Author Topic: SLS General Discussion Thread 2  (Read 224844 times)

Online Endeavour_01

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Re: SLS General Discussion Thread 2
« Reply #380 on: 04/29/2016 07:54 PM »
Where do you get SLS getting 2.5 times the LEO payload vs FH? 

Mr. Kyle was referring to escape velocity payload, not payload to LEO.

Edited to add:

Right now, EM-1 is giving me uncomfortable Ares-I-X flashbacks.

I am feeling some of that too but there are several differences between EM-1 and Ares I-X

1. EM-1 is a flight of a completely operational rocket. The core stage, boosters, and upper stage are all ready to go, as well as the LAS. Ares I-X had only the first stage operational, the upper stage and LAS were dummies.

2. EM-1 has a payload/mission. EM-1 will launch an unmanned Orion around the moon. Ares I-X had a dummy Orion that never made it to LEO.
« Last Edit: 04/29/2016 08:17 PM by Endeavour_01 »
I cheer for both NASA and commercial space. For SLS, Orion, Falcon 9, Falcon Heavy, Dragon, Starliner, Cygnus and all the rest!
I was blessed to see the launch of Space Shuttle Endeavour on STS-99. The launch was beyond amazing. My 8-year old mind was blown. I remember the noise and seeing the exhaust pour out of the shuttle as it lifted off. I remember staring and watching it soar while it was visible in the clear blue sky. It was one of the greatest moments of my life and I will never forget it.

Offline TomH

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Re: SLS General Discussion Thread 2
« Reply #381 on: 04/29/2016 08:45 PM »
Where do you get SLS getting 2.5 times the LEO payload vs FH? 

Mr. Kyle was referring to escape velocity payload, not payload to LEO.

And Spacenut clearly mentioned:

The Raptor upper stage engine is supposed to be developed in the next 18-24 months

I surely imagine the Raptor US will fly on a FH long before EUS flies on an SLS Block IB. With FH now based on Falcon 9 v1.1FT, if cross feed were employed on a fully disposable FH with Raptor US, I highly doubt Block IB would get 2.5 x the payload to GTO or escape. And if you think of Block I (with iCPS) coming online about the same time as such a FH, the comparison is much closer...................until you look at the dollar signs attached to each.

I think MCT (at least the BFR booster) may fly before SLS Block IB ever does. In fact, I think a single Block I will fly. I now believe Blocks IB and IIB will never see the sky.

Jim used to predict that SLS would not succeed. He also was skeptical about SpaceX' Mars ambitions. I now believe he was right about the first one, not because of the reasons he enumerated, but rather because he underestimated the second one. Though it might have eventually fallen of its own problems, I think Super-FH and MCT will hasten the demise of SLS by years.

Offline Coastal Ron

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Re: SLS General Discussion Thread 2
« Reply #382 on: 04/29/2016 08:49 PM »
The gap between Apollo 7 and Skylab 2 was even greater, 4 years 7 months and 14 days. Similarly the Delta II has some pretty big gaps in its recent launch history. The gap between Delta flight 357 and 367 is 2 years 8 months and 4 days. There is an almost 2 year gap between the last Delta II flight and the next one.

Apollo had already proven out their launch operations, and so mothballing them for a few years was OK to do, and back then salaries for their ground crew would probably not have been much of a budgetary problem.

Plus you can't look at the vehicle launch rate per se, since it is all facets of the rocket - production, launch operations, etc.  So for Delta II ULA was using the same factory personnel that were already trained, the same manufacturing support systems, the same launch ops personnel, etc.

For the SLS it's a combination of running the SLS at the very slow production rate of one per year, and only launching once per year.  Only doing something in the factory, or only doing something on the launch pad once per year does not promote good learning and retention.  And the currently forecasted launch rate means the SLS won't exit the "learning curve" for something like a decade.

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Accordingly I don't think the issue of launch cadence as it relates to reliability should be a factor the decision to continue or cancel the program.

