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Comment Re:Even this is wrong (Score 1) 684

No, turbine engines operate at an entirely lesser, though still quite significant, level of performance compared with rockets.

The most complicated part of a rocket engine? The turbopump. Which has an amazing amount of design commonality with a turbine engine, it's basically the same concept but with different working fluids. From the Wiki: "Turbopumps in rockets are important and problematic enough that launch vehicles using one have been caustically described as a 'turbopump with a rocket attached'–up to 55% of the total cost has been ascribed to this area." So go educate yourself first. The point isn't that rocket engines are easy, but that similar materials challenges have been solved in the context of jet engines to make them affordable and reliable, and so with enough time and development, there's no reason to think those problems can't be solved with rockets.

The problem with imagining 1000's of launches is that near-Earth space simply cannot accept that much stuff.

De-orbiting debris is not a problem. These things aren't all going to live in LEO in perpetuity.

Your's is at least as likely to be wrong as mine.

You said we will never see 100's of launches a year. We're seeing a launch pace of ~15 Falcon 9/Atlas V class rockets per year. SpaceX alone could get to that level within a decade if their plans come to fruition (and they've had a good track record of fulfilling their promises thus far). You are being far too pessimistic, and the comparison to Watson is therefore apt.

I don't accept that what has not been done is possible, do it, that's the only real proof.

VentureStar was cancelled because it was mismanaged, not because of technical problems. The administration was actively ignoring the recommendations of the engineers. You are claiming it is impossible because it hasn't been done before. Why don't you apply those same criticisms to the moon base you are so fond of, which is far less developed and far more complex?

There is no 10x improvement possible with rockets, you, and many other people, are simply deluded if they think so.

The cost of fuel in a Falcon 9 launch is ~$200k. The cost of a launch (at least for the government) is >$80million. If we get comparable performance to airlines, where the cost of fuel is ~25% of the flight, that brings the launch cost to $800k. There's a 100x improvement in cost, exactly. Even assuming that we never get there, a 10x improvement would still be possible if we assume that the recurring costs of rocket launches are always 10x the price of airline flights. In fact, that's what SpaceX is targeting in the not-too-distant future. What fundamental problems prevent us from getting there? So far your arguments have amounted to "materials challenges are hard". Let's get some substance. I'm inclined to believe the owner of a rocket company before you, especially when he has a track record of making good on his claims.

Look, we're not talking about colonists here... This is about science.

If that's really what you believe then Mars wins yet again. There's far more of scientific interest to be done there.

Don't make grand sweeping proclamations about things that you can't know even in principle. I understand your preference for the Moon, but your arguments are devolving from technical ones to arguments about stating right out that things you don't like are impossible. Debating the technical merits of Moon missions versus Mars missions is interesting, but when it turns into mostly emotional arguments I see no value in continuing the conversation.

Comment Re:Even this is wrong (Score 1) 684

The problem with rockets is they operate at temperatures and pressures very near the uttermost physical limits of material objects.

Same can be said of turbine engines, and we've made those very cost effective to use. Reusability is key, and we've seen immense progress in that area recently.

...but its hard to argue that the demand for 100's or 1000's of launches per year will ever exist.

"I think there is a world market for about five computers." - Thomas J. Watson, 1940's

Maybe an SSTO will become possible and practical in 50 years with advanced materials.

It was possible in 2001. X-33/VentureStar.

As for loops and fountains, and bolos and etc. All very nice ideas, but none of them is anywhere close to realization.

It doesn't really matter if they are close or not - we've got 10x-100x of improvement available to us with chemical rockets, and likely another 10x-100x improvement available beyond that with one of these alternative methods. Once we've gotten everything we can out of rocket propulsion (a few decades of refining reusability, at least) the business case and technical know-how will be abundantly present for these other technologies.

TIME however, is irreplaceable. I think its a choice between the Moon, and NEOs really. At least in the medium term.

The journeys in question are the same or less in duration than those that faced previous colonists. The thing that matters most is whichever location offers the greatest opportunities for freedom, adventure, and wealth. As I said previously, the people who are putting real money on the table aren't betting on the Moon thus far, which suggests to me that the business case is better elsewhere.

