SLS General Discussion Thread 8

[RickA]

This became 'about me' (and, incidentally, 'about you') with the very first line of your original reply which assigned views to me that were a distortion of what I actually said. And you did it in a way that attacked me. 'I'm puzzled how anyone could think SLS is some sort of "National Prestige"'

What I actually said was that National Prestige is one factor to be considered when evaluating projects. And nothing more.

To expand slightly on that, it is a factor that can be considered. And it almost always is, in large, high profile, projects, consciously or unconsciously, even if the answer is 'zero'. And projects can have negative National Prestige impacts, especially if they fail (or are perceived as failing).

You then appear to have taken that and run with it to insert the idea that I ascribe positive National Prestige to SLS and a whole lot more.

Having assigned various views to me is it somehow unreasonable for me to correct that?

Anyway, to run through your latest post quickly...

Nope, I did not list a series of metrics with which to evaluate SLS. I listed a series of metrics with which to evaluate ANY project.

I didn't state anything about my personal evaluation of SLS. And I didn't take your views on SLS as a personal attack. I took assigning views that I don't hold and statements I didn't make to me as something to be corrected, with some asperity because of their wide range and they way they were expressed.

As a BTW, I will add a hostage to fortune and state that my paragraph on my background was for context only, not some form of 'Argument from authority'. I may be wrong, but if so I am wrong from a background of knowledge (and should, therefore, probably know better).

It is not pretty clear from my statement about SLS vs Starship that I think Starship is the only alternative to SLS. I was making a comment on how some people misremember history, in this case people who do hold the view on Starship vs SLS that you ascribe to me.

'Clearly you think that taking Hurricane risks into account ... more favourable to SLS'. Again, the meaning is in the wording.

'I wouldn't be surprised to see comparison between Starship and SLS risks that included Hurricane risks to the latter but not the former.' - Nowhere do I mention ignoring hurricane risks for both vehicles or including them for both vehicles or my views on the outcome of an evaluation of either case.

I will repeat and expand on what I have said several times. I am not a fan of any particular option (yes, including those that aren't SLS or Starship). In fact I have big concerns with all of the ones I have seen (even Apollo!) - and I have seen 'a few'.

Yes my original posts were triggered by the way that I felt that pro and anti SLS posters were distorting their evaluations, particularly on costs. To the extent that I feel that various parties are costing significantly different things (e.g. Future vs Past costs, or both) and preparing themselves to compare those costs against against others that are incompatible with them.

I'm now going to drop this because it consumes time and effort I don't have. If people regard that as having 'lost' then so be it.

I just hope people have stepped back a bit and will try and be evenhanded in their evaluation of SLS and, inevitably, alternatives (there are always alternatives, even things like 'stop all US Human Spaceflight', they may not be that good an idea however). And also in their evaluation of how we got to where we are and where the US is, and/or should be, going. What I was trying to do was give (or remind) people (of) the tools to do the job.

[RickA]

Addendum: You can be 'even handed' and still come out with the result that 'this is/was a very very bad idea'. I have done that a few times in the past professionally. In fact being scrupulously even handed is the best approach when your analysis may result in the cancellation or significant modification of a popular project.

[woods170]

THIS is a large part of why I left NSF many years ago and why I will probably do so again very shortly. Try to be helpful or get people to be balanced about their thinking and you will be roasted for it.

The anti SLS is warranted.   Anything else is better.   It is the SpaceX only fanatical young males are the issue.

I'm with Rick.  95% of the discussion on this thread has been to complain about cost, schedule and flight rate.  While valid issues, it is a dispiriting drumbeat.  I would much rather have discussions on technical and programmatic changes that could improve the SLS program.  The latter discussion would educate and maybe lead to positive improvements.  For example:
* Design improvements to mitigate hydrogen leaks and improve sensor reliability
* FTS design changes to increase the batter life or allow for charging after installation
* Pad flow improvements to reduce roll-out times
* Identify and resolve bottleneck issues to increase production rate of SLS so that you could have a higher flight rate.
* Co-manifest options with Orion
* Mobile launcher upgrades to improve serviceability, weight, and alignment issues
* Refueling of the core hydrogen tank in LEO as a cryo depot or wet workshop, perhaps after BOLE is implemented that could get the core into a stable LEO orbit.
* Recovery and reusability upgrades for SLS components
* Material science discussion on alternatives to the foam insulation around the core tank.

Those are just a few ideas, many more are out there.       

Emphasis mine.

Sure...let's just throw more good money after $31B of bad money already spent, in an attempt to fix the many technical shortcomings of SLS, while the result will still be an unsustainable rocket in the long run.

This excercise to fix SLS would have been completely unnecessary if NASA had not bowed to political pressure and had just come up with a clean slate design.