It is a significant factor that needs to be part of the decision, since it automatically removes any suggestion that the SLS could fly less often than once per year safely.  That pretty much mandates that unless Congress funds enough payloads and missions to fill up a yearly flight manifest that NASA won't feel the transportation is safe enough to use.  You have to draw the line somewhere to avoid "safety creep".

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There are many pros and cons to the SLS program that are way more important than this hypothetical concern.

None that seem to include the phrase "We have more than enough SLS-only payloads funded and on track for launch to keep the SLS busy flying at least once per year for many years to come".  Which is main reason there is anything to debate about the SLS in the first place...
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Online Endeavour_01

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Re: SLS General Discussion Thread 2
« Reply #383 on: 04/29/2016 08:59 PM »
And Spacenut clearly mentioned:

The Raptor upper stage engine is supposed to be developed in the next 18-24 months

I surely imagine the Raptor US will fly on a FH long before EUS flies on an SLS Block IB. With FH now based on Falcon 9 v1.1FT, if cross feed were employed on a fully disposable FH with Raptor US, I highly doubt Block IB would get 2.5 x the payload to GTO or escape.


Ed was using the numbers we have currently for both SLS Block I/IB and Falcon Heavy. There are still many questions and unknowns on what the Raptor upper stage will actually be used for or what size engine it will be (mini or full scale) let alone payload performance numbers. I think he was justified in using the numbers we currently have vs. hypotheticals with plenty of unknowns.

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I think MCT (at least the BFR booster) may fly before SLS Block IB ever does. In fact, I think a single Block I will fly. I now believe Blocks IB and IIB will never see the sky.

We will see. Given how much trouble and hard work SpaceX has had to do to get Falcon Heavy off the ground I doubt BFR will be flying until at least 2025.
I cheer for both NASA and commercial space. For SLS, Orion, Falcon 9, Falcon Heavy, Dragon, Starliner, Cygnus and all the rest!
I was blessed to see the launch of Space Shuttle Endeavour on STS-99. The launch was beyond amazing. My 8-year old mind was blown. I remember the noise and seeing the exhaust pour out of the shuttle as it lifted off. I remember staring and watching it soar while it was visible in the clear blue sky. It was one of the greatest moments of my life and I will never forget it.

Offline TomH

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Re: SLS General Discussion Thread 2
« Reply #384 on: 04/29/2016 11:14 PM »
Given how much trouble and hard work SpaceX has had to do to get Falcon Heavy off the ground I doubt BFR will be flying until at least 2025.

You're working off of incorrect presuppositions. SpaceX has been smart enough to finish their refinements of F9 before proceeding to FH. Had they gone ahead with FH, then decided to refine F9, and then FH, they would be like the F-35 program: building production models prior to finishing with the test models. That's not working so well. Putting FH on hold while refining F9, mastering RTLS and at sea landing, then proceeding with FH has been a strategically shrewd, intentional, and practical move. It brings a much more robust as well as cost effective LV. There has been nothing troublesome or problematic about it.
« Last Edit: 04/29/2016 11:23 PM by TomH »

Offline spacenut

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Re: SLS General Discussion Thread 2
« Reply #385 on: 04/29/2016 11:47 PM »
Someone figured several years ago, that if they stayed with the 4 seg solids and 5 SSME's and a good upper stage, they could have flown 4-5 times a year for $1 billion.  Now one time for $1 billion.  To me it is sad. 

You are right about SpaceX.  They got Falcon 9 going by launching satellites from paying customers, Then upgraded the engines, then stretched the first stage, then attempted landing, then went full thrust.  Now a Raptor based upper stage for more capacity. 

IF again big IF, we had gone ahead with the 4 segment boosters and 3 SSME's we could have had the "Direct" booster already and be actually doing something in space.  Then we could have upgraded the boosters to either 5 segments or to the composite boosters, then added one or two more engines, stretched the core, and added J2X upper stage.  This could have been done over time.  Seems like they have over-engineered the SLS with all the changes.  Instead of getting started a few years ago, they had to wait for the new boosters, wait for the expendable SSME, develop the J2X and then cancel it.  Even Orion capsule seems to have taken forever to develop.  I don't know, it just seems like a huge waste of money instead of using what we already had off the shelf, then make upgrades. 

