 to 15 years, either. Read the first part of the previous sentence and let that sink in.
Even if this SEP tug that Boeing wants to build to send humans to Mars was available today, it wouldn't matter because there's no rocket capable of launching it.
The SEP tug, less propellant, could be launched on a F9H. The propellant mass is above current SLS capability. It requires SLS Block IA.
Boeing's proposal requires fewer SLS launches than DRM 5 due to the absence of one cargo mission, use of inflatable heat shields, and refueling of the SEP tug at EML2.
WOW, Boeing actually made a plan on a piece of paper to USE the vehicle that is the current NASA official goal to create. That sure is a lot of unwarranted faith in THEMSELVES to be able to build it don't you think?
Oh and it's not ready to fly this bloody second either?? Did it ever occur to you that this Boeing plan is perhaps INTENDED FOR THE FUTURE, you know when NASA said they were actually aiming to go to Mars? Now I know your a smoking that Zubrin pipe that says we 'SHOULDA' been on Mars in oh around 1875 or some junk but in the real world things like landing more then 1 ton on Mars and having remotely closed loop life-support are real barriers that can't be glossed over.
Seriously you are absolutely insufferable, it takes decades to develop space vehicles and planning and thinking about how to use them before they are ready to use it the only prudent thing to do, one of the biggest problems with SLS is we DON'T have payloads for it, now you want to rule out even THINKING about payloads of 130 mt until the vehicle is their waiting on the launch pad? That is a guaranteed way to never use the capacity created.
Forgive me, but did you just post a document where the author recommended the development of advanced nuclear power technology?
No, that would be your desperation speaking, the VASIMIR folks want power at high density, they look at literature on potential solar and nuclear power in terms of theoretical potential and are indifferent as to which ends up providing it. They are not power system experts and can be forgiven for not being well informed about the relative costs to develop these systems or the current state of the art. People who are actually developing Electric propulsion vehicles do not waste time on nuclear fantasies.
You're using an argument about the theoretical potential of SEP against the theoretical potential of NEP or NTR.
Dose an apples-2-apples comparison frighten you? The fair comparisons are theoretical potentials to theoretical potentials, or current systems to current systems. I've done both and you've been crushed both ways and even the grossly unfair comparison of nuclear theoretical potential to SEP current systems the SEP system is basically tied. I make that intentionally unfair comparison simply to demonstrate how inferior your position is, yet you refuse to see it.
kb: As usual everything you say is flat out wrong, you have clearly not even read the material and simply have the idea stuck in your head that Nuclear is superior in every way and in every application to "dirty hippy solar", your rantings on Nuclear power not getting used on Earth (which have zero bearing on in-space use) show that your nothing more then a nuclear ideologue who is trying to re-fight that battle in a new territory, one you haven't done the slightest research in.
And by the way your '20 years ago' was 1994, any one who could not extrapolate Mores law (which had been roaring along for 20 years already) out another 20 years to reach to obvious conclusion that YES your phone would be hugely more powerful then a server would have been a FLIPPING IDIOT. Just as someone today who has ANY doubt that SEP are going to continue the relentless advances they have made in the last 20 years after the technology come to the west. Conversely people who think a dead technology like NTR, aka trend line of ZERO improvement in 30 years is going to suddenly and for no compelling reason take off would be just as foolish. While you TALK about huge progress potential you show your naked bias by saying you 'hope' SEP advances, while having blind-faith in all things Nuclear.
For specifics, as Terraformer points out you DO NOT TIME FROM LEO TO LMO, your repeated attempts to define this a the goal is blatantly dishonest. You send the mission hardware and/or habitat ship to High Earth Orbit first and then send the crew up to it by a taxi capsule crossing the Radiation belt at speed as has always been done. The crew needs that capsule for return to Earth surface ANYWAYS irregardless of the main propulsion system so it is not a disadvantage vs any other main propulsion system. THAT is what Boeing proposed in the mission concept on the FIRST POST, so your apparent ignorance of this indicates you haven't even read that. Second this proposal has SIGNIFICANTLY reduced SLS launches over NTR DRM5 as I already pointed out to you, again you are simply spewing bullshit when you say that SEP doesn't reduce launch mass.
