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Maybe a dumb question, but when they do tests like these, how does the engine not go flying away? Especially since it doesn't have a payload on top. Do they just weigh it down as much as they can beforehand and hope it's enough?

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27 minutes ago, Mitchz95 said:

Maybe a dumb question, but when they do tests like these, how does the engine not go flying away? Especially since it doesn't have a payload on top. Do they just weigh it down as much as they can beforehand and hope it's enough?

AFAIK it's firmly attached to the test stand using a bunch of huge bolts. They have to build those bolts pretty strong, too - they need to be able to handle 16,000 kN of force.

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41 minutes ago, RealKerbal3x said:

AFAIK it's firmly attached to the test stand using a bunch of huge bolts. They have to build those bolts pretty strong, too - they need to be able to handle 16,000 kN of force.

Basically they attach a lot of ropes.

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From the Politico interview:

Quote

‘SLS will go away’: Boeing’s Space Launch System rocket could face trouble though, regardless of who is in office in 2021, he predicts. “SLS will go away. It could go away during a Biden administration or a next Trump administration … because at some point commercial entities are going to catch up,” he said. “They are really going to build a heavy lift launch vehicle sort of like SLS that they will be able to fly for a much cheaper price than NASA can do SLS. That’s just the way it works.”

 

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38 minutes ago, RCgothic said:

 

Eric is so transparent and shameless with his bias that it’s a wonder that people still take him seriously as a ‘journalist’. Maybe if he prays a little harder SLS will eventually go away lol.

33 minutes ago, GuessingEveryDay said:

I wonder why?

  Reveal hidden contents

oncestarship.jpg

I know it seems rude, but Elon Musk did say that we could see a OFT of the full Starship with the Super Heavy Booster some time in Dec 2020-Feb 2021

 

First of all, taking anything that comes out of EM’s mouth seriously is a massive brainlet moment. Secondly, in the exact same interview EM talked about SH doing “hundreds” of satellite launches before a crewed mission; so even IF SH somehow sticks to EM’s fictitious timeline, it won’t be taking crew to the Moon for a very long time. Thirdly, Congress and not public opinion or a mediocre former NASA administrator controls if or when SLS will go away or not.

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That sounds a lot like 'When there exists a commercial SHL vehicle, we can stop paying the SLS 'insurance premium' which is currently being paid to make sure that such capability comes into existence'

Personally, I was kind of expecting them to wait for multiple commercial options, just to make sure they always have a backup should one of the options become unavailable for some reason.

(which may still be the case, as Blue Origins will probably launch in the next 4 years in addition to Starship)

 

That sounds eminently sensible... and entirely unlike congressional appropriations...

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Berger's not wrong. SLS/Orion is stupidly overpriced. If it all worked perfectly for launch tomorrow it still couldn't put boots on regolith. It can't co-manifest a lander with Orion and the lander isn't ready anyway.

For the price of the SRBs and RS25s alone you can get ten fully expendable Falcon Heavy flights or 20-30 Falcon 9s. You can build a better moon mission around a fraction of that lift capacity with a little in orbit assembly.

The only reason they haven't is because those boosters came along after Congress made its mind up.

With even greater commercial heavy lift coming along there's no reason for SLS to continue to operate.

Edited by RCgothic
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A full diameter SLS (requires EUS to exist) can loft larger cargoes that are volume constrained, but that's not a thing yet, and NG will obviate much of that need (ignoring SS).

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5 hours ago, V_Bomb2001 said:

Thirdly, Congress and not public opinion or a mediocre former NASA administrator controls if or when SLS will go away or not.

Pretty much this.  And Congress doesn't care if a commercial option exists or not.  Heck, they don't even actually care if SLS ever flies or not.

The Senate Launch System is a jobs & pork project.

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10 hours ago, V_Bomb2001 said:

Eric is so transparent and shameless with his bias that it’s a wonder that people still take him seriously as a ‘journalist’. Maybe if he prays a little harder SLS will eventually go away lol.

That's a tweet about a politico interview, it's not his interview (but he characterizes it fine, I provided the quote from the actual interview).

What can SLS actually do? Launch Orion almost to someplace useful. That's it. Evolved, it can send a useless comanifested payload almost someplace useful. To be actually useful (assuming Orion doesn't go away) it needs to throw 60-70t to TLI. That or Orion gets dumped in favor of something more Apollo like (capsule mass and SM capability), and then it can get that new CSM (and a lander) to LLO and back.

