Quote from: envy887 on 08/03/2018 07:39 pm... the ET tooling would have required modification to build it (and possibly an even bigger core, to handle the difference in strength between plasma arc and friction stir welds). It was not necessary to change anytime soon to FSW as Plasma Arc was just fine. As far as strengthening the core to the 2-stage vehicle, that was essentially just a software change that was needed to mill less material from the core airframe, making it stronger. All this was thoroughly investigated and documented at the time. So tooling changes were not required and FSW could have been phased in over time as the program continued if that direction was desired, but even that was not needed. It would have been an enhancement to use the latest welding techniques rather than the existing ones, which were working fine.
... the ET tooling would have required modification to build it (and possibly an even bigger core, to handle the difference in strength between plasma arc and friction stir welds).
The more I think about it, the more I think it isn't intended to succeed. If the politico's behind SLS can get the program overturned again, they can set themselves up to be able to push another set of 10-year development contracts through - and that's where they benefit the most through the jobs and federal cash disbursal.If they do transition SLS from development to operational, then the high-value development jobs will no longer be required in Alabama and Utah, and there will be a general transition towards lower-value technician-style jobs going to Louisiana, California, Florida and back to Texas too.But those aren't the states currently represented by the controlling folk on appropriations. And they will not like losing jobs and federal income. I predict they will do 'something' to protect their own back yards before the transition comes - and I don't believe LOP-G could possibly be sufficient for them.Now would be an especially good time for some smart people to put together a comprehensive plan that would lay out a path of transition away from SLS, to enable future surface activity programs on the Moon and Mars, IMHO - plans that would still keep all that development money exactly where the appropriations folk want it, but would - for once - actually deliver some products that the program really needs instead of these "make-work" government rockets.I've said before, landers, habs, rovers, ISRU, power, mining & processing - there's a sh*t ton of development projects that could be undertaken if the SLS' budget were made available, and any combination of those would deliver everyone far, far better return on investment than a shiny new $2 billion/flight rocket ever will.Ross.
Are you talking about building DIRECT's ET-based core, ...? ... while DIRECT's ET-based core was much shorter and could have been built on the tooling as it was. At least that is my understanding, and I think it's matches what you are saying.
Quote from: JDTractorGuy on 08/07/2018 10:54 pmEG, the development of the tooling and vehicle falling behind. Is it safe to assume then that once the first flight is conducted that the planned schedule will be more stable? ~1 flight per year type deal?Production typically has far less potential for delays than development - it's just the nature of the beast.
EG, the development of the tooling and vehicle falling behind. Is it safe to assume then that once the first flight is conducted that the planned schedule will be more stable? ~1 flight per year type deal?
Quote from: Coastal Ron on 08/08/2018 03:42 amQuote from: JDTractorGuy on 08/07/2018 10:54 pmEG, the development of the tooling and vehicle falling behind. Is it safe to assume then that once the first flight is conducted that the planned schedule will be more stable? ~1 flight per year type deal?Production typically has far less potential for delays than development - it's just the nature of the beast.That presumes development actually... finishes. SLS/Orions development schedule, by years, would be reasonable if it was flying several times a year, but as it is, most flights for the first decade of operations will be unique.
EM-1, first flight, everythings new. Europa Clipper, first cargo flight (not a huge amount of risk, but some).EM-2, first manned mission, first functioning ECLSS, first live LAS, redesigned ESM plumbing.EM-3, first Block 1B, first comanifested payload, probably first LOP-G mission.EM-4, first RS-25E.EM-5, possibly new EUS main engine.EM-6, new Orion Main Engine and possibly Block 2 ESM.EM-9, Advanced Boosters.All of these have major delay potential. Nevermind the usual post-flight "oh, that didn't work as planned, gotta fix that" stuff.
Quote from: TripleSeven on 08/02/2018 06:07 pm... with no real mission. [SLS] It has missions...After that it will build Lunar Gateway. - Ed Kyle
... with no real mission.
Quick observer question. It seems from what I'm reading that a lot of the delays that SLS has faced, though ridiculous and frustrating, seem to stem from what I'll call "first flight jitters". EG, the development of the tooling and vehicle falling behind. Is it safe to assume then that once the first flight is conducted that the planned schedule will be more stable? ~1 flight per year type deal?