I disagree with Terraformer that gravity assist can reduce transit times to 3 months even from EML1, I think he is confusing gravity assist with oberth-assisted impulsive burns. I've read that three impulsive burns at EM1, Lunar flyby and Earth flyby totaling just 1.2 km/s can send one on a good 6 month transit to Mars, a big savings from doing 4.4 km/s for the same thing from LEO. But 3 months would take considerably more DeltaV then that and I don't think that gravity assists off the Earth itself can be done quickly enough to be useful for human missions (robotic missions needed years of time to do multiple flybys).
Remember HOW LONG YOU TAKE TO REACH EDGE OF EARTH SPHERE OF INFLUENCE IS IRREVERENT TO HELIOCENTRIC TRANSFER TIMES, but climbing the Earth Gravity well is NEARLY ALL OF THE DELTAV of a slowest Holman transfer. We can go slow and efficient inside the Earth Sphere of influence and switch to faster but less efficient propulsion for the Heliocentric transfer once the crew is on board.
Thus the total DeltaV between 6 months and 8 months transit is VERY small, it is only when you try to go below 3 months that DeltaV starts to get really hard. We can do 6 months with SEP with 5k static ISP and a SEP system (solar and thrusters) totaling just 80 W/kg, or using the 'alpha' spec common in SEP system design which is 12.5 kg/kW. And that is COMPLETELY within current technology, our HALL thrusters and power processing units combined are 2 kg/kw which leaves the Solar a full 10 kg/kw, which is a pathetic 100 W/kg, ROSA array already beats that. And both of these numbers are going to keep improving, but basically we can do a transfer of that duration now if were willing to have a SEP hardware mass of around half the total vehicle mass with payload around 25% using these SANDBAGGED numbers and off the shelf components, that's 'ugly' by SEP standards (but normal by rocket standards) and their is so much potential improvement it would be wasteful to do such a mission now, what will happen is that we will do another decade or two of development and end-up sending vehicles that are 10-20% hardware mass and >50% payload. All the other systems like EDL and life-support are at least that far away from being completed anyways.
This is Ad-Astra's mission to Mars trajectory plan, applicable to any SEP as they have numbers for fixed and variable ISP
http://www.adastrarocket.com/Andrew-SPESIF-2011.pdf
Here are the numbers on current alpha and ISP values of thrusters
http://enu.kz/repository/2010/AIAA-2010-6771.pdf
Basically where SEP is RIGHT BLOODY NOW, is already competitive with your nonsense Nuclear HIGHEST THEORETICAL POTENTIAL, but SEP has not even scratched the surface of it's theoretical potential. When we start talking highest theoretical potential of SEP the transit times are 1 MONTH, which I pray we don't ever NEED because it's terribly wasteful of payload fraction and we should send more payload to help mitigate radiation and other dangers and in general enhance the surface stay.
The first people will NOT be colonists, that is pure Mars One fantasy land. Even if we had ALL the necessary systems, technology and vehicles (like SpaceX Mars Colonial Transports capable of hauling 100 people at a time to Mars), we would STILL not have the first people on Mars be colonists. They would be SCOUTS to find the most desirable colony location. Plopping yourself down on the first place you find at your destination is ALWAYS the wrong move at any scale, all the way from backpacking to crossing an ocean to crossing space.
You keep throwing out this TRL9 term to describe technologies that don't seem to quite measure up to NASA's standard for TRL9 technology.
This is what TRL9 means to NASA:
TRL 9 Actual system "mission proven" through successful mission operations (ground or space): Fully integrated with operational hardware/software systems. Actual system has been thoroughly demonstrated and tested in its operational environment. All documentation completed. Successful operational experience. Sustaining engineering support in place.
VASIMR isn't fully integrated with anything, has never been demonstrated in its operational environment, and there have been no spacecraft propelled with VASIMR technology, successful or otherwise.
Your attempt to nitpick is as tiresome as always. Hall and Gridded Ion are TRL 9 which is what I am referring to when I say SEP, aka CONVENTIONAL SEP, If I am talking about something unconventional like VASIMIR I will call it out specifically and never said VASIMIR was TRL 9. As the words 'Solar Electric Propulsion' can be satisfied by any combination of any solar power and any electric propulsion system and their are NUMEROUS concepts for both solar collectors and electric propulsion out their at a variety of TRL's so any twat can come up with a combination of thouse two with any arbitrarily low TRL like concentrated solar-steam engines running a Mach-effect reaction-less drive (a piece of complete nonsense that violates conservation of momentum, TRL 0), thus what I say SEP is TRL X, the only sensible interpretation is "the current highest TRL of techs under the SEP umbrella is TRL X". VASIMIR is TRL 8, it just needs the in flight test as the system has gone full ground testing. And again Solid-core NTR is 5-6 (generous) and Gas-core is 1, simply no contest.