Comment Re:Even this is wrong (Score 1) 684

ISS was a necessary step, as it has greatly advanced our long-duration expertise and general operations capabilities that will be needed regardless of if you are in Earth orbit or not.

ISS has at least maintained a manned presence in space. There are things that could have been done, but at least we've maintained and increased our technological capacity to support human life in orbit. Like I said, it's a bright spot of non-cancellation in a vast field of plans that never got past paper.

The fundamental thing that people don't understand, even space people, is that space is NOT going to really get cheaper.

The only thing that's inherently inefficient about rockets is the fuel costs, and it is true that from a mass/fuel perspective rockets are incredibly inefficient. If you had to carry around 100,000 lbs of gas to move your 2000 lbs car nobody would get anywhere. The thing is, though, fuel is still a tiny, tiny fraction of a rocket's cost. We can definitely achieve a 10x reduction in cost, and likely 100x. 1000x, maybe not, but I bet that >10x is enough to turn us into a spacefaring civilization.

And, long-term options to get us into space really cheaply are abundant. I personally favor the Launch Loop. On-orbit refueling or ISRU doesn't really change the difficulty of getting to LEO, which is the majority of the Delta-V challenge.

Since we need to go the Moon anyway, we might as well go now and get the process in motion.

Conclusion doesn't follow from the premises. The Moon offers opportunities, but so do asteroids, and Mars, and Venus, and every other body in the solar system. It is close, but linear distance doesn't matter much in orbital mechanics. The single biggest obstacle to humanity reaching space on a large scale is cheap access to LEO, after that, the Moon is just one of many options.

One thing you might consider... there are prominent companies actively working on: orbital space stations (Bigelow), Mars colonization (SpaceX), and asteroid mining (Planetary Resources). I know of none that are focused on a Moon base. Either that's a hell of an opportunity that nobody has paid any attention to, or a bunch of very profit-driven people with access to the world's leading space expertise have determined that the moon doesn't have as much to offer as the alternatives.

Comment Re:Even this is wrong (Score 1) 684

...blind quotations of 'delta-V is about the same' are nearly meaningless.

Delta-V to the moon from Earth is ~ 16km/s. By your own figures, going to Mars adds 1.4km/s. So the difference between the two is less than 10% in terms of Delta-V, plus you have aerobraking to aid you on Mars. It is absolutely correct to say that Delta-V doesn't enter into it. So let's leave that out of the calculus for which one is preferential. Trip length is the main difference between the two (and it is a big difference) but ISRU on Mars goes a long way to help with that because it frees up so much mass budget that would otherwise go to rocket fuel.

In other words the costs would be expected to be in the same range, with the Lunar project resulting in a permanent manned presence and some production of materials (besides just CH4 and O2) on an ongoing basis.

I'd like to see a citation on your figures for the Moon base. For that amount, "permanent presence on the moon" would mean something like ISS on the moon - completely dependent, etc. Actually, $150B is right in line with what has been spent on the ISS thus far, and that is after having decades of experience building prior stations. So, if my options are: build a completely dependent Moon ISS, or begin a campaign of human exploration on Mars, which also happens to provide useful settlement infrastructure with every launch (rovers, power generation, ISRU modules, habs), what is the best choice? I think we'll get much more science and space exploration for our dollar with the Mars missions.

As for the Sabatier reaction, etc... its not just something you can take for granted.

I'm not taking it for granted. There will be extensive engineering work to do to make this operate reliably on Mars. The thing is though, this is FAR from the biggest technical challenge of any Moon or Mars mission. And, this is dramatically simpler (and better vetted) than an equivalent level of self-sufficiency on the moon.

None of those possible costs is factored in by Zubrin, but a two-year program delay easily adds billions, and there's almost bound to be one.

I don't care how 'harshly critical' Zubrin is of a Moon Base, he's not objective about it. Just because someone is an engineer doesn't make them objective or unbiased about everything.

Zubrin is unashamedly hellbent on getting humans to Mars (he's the president of The Mars Society, so that should settle it). The thing is though, he didn't start out with some strange predilection for Mars and nothing else. He became convinced of that through his engineering work on mission profiles, that showed how much potential there is to "live off the land" and take advantage of Martian resources straight from the first missions. No other body in the system gives us that same opportunity.

