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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 Thu, 23 May 2019
23:28:35 -0400: On 2019-05-23 07:06, Jeff Findley wrote: Nope. NASA Administrator Bridenstine has assured the SLS/Alabama mafia that SLS/Orion are integral to NASA's plan to return US astronauts to the lunar surface. So basically test everything on commercial and keep the few SLS lainches you have for the bare minimum dress rehersals and first flight to moon. Congratulations on finally catching up. It won't last, though. I'm sure you'll forget everything in a few days. By "hatch", I assume you mean docking system. Yes, Orion, Starliner, and Dragon 2 will all use the same mechanism. If Orion is deemed too heavy, how difficult would it be to put a Dragon2 on top of the european service module so that it would be a Dragon2 and the new LEM that go to the moon in 2024? You'd have to invent a new forward adapter for the SM. You'd have to reengineer Dragon to be able to use it. You'd have to retest everything, including abort tests. It would probably be faster and cheaper to have SpaceX design something clean sheet. And you still don't have a 'LEM'. Nope. They're building the five segment SRBs for SLS from the leftover steel space shuttle SRB casings. When those are gone, they're gone. Wow. this SLS thing is much worse than I though. They need 10 segments per launch. How many are leftover from Shuttle programme? They've got more SRB sets than they have Shuttle Engine sets. Note that the Service Module is ALSO using legacy engines from the Shuttle program and there are only like four of those. Things that are different just aren't the same. Different requirements, different designs. Saturn V had 140t to LEO. SLS starts with 95T with dreams of going to 130t. Is this a case of not worrying about mass too much because they are planniong on having multiuple launches to LEO to assemble/fuel before the "ship" leaves to the moon ? As I recall, for Apollo, they were paranoid about cutting every gram thet could to make it. So I am puzzled why with the same laws of physics, they now think they can sent luxury payloads to the moon even if SLS has less capacity. Because payload to LEO is irrelevant. Payload to TLI is what matters. Orion plus service module weighs in at just under 26 tonnes. SLS Block 1B can do 37 tonnes to TLI. So for an Apollo-style mission that leaves around 10 tonnes for the Lander + Ascent Element and that's just not enough. The original LEM weighed in at a bit over 15 tonnes (or over 16 tonnes for the extended version). Saturn V could get 48.6 tonnes to TLI. And this is why Gateway makes sense to them. You can send Orion, Descent Element, and Ascent Element all on separate launches out to Gateway. Having a "design" isn't enough. You have to be able to manufacture everything to spec. And much of the manufacturing knowledge has likely been lost. Whether you create new design or re-use antique one, they need to create the tooling and program the CAD/CAM machines to build the parts. Building something in the shape of the old LEM shouldn't be more difficult than building something of another shape. This is engineering. You cannot just reach into your ass and pull out a "shouldn't be more difficult" and declare things a non-problem. The difference is that by re-using LEM desiogns, you can give the drawings to manufgacturers much more quickly so they can start to built/test/certify their parts. Starting from scartch means a delay of when manufacturers can do that. LEM drawings are paper. You can't run CAD/CAM machines off of that. have passed. No one has the type of knowledge that was simply assumed at the time anymore. So anything that wasn't written down has been lost. But of the laws of physics haven't not changed, and gravity on the moon hasn't changed, why would the design concepts of the LEM not be as valid today as they were back then? They are, but so what? The mission is different this time around. Or do they expect a ship large enough to have separate airlock, a couch for crew to sit on, and a 60" TV so they can watch Netflix while on the moon? They expect someone with a brain in the loop to be involved in the decision. This lets you and your recommendations right out. -- "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
JF Mezei wrote on Thu, 23 May 2019