I do not even think the VASIMIR concept is going to prove decisive or perhaps even viable in the marketplace as it is getting left behind by improvements in conventional SEP and it's features set of variable impulse and variable propellents are just not particularly unique given whats happened with HALL thrusters lately, someday VASIMIR might be picked up when we start to max out the capability of HALL but that will be a while.
RobertDyck wrote:why?
Why does funding have to be available for SEP tugs or why do we have to kill other programs to fund SEP tugs?
You do realize the SEP is already funded and in development, no other program had to DIE for it because it's costing a pittance compared to what your proposing. The fact that you need to kill SLS and Orion and take it's WHOLE budget to get your Nuclear fantasy off the ground just shows have utterly unrealistic it is. That SLS/Orion money is unfortunately lost to any useful purpose due to congress (not NASA stop harping on them for having their hand forced). But if by some miracle that money were available to redirect to other uses it would better go to the aerocapture, ISPP, life support trinity that was just mentioned as KEY must have technologies.
kbd512 and Impaler: SpaceNut asked you to simply agree to disagree. Your constant bickering is annoying. Neither of you will convince the other. But I do have to take exception to one point:
Impaler wrote:in a variable specific impulse system you can trade off between thrust and ISP, but you can also just add more electric power to get more absolute thrust which keeping your trip times up. 'Low gear' aka high thrust and low ISP for current thrusters is still in the 3000s range which is bloody fantastic compared to NERVA and as good as your pixie-dust coated fantasy of GassCore NTR.
The only engine capable of variable specific impulse is VASIMR. That's an electric engine, it doesn't matter if electricity is generated by solar or nuclear reactor. But the important point is this is "pixie-dust coated fantasy". VASIMR has never demonstrated the ability to do this. VASIMR is about as "ready" as gas core NTR. To be fair, VASIMR has demonstrated one single Isp using Argon gas and 5000 second Isp. They claim "First stage operation with krypton was also demonstrated in 2012." However, their paper does not quote Isp for that propellant. There is no work at all with LH2.
http://www.adastrarocket.com/AndrewIEPC13-336-Paper.pdf
Wrong, latest Hall thrusters are able to varying Impulse as well, the range is not as large as VASIMIR which is specifically designed to maximize that aspect but it exists and it not something fundamentally limited to the VASIMIR concept. Also your caracterization of VASIMIR as equal TRL to Gass-Core is absurd, they have working VASIMR units being tested in vacuum chambers, it only needs to be validated in space to be TRL 9, while GCNTR is a TRL 1 concept with no idea how it would even be built with materials that don't even exist yet. Your giving kb a race for greatest intellectual dishonesty here.
- These vehicles require a SLS launch of their own because they're so massive and those launches cost more than a STS launch
- Burns that reduce the trip time to 6 months dramatically lower the Isp of the supposedly more efficient electric thrusters
- There is no comparison whatsoever between what a kilo of enriched Uranium yields in energy output and a solar panel that operates at theoretical maximum efficiency; no amount of efficiency improvement is going to make solar technology more efficient than fission or fusion
- The drag produced by these enormous solar panel arrays would bring a SEP tug down in days if we do assembly in LEO or require burning propellant to maintain orbit
- Massive increases in surface area increase the risk of the vehicle being struck by space debris, both in LEO and in transit
- No alternative means we're stuck with a technology that doesn't operate efficiently in places beyond Venus or Mars
- When SpaceX produces their Raptor based Rocket it will certainly supplant the SLS, if SpaceX doesn't produce this rocket we are not going to Mars so their is no point in fixating on the launch vehicle other then to specify that it is in a particular size class.
- Again you speak out of an appalling ignorance of SEP, in a variable specific impulse system you can trade off between thrust and ISP, but you can also just add more electric power to get more absolute thrust which keeping your trip times up. 'Low gear' aka high thrust and low ISP for current thrusters is still in the 3000s range which is bloody fantastic compared to NERVA and as good as your pixie-dust coated fantasy of GassCore NTR.