As expensive as Mars is now, it will SURELY be much cheaper over time, correct? A manned Mars mission in the 2050 time frame could easily be 1/3 or 1/4 of the cost of one carried out in the 2030 time frame. Mars isn't going away.

Same arguments apply equally well to the Moon. Also, SpaceX notwithstanding, we really haven't seen space get cheaper. The only way to get it cheaper is to do lots and lots of it, and design from the ground up for cost-cutting and to hell with Congress, the Air Force, or whoever wants to introduce pork and feature creep. NASA doesn't seem to have the incentives, permission, or ability to design this way. The shuttle was more expensive per launch than the Saturn V. SLS promises to be far more expensive yet.

Overall, though, here's the thing: Mars or the Moon doesn't really matter the most. I would be as delighted with a Moon base as I would with sustained Mars missions, to be honest. The fundamental thing that gets me riled up is the contention that Mars is too hard/expensive to do. The technical challenges of human space exploration have been well within both our ability and our budgets since we put boots on the Moon. The thing that is lacking is focus. The biggest successes of NASA in recent years have been 1. ISS and 2. Smaller projects that are well within our technical ability (Hubble, Mars rovers, etc). ISS has only succeeded because it is international, and therefore almost impossible to cancel. Smaller projects have succeeded because there isn't enough money on the line for politicians to twist them to produce serious pork. Everything else is a wasteland of bureaucratic destruction.

So we can keep debating the merits of the Moon vs Mars if you'd like, but neither of them is going to happen if NASA continues on the current path. The main thing I wanted to drive home is that Mars is not nearly as big of a challenge as this budget and plan would have you believe - once we overcome the institutional obstacles, Moon or Mars becomes Moon AND Mars eventually.

That said, I'm still a strong proponent of Mars first, I just want to make it clear what I really think is important in this discussion.

Comment We already know how (Score 2) 211

We know how to do this, and NASA has known how since at least the mid 90's.

Mars Direct is the answer. This would get boots on Mars in 10 or so years, and if we cancelled SLS and put that money into Mars development and commercial crew, this could happen without even increasing the current budget.

The problems are NOT technical. They aren't even budgetary. The problems are political - spasmodic direction every term or two from new presidential initiatives, the use of NASA solely for vote-buying pork by congress, and the institutional dysfunction of NASA administration, favoring the most complicated, expensive, and high-risk technologies possible with these plans. If people get educated about mission profiles like Mars Direct, and start recognizing initiatives like "road to Mars" for the political pandering that they are, perhaps we can see some sanity restored to the space program.

Comment Re:We should NOT go to the moon first... or use SL (Score 1) 194

Most of the technology doesn't in fact actually exist today. The whole handwaving scheme relies on technologies and systems that have been tested (at best) on the the bench under strict laboratory conditions. (Some of it hasn't even made it off the back of Zubrin's envelope.)

There's engineering to do, certainly. The technical details are only a small part of what matters though: if we don't get away from this institutional habit of doing engineering in the most inefficient way possible, we're never going to get anything done. Politics shouldn't enter into engineering decisions, and as long as they continue to NASA will be enormously dysfunctional.

Another great example of this - the X-33 VentureStar actually had a lot to offer as a shuttle replacement, and was showing some serious promise as an SSTO vehicle that would have a much faster turnaround and be far cheaper in the long run than the shuttle. However, NASA and LockMart administration insisted on doing new technology for the sake of new technology even when the old technology was superior . This exploded cost and risk, and ultimately the program was cancelled because the new carbon fiber tanks weren't workable, even though engineering had been saying that all along, and standard aluminum alloy tanks would have worked just fine (and likely saved weight in the end). We've got politicians and ideologues making engineering decisions, so is it any surprise that much of our space program is ineffectual?

Comment Re:Even this is wrong (Score 1) 684

If it doesn't there's a 3 day transit time for a cargo lander, big deal.

Whether it is a 3 day or 9 month transit for supplies, you've got to pay the immense penalty to get out of Earth's huge gravity well. That's 90%+ of the challenge so it is disingenuous to suggest the moon has a significant advantage there.

