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[New] Space Launch System / Orion Discussion Thread


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On 9/7/2019 at 7:02 PM, jadebenn said:

Spaceport survey finds little damage from Hurricane Dorian

No significant damage of any kind to any of the KSC infrastructure, thankfully. They're going to roll the ML back out on Tuesday.

I can attest to this. If no one told me there was a hurricane, I would've thought we merely had a wet and windy day. No damage done. 

Edited by ZooNamedGames
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2 minutes ago, .50calBMG said:

Sorry zoo, but it's hard to get hyped about something that is moving at such a slow pace that turning a section of it can be considered newsworthy. How long until it's fully integrated?

It's exciting for me since I've been reading the news feeds almost habitually since 2014. This is a huge leap in it's development. No longer is it a "piece of a rocket", just a "component". It will be a complete vehicle once these engines are attached. No longer a 'paper' rocket. Now a real vehicle. For me at least, it's massive.

When will it complete? I'd expect by the end of the month. Maybe sooner. Aligning the engine section is the slowest part, since they have to connect electrical systems, plumbing, hydraulics, data relays and a whole smorgishboard of other things. x4 for multiple engines.

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I was excited for SLS back when I was in highschool (2011-2015), but it seems like almost no progress has been made on it compared to almost anything else, and I'm not just comparing them to SpaceX. Ariane 6, for example has, if you really think about it, a lot in common with Ariane 5, and it took less then 5 years to go from the announcement to component testing. SLS has been around in some form or another since the 80s iirc, and still hasn't been fully integrated. It just astounds me how long it has taken, and the pace that seemingly everyone else is taking, especially SpaceX, just exacerbates it further.

Edited by .50calBMG
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1 minute ago, .50calBMG said:

I was excited for SLS back when I was in highschool (2011-2015), but it seems like almost no progress has been made on it compared to almost anything else, and I'm not just comparing them to SpaceX. Ariane 6, for example has, if you really think about it, a lot in common with Ariane 5, and it took less then 5 years to go from the announcement to component testing. SLS has been around in some form or another since the 80s iirc, and still hasn't been fully integrated. It just astounds me how long it has taken, and the pace that seemingly everyone else is taking, especially SpaceX, just exacerbates it further.

Issue is it was a paper rocket up until 2013-2014. No hardware and a constantly shifting design (akin to a lot of rockets in development)- and a true need wasn't established until after the Shuttle was retired and NASA was left empty handed. NASA intended to smoothly transition into Constellation but after President Obama cancelled it, that wasn't feasible (and there's plenty of discussion on this thread that goes into the specifics as to why the programmed was delayed, but who, why and so forth so I won't retread those topics). Yes, progress has been slow- but that's the nature of bigger developments. I'm just happy to have what we have- and not at a breakneck pace as some companies do... or at least one of them.

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My problem is that not only am I tired of waiting for it to do literally anything useful, I'm tired of having to pay for it to get built at a speed that makes glaciers look fast. Sure, I don't pay that much for it, but I'm paying for it none the less. It's getting built by some of the wealthiest, biggest, and arguably most reputable companies in the US, but it's still not even ready for an all up test. I understand that large projects take a long time, but they've had time. I didn't have to pay a cent towards starship, and it's not even a quarter as old as SLS, but they are both at about the same stage in development. Sure, SLS has the advantage of a larger fairing, but we don't have anything that needs all that volume. As @tater has pointed out multiple times, the Artemis program is a make work to at least sort of justify even having SLS to begin with. Constellation was a much better program, aside from the faults with the Ares 1, than SLS can ever hope to be at this point, and it should have been revived instead of creating a "new program from scratch".

Edited by .50calBMG
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NASA could rush it's development and make an unsafe vehicle and an unready vehicle however NASA is methodical and precise in it's work. If you want to get frustrated, get frustrated with the politicians as NASA has been committed to the SLS since 2010. They've just been side tracked, and delayed by every possible hurdle politics could throw at NASA- and today, NASA has finally managed to overcome all of them to make SLS a real vehicle and soon it'll finally be fully built. Not too long after (around the same time as SpaceX is deploying LEO payloads with Starship), SLS will be sending the first crews to lunar orbit since the 70s. 