- Actually their is a comparison, the fuel pellet in a nuclear reactor have a heat output 20,000 - 30,000 W/kg Thermal, only 8-15x the theoretical maximum of thin-film-solar. But of course by the time you actually contain them within cladding rods and coolant flows and the like your looking at substantially lower density for the whole thing and these parasitic masses for Nuclear are vastly high then the parasitic mass on solar which is basically a rod or mast to hold the film. What matters is the system level performance, not machismo chest thumping about power density in some tiny portion of the whole system. If you want to look at life-time energy output then Solar is likely to come out ahead because nuclear fuels last less then a year before needing reprocessing while solar systems can operate for decades thus yielding more total energy as they are COLLECTORS rather then fuels and are not limited by their own mass. A NTR is actually even worse then a nuclear power plant because as a high thrust system it operates for only a few MINUTES before it's out of propellent and has to be shutdown with control rods, thus it ultimately imparts LESS energy into it's propellent and wouldn't you know it, LOWER ISP results from lower energy (who would have imagined!!!). When you actually do the math nuclear is pathetic.
- Again your pathetic concern troll falls flat, if we are assembling a SEP vehicle we won't deploy the panels until were going to depart, or we will simply rotate the panels edge on the atmospheric drag and largely eliminate it. Only when we go to thrust do we need to orient the panel to the sun and incur drag when that angle happens to be broadside to the atmosphere. We can easily calculate the drag force at altitude and know how high we must be to escape the drag, it works out to about 300 km for most SEP system, they would have over a month before orbital decay at that altitude with panels deployed.
- Solar panels on EVERY single object in LEO are struck by debris all the time, including the huge panels on ISS and it has not destroyed it. With modern thin-film solar the damage from such impacts are likely to be even less severe as they just poke clean holes right through it. Their is also no risk of being hit 'in transit' as in actually flying between Earth and Mars, space that hasn't been polluted by humans is in fact mind blowing EMPTY, being hit by meteorites in space is a science-fiction plot device not something that has any statistical likelihood of happening regardless of the size of the vehicle, even in LEO where all that space junk resides it is still fantastically empty. The core vehicle obviously has the same risk of being hit as any other vehicle and is a wash.
- SEP is good at least to Jupiter before solar power becomes too weak. But even then we either use Nuclear powered electric propulsion or do something like plunge inward toward the sun and burn our propellent rapidly in a Oberth maneuver to slingshot ourselves into the outer solar system and use a ballistic capture at our destination planet (getting back might be tough though). In any case your argument that we need to develop NOW a propulsion system that only going to be used for a trip to Saturn is laughable, Mars is the most aggressive destination currently under consideration for 'next' and it is unquestionably the limit of our technological reach for all the non-propulsive aspects of a mission and or settlement and may even be beyond it. Your simply grasping at straws here to try to come up with something to slander SEP with, you might as well say we should put ALL our money into anti-matter drive so we won't be 'limited' to destinations within the solar-system.
Are you truly going to stand on this ridiculous sunk-cost fallacy? That all the money spent in the past to develop solar should be added up and used decide if future investment is justified? Will we add up all the money ever spend on Nuclear technology as well? Past costs for every technology are irrelevant, we should only ever look at the future costs and the future additional benefits thouse investments will bring. This is a WELL established principle which better economists they both of us came up with, if you are not capable of understanding it then you have no business making ANY kind of decision involving money PERIOD.
Frankly your arguments have been one of poorer defenses of NTR that I have seen on this forum. Other NTR proponents at least know something about SEP, and stick to basic NERVA types systems without going into fantasy land Gass-Core stuff. This entire thread has been pearls-before-swine waste of my time as it seems every NTR advocate has a cranium capable of shielding them from not only from deadly neutron radiation but facts and reason as well.
Fortunately NASA make the right choice in the 1990's to commit to SEP and to drop Nuclear like bag of kittens into a river, we have been on that development track now for 20 years and it's an unstoppable freight train of fruitful development that is not going to stop. Instead it is going to open the solar-system to larger and larger probes and eventually manned missions BLEO. But I expect even THEN dolts on this forum will still be pining their hearts away on Nuclear fantasies.
Didn't they already? Or are you saying that Orbital also made some solids and now the merged company has all solids under it's control.
By 'Da Stick' do you mean Ares I or the 'Liberty' concept. I'd think the Liberty thing has a better chance of coming back as it wouldn't need to lift the bloated Orion. Or maybe some kind of large Cygnus on the end of a a SRB though is even more likely, putting a man on the end of the fire-cracker is just not safe.