Reading the replies to this, I still have a question. I know the Orion for EM-2 is under construction, but has any parts for the core for the second SLS been produced yet?
I doubt we will ever see this thing in an assembly line like photo like we do of Saturn Vs.
Quote from: Ronpur50 on 08/17/2018 03:18 pmReading the replies to this, I still have a question. I know the Orion for EM-2 is under construction, but has any parts for the core for the second SLS been produced yet?Likely not, for a couple of reasons:A. EM-2 is planned for around 2022, ~4 years away, and it should take less than a year to build an SLS core.B. Ideally you want to fully test your first production unit before you commit to building your second one, so waiting until EM-1 flies and they can evaluate how it did would be best. QuoteI doubt we will ever see this thing in an assembly line like photo like we do of Saturn Vs.You have to remember that the Apollo program had a defined end when it was started, so they knew how many rockets they would commit to building. Of course the hope was that the prime goal (land a man on the Moon and return him safely) would be accomplished before they ran out of rockets, and luckily they did.So for the Saturn V they built them as one "batch".For the SLS, which is supposed to be a transportation system that lasts for decades, there is no need to build ahead of the known need. So no, for the sake of taxpayer money (i.e. inventory is not an asset), we should never hope to see a bunch of completed SLS cores lying around on the factory floor.
Core Stage 2 structures built to date:- Forward Skirt barrel- Engine Section barrel- Domes for cryo tanks and some barrels - Intertank structural assembly in workSee this L2 thread: https://forum.nasaspaceflight.com/index.php?topic=45407
I was strongly in favor of sticking with Block 1. Designing an SLS-specific EUS at this point is a total waste when it's basically the basic same specs as Vulcan's ACES but (probably) more dry mass and less capability. The IUS shares Delta IV infrastructure and thus reduces cost and risk. And using block 1 means that EM-2 can be crewed.
ACES would only carry about 60-ish percent as much propellant as EUS. ACES or Centaur 5 Long would be better than ICPS, but not as good as EUS.
Quote from: edkyle99 on 08/23/2018 03:46 pmACES would only carry about 60-ish percent as much propellant as EUS. ACES or Centaur 5 Long would be better than ICPS, but not as good as EUS.So what? What known payload does that affect?Optimizing for performance when you don't have any hard data on what your customers really need is a waste of money.
The payloads are well known. Orion and lunar platform. That's the plan [1]. Maximizing mass toward the moon for these missions is a no-brainer.
Quote from: Coastal Ron on 08/23/2018 03:52 pmQuote from: edkyle99 on 08/23/2018 03:46 pmACES would only carry about 60-ish percent as much propellant as EUS. ACES or Centaur 5 Long would be better than ICPS, but not as good as EUS.So what? What known payload does that affect?Optimizing for performance when you don't have any hard data on what your customers really need is a waste of money.The payloads are well known. Orion and lunar platform. That's the plan [1]. Maximizing mass toward the moon for these missions is a no-brainer. Block 1 can do 24-25 tonnes trans-lunar. Block 1B is about 39 tonnes. A Block "1.5" with an ACES might only do 30 tonnes or so. - Ed Kyle[1] https://www.nasa.gov/feature/nasas-exploration-campaign-back-to-the-moon-and-on-to-mars
Quote from: edkyle99 on 08/23/2018 05:49 pmQuote from: Coastal Ron on 08/23/2018 03:52 pmQuote from: edkyle99 on 08/23/2018 03:46 pmACES would only carry about 60-ish percent as much propellant as EUS. ACES or Centaur 5 Long would be better than ICPS, but not as good as EUS.So what? What known payload does that affect?Optimizing for performance when you don't have any hard data on what your customers really need is a waste of money.The payloads are well known. Orion and lunar platform. That's the plan [1]. Maximizing mass toward the moon for these missions is a no-brainer. Block 1 can do 24-25 tonnes trans-lunar. Block 1B is about 39 tonnes. A Block "1.5" with an ACES might only do 30 tonnes or so. - Ed Kyle[1] https://www.nasa.gov/feature/nasas-exploration-campaign-back-to-the-moon-and-on-to-marsACES would obviate the need for SLS entirely, so... yeah. Of course, EUS with IVF would be even more capable, but are there any 100+ tonne payloads to send to TLI?