This is not the first time the Federal government has wasted money.  Just like the F-35, trying to make it a jack of all trades, but a master of none.  Seems like everything the Senate and House get involved in something, it becomes very expensive and seems to create more problems than it solves, especially when it is technical. 

Online Endeavour_01

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Re: SLS General Discussion Thread 2
« Reply #386 on: 04/30/2016 01:37 AM »

You're working off of incorrect presuppositions. SpaceX has been smart enough to finish their refinements of F9 before proceeding to FH. .....Putting FH on hold while refining F9, mastering RTLS and at sea landing, then proceeding with FH has been a strategically shrewd, intentional, and practical move. There has been nothing troublesome or problematic about it.

I am not saying what they did was wrong. I think they did a great job and their iterative technique has worked wonderfully. What I am saying is that bigger projects have more issues and take more effort. Elon himself has said that Falcon Heavy was a much trickier proposition. I am sure if you asked any SpaceX engineer they would tell you that development of FH wasn't a breeze and they ran into troubles and problems that they fixed in the end. That is the case with any rocket development program.

BFR/BFS will be an order of magnitude more difficult. I am not saying they can't do it, just that it is not going to come out as soon as some people believe. It may be even longer if they plan to develop BFS alongside it.

SLS will have more than one flight as long as it isn't canned in the next admin. Even when BFR is flying SLS would still have a couple more flights given that it is crew rated (assuming BFS isn't ready yet).
I cheer for both NASA and commercial space. For SLS, Orion, Falcon 9, Falcon Heavy, Dragon, Starliner, Cygnus and all the rest!
I was blessed to see the launch of Space Shuttle Endeavour on STS-99. The launch was beyond amazing. My 8-year old mind was blown. I remember the noise and seeing the exhaust pour out of the shuttle as it lifted off. I remember staring and watching it soar while it was visible in the clear blue sky. It was one of the greatest moments of my life and I will never forget it.

Offline oldAtlas_Eguy

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Re: SLS General Discussion Thread 2
« Reply #387 on: 04/30/2016 02:52 AM »
I doubt SLS/Orion 2017 appropriations will be threatened by this current news event. But add a successful test flight of FH, its publication of capabilities and prices and the 2018 appropriations may be in severe jeopardy. Also add to that a new administration a new congress makeup and it could be in really serious trouble. That's even if the media doesn't label it the "Rocket to Nowhere".  If that happens the congressmen will be ducking for cover and all political support for SLS/Orion will evaporate and funding for it would never even make it out of committee.

Hopefully some very useful payload projects that congress has started to fund, DSH for one, won't get axed with it. DSH does not care who launches it. It still has the same usefulness and the directions that NASA is going with the program is more in the direction taken with CRS and CC by looking for a development partner vs doing it all themselves. But the program is still just in its definition phase and not in its detailed design phase.

There are also other programs, the dual vehicle planetary probe launch being explored for launch using SLS, hopefully will not get damaged by a cancellation of SLS as well. When a LV that is being planned on by payloads disappears then addition funds are required to manifest to another LV if one is available at all!!!!

I look at the SLS/Orion program and see a train-wreck for NASA coming that is not avoidable. It is just a matter of when not if and how many other programs will be harmed when the wreck occurs.

Offline rayleighscatter

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Re: SLS General Discussion Thread 2
« Reply #388 on: 04/30/2016 03:06 AM »
There is a space policy forum, but this isn't it.

Offline Mark S

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Re: SLS General Discussion Thread 2
« Reply #389 on: 04/30/2016 05:20 AM »
.... Ares I-X had only the first stage operational, the upper stage and LAS were dummies.