Calling people names isn't a form of argument, it's just a personal attack. Could development of a GCNR be expensive? Yes. Will it be dramatically more expensive than any other advanced technology that mankind has developed? If history is any indicator, probably not. It won't be done on feel good funding, though. Let's put it that way.
All historical evidence says just the opposite, you are clearly basing your opinion on personal wishes and desires and not actual evidence.
Your argument is that development of GCNR will be extremely expensive and, as you continue to note, it isn't available right now. The reason it isn't available right now should be fairly obvious. Nobody is working on the technology.
NOBODY is working on it BECAUSE it is expensive (AND pointless) not the other way around, think about that for one second, Russia has absolutely no qualms with nuclear technology but they aren't doing it. Instead EVERY MAJOR SPACE AGENCY is putting money into SEP. Do you really think that NASA, ESA, JAXA, Roscosmos are ALL stupider then you?
An enormous magnet is not necessary if you can direct and intensify the magnetic pressure generated. Alvaro Sanchez, from the Autonomous University of Barcelona in Spain has done some ground breaking work in development of this technology.
Site it and give me some kind of estimate.
Solar panels and SEP technology didn't leap into existence with NASA funding ten years ago. Aerojet-Rocketdyne put the first electric thruster on a spacecraft more than thirty years ago. Many billions of dollars have been invested in solar technology and electric propulsion for spacecraft and rightly so. I see no reason whatsoever to discontinue funding. SEP technology is quite useful if the period of time in space is measured in years and maximum efficiency is more important than how fast you get there. The highest efficiency electric thruster flown to date was, I think, on JPL/NASA's Dawn mission. IIRC, the thruster's efficiency was quoted as being around 3100s.
As usually you are utterly ignorant of the technology your criticizing. Dawn was launched more then 10 years ago and we have had whole generations of thruster tech between then and now. The NEXT ion thrusters which completed 5 years of endurance testing in 2010 gets 4200s while being having higher thrust:weight. Hall thrusters running on Krypton are hitting ~3000s ranges and will likely start to take over from gridded ion thrusters going forward because their better thrust density and ability to throttle across a wider range of ISP, the ARM mission would likely use them. Also efficiency in a Electric thruster has a meaning different from ISP (in fact it is sloppy to ever use efficiency as a synonym for ISP in regular rockets), it means the percentage of electrical energy converted to kinetic energy and it is around 50-70% for most thrusters and rising as technology improves.
The highest theoretical limit of efficiency for a gas core NTR was calculated to be around 6000s with a core temperature around 100,000K. I think 3000s is achievable. NTR efficiency centers around how fast you can accelerate the propellant through the core with the thermal flux provided by the fissioning core material. NTR efficiency is not a SWAG on the part of the engineers who were involved with Rover and NERVA, it was determined through actual testing. Whether it is practical to approach the limits of the technology has a lot to do with materials development and the size of the reactor. A reactor the size of a house is obviously a non-starter for space propulsion applications.
Your 'think is achievable' seems to be nothing more then chopping the first number in half, it's baseless speculation on your part. Your continuing to pretend that NERVA somehow validates Gas-Core, they are RADICALLY different and the Gas Core is orders of magnitude harder. NERVA operates at ~850s ISP and completely in the range of NORMAL ROCKET TEMPERATURES. Gas Core would push material science into unknown territory to contain the temperatures AND pressures to achieve these theoretical numbers, because these numbers assume no barriers imposed by materials being slagged.
I think a lot of the work performed in NERVA is relevant and applicable to GCNR design and there's no need to reinvent the wheel to prove that we know what we know. NASA is spending what precious little money it does have to try to recreate the fuel elements used in the NERVA engines.
Again your so called thinking here is dead wrong. And as for making fuel it's actually the DOE that's doing that, but it is fuel for RTG, not the stuff that would go into NERVA, these RTG fuels don't get anywhere near that hot.
As far as testing is concerned, it can be done underground. The US already stores nuclear waste underground in rather expansive facilities. So long as we're not overly concerned with nuclear waste becoming contaminated with radiation if there's a containment breach, I would perform testing there.
Underground might be cheaper then launching, but it won't be CHEAP. You need to have a cavity capable of holding all that exhausted gas which is absolutely huge.