Something has to change for SLS to be useful, and nothing will make it cost-effective.

10 hours ago, V_Bomb2001 said:

First of all, taking anything that comes out of EM’s mouth seriously is a massive brainlet moment. Secondly, in the exact same interview EM talked about SH doing “hundreds” of satellite launches before a crewed mission; so even IF SH somehow sticks to EM’s fictitious timeline, it won’t be taking crew to the Moon for a very long time. Thirdly, Congress and not public opinion or a mediocre former NASA administrator controls if or when SLS will go away or not.

No more a fictitious timeline than SLS's (required by law to have launched by the end of 2016).

First test launch of SLS will be next year. First almost all-up launch will be Artemis II (2023?), first actual all-up launch is supposedly the Moon landing in 2024.

So not-fictitious, much more real than SS (with a lander that doesn't exist somehow getting tested before 2024). :confused:

Some people will always dump SpaceX into the Orion/SLS thread (though it's usually the SLS people). In an Artemis thread, Starship is a totally legit thing to discuss (it's still on the table as the lander). The bottom line WRT SLS is that it's designed to spend money, not designed to do anything useful. Congress is interested in money spent in districts, doing something is incidental, so SLS/Orion will certainly continue until they look so stupid for wasting money on it they have to pivot. That's certainly down the road a ways, but it is inevitable.

The one thing about the inevitability, it didn't have to be so obvious that this is true. Had a decent vehicle been designed in the first place, it wouldn't look as useless as it does.

 

Edited by tater
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I should add, I wasn't a huge Shuttle fan from the standpoint of moving the ball down the field, I thought it spent a lot of money for a very static capability—but that said, the Shuttle had some remarkable capabilities. If SLS was another Shuttle-like program in terms of not really evolving much, and just being a super capable, or indeed overly capable vehicle that was really expensive, I'd be cool with it.

Did we need the ability to send 8 people up at once to LEO? Nope, not really. But for the same sort of budget per year as SLS/Orion has, Shuttle would have that excess capacity for it's LEO mission, and do it up to 9X a year. If all SLS did was send 4 people to a useful place around the moon with a decent comanifested cargo 3-9 times a year for the exact same money we are paying, I'm all in.

Instead for the amount of money spent on X flights per year of Shuttle—a vehicle where the problem was it was over-capable—we maybe get 1 flight of an under capable vehicle per year.

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STS could put what, 110t of mass in LEO, 78t of which being orbiter?

If SLS could put 10m diameter payloads of up to 110t into LEO 3-9 times a year at roughly the same cost as the space shuttle, then that would be a useful capability no matter what it was used for, even in the face of new commercial competition. Sometimes that 110t could be a departure stage for BLEO missions. Useful! I think it would save a lot of money in assurance if crew never had to go up on it, but even so it could still work.

But I don't understand how you start with shuttle, add an engine, and get less mass to LEO, a quarter of the flight rate, 3x the entire marginal cost of a shuttle flight on SRBs and RS25s alone, and a lunar rocket that can't even put boots on moon properly.

Edited by RCgothic
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5 hours ago, RCgothic said:

STS could put what, 110t of mass in LEO, 78t of which being orbiter?

If SLS could put 10m diameter payloads of up to 110t into LEO 3-9 times a year at roughly the same cost as the space shuttle, then that would be a useful capability no matter what it was used for, even in the face of new commercial competition. Sometimes that 110t could be a departure stage for BLEO missions. Useful! I think it would save a lot of money in assurance if crew never had to go up on it, but even so it could still work.

But I don't understand how you start with shuttle, add an engine, and get less mass to LEO, a quarter of the flight rate, 3x the entire marginal cost of a shuttle flight on SRBs and RS25s alone, and a lunar rocket that can't even put boots on moon properly.

This.

SLS was really a follow on of the failed Constellation program (for reasons that have been discussed). The problem is that it didn;t keep the one part of Constellation that was most important:

Big rocket is a cargo rocket.

That's it. By switching from the RS-68s to RS-25s, ther went from "not man rated" to "man rated," so why not put a capsule on top? Then the capsule got heavier and heavier, the SM stayed the same as the Constellation days (where it was basically an overly capable LEO capsule, as it was to do ISS missions as well), and SLS/Orion became useless as a result.