23:51:02 -0400: On 2019-05-23 14:22, Fred J. McCall wrote: Contrary to your TDS delusions, this is not intended to be a 'one-off' mission after which we throw all the hardware away. With your 'new LEM' you get four days on the surface with two people. Or you could do the 'extended' LEM, which gets you up to 75 hours but adds several tonnes to the mass. What I am trying to understand is how, with SLS having less payload than Saturn V, one can talk about several more tonnes to the moon than they were able to do with Apollo/Saturn V. Why are you trying to 'understand' something that no one ever claimed? Blue Origin started developing their lander some three years ago and says it will be ready for use in 2023. A year later their Ascent Element will be ready for manned landings in 2024. Yep. and Dragon 2 was ready on time, so was every module on the ISS. So since nothing can ever meet schedules your claim is that nothing can meet this one, either? The Blue Moon Ascent Element weighs in at around 6.5 tonnes, which is almost half again as heavy as the LEM Ascent Element. Want to guess why? I will let you, the expert, explain how you can have 4 people, and consumables for 75 hours in a ship that is half the mass, yet has the shielding that the LEM didn't have, and structural strength to have 14.7 psi cabin pressure instead of 5 Simple. "Half again as heavy" is not the same as "half as heavy". "Half again as heavy" means 1.5 times the mass, not 0.5 times the mass. If it is because the transfer element does part of the job of dropping the "LEM" to the moon, consider that this transfer element still has to be brought there from Earth, so it still mass you need to carry from Earth surface. It's because you apparently can't read simple declarative English sentences. It doesn't matter that much how much mass you have to get out there if you can get it out there in small pieces. You cannot get your 'new LEM' out there in any smaller pieces than the Lander Element and Ascent Element as one piece. Meanwhile, the Gateway architecture says that a 'mission' gets out there as four discrete pieces; Orion, the Lander Element, the Ascent Element, and the Transfer Element. -- "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
In article ,
says... Jeff Findley wrote on Thu, 23 May 2019 07:13:11 -0400: Unless something has changed, they've been using shuttle SRB components from the very beginning for the 5 segment SRBs: https://www.space.com/28775-worlds-l...nasa-test.html From above: The individual segments though, use the same case parts that were recovered and reused during the space shuttle program. As such, the first SLS qualification motor (QM-1) being tested on Wednesday is comprised of hardware with a historic past. Do you have a cite for the assertion that new casings have been made? Turns out that a lot of Shuttle legacy parts are used in the SLS SRBs. They're different, though. The big difference is that SLS SRBs have an extra segment over the Shuttle SRBs (5 vice 4). So they will eventually run out of those legacy parts (but not until well after they run out of RS-25 engines). Agreed. What's not clear to me is what happens when they run out of SRB segments. The press hasn't reported on this much. Next time I meet up with someone from Northrup Grumman Innovation Systems, I'll ask. But I don't think that will be for a while since they only come to where I work less than once a year for beta testing our products. Jeff -- All opinions posted by me on Usenet News are mine, and mine alone. These posts do not reflect the opinions of my family, friends, employer, or any organization that I am a member of. |
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NASA's full Artemis plan revealed: 37 launches and a lunar outpost
In article ,
says... In article , says... Jeff Findley wrote on Thu, 23 May 2019 06:52:56 -0400: In article , says... On 2019-05-20 22:05, Fred J. McCall wrote: You understand that the Gateway isn't in an orbit around the Moon, right? It's in a LaGrange halo orbit. Was not aware of that. I was under the impression it was in lunar orbit. Orion has nowhere near the delta-V capability of the Apollo CSM. True, but I don't see why it matters since the CSM had about twice as much delta-v as required. Orion has about a third less than the Apollo CSM, so it still has enough to do the missions that Apollo did. And I'm not sure that getting into an L2 NRHO is that much 'cheaper' when it comes to delta-v. Orion simply does not have the delta-V to enter a low lunar orbit and then get back to earth and have the margins that NASA requires. This fact is all over all of the online space forums. But I've done a quick search for an actual NASA study. This looks promising: Options for Staging Orbits in Cis-Lunar Space https://ntrs.nasa.gov/archive/nasa/c...0150019648.pdf LEO was ruled "infeasible" for use by Orion by NASA. See Table 6 on page 8 of the above document. Jeff Ugh, I said LEO above when I meant LLO (low lunar orbit). Oops. Jeff -- All opinions posted by me on Usenet News are mine, and mine alone. These posts do not reflect the opinions of my family, friends, employer, or any organization that I am a member of. |
#38
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NASA's full Artemis plan revealed: 37 launches and a lunar outpost
Jeff Findley wrote on Fri, 24 May 2019