An honest estimate of what a transition from gas powered motor vehicles to electric powered motor vehicles would cost should not ignore the many billions expended to develop internal combustion engines, the billions spent maintaining them, and the billions spent making them more efficient so we're not all choking down the exhaust fumes. Every new technology has up-front costs. Many billions of dollars have already been poured into research for the technologies required to make SEP a reality and it didn't happen in five, ten, or even twenty-five years. The SEP tech doesn't exist in a neat vacuum where only the cost of some small portion of the overall development effort should be considered.
Oh brother a sunk-cost fallacy, your really embarrassing yourself now. All costs in the past are GONE, UNRECOVERABLE, IRRELEVANT. We make all decisions on future actions with the world as it currently is as a given, if a million dollar project $2 from completion and and a $1 alternative appears you cancel the incomplete project and save $1. Yes billions have been spent on Solar technology, and millions on electric propulsion, but ALL of thouse costs are both irrelevant now AND in fact thouse costs already payed for themselves a hundred times over in making ALL OUR CURRENT SATELLITES possible which provide services every year valued at over $100 BILLION. All that matters is the MARGINAL costs to get the next generation improvement and the benefits of that next generation vs the marginal costs. This is why these technologies are still being developed, their benefits are huge and the costs are less then the near term benefits. Any alternative propulsion technology is going to need to compare it's full costs vs the marginal costs of improved SEP, this is why Nuclear is never going to happen, it's decades behind and falling further behind every day.
Do you work for a company that sells solar panels or electric thrusters?
No, I just know how to judge technologies rationally.
Did everyone at LANL have their brain fall out of their head recently? I stated that men with far less than what we have to work with today developed nuclear rocket propulsion from scratch. With all of our advanced technology and computational capabilities, are we somehow utterly incapable of creating a fission reactor and flowing hydrogen through it?
Typical space cadet straw-man, I've said it can't be done cheaply and your exaggerating that to 'impossible to achieve at all'. I have said repeatedly that it COULD be done just that it will be gawd awful expensive. Stop trying to put words in my mouth.
No, they didn't just have to fuel a rocket and launch it, but to pretend that there was or is some sort of absolute impossibility to picking up where we left off is just silly.
Again your trying to turn my critique of cost in to a proclamation that the technology cant be developed at all. How can a person be this dishonest?
Yes, we're spending billions to re-invent Saturn V using inappropriate hardware and the result is a rocket that can't even throw an orbiter into LEO. If we think nothing of spending billions to re-invent what we had four decades ago, in terms of chemical rocket throw capability, then we can damn well spend some money on something that has long term payoff and permits us to explore virtually all of the solar system. Stop with the Wikipedia nonsense. The information I have comes from the papers published by the people who worked on the technology.
Then site your sources, give me some links to real technical papers.
We could use a huge magnet. Or we could use technology that permits us to direct a magnetic field… Muchas gracias, Alvaro.
What part of huge mass killing thrust:weight ratio did you not understand? How dose 'directing' a magnetic field reduce the mass? Are you simply grasping at random words to avoid acknowledging this problem? Do you have even the slightest idea what your talking about?
No advanced propulsion technology has ever been "cheap" to develop and this solar electric propulsion that you so love is not an exception to that rule. Many billions of dollars have been invested in the technology and that is the only reason it works as well as it does today. Rather than blowing money on unnecessary make-work projects, like Orion/SLS, I'd rather see NASA actually develop a technology that permits us to explore all of our own solar system, instead of just the parts that are close to the Sun. In finance, it's what you'd call a long term investment. It requires enough wisdom to accept that there will be a tomorrow. Apparently you think it's too difficult or maybe you can only focus on what's right in front of you. I, for one, am quite thankful that those who came before us did not give up simply because a particular problem was difficult or expensive to solve. Few things worthwhile are simple, cheap, or easy. There is such a thing as squandering money and opportunity, though. That is what I believe Orion/SLS are. I have nothing against your precious solar electric technology, but the technology does have limitations and I would like to see development of a complementary technology that does not have those limitations.
As usual you couldn't be more wrong, SEP technology has been ongoing for a decade already as part of NASA's Exploration Technology development program, that whole program has a budget of only ~200 million a year and is developing a dozen different things at any one time such as hypersonic decelerators and thouse Sterling RTG you mentioned earlier. Because this is already a know technology that is actively being used by commercial satellites every day the risks for incremental refinement are very low. The Asteroid Redirect vehicle has been budgeted 133 million per year http://optics.org/news/5/3/3 and that is for both the technology and to actually make for the WHOLE vehicle.
