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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
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NASA's full Artemis plan revealed: 37 launches and a lunar outpost
David Spain wrote on Sat, 25 May 2019 09:27:56
-0400: We'd be better served if NASA acted like an investment bank and Congress gave it the funds necessary to buy the desired end goal with as little micro-management as possible. That has not been the established paradigm and is not evident in this work of fiction either. I've said for decades that we'd all be better served if NASA operated more like the NACA upon which it was originally modeled, as a technology development agency that did experimental projects and helped fund the same by industry. -- "Millions for defense, but not one cent for tribute." -- Charles Pinckney |
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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
JF Mezei wrote on Sat, 25 May 2019
19:39:13 -0400: On 2019-05-25 18:13, Fred J. McCall wrote: Well, there's that and there's the problem that if you combine everything in LEO now you need an upper stage with enough grunt to get the whole works to where it's going all at once. Sending little pieces is easier. So they are hoping to have pieces small enough to get to Gaweway with standard Falcon 9 second stage? No. Falcon 9 flown as expendable can get around 6 tonnes to TLI. Lander Elements will likely mass more than that. Falcon Heavy flown reusable has about the same capability, but if expended can manage around 20 tonnes or so to TLI If you need to build a new second stage to get the pieces to Gateway, why not build 1 hefty one which you fuel from LEO and get everything in one go? Because that's more complicated and requires a tanker vehicle that's capable of refueling it. In other words, YOUR way takes longer, costs more, and is more expensive to operate. Perhaps NASA has a job for you? During ISS assembly, people here complained about the 53° inclination "costing" many more Shuttle flights since cargo capacity was more limited. And rightly so, since the only reason to launch to that high an inclination was because of Russian limitations. If you need to ship separate stage II to Gateway to deliver each component, don't you end up with same problem of extra mass being carried and thus reducing payload? No, you don't. What you get is the difference between "possible" and "impossible". You don't ship "stage II" to Gateway. That stage gets you to the point where you can insert into Gateway's orbit. When in doubt, look at reality to check your logic. You could perhaps throw it all direct once you have SLS Block 1B on a pair of launches at $850 million dollars or more per launch. Or you can launch pieces on Falcon Heavy expendable at around $150 million per launch and use three launches (less than half the cost of SLS) plus an SLS launch for Orion. So by breaking things up you SAVE around half a billion dollars. -- "Some people get lost in thought because it's such unfamiliar territory." --G. Behn |
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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
Jeff Findley wrote on Sun, 26 May 2019
08:43:17 -0400: In article , says... Jeff Findley wrote on Sat, 25 May 2019 08:47:58 -0400: In article , says... On 2019-05-24 06:34, Jeff Findley wrote: Because if you look at the damn picture of the proposed time-line that's all over online, *none* of the stages of the lunar lander are launched by SLS. They're *all* launched on *separate* commercial launch vehicles. Are the separate launches all going to "Gateway" to deliver their hardware, or would there be LEO dockings involved before the combined parts get to Gateway ? Everything possible goes to Gateway in order to justify its existence. The only exception would be uncrewed landers with surface instruments, robotic rovers, or modules/supplies to be prepositioned on the surface for longer term crewed missions. Well, there's that and there's the problem that if you combine everything in LEO now you need an upper stage with enough grunt to get the whole works to where it's going all at once. Sending little pieces is easier. That's one of the 'justifications' for doing a Gateway is to give an 'assembly area' to send pieces too without having to send them all at once. NASA is trying its best not to need LEO refueling. But, if they ever get to the point where they're reusing crewed lander ascent stages and transfer stages (Gateway to LLO), they'll need to be doing similar refueling at Gateway. True, but the 'argument' there is that everyone is docked up to Gateway and 'tended' in order to refuel. Ultimately, we need in orbit refueling to perform missions that are bigger than Gateway/lunar surface. Whether that first refueling happens in LEO (likely with cryogenics) or at Gateway (likely with hypergolics), it's got to happen sooner or later. One of those approaches gets us ready to go to Mars while the other simply doesn't. NASA is making all the wrong long term investments in order to justify SLS/Orion to the greatest extent possible. So that means delaying the development of refueling and descoping that development to hypergolics instead of cryogenics. NASA is deliberately choosing a path which delays any "exploration" beyond the moon. I think folks going to Gateway will do what Blue Origin has done and opt for LH2/LOX engines, so it will be cryo either way. It will be large volume 'mild cryo' in LEO (Starship) or deep cryo (LH2/LOX) at Gateway. The big 'delay' in exploration beyond the Moon is that I think the NASA plan assume in situ fuel manufacturing on the Moon before they go for deep space. Deep Space exploration vehicles would fly to Gateway, refuel with lunar LH2 and LOX, and depart. This makes some sense in that getting fuel up from the Moon is much 'cheaper' energetically than boosting it up from Earth, but it impacts your Mars infrastructure as well, since now your in situ fuel factory there has to find ice and make LH2/LOX out of water rather than making LOX and liquid methane out of the atmosphere. -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