There's no working prototype of a Martian ISRU unit either.

Completely wrong. Zubrin (who is not even a chemical engineer) built one at Martin Marietta on a shoestring budget and tight schedule and it worked the first time. That's probably because it is so damn simple. If you are a chemist you should be very familiar with the Sabatier Reaction, which has been done since 1910, and hydrolysis, which I did in my kitchen as a 5th grader. That's really the extent of the chemical engineering that's involved. You don't have anything to teleoperate - unless you consider hitting the "on" switch teleoperation. That's the extent of the control that's required, it is literally going to be as simple as the ignition switch on your car (which is utilizing atmospheric ISRU: where do you think the oxygen comes from for combustion?)

Actually polar orbits are quite good for both landing on and leaving the Moon, you might want to study that....

What are you talking about? You would never want to land on the moon to refuel, you are paying the Delta-V penalty to take your entire ship down and back up again. You would want to rendezvous with lunar supplies that have been launched into orbit. Equatorial orbits would be more convenient for that because you stay in the same orbital plane as the original Earth orbit.

You claim to have read Zubrin's work but I highly doubt that because he is harshly critical of a lunar base and makes the argument for Mars much more eloquently than I do. It would save us both a lot of time if you would give the whitepaper (or at least the wikipedia article) a good read.

Comment Re:Moon as a gas station (Score 1) 194

Yes!!!! Thank you, another voice of reason. There have been so many threads recently on this Mars plan, and nobody seems to realize that it is literally the most inefficient way you could ever get to Mars. It's like saying you have to build a yacht to cross the Mississippi. Mars Direct is the way to go.

Comment We should NOT go to the moon first... or use SLS (Score 2) 194

First of all, the proposed SLS plan has nothing at all to do with getting to Mars, and everything to do with giving the illusion that SLS has a nice full launch manifest. The mission profile is deliberately designed to require the maximum number of launches of an insanely expensive rocket - so basically, the point is to take as long as possible and spend the maximum amount of money to get to Mars.

Instead, using technology that exists today (no on-orbit ship manufacturing or propellant depots) we could get to Mars in 10 or so years using something like Mars Direct. The only reason NASA isn't pursuing this, or a plan very much like it, is because it completely obviates the need for many of NASA's pet projects, and SLS. Also, it doesn't funnel maximum $$$ into certain congressional districts.

The reason we can't get shit done in space is because the politics of NASA are broken. The moon is just a distraction - it's like taking off from Kansas and stopping at Iceland on your way to Australia. There might be some things of interest on the moon, but it makes absolutely no sense as a Mars stepping stone.

Comment Re:Even this is wrong (Score 1) 684

AGAIN, you are wrong about Apollo.

I am? Tell me where I said that they performed no testing of the Apollo hardware. You made a very specific contention: that ISRU could not work until it has been tested on multiple Mars iterations spanning decades. I made a very specific contention: that the Apollo Lunar Module was never tested on the moon until it was carrying people. That proves that analogous testing can get the job done, and that you are placing requirements on this notional Mars mission development that are stricter than those used for the successful Apollo missions.

And again with ISRU, all it takes is one factor we haven't counted on to gum up an ISRU attempt. Yes, that won't risk anyone's life, but its quite likely that the first attempt will be marginal or even unsuccessful, and thus we should expect to make more than one attempt.

You prepare for the worst and hope for the best. The ISRU system is automated and sent far in advance of the astronauts. If it isn't working, they don't go. If it breaks some time after they leave, they do a flyby instead of landing. If it breaks after they land, there's another one close behind as a backup, within their supply margin. This isn't a deal breaker, there is more redundancy than Apollo had, and I seriously doubt that you've read about Mars Direct in any detail or you'd know that there's plentiful redundancy in the mission profile.

At the South Pole of the Moon sunlight is available for long periods of time, and in a relatively small area there are always spots where solar power will work, without any gaps... Certainly digging up 50 grams a minute of regolith at 50% duty cycle and extracting its volatiles is not THAT much of a challenge, and would drastically cut back on costs... Small railguns can place materials into Earth orbit, even building a beanstalk is well-within our existing capabilities if we so choose.