You yourself just pointed out a host of things of technical nature that could with improvement. But those merely come on top of the fundamental problems with SLS (which have been called out in this thread many times before).

[tea monster]

Compared to what?  The other two PRIVATE space programs?  Weren't those big rockets supposed to launch.....2 years ago? Lit 7 out of 33 engines and then had to swap them out!  Whoohoo! Then there's the other one with, no engines?  But hey nice launch towers/pads and great inflight abort test!  We don't know much more because they're PRIVATE. 

Wasn't SLS supposed to launch in 2016? Something about people in glass houses comes to mind.

[DanClemmensen]

Compared to what?  The other two PRIVATE space programs?  Weren't those big rockets supposed to launch.....2 years ago? Lit 7 out of 33 engines and then had to swap them out!  Whoohoo! Then there's the other one with, no engines?  But hey nice launch towers/pads and great inflight abort test!  We don't know much more because they're PRIVATE. 

In theory, NASA is more transparent because it's a government agency subject to public oversight, while BO and SpaceX are private and not required to tell anyone anything.

In practice, NASA has a large PR organization that tightly manages and controls its information flows.

BO seems to do a pretty good job of staying private. IMO that's because there are not a lot of interesting things happening.

SpaceX is a whole new story. Boca Chica is a small sand spit on the Texas coast completely surrounded by fanatics with long-range telephoto lenses, with a public road running down it. SpaceX does not need to say anything, because almost everything they do is right out there in the open.

[Proponent]

Wasn't SLS supposed to launch in 2016?

This is one of my pet peeves.  As discussed upthread, it and Orion were supposed to be operational to LEO by 2016, implying a first launch in 2015 or earlier.

[tea monster]

This excercise to fix SLS would have been completely unnecessary if NASA had not bowed to political pressure and had just come up with a clean slate design.

To be fair, was there ever a real option that NASA would be able to design a clean-slate option? IIRC, the government forced SLS on NASA and commanded that they build it using legacy shuttle hardware (read as: contractors). This has been a feature of HSF for decades now. Even Apollo could be seen as a similar program. The President needed a goal for the country and decided that the Moon was a feasible option. It wasn't driven by any research, scientific or technical goal. The difference between Apollo and SLS is that Apollo did it's job quickly and successfully. Constellation, SLS and Artemis have all been political directives. None of the programs have been driven by any directive by NASA. Program creation and cancellation for HSF nearly always is at the whim of political direction - as with SLS - to the design of the vehicle itself.

What is needed is for NASA to be given more power over it's direction and goals. We need to remove politics from how HSF directives are arrived at. It is often said "Just cancel SLS and Orion". That would be probably the best outcome for the direction of human spaceflight. The problem with that is that once you did cancel SLS, just like as happened with Constellation, the powers that be will decide that all those jobs in the usual districts will need to be kept and another program with similar designs and aims (not HSF) will be created for NASA to herd over. Politics have to be removed to allow the real progress of humanity into the Solar System. If we don’t, then there is a chance that our kids will be on this forum in another fifty years time having the same arguments that we did about the latest NASA flags and footprints spectacle.

[Proponent]

A private-sector super-heavy rocket is yet to be proven. SpaceX is making great strides and they seem to be on the right track. More power to them, I hope they are successful. But that is at Elon Musk's discretion, SH/SS could be canceled at any time. Blue Origin seems to be stuck in permanent engine development mode with BE4, and nothing concrete about New Armstrong at all for years. All they have at the moment is New Shepard doing vertical 100 km hops, nowhere near reaching orbital speeds. At least they are getting good practice in on launch, land, and recovery.

Am I missing anybody? Any other entries in the fiercely competitive super-heavy market segment? The fact is that there is no commercial market demand for super-heavy launch at this time.

Why is the presence of lack of market demand for super-heavy lift relevant to the decision to build SLS?

[Proponent]

To be fair, was there ever a real option that NASA would be able to design a clean-slate option?

Why should NASA be in the rocket-building business at all?

[Coastal Ron]

I'm with Rick.  95% of the discussion on this thread has been to complain about cost, schedule and flight rate.  While valid issues, it is a dispiriting drumbeat.

Yes, it is. But taxpayer money is not free. The same $20B+ spent so far on the SLS could have been spent on other high-priority taxpayer projects (too many to name), or returned to the taxpayers.

We could have also spent that same amount of money and used a small part of it to buy launches on existing launch vehicles, and the rest on reusable hardware systems that could have taken us back to the Moon by now.

As for your list, how would it looks if you instead focused on the cost of doing things in space, instead of trying to fix things that are the most costly alternatives?

For instance, do you know why America has not returned to the Moon before now? It isn't because there isn't an interest, it is because of how much it costs to send humans to the Moon.