JF Mezei wrote on Sun, 26 May 2019
14:01:35 -0400: On 2019-05-26 12:09, Fred J. McCall wrote: Because that's more complicated and requires a tanker vehicle that's capable of refueling it. In other words, YOUR way takes longer, costs more, and is more expensive to operate. Perhaps NASA has a job for you? SpaceX already has the software for Dragon2 to dock to another ship. You say this like you have a point. You don't. SpaceX is already planning on-in-orbit refueling and originally set to go to mars by 2024. Surely the refueling mechansims are already in development? You say this like you have a point. You don't. Surely those mechanisms could be fitted/tested on Falcon based vehicles before BFR/BFS are in service? Gee, USAF already knows how to do in flight refueling of aircraft. Boeing already knows how to build supersonic aircraft. Surely all that stuff could be fitted/tested on Piper Cub based vehicles? Also, if a Falcon Stage 2 were sent up with a large tank for itslef in lieu of any payload. Could the actual payloads launched separately then dock/attach to it and the bit-tanker Stage2 then act as the CDM to bring all the hardware between LEO and Moon ? Unlikely and I'm not going to go to the effort to do the math to prove or disprove it. It's your loony idea. YOU prove whether it will work or not. Or is the extra fuel needed for LEO-Gateway trip with all the hardware attached to it (lander, ascent, transfer) too much to be carried to LEO by a Falcon Heavy in single launch? Using a Stage 2 with big fuel tanks would eliminate the need for fuel transfers. OK, but even Falcon Heavy cannot get a second stage to LEO with more than about 54 tonnes of fuel on board in lieu of cargo. So that's what I've got to get from LEO out to Gateway. I have to take the dry mass of the second stage (a little under 4 tonnes), the mass of the Ascent and Descent Elements (if we assume something about the mass of the old LEM that's around 15 tonnes, give or take; using NASA numbers for something more modern with more people you get 24-28 tonnes), and the mass of the Transfer Element (which NASA thinks comes in around 12-15 tonnes). So the total mass you need to get to the Gateway from LEO comes in at around 40-45 tonnes with 54 tonnes of fuel on a stage with an Isp of 348 seconds. Getting from LEO to L2 is around 3400 m/s delta-v. The kludge vehicle can manage a little over 2900 m/s of delta-v. You can't get there the way you're proposing, even using a pair of Falcon Heavy launches. If you assume you can fully fuel the Falcon second stage, you can get a little under 4100 m/s and you can. But you need a second stage that can 'dock' to your other assembled components, that can be refueled on orbit (you need at least 80 tonnes of propellant aboard), and a 'tanker stage' that can refuel it. You need three Falcon Heavy launches to get all this up there. Easier and cheaper to change no vehicles, load the three pieces on separate Falcon Heavy, and make three Falcon Heavy launches. Will you stop proposing stupid **** now? -- "Some people get lost in thought because it's such unfamiliar territory." --G. Behn |
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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
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NASA's full Artemis plan revealed: 37 launches and a lunar outpost
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NASA's full Artemis plan revealed: 37 launches and a lunar outpost
JF Mezei wrote on Sun, 26 May 2019
23:45:14 -0400: On 2019-05-26 22:44, Fred J. McCall wrote: NASA is saying that they need something like $32 billion in additional funding over the 2020-2024 timeframe. But the amount is really irrelevant. What's relevant is that one of the houses of Congress is controlled by Democrats and they would go out on the launch pad and shoot down vehicles before they'd allow Trump to have this. Trump has not included NASA in his reality show scripts because it is of little interest to his audience/base. He doesn't tweet about it, doesn't rant about it in press conferences and doesn't raise it during campaign speeches. And yet it is Trump who first set the 2024 date. Since either passing or blockng would have no political value because it won't generate any fireworks at the 1600 Pennsylvania studios, it is much easier to just process the funding and get it approved quietly. Politically, there is nothing to win on either side. But from the lobby side, both political parties likely benefit from approving it. How much crack did you smoke to get far enough from reality to arrive at your preceding conclusions? -- "Ordinarily he is insane. But he has lucid moments when he is only stupid." -- Heinrich Heine |