06:28:51 -0400: In article , says... Jeff Findley wrote on Thu, 23 May 2019 06:52:56 -0400: In article , says... On 2019-05-20 22:05, Fred J. McCall wrote: You understand that the Gateway isn't in an orbit around the Moon, right? It's in a LaGrange halo orbit. Was not aware of that. I was under the impression it was in lunar orbit. Orion has nowhere near the delta-V capability of the Apollo CSM. True, but I don't see why it matters since the CSM had about twice as much delta-v as required. Orion has about a third less than the Apollo CSM, so it still has enough to do the missions that Apollo did. And I'm not sure that getting into an L2 NRHO is that much 'cheaper' when it comes to delta-v. Orion simply does not have the delta-V to enter a low lunar orbit and then get back to earth and have the margins that NASA requires. This fact is all over all of the online space forums. But I've done a quick search for an actual NASA study. This looks promising: Options for Staging Orbits in Cis-Lunar Space https://ntrs.nasa.gov/archive/nasa/c...0150019648.pdf LEO was ruled "infeasible" for use by Orion by NASA. See Table 6 on page 8 of the above document. Note that the figures they used to rule out LLO underestimate the capability of the Orion/SM combination. It has about 12% more fuel than they state (9 tonnes vice 8 tonnes) and more delta-v than they say (1800 vice 1650). Note that with 1800 m/s delta-v LLO changes from infeasible to feasible. -- "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
Jeff Findley wrote on Fri, 24 May 2019
06:37:22 -0400: In article , says... Jeff Findley wrote on Thu, 23 May 2019 07:13:11 -0400: Unless something has changed, they've been using shuttle SRB components from the very beginning for the 5 segment SRBs: https://www.space.com/28775-worlds-l...nasa-test.html From above: The individual segments though, use the same case parts that were recovered and reused during the space shuttle program. As such, the first SLS qualification motor (QM-1) being tested on Wednesday is comprised of hardware with a historic past. Do you have a cite for the assertion that new casings have been made? Turns out that a lot of Shuttle legacy parts are used in the SLS SRBs. They're different, though. The big difference is that SLS SRBs have an extra segment over the Shuttle SRBs (5 vice 4). So they will eventually run out of those legacy parts (but not until well after they run out of RS-25 engines). Agreed. What's not clear to me is what happens when they run out of SRB segments. The press hasn't reported on this much. I think the original plan was that they'd switch to 'advanced boosters' at that point, but I think those may be too far out now to make the timeline. Also the original plan was to have a Block 1A vehicle that got the new 'advanced boosters' before the Block 1B EUS milestone (which at that point would have been Block 2). Block 1A was cancelled, adding EUS became Block 1B, and Block 2 was moved to after that. A little poking around tells me that there is enough SRB hardware for 8 SRB sets, which will carry them through 2027 or so. They currently have 4 RS-25 engine sets and contracts for another set and a half of 'new' RS-25 engines. This gets them into 2026. Another half engine set (2 more engines) would get them through 2026. There are apparently 3 AJ10-190 engines available for use on the Orion Service Module. That gets them through 2024 and the first landing, at which point they'll have to change engines. There are engines currently in production that they could use, like the AJ10-118k used on Delta II. So in summary the real long pole is the SRB hardware. There are contracts and contingencies in place for the other two pieces of the system that are limited by availability of old Shuttle hardware, but once those SRB components are gone, they're GONE and the program to replace those boosters is way out there. -- "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
Jeff Findley wrote on Fri, 24 May 2019
06:39:00 -0400: In article , says... In article , says... Jeff Findley wrote on Thu, 23 May 2019 06:52:56 -0400: In article , says... On 2019-05-20 22:05, Fred J. McCall wrote: You understand that the Gateway isn't in an orbit around the Moon, right? It's in a LaGrange halo orbit. Was not aware of that. I was under the impression it was in lunar orbit. Orion has nowhere near the delta-V capability of the Apollo CSM. True, but I don't see why it matters since the CSM had about twice as much delta-v as required. Orion has about a third less than the Apollo CSM, so it still has enough to do the missions that Apollo did. And I'm not sure that getting into an L2 NRHO is that much 'cheaper' when it comes to delta-v. Orion simply does not have the delta-V to enter a low lunar orbit and then get back to earth and have the margins that NASA requires. This fact is all over all of the online space forums. But I've done a quick search for an actual NASA study. This looks promising: Options for Staging Orbits in Cis-Lunar Space https://ntrs.nasa.gov/archive/nasa/c...0150019648.pdf LEO was ruled "infeasible" for use by Orion by NASA. See Table 6 on page 8 of the above document. Ugh, I said LEO above when I meant LLO (low lunar orbit). Oops. That's OK. I misread it as LLO. :-) -- "Adrenaline is like exercise, but without the excessive gym fees." -- Professor Walsh, "Buffy the Vampire Slayer" |
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