Think about it. If it only cost $1M per person to go to the Moon, then there would likely be hundreds, if not thousands of people going there every year, right? But as of today, ignoring the $40B+ it has cost to develop the SLS + Orion, NASA is projecting that it will cost $1B per person just to get to lunar orbit. $1B per person.

But for NASA it doesn't cost $1M to send someone to the Moon, so far it has cost ~$50B just to develop the SLS and Orion test versions. And NASA still has to develop the rest of the hardware systems that will allow humans to get from lunar orbit to the surface of the Moon.

And just from an operational standpoint, the SLS+Orion combo will cost $1B per person just to get them to lunar orbit. $1B per person.

So do you see how money matters? That if we were to focus on the cost of doing things in space, that we might actually be able to do MORE in space?

That is really what the SLS debate is about.

[tea monster]

The problem with that is that if we cancel SLS tomorrow, that money won't get plowed back to a sensible plan to explore and settle the solar system. The government will instead create yet another make-work program to distribute it to the usual suspects. THAT is the real problem with SLS, which was the same problem with Constellation.

NASA direction needs to come from scientists and engineers, not politicians.

People tell me "You had your 'Apollo moment', I want one too!" I tell them "That's great, I want you to have one as well, but you should have had your Apollo moment anything up to twenty years ago. Now you should be sitting down with your kids and watching us go on to Mars. That's why you should be upset with the modern state of human spaceflight!"

[mandrewa]

I listed a series of metrics with which to evaluate ANY project.

RickA, I've read all of your comments.  And I don't understand what you are saying. I don't understand your metrics.  I have a vague sense of what you might mean.  But I don't really know.  It would help if you would give an example.

And to start things off, I'll give an example of how I might compare things:

The first number is the NET year of first launch, if it's not current.
The second number is max. payload to LEO (nominal).
The third number is the estimated or actual price for a launch.

16.7 mt Falcon 9, booster and fairing recovered: ~$ 55 million
22.8 mt Falcon 9, expended: ~$ 90 million
57.0 mt Falcon Heavy, core booster expended: $ 97 million
63.8 mt Falcon Heavy, expended: $ 150 million
[NET 2022] 95.0 mt SLS Block 1: $ 2.2 billion
[NET 2022] 130.0 mt Starship, expended: ~$ 50 million
[NET 2023] 27.2 mt Vulcan Centaur VC6: ?
[NET 2023] 4.0 mt H3: ?
[NET 2023] 10.3 mt Ariane 62: $ 75 million
[NET 2023] 21.6 mt Ariane 64: $ 115 million
[NET 2024] 130.0 mt Starship, everything will be recovered, refuelable in orbit: ~$ 50 million
[NET 2024] 45.0 mt New Glenn, booster is recovered: ?

The prices are somewhat nominal. They often don't take inflation into account and they are tentative forecasts other than for the Falcon rockets. And it's been a while since I have heard the price for a fully expended Falcon Heavy so I suspect that has changed. If anyone knows what any these prices are expected to be please say so. I'm looking for the price that an ordinary commercial customer would be charged, not what the government pays (which is usually for much more than just the launch) and not the price for a megadeal on the commercial side. The price I gave for the Starship was just a guess. I know that SpaceX is aiming for lower than that, but I'm thinking about what it might actually be at first.

I think these are the key numbers and the only way we can be led astray by them is if some of these vehicles accomplish less than the others in a way that isn't being captured by the numbers in the table.  And there is an example of that in the table.  The Starship is intended to be refuelable in orbit, and that is an hugely important ability that radically expands what can be done with the vehicle, and in that respect the others simply aren't comparable, almost regardless of what they cost.

Edit: As per lazlo below.

[tea monster]

So the SLS has many good things about it:
1) It uses LOX/LH2
2) It uses SSMEs

And then drops them into the Atlantic 

3) It uses advanced aluminum alloys with the core tanks that are colored with orange foam.

That 95% good stuff by weight

So when folks oppose it, they cannot point to specific thing they’d change.

However the Orion payload is a very non-inspirational design.  It doesn’t invoke anything about innovation.  Just looks like a capsule from the 60’s.  People were pretty negative when about it was launched on a Delta launch vehicle.

So hypothetically, what if there was a Starship on top of SLS?   I think folks would be more positive.


Again hypothetically, what if Orion was on top of a Super Heavy Booster? 😱. That would likely be a pretty awful sight.

 
Be very careful what you wish for!
There is a guy on Twitter called 'The Cursed Rockets Guy'. He does what it says on the tin.
https://twitter.com/TheKSPManiac/status/1562510112337514497

Daily cursed rockets #164:

Orion and ICPS on Superheavy

Requested by @starsea099

[laszlo]

[NET 2022] 130.0 mt Starship, everything will be recovered, refuelable in orbit: ~$ 50 million

NET 2025, if at all, for all 4.