Starship, is no where near the same degree of ready as SLS/Orion. Orion, though unmanned, is at least has all of the details of a crewed flight ready- merely sticking in the life support. Starship has no plans for crew space, what it will be designed like, the life support systems, life support capacity, life support testing, and a dozen other things that would prove Starship as remotely ready. Not to mention it's LEO only whereas Orion and SLS is going all the way to the moon. Despite it's 20km hop coming up- it's still a water tower. It has no re-entry systems (no thermal tiles or the now abandoned plan for metholox cooling ports), no payload space/capacity. At best it's comparable to New Shepard, seeing as they do much of the same thing (or at least will once it flies)- taking off,  going to altitude, and then coming back down to power land at a set destination. Only difference is New Shepard at least has gotten to the stage it's carried payloads. Starship has not and cannot unless a modification to the design is made to make payload support feasible. 

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At the risk of going off topic (and getting caught by my boss), I'll keep this sort of brief.

My argument for them being at the same level is based on the fact that, even though technically SLS is an SDLV, nothing on it has been flight tested except for the launch escape tower, unless EM-1 had an ICPS instead of a DCSS, which iirc it didn't. While the difference between the two is minimal, they are still different enough to warrant a name change.

Starship, more specifically star hopper, has flown twice with the same model of engine that will be used on the full scale production version. The heat tiles that they still plan on using have been flown both on the hopper itself and on dragon for full reentry testing.

Starship may not have it's life support, but neither will Artemis-1. Neither ship is ready, but they are both getting close. Right now, they're both just tubes with some bulkheads in them, but nothing that they actually need to function (boosters, engines, landing legs, etc.). 

Starship at the very least has had the same goal since it's inception, to get to Mars. SLS has had the Artemis program for a few months, and seemingly less than half of that program, arguably none of it, needs SLS.

Edited by .50calBMG
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There are 2 Starships, one will likely do terminal guidance testing (quite soon) (20km to the LZ is basically everything post reentry, if they can do that, they need only survive entry).

The FL SS can likely do full EDL without SH. Without payload it's a SSTO, even with reserve props for landing (SL Isp is higher than thought, @350s).

Orion is certainly better as a crew vehicle right now, because it's a crew vehicle. It will always be just "man rated," however. I honestly think that we'd be better (it'll slow dev to be sure) if crew vehicles went to an airworthiness standard (elements of the USAF wanted that for the early, 100% reusable Shuttle designs). That pretty much requires prototypes, then operational flights of the same vehicle (not the same type of vehicle, the same actual vehicle, all of it). At some point that will have to happen for spaceflight for humans to be more than a test pilot activity (that's really what astronauts are signing up for---brave humans, all of them).

Starship as a crew vehicle? I doubt we see that until after SLS flies with crew, frankly. SS will likely fly to space (orbital, not suborbital) in the Artemis 1 time frame, I think. Certainly before crew ever flies on SLS. Payload support feasible? Yeah, that's trivial, SpaceX knows how to deploy payloads, they don't need to bother with that until they need or want payloads, however. The goal is fly, improve, iterate.

Once Starship can deliver a payload to LEO, even with the upper stage expended, SLS makes no sense at all. Orion still does (though as always, it needs a real SM), it's a useful crew vehicle (or a useful core for others (that LM lander design uses an Orion pressure vessel for crew)).

Edited by tater
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7 minutes ago, Barzon Kerman said:

RS-25s have flown to space over 100 times tho, while Raptor has flown under 5 times.

RS-25 is a great engine, though this particular iteration has yet to fly (they've upped the thrust). More importantly than the 135 (whatever it is) flights total, a number of the engines individually flew to space many times. It'd be interesting to see the data on the required engine refurb over time---that said, the engine refurb on the SLS RS-25s was insane, they literally cost something like 3X the cost of the engines new.

You know what, I think it's a shame they wasted RS-25s on the SLS core stage.

They spent over 2 billion refurbing the SLS engines, imagine a different SHLV that NASA might have built (the advanced SRB includes a couple liquid fuel designs that could simply change the architecture to a proper staged rocket instead of side boosters and sustainers, frankly). So we'd have a RP-1/LOX SLS booster. Then we use RS-25 where it belongs, in SPACE. High thrust, killer Isp. It can not restart (dunno if adding that capability is even possible), but it could start in flight. As stage 2, it would be pretty powerful.