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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
Jeff Findley wrote on Mon, 27 May 2019
06:51:00 -0400: In article , says... I think folks going to Gateway will do what Blue Origin has done and opt for LH2/LOX engines, so it will be cryo either way. It will be large volume 'mild cryo' in LEO (Starship) or deep cryo (LH2/LOX) at Gateway. True, but this depends on what lander parts NASA picks. HSF at NASA has been risk averse since the Challenger disaster. That means they'll likely pick lander parts that use hypergolic propellants. Unlikely, since the stated goal is to shift to in situ fuel production on the Moon and you aren't going to be making hypergolics down there. So Blue Origin would be out. Starship is never going to be picked as part of the lunar architecture because it will be seen as "high risk". I think it's quite likely that choosing LH2/LOX will be seen as a feature for Blue Moon, not a bug. We've come a long way from the days when we used to worry about being able to get a restart on a rocket engine (which is one of the justifications for accepting the poorer performance of hypergolics). Plus NASA mandated a three stage lander. That screams hypergolics from the start. Neither Blue Origin's Blue Moon lander nor Starship would qualify in NASA HSF's mind. Actually, no. The Transfer Element isn't part of the lander. The Blue Moon lander is a Landing Element. Blue Origin doesn't seem to think they'll have any problems adding a 7.6 tonne Ascent Element on the cargo platform and the Blue Origin effort is pretty much EXACTLY what NASA has asked for. The big 'delay' in exploration beyond the Moon is that I think the NASA plan assume in situ fuel manufacturing on the Moon before they go for deep space. Deep Space exploration vehicles would fly to Gateway, refuel with lunar LH2 and LOX, and depart. This makes some sense in that getting fuel up from the Moon is much 'cheaper' energetically than boosting it up from Earth, but it impacts your Mars infrastructure as well, since now your in situ fuel factory there has to find ice and make LH2/LOX out of water rather than making LOX and liquid methane out of the atmosphere. I've heard the water to LH2/LOX argument before. I find it lacking. Well, if you're going to pick and choose which bits of reality you accept you can arrive at any conclusion you like. Again, we're talking NASA here. The agency who signed off on solid aluminum wheels for all of its Mars rovers. The wear and tear on those is mind boggling. They're literally falling apart after what I would consider to be a pathetic number of miles/km traveled. You say that as if it's somehow relevant. It's not. And what is the design lifetime of these things supposed to be, again? And we expect NASA to mine water, on the moon (with its abrasive dust environment), and turn it into LH2/LOX? I'll believe that when pigs fly. No, I expect them to let some contract to have someone do it, just like they're doing with landers and such. As I said, if you're going to pick and choose which bits of reality you accept you can arrive at any conclusion you like. Me, I'm going to go with what people have said. You understand that one of the drivers behind the NRHO that Gateway is in is ease of access to the Moon's south pole (where we think the highest chance is of finding water), right? All the engineering competitions (mostly college level) I see to mine lunar regolith have everyone starting from scratch. Because we all know that no one on earth moves around dirt/rock or mines anything, right? There are industries on earth that know how to do this and they aren't run by aerospace engineers. Adapting earth equipment to do this on the moon would be the most straightforward way to go. The problem with that is this equipment is *heavy*. But there are reasons it's heavy! At any rate, once you reduce launch costs to put a reasonable amount of equipment on the moon to start production of LH2/LOX in quantity, you need to compare the new, lower, cost of launching LH2/LOX (or better yet, methane/LOX) from earth to that mined on the moon. If you take into account all the money it's going to take to maintain that (expensive) infrastructure on the moon to produce that propellant, I'm not convinced that it's going to break even in terms of the economics in the next 25 years or so. So Mars is right out, then, since in situ fuel production is so hard and it's REQUIRED if you're going to do Mars? I'm not arguing that we shouldn't invest in lunar water mining. I'm just against putting it on the critical path to send people to Mars. It's simply not needed if something like Starship/Super Booster works out. It's quite simply a hell of a lot easier to refuel a Starship/Super Booster on earth using methane/LOX (both super cheap on earth) than it is to mine water on the moon. I think I made that argument somewhere along the way. Mostly it's a bad idea because it leaves you with Mars vehicles that are burning the 'wrong' fuel for in situ production on Mars. Yes, there's water there, but going with LH2/LOX for Mars vehicles makes things harder. -- "The reasonable man adapts himself to the world; the unreasonable man persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." --George Bernard Shaw |
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NASA?s full Artemis plan revealed: 37 launches and a lunar outpost
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