As for limitations, please elaborate, you seem to have no problem assuming the highest theoretical possibilities of Nuclear propulsion as givens so why don't you apply the same standard to Electric propulsion? You can not seriously be worried about transit times, it has been shown conclusively that SEP can perform a transit to Mars that is comparable to a high thrust system when provided with adequate power.
I believe that you actually have to try to do something before you know how much it's going to cost. Since we're doing nothing of the sort, your guesses about how much development would cost and how long it would take are every bit as imaginary as mine are. I believe that the cost of development would not be outrageous or impossible for NASA to bear, but it would mean that some money squandering programs would have to go.
Again wrong, no less then wrong your expressing nothing but a blind wish and an appeal to ignorance. We can make very reasonable minimum estimates of cost based on the TRL, the size/energy/mass of the thing we want to develop and basic nature of the technology in question. Nuclear Thermal Rockets as a technology BIG, HIGH ENERGY, HIGH DIFFICULTY. The NERVA has a reasonable TRL 5-6 which is the only factor that isn't bad for it, but even here it is inferior to SEP which is TRL 9. The size, mass and energy density of SEP are all lower then Nuclear propulsion systems, Electric propulsion systems can be tested in vacuum chambers, nuclear rockets aren't going to be tested in the earths atmosphere ever again and would require extensive in-space testing. No honest estimate would put SEP and NTR even remotely in the same ballpark for development costs.
Should we cancel SLS and spend all that money on technology, YES, but not one dime of it on Nuclear propulsion.
It doesn't confirm anything other than what you want it to confirm. As I stated before, these men were designing things with slide rules and precious little knowledge of nuclear power. We had only detonated the first nuclear weapon fifteen years prior to the start of the program. This is 2015, not 1960. We have better technology at our disposal now. We're not starting from scratch.
Just a second ago you were praising the slide-rules, now they seem to be stone knives and bear skins. Our tools are better now yes, but development costs in Aerospace and Nuclear science are still astronomical and a lot of degeneration has occurred much of what they would have accomplished back then would need to be redone.
After you falsely claimed that we were nowhere near having flight capable nuclear propulsion hardware in the early 1980's, you provide an excerpt stating that the R&D phase of the project was over and they were busy with the development of flight hardware. I'm perplexed.
They did not have a flight capable system, subsystems were being built and tested but had never been assembled into a finished engine, they were hoping to have a finished engine after several more years of development. I don't see any reason to believe they would not have gotten their with the time and money originally budgeted, but the program was halted many years short of that goal. You seem to be under the false impression that they were one screw turn away from completion.
We're going to launch SLS rockets that have already cost significantly more money to develop that use a good number of existing elements of the previous man rated launch system, but you're whining about what NERVA cost? The GCNR has had multiple studies of every aspect of the design, including CFD modeling to determine what the best shape of the core would be to reduce fuel loss, maximize the cross section of the propellant heated by core, and best use of the propellant for heat transfer.
Why must you keep throwing SLS at me as if I am an advocate for it or it is somehow in competition with NTR technology? Dose that fact that just assembling this SLS rocket out of 'off the shelf' shuttle leftovers is in fact costing ungodly amounts of money give you no pause for how expensive right rocket development is? And yet your completely sure that development of Nuclear propulsion with be chump change, and not just solid core but some crazy gass core idea that your convinced is worth it because of some numbers you read off Wikipedia.
Complete isolation. That's the general idea. Power level ranges between 5 and 10 GW. If a plasma that's tens of millions of degrees can be contained, is there a specific reason why a plasma that's tens of thousands of degrees can't be contained?
Of course it can be contained WITH A HUGE ENOUGH MAGNET, that is the problem! Your not going to control a Gigawatt of plasma with a something that has the kind of mass ratios that we have in the combustion-chamber/nozzle of a chemical engine, a magnetic equivalent is going to be massive and the thrust:weight of the engine is going to tank.
If you were to tell a Marine from 2MARDIV in August of 45, having seen three years of combat, that a single bomb smaller than a car could destroy an entire city, he'd have laughed his rear end off. Around the second week of September, he required no further convincing. Sometimes you have to suspend a little disbelief that something is possible. You make it seem as if we could spend a trillion dollars over 50 years and have nothing to show for it. You've made so many arguments that are so far out of proportion to reality that it's laughable.