You'd likely be able to get away with using only 1 per SLS then, so the existing stock would never need to be added to.

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I personally wouldn't mind the use of the RS-25 for SLS if they were doing something like ULA so that they could get them back and use them again. The RS-25 is a pain to refurb, yeah, but I wouldn't put it past the incredibly smart people at NASA to find a way to bring that down. The way SLS is now, with a stupidly high price, under-powered first stage, and a useless upper stage (ICPS has no business as an upper stage for an SHLV. Great for a mid-sized LV like Delta IV and still useful for an HLV like D IV heavy), is not useful to anything other than... Wait... It will come to me eventually... Maybe...

As far as staging arrangement goes, I remember seeing somewhere that that staging arrangement is the most efficient way to build a rocket. If it wasn't, then how are Soyuz and Ariane 5 (and hopefully 6) as successful as they are? 

Finally, I don't want to come across as ignorant on some of these things. I know SLS has been bogged down by politics, as are most government projects. It's a given that that's going to slow stuff down, but I also didn't feel the need to address it because it's something that was going to happen no matter what.

It just seems to me like SLS is more and more like some British aircraft, namely the fairey albacore, or half the stuff they made in the late 40s, in that it was advanced at the point of it's design and promised to be better than it's predecessor, but by the time it finally made it into service it was so outclassed that wasn't even useful. I don't hate SLS, in fact, like I said earlier, I was super excited for it. I'll be excited for the first launch of something useful on it, like if it keeps Europa Clipper. I'm not hating on SLS just because everyone else does, or because it's easy. If anything, I'm just disappointed that it will never reach it's full potential under it's current program, and it won't be sustainable enough to be around for the next one.

Edited by .50calBMG
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SLS dumps the core stage short of orbit entirely for disposal, so recovering the engines would require a LEO reentry, basically. Engine recovery makes more sense with a lower staging/entry velocity.

The 2 B$ on RS-25 might have been better spent figuring out how to make a restartable version---then reuse the engine in space.

Not sure how possible that is, however, and WRT SLS, once you're wed to a sustainer architecture you're hosed (unless you look into fly back boosters or something (like early Shuttle concepts)).

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31 minutes ago, tater said:

SLS dumps the core stage short of orbit entirely for disposal, so recovering the engines would require a LEO reentry, basically.

I think the best mode of reusability for SLS would be SMART reuse like what ULA wanted for Vulcan. Take that engine section that was rotated today, add an inflatable heat shield+parachutes somewhere, decouple after upper stage separation. No need to reserve props, have fins or legs, or stage at lower velocity.

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32 minutes ago, tater said:

SLS dumps the core stage short of orbit entirely for disposal, so recovering the engines would require a LEO reentry, basically. Engine recovery makes more sense with a lower staging/entry velocity.

The 2 B$ on RS-25 might have been better spent figuring out how to make a restartable version---then reuse the engine in space.

Not sure how possible that is, however, and WRT SLS, once you're wed to a sustainer architecture you're hosed (unless you look into fly back boosters or something (like early Shuttle concepts)).

I’d support literally any of your LEO construction projects if we had literally any experience building anything that actually traveled. So far we have a single multi piece space station that’s locked to earth orbit and a 50+ year old capsule-space probe combo that stands as the only vehicles to actually dock then boost their orbit with crew. Even without crew I can’t immediately think of any payloads that rocked and traveled- though admittedly if someone can cite a spacecraft that did so and traveled beyond LEO- I will wholly admit my fault here, and concede that my point is only true for manned spaceflight.

1 minute ago, sh1pman said:

I think the best mode of reusability for SLS would be SMART reuse like what ULA wanted for Vulcan. Take that engine section that was rotated today, add an inflatable heat shield+parachutes somewhere, decouple after upper stage separation. No need to reserve props, have fins or legs, or stage at lower velocity.

It’s also lower risk in my opinion. Less to go wrong for the recovery to be botched and requires less development time.