No, it was worse than that. The Ares-1X first stage was not operational either. It was a standard four-segment Shuttle SRB with a dummy fifth segment bolted on top to make it look like a 5-segment RSRMV. The fifth segment was weighted down with ballast to simulate the mass of a real fifth segment. Which of course made the booster so heavy that the steel motor casing bent when it parachuted into the ocean.

Cheers!
« Last Edit: 04/30/2016 05:34 AM by Mark S »

Offline Oli

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Re: SLS General Discussion Thread 2
« Reply #390 on: 04/30/2016 01:42 PM »
.... Ares I-X had only the first stage operational, the upper stage and LAS were dummies.

No, it was worse than that. The Ares-1X first stage was not operational either. It was a standard four-segment Shuttle SRB with a dummy fifth segment bolted on top to make it look like a 5-segment RSRMV. The fifth segment was weighted down with ballast to simulate the mass of a real fifth segment. Which of course made the booster so heavy that the steel motor casing bent when it parachuted into the ocean.

Cheers!

 ;D

Offline woods170

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Re: SLS General Discussion Thread 2
« Reply #391 on: 04/30/2016 03:55 PM »
.... Ares I-X had only the first stage operational, the upper stage and LAS were dummies.

No, it was worse than that. The Ares-1X first stage was not operational either. It was a standard four-segment Shuttle SRB with a dummy fifth segment bolted on top to make it look like a 5-segment RSRMV. The fifth segment was weighted down with ballast to simulate the mass of a real fifth segment. Which of course made the booster so heavy that the steel motor casing bent when it parachuted into the ocean.

Cheers!

Minor nit: what also contributed to the bent casing was the fact that two of the three main parachutes failed before splash-down. The first one failed outright (ripped apart) upon deployment. The second one deployed more-or-less normal but partially ripped apart a few seconds later. The end result was that the Ares I-X booster impacted the water with a higher velocity than anticipated.

Offline Coastal Ron

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Re: SLS General Discussion Thread 2
« Reply #392 on: 05/02/2016 03:29 AM »
Someone figured several years ago, that if they stayed with the 4 seg solids and 5 SSME's and a good upper stage, they could have flown 4-5 times a year for $1 billion.

Whoever said that was clearly not rooted in reality.

Based on actual contracts for the Shuttle program when it was still in volume production, a flight set of SRB's (not including the SRM components) cost $68M.  For the External Tank (ET), which is smaller and less complex than the SLS 1st stage, it cost $173M each.  That's a total of $241M just for those two elements.

The SLS is far larger and more complex for the expendable hardware than the Shuttle was, plus the maximum capable production rate at this point in time is less than two per year, which doesn't really provide for cost reductions based on volume production at suppliers.  No one outside of NASA knows what the actual SLS cost will be, but I'd say it will be significant.

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Now one time for $1 billion.  To me it is sad. 

Cost can only be evaluated when compared to the value one gets in return, and what the alternatives are in comparison.  There are many things U.S. Taxpayers pay more than $1B for and we feel it's worthwhile.  Will the SLS fall in that category?  Time will tell...
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Offline chrisking0997

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Re: SLS General Discussion Thread 2
« Reply #393 on: 05/02/2016 04:28 PM »
maybe Im confused on the whole payload funding thing, but what SLS payloads has NASA proposed that Congress has not funded? 
Tried to tell you, we did.  Listen, you did not.  Now, screwed we all are.

Offline oldAtlas_Eguy

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Re: SLS General Discussion Thread 2
« Reply #394 on: 05/02/2016 05:41 PM »
maybe Im confused on the whole payload funding thing, but what SLS payloads has NASA proposed that Congress has not funded?
For info on SLS payloads (manifest plans) or lack thereof see this thread: http://forum.nasaspaceflight.com/index.php?topic=39300.0

Currently there is Orion and DSH (DSH only recently in FY2016 started receiving any funding). With Europa investigating SLS suitability. It is both a problem of NASA putting forth more candidates and congress funding them. NASA doesn't want to put a new program in front of congress if they know it has almost no chance of getting funded. They wait for funding chance to increase before trying to get it funded. Look at what has happened to ARM.