Now your siting the Manhattan project to me as proof of affordability, have you lost your mind? This is typical space cadet thinking, damn the costs we can do ANYTHING!!!! This is the kind of thinking that has lead to our unending series of space boondoggle, and while you seem to be able to recognize all the other boondoggles like SLS but you have a giant blind-spot for your own boondoggle. I've told you repeatedly that Nuclear rockets are 1) Expensive to develop and 2) don't have the performance to be attractive compared to Electric alternatives. And your response is basically to insist against all evidence that Nuclear rockets will be cheap to develop if we just 'hope' and 'try harder'.
I think your problem is that you think COST during development is just another metric of performance that can be beaten into submission by engineering, like needing more speed, more thrust, more what ever. When we hit a snag in the development we will just apply more engineering to 'fix' the cost thing like we would fix any other performance issue. That is not how it works, cost is not something that goes down as you engineer something more, it only goes UP because cost is incurred by engineering. No act of brilliant engineering can un-spend a depleted budget and when your doing cutting edge engineering your going to frequently hit snags that force costs upwards above the original estimate. Costs are more of a floor with the general technology or system architecture setting your best case with reality being considerably above that and a worst case scenario vastly higher. Only after something is DONE being developed can you even hope to start reducing costs, and that is a slow iterative process that's only justified by a high volume of usage to amortize the improvement over.
Here's some actual REAL research on what NERVA cost and how long it would have taken to complete, THIS is what you base your cost estimates on if you have a shred of honesty and it confirms everything I've been saying.
From http://history.nasa.gov/SP-4221/ch9.htm
"During FY 1970, NERVA moved into a phase of detailed design and hardware fabrication. The goal now was not further research, but rather the development of a flight-qualified engine with 75,000 pounds of thrust, at a cost of $860 million over a period of eight to nine years. The program received $88 million in FY 1970 and $85 million in FY 1971, with the funds coming jointly from NASA and the Atomic Energy Commission."
$860 million 1970's dollars is $5.25 BILLION in today's dollars. And that was just the lowest end NERVA rocket which is not even worth going back too, if you go for anything more advanced like this Gass-core nonsense it would be at least 10 times more, their is nothing but a vague notion of what this core would look like, no actual engineering AT ALL and nothing that could put any reasonable upper limit on development costs, it would be an absolutely unbounded development effort and we do not have infinite money to throw at problems.
Yes I am going to compare the Magnetic confinement needs of the GassCore NTR to a Tokamak even if they are hugely different in temperature. Because your nozzle just as slagged at 10 degrees above it's melting temperature as it is at 10 million degrees above. And your talking about an absolutely huge amount of mass and power transfer through these engines, hundreds of Megawatts possibly Gigawatts, your either going to be completely isolated from that kind of heat flux or your going to instantly melt. Any kind of low-thrust engine like a VASIMIR or a Lorentz force based thrusters is moving GRAMS of material per second and they need active cooling, they can get away with it because it's an all electric system, all heat and all plasma confinement is by microwaves and magnets respectively, hot stuff never comes into contact with cold stuff.
It should be plain enough that 'Engineering compromises' are the add-ons, losses of performance, cost over-runs that inevitably result when you move from theoretical engineering to REAL engineering and testing of a real system. No pie-in-the-sky piece of engineering survives contact with the physical world just as no battle plan survives contact with the enemy. You must be beyond naive to look at piece of theoretical potential based engineering and think that full potential is what your going to get at the end of development effort, the more speculative the concept the shorter of the goal it will fall.
Small electric dirt-bikes make a lot of sense on Mars, they would have a considerable range, would be light enough that it a person could lift them making it impossible to become stuck as well as strap onto the side of other vehicles like ATV's to act as self-rescue vehicles or for taking brief forays into especially rough terrain.
But pedal power just doesn't sound viable too me, people just cant produce the force necessary to take a wheeled vehicle up significant inclines especially over rough ground. Virtually all pedaling done on Earth in a bicycle is on a compacted road or trail, even mountain biking is done on mountain bike trails and is generally more downhill then up. And it's done by people at peak physical fitness with unlimited oxygen supplies. Human metabolism can use up Oxygen a LOT faster then normal when under high exertion, your likely looking at using up EVA oxygen supplies in 1/4 the normal time frame if people are exerting like that.
And MCP suit is utterly impractical for a dozen separate reasons, fortunately we have next generation suits in development that would be up adequate for Mars surface, I repeat ADEQUATE for walking, riding vehicles, exploring and working, not fantasy suits that let you forget you are in a lethal environment.