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9 minutes ago, sh1pman said:

I think the best mode of reusability for SLS would be SMART reuse like what ULA wanted for Vulcan. Take that engine section that was rotated today, add an inflatable heat shield+parachutes somewhere, decouple after upper stage separation. No need to reserve props, have fins or legs, or stage at lower velocity.

Yeah, Dunno what speed they dump the BE-4s at, but yeah, SLS would need a huge, deployable heat shield, and it likely harms margin, which it doesn't really have for Orion ops (none at all for block 1, and a small amount meant for comanifested payload on 1b).

10 minutes ago, ZooNamedGames said:

I’d support literally any of your LEO construction projects if we had literally any experience building anything that actually traveled. So far we have a single multi piece space station that’s locked to earth orbit and a 50+ year old capsule-space probe combo that stands as the only vehicles to actually dock then boost their orbit with crew. Even without crew I can’t immediately think of any payloads that rocked and traveled- though admittedly if someone can cite a spacecraft that did so and traveled beyond LEO- I will wholly admit my fault here, and concede that my point is only true for manned spaceflight.

This is silly. ISS gets boosted all the time. Apollo docked 3 times every mission. Everything in LEO is traveling, 100% of the time, the difference between traveling and not traveling is reference frame, nothing more. There is nothing magic about leaving LEO.

You're basically fine with docking AND "traveling" when it's around the Moon, but not safely in LEO. For reasons. Artemis landing ops require a possible docking en route to the moon (B1b modules), docking at Gateway automatically by multiple parts. Docking near Gateway (or in LEO?) by lander elements. Docking of a tug, possibly with the lander, THEN to the gateway, or more likely with the lander after the crew boards. The another docking coming back to Gateway from the Moon. The docked tug "travels" with the also docked together 2 stage lander. If you have any issue with docking, you have to scrap the entire notion of an Artemis lunar landing. Docking is fine, or it isn't, pick one.

 

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42 minutes ago, tater said:

Yeah, Dunno what speed they dump the BE-4s at, but yeah, SLS would need a huge, deployable heat shield, and it likely harms margin, which it doesn't really have for Orion ops (none at all for block 1, and a small amount meant for comanifested payload on 1b).

This is silly. ISS gets boosted all the time. Apollo docked 3 times every mission. Everything in LEO is traveling, 100% of the time, the difference between traveling and not traveling is reference frame, nothing more. There is nothing magic about leaving LEO.

You're basically fine with docking AND "traveling" when it's around the Moon, but not safely in LEO. For reasons. Artemis landing ops require a possible docking en route to the moon (B1b modules), docking at Gateway automatically by multiple parts. Docking near Gateway (or in LEO?) by lander elements. Docking of a tug, possibly with the lander, THEN to the gateway, or more likely with the lander after the crew boards. The another docking coming back to Gateway from the Moon. The docked tug "travels" with the also docked together 2 stage lander. If you have any issue with docking, you have to scrap the entire notion of an Artemis lunar landing. Docking is fine, or it isn't, pick one.

 

ISS gets a piddly boost of a few dozen meters per second- even considering it on the same level as injection/orbital insertion maneuvers is what’s truly silly- As to Apollo- 2/3 dockings didn’t lead to burns. There was only 1 burn which I’ll admit meets the criteria I set (the LO capture burn), though only Apollo 13 meets the criteria of using an engine not connected to the crew module at launch (by using the LM descent engine). 

Whats magic is docking large spacecraft and making sure they don’t shear themselves apart due to the acceleration forces of a burn. The larger the vehicles the larger the forces at play- which goes from mildly denting thick metal frames and beams with something to the size of Apollo to tearing it like paper with bigger builds. It’s something we simply don’t have experience with. ACES honestly is the best way to get experience without being too overly ambitious. It’s smaller sized but can be used to have payloads flown to it. Slowly maybe we can see multisegmented payloads. A kickstage attached, then something else like an upper stage. Slowly growing to a more complex vehicle of your scale. Life isn’t KSP- we can’t just jump from one tier level to the other without consequences. We need to know what can happen when things change and scale a big part.

The difference between Artemis and your plans is that Orion goes to a destination, Orion does not tug any payloads- not even a lander like Apollo did. All modules will be deployed commercially as will the lander. Orion will just be a ferry between the earth and LOP-G. No tugs involved. 