You are quite simply being intellectually dishonest. You are complaining about atmospheric ISRU on Mars which is simple with prototypes functioning today, and handwaving away the difficulties processing and refining lunar regolith, which has NO working prototypes. Polar sites are directly at odds with railgun-type launches, because a polar lunar orbit is undesirable - equatorial would be much more efficient for rendezvous, etc. On top of that, your options of landing site are severely restricted if you must stay at the poles - that doesn't work for a large radio telescope, for instance. And, rail guns are completely unproven technology! You've got far more engineering to do to support the moon colony you describe.

Bottom line - I'm not saying that the Moon has nothing to offer, but it is utter nonsense to claim that it is necessary or sensible as a stepping stone to Mars.

Comment Re:Even this is wrong (Score 1) 684

It will require at least 2, maybe 3 unmanned attempts to man-rate such a system. That's several years of just flight time, which can't overlap.

Sure they could - you want to accelerate the schedule, send multiple tries in a single launch window. Insert money to save time. Also, it's disingenuous to call Dragon 2's Mars capability 'back of the envelope'. It's designed from the ground up to support Mars, look into the Red Dragon concepts that have been proposed for very near-term Mars science missions.

2. You are utterly incorrect about Apollo. Apollo's systems and technology were incrementally developed and tested in 26 Mercury Program missions (6 manned, 20 unmanned), and 10 manned missions of Project Gemini, which were explicitly used to develop and test each of the necessary steps required by Apollo (long duration flight, EVA, rondezvous and docking, etc.).

Your contention was that ISRU won't work without multiple iterations on Mars first. My point is that ground testing can remove a great majority of that risk, and of course that iterative development would be done. Arguably, we can test ISRU on Earth much better than Apollo engineers could test the lunar landing module. And, regardless of how many sims had been done, the first time that thing was tested *in flight* was with people on it. That was an insane risk, but one that couldn't be avoided. Our risks will be far smaller by comparison.

Yes, I've read Zubrin, etc. I think they somewhat underestimate the difficulties that will ACTUALLY adhere to a program.

Nobody is saying that Mars is easy. What Zubrin says (and I agree with him) is that the 30 year NASA path to Mars is expensive and impossible because it is specifically engineered to be. They want to involve as many new technologies, NASA centers, and congressional districts as possible, which is the exactly wrong way to do efficient, effective engineering. The problem is grossly overstated. It is certainly not a 30 year problem. Also, if you've really read Zubrin, you'd know that he predicts SpaceX's developments accelerate the schedule to Mars significantly - Mars Direct was proposed before we had a launch vehicle manufacturer that is ideologically committed to building infrastructure for a Mars colony.

The Moon is a massive gift, a stepping stone to space, our door stoop, use it.

The Moon is almost as hard and way less useful. The only resource to mine is lunar regolith - unsolved engineering problem there. Long nights make energy storage a huge challenge. There's very little of scientific value. Supposing you wanted to make an intermediate stop-over for deep space rockets - the moon is at the bottom of a gravity well, on-orbit refueling from asteroids would be far better. If your only argument for the moon is as a pit stop to places we actually want to go, why not just skip the middle man and go there directly? I'm not inherently opposed to a moon colony, but to say we need one to get to Mars is just silly.

The only thing that makes Mars seem so tough is that the mainstream proposals all include the costs of orbital manufacturing facilities and propellant depots and moon colonies and all sorts of totally unnecessary infrastructure that has yet to be developed. Focus is about saying no, and what NASA has needed ever since Apollo ended is focus. Not more budget, not more public support. Pick one target and go for it with singleminded determination, because otherwise we're going to keep getting rockets to nowhere and a bunch of half-assed initiatives that never get off the ground, figuratively or literally.

Comment Re:Yes, let's run before we can walk... (Score 1) 130

Still, until you have an orbiting space station that can be on it's own for a few years, there's no realistic way of going to Mars.

This shows otherwise: Mars Direct

For comparison, how many launches would be required before an orbiting colony could generate its own water, oxygen, CO2, and rocket fuel?

"Lead us in a few words of silent prayer." -- Bill Peterson, former Houston Oiler football coach