SLS isn't entirely useless.

Orion isn't entirely useless.

The ESM is in fact entirely useless.

Combined the system can accomplish zero useful missions. Something needs cutting. A smarter program would see this issue, and cut SOMETHING.
 

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I think the most telling thing about that last Ars Technica article - and I don’t recall whether it was in the actual article or the comments - was the reminder that we’ve moved from wondering whether Falcon Heavy would fly before SLS to whether Starship/Superheavy will fly before it.

The cheerleading for either side hasn’t changed much either.

And yes, I’m being that person who dumps SpaceX into an SLS conversation. 

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We are in the same position our grandfathers were, when they witnessed steamships replacing sail ships. Or automobiles replacing horse-drawn carriages. Or passenger airplanes replacing ocean liners. Paradigm of space travel is shifting, but the thing is - any guesses about what will finally emerge as an optimal solution are hit-or-miss at this point.

Maybe Starship will work as advertised. Or maybe it will be a literal flop, and New Glenn type rockets will emerge as the way to go. Or maybe Skylon-like spaceplane will prove itself as optimal solution. Or maybe someone will build a space elevator and all rockets will go the way of dodo :)

We certainly live in exciting times :) So, lighten up and enjoy the show guys.

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Here's the thing.

Even if Starship completely fails to survive EDL and they can't fix it. If they never get refuelling in orbit to work. If Superheavy never sticks a single landing.

Then you can still retool the system as a conventional expendable rocket with ~250t payload to LEO and IDK, a 12m payload fairing, and all 34 engines *combined* will cost about half as much as a single RS25.

Even if Starship/Superheavy is a complete abject failure, it still renders SLS totally obsolete.

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1 hour ago, RCgothic said:

Here's the thing.

Even if Starship completely fails to survive EDL and they can't fix it. If they never get refuelling in orbit to work. If Superheavy never sticks a single landing.

Then you can still retool the system as a conventional expendable rocket with ~250t payload to LEO and IDK, a 12m payload fairing, and all 34 engines *combined* will cost about half as much as a single RS25.

Even if Starship/Superheavy is a complete abject failure, it still renders SLS totally obsolete.

Heck, looking at it a bit more optimistically and assuming that Superheavy can be reliably landed. All (all?) that gives us is a supersized replacement for Falcon 9 - and that's if nothing else you listed works. 

Although I suspect that would be something of a rocket to nowhere for anything other than launching enormous chunks of Starlink at a time.

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6 hours ago, KSK said:

Heck, looking at it a bit more optimistically and assuming that Superheavy can be reliably landed. All (all?) that gives us is a supersized replacement for Falcon 9 - and that's if nothing else you listed works. 

Although I suspect that would be something of a rocket to nowhere for anything other than launching enormous chunks of Starlink at a time.

Yeah, then you need a business case for operating it.

That said, I remember when space people were talking about "big dumb boosters" all the time. The concept was another from the 60s, but it was talked about in the 80 and 90ss as well. The only customer of course was the government.

The bottom line is that for a space-fairing future we need operational reuse. That happens, or we're on this world forever, with the occasional foray out to put boot prints on the Moon or Mars, and that's it. I personally don't see much rationale for space colonization, and certainly no business model for it, but I like the idea of it anyway. That's the part of Musk's talks that really hit home with me (just as Bezos saying this is the best planet, and we should move dirty stuff off it resonates with me).

This is all really tangential to SLS/Orion, though.

It would be an interesting thing to see someone, anyone at NASA talk seriously about what the goal is, and what could be done to evolve the concept into one that actually moves the ball. I've said in parts of this thread, or Artemis that since BO has always said NG is designed as crew rated out of the gate (ditto Vulcan), Orion should transition to NG the second that becomes an option. A distributed NG launch (1 with Orion, another "naked" upper stage) can get probably Orion to LLO (assuming the upper stage can mitigate boil off to do the LOI burn). Might have to use a couple hundred m/s of SM props, unsure (depends on dry mass of NG upper stage, and Be-3U Isp). Could always use RL-10s, though.

Cutting Orion from SLS changes a lot. The crew-rating is then sunk cost, but at least it's just a big dumb booster (as it always should have been). Course it lacks the "cheap" part of that equation, but it was always intentionally to maximally spend money, not to do anything, so that's fine.

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