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18 minutes ago, ZooNamedGames said:

ISS gets a piddly boost of a few dozen meters per second- even considering it on the same level as injection/orbital insertion maneuvers is what’s truly silly- As to Apollo- 2/3 dockings didn’t lead to burns. There was only 1 burn which I’ll admit meets the criteria I set (the LO capture burn), though only Apollo 13 meets the criteria of using an engine not connected to the crew module at launch (by using the LM descent engine). 

Whats magic is docking large spacecraft and making sure they don’t shear themselves apart due to the acceleration forces of a burn. The larger the vehicles the larger the forces at play- which goes from mildly denting thick metal frames and beams with something to the size of Apollo to tearing it like paper with bigger builds. It’s something we simply don’t have experience with. ACES honestly is the best way to get experience without being too overly ambitious. It’s smaller sized but can be used to have payloads flown to it. Slowly maybe we can see multisegmented payloads. A kickstage attached, then something else like an upper stage. Slowly growing to a more complex vehicle of your scale. Life isn’t KSP- we can’t just jump from one tier level to the other without consequences. We need to know what can happen when things change and scale a big part.

The difference between Artemis and your plans is that Orion goes to a destination, Orion does not tug any payloads- not even a lander like Apollo did. All modules will be deployed commercially as will the lander. Orion will just be a ferry between the earth and LOP-G. No tugs involved. 

The Artemis lander stack (also itself docked together since nothing can launch it in 1 piece) is moved with a tug, so it will push through one docking port, to a vessel linked by another docking link (not crew in this case).

ISS is vastly more complicated than what we are talking about, so the boosts matter (it's not all inline forces). they could have done EoR to the Moon in the '60s, it's not a big deal, or even a little deal. The only reason to pretend it's a problem is to make it seem like the current architecture is the only way to do it. Nothing about the complex LoR architecture of Artemis is less dangerous than any such architecture in LEO.

Apollo S-IVb pushed the TLI stack at all of ~1.4g. Anything that can survive launch can survive those forces. LOI was under 1 g. Not a problem. We're talking about docking Orion to what would in effect be a large ACES. 5.4m ACES carries 68 tons of props. So that is in effect exactly what we are talking about to send Orion, plus a lander (Apollo LM was 16.4t, Orion is 26t), something close to ACES in capability.

Edited by tater
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9 minutes ago, .50calBMG said:

The tugs will be needed to put the modules into LO...

Those are upper stages at that point- it becomes a tug (to me) when it docks and then is transported. As on earth when I think of tugs, I generally don’t imagine they come preattached at launch. Ie tug boats and train tugs.

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Just now, ZooNamedGames said:

Those are upper stages at that point- it becomes a tug (to me) when it docks and then is transported. As on earth when I think of tugs, I generally don’t imagine they come preattached at launch. Ie tug boats and train tugs.

Pre-attached makes it stronger, not weaker. No reason not to dock something like Orion to the lander/upper stage stack, then send the whole thing to TLI.

NASA was considering a tug/ferry architecture in the 1960s. The idea that this is somehow super hard is goofy. It's an engineering problem, you design the docking rings to deal with it, and you're done.

(course changing Orion's docking system would likely take 20 years and cost at least that many billions (change orders are expensive!))

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5 minutes ago, tater said:

Pre-attached makes it stronger, not weaker. No reason not to dock something like Orion to the lander/upper stage stack, then send the whole thing to TLI.

NASA was considering a tug/ferry architecture in the 1960s. The idea that this is somehow super hard is goofy. It's an engineering problem, you design the docking rings to deal with it, and you're done.

(course changing Orion's docking system would likely take 20 years and cost at least that many billions (change orders are expensive!))

It’s only weaker with larger builds due to the increased stresses involved- and its not that we can’t but that we aren’t prepared for what we don’t know with such scales. Could we make a massive multijoint vessel with 8 modules to speed off to Mars? Yes, we have the vehicles and the technology to do so- what we don’t have is the knowledge of how those vehicles will behave under the circumstances of acceleration, deep space flight or anything else since we haven’t made something to those scales. We don’t know what could happen- not that those make it impossible to do- just irresponsible to take risks and to wave potential unknowns just because we’ve done something far smaller and simpler than such a larger task as I described.

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