Offline spacenut

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Re: SLS General Discussion Thread 2
« Reply #395 on: 05/02/2016 06:27 PM »
I think BFR would be easier than Falcon Heavy, or heavy of any rocket.  It is a single core rocket, more or less only a sized up Falcon 9 with different engines.  Engines are the hardest to develop it seems.  SLS could have been a 9 engine RD-180 with the 8m core without solids.  It could have lifted far more than SLS and there could have been a twin engine J2X upper or 3 engine upper.  That would have lifted what a Saturn V lifted.  Then add Atlas V strap on's for additional boost.  I think that would have been cheaper than the current SLS. 

Offline Coastal Ron

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Re: SLS General Discussion Thread 2
« Reply #396 on: 05/02/2016 06:44 PM »
I think BFR would be easier than Falcon Heavy, or heavy of any rocket.

Much as I love discussing alternatives, for this specific thread it doesn't matter that there may or may not be alternatives to using the SLS, it only matters whether Congress will fund the continuous use of the SLS via funding payloads and programs that can only use the unique services of the SLS.

And that is because the SLS is a government-owned transportation system that has unique capabilities, so as long as Congress funds things for it to move to space it will have a use - regardless what the possible alternatives are.

Which is why it doesn't really matter how much money is being spent on the SLS, or whether it's "on schedule".  What will decide the fate of the SLS is whether it's really needed to fly no-less-than once per year, and that clock starts in 2022 when it's supposed to become operational.
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Offline ncb1397

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Re: SLS General Discussion Thread 2
« Reply #397 on: 05/02/2016 07:14 PM »
maybe Im confused on the whole payload funding thing, but what SLS payloads has NASA proposed that Congress has not funded?
For info on SLS payloads (manifest plans) or lack thereof see this thread: http://forum.nasaspaceflight.com/index.php?topic=39300.0

Currently there is Orion and DSH (DSH only recently in FY2016 started receiving any funding). With Europa investigating SLS suitability. It is both a problem of NASA putting forth more candidates and congress funding them. NASA doesn't want to put a new program in front of congress if they know it has almost no chance of getting funded. They wait for funding chance to increase before trying to get it funded. Look at what has happened to ARM.

It is now law that the Europa mission will use SLS. That is about as firm of a payload as you can get. I don't even think that Orion and DSH are required legally to be launched on SLS and so those are comparatively less firm.

Offline The Amazing Catstronaut

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Re: SLS General Discussion Thread 2
« Reply #398 on: 05/02/2016 08:05 PM »

It is now law that the Europa mission will use SLS. That is about as firm of a payload as you can get. I don't even think that Orion and DSH are required legally to be launched on SLS and so those are comparatively less firm.

Orion is a questionable spacecraft design. I don't see much use for it unless it has some dedicated BEO missions on SLS. The first should be used as an enabler for the latter if Congress wants to be smart about it and draw SLS out.
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Offline Robotbeat

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Re: SLS General Discussion Thread 2
« Reply #399 on: 05/03/2016 01:03 AM »
maybe Im confused on the whole payload funding thing, but what SLS payloads has NASA proposed that Congress has not funded?
For info on SLS payloads (manifest plans) or lack thereof see this thread: http://forum.nasaspaceflight.com/index.php?topic=39300.0

Currently there is Orion and DSH (DSH only recently in FY2016 started receiving any funding). With Europa investigating SLS suitability. It is both a problem of NASA putting forth more candidates and congress funding them. NASA doesn't want to put a new program in front of congress if they know it has almost no chance of getting funded. They wait for funding chance to increase before trying to get it funded. Look at what has happened to ARM.

It is now law that the Europa mission will use SLS. ...
Then you might want to explain that to the mission designers who still baseline an EELV...
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