[Mackilroy]

BO seems to do a pretty good job of staying private. IMO that's because there are not a lot of interesting things happening.

As an aside, Blue is working on quite a bit, but they’re incredibly secretive for whatever reason. If you like, DM me, and I can send you a link to a Google Doc of painstakingly uncovered information about their projects, from Lunar Clipper, to New Glenn, and beyond.

[Jim]

So hypothetically, what if there was a Starship on top of SLS?   I think folks would be more positive.

SpaceX would be very negative about it.

So if I had to give up something from ARTEMIS I, you could get me to budge with Orion.  It hasn’t flown any astronauts yet.  And the basic concept of Orion seems too cramped and limiting for traveling to the lunar surface.

No Orion, no need for SLS.

[DanClemmensen]

[NET 2022] 130.0 mt Starship, everything will be recovered, refuelable in orbit: ~$ 50 million

NET 2025, if at all, for all 4.

Why do you think this? you may be right of course. IMO SLS/Orion is riskier. It must either fly in November or not fly for at least a year, based on rollout-rollback and SRB constraints. We've seen that it only takes one little thing going wrong to stop a launch, so the November launch is statistically risky. I hope it launches, but it might not. If it launches, I hope the mission succeeds, but it might not.

IMO Starship is more likely to launch in November. I hope it does. It's first goal (reach space) is easier than Artemis I and I think it will succeed. Its more ambitious goals are much less likely to be achieved.

Vulcan continues to slip at a rate of about one month per month. This does not converge, but surely things will eventually change?

[laszlo]

[NET 2022] 130.0 mt Starship, everything will be recovered, refuelable in orbit: ~$ 50 million

NET 2025, if at all, for all 4.

Why do you think this? you may be right of course. IMO SLS/Orion is riskier. It must either fly in November or not fly for at least a year, based on rollout-rollback and SRB constraints. We've seen that it only takes one little thing going wrong to stop a launch, so the November launch is statistically risky. I hope it launches, but it might not. If it launches, I hope the mission succeeds, but it might not.

IMO Starship is more likely to launch in November. I hope it does. It's first goal (reach space) is easier than Artemis I and I think it will succeed. Its more ambitious goals are much less likely to be achieved.

Vulcan continues to slip at a rate of about one month per month. This does not converge, but surely things will eventually change?

It's because of what's left to do to develop and demonstrate all 4 of the features in mandrew's table. SS may very well make an orbital flight next month, but it won't fully reusable, (if at all), in-space refueling is only a gleam in Musk's eye with no hardware support on any of the SS yet, payload numbers are purely aspirational and will change depending on all the other changes required and the launch cost is based on a stack of as-yet unproven assumptions. That's not a slam on anyone, just saying the mandrew's metrics need some tweaking.

[mandrewa]

[NET 2022] 130.0 mt Starship, everything will be recovered, refuelable in orbit: ~$ 50 million

NET 2025, if at all, for all 4.

Why do you think this? you may be right of course. IMO SLS/Orion is riskier. It must either fly in November or not fly for at least a year, based on rollout-rollback and SRB constraints. We've seen that it only takes one little thing going wrong to stop a launch, so the November launch is statistically risky. I hope it launches, but it might not. If it launches, I hope the mission succeeds, but it might not.

IMO Starship is more likely to launch in November. I hope it does. It's first goal (reach space) is easier than Artemis I and I think it will succeed. Its more ambitious goals are much less likely to be achieved.

Vulcan continues to slip at a rate of about one month per month. This does not converge, but surely things will eventually change?

It's because of what's left to do to develop and demonstrate all 4 of the features in mandrew's table. SS may very well make an orbital flight next month, but it won't fully reusable, (if at all), in-space refueling is only a gleam in Musk's eye with no hardware support on any of the SS yet, payload numbers are purely aspirational and will change depending on all the other changes required and the launch cost is based on a stack of as-yet unproven assumptions. That's not a slam on anyone, just saying the mandrew's metrics need some tweaking.

I agree actually with a good part of that.  It's not NET 2022 for recovering any of the Starship.  NET 2024 is a more reasonable date for recovering the Starship and NET 2024 is a more reasonable date for first demonstration of orbital refueling.

[kdhilliard]

... IMO SLS/Orion is riskier. It must either fly in November or not fly for at least a year, based on rollout-rollback and SRB constraints. ...

You don't know that, unless you know more than what has been publicly revealed.
*Perhaps* a two year stack-time will be declared the maximum for those SRBs, but all we currently have from NASA is that they are tracking life-limited items and are revisiting and, where possible, reevaluating those limits as necessary.  At some point a true limit will be reached, but we've no idea just how finely they can "sharpen their pencils".