Author Topic: SLS General Discussion Thread 2  (Read 225396 times)

Offline Robotbeat

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Re: SLS General Discussion Thread 2
« Reply #540 on: 08/06/2016 09:14 PM »
how the heck are they going to test a 10m diameter fairing? Where? Or even an 8.4m fairing?
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline Zed_Noir

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Re: SLS General Discussion Thread 2
« Reply #541 on: 08/06/2016 09:35 PM »
...
I used a lower per flt cost for SLS 2B in the hope that the cost per flt would go down with more use.
That is wishful thinking. Expect the SLS 2B to be more expensive than the SLS 1B, IMO. Also to get to the SLS 2B you need to restart RS-25 production and developed some flavor of advance booster. The advance booster is iffy considering the past with the STS's booster history.

And your table shows how noncompetitive the SLS is for assembling vehicle stacks in LEO in price. Of course the SLS will have a bigger payload fairing.

Offline oldAtlas_Eguy

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Re: SLS General Discussion Thread 2
« Reply #542 on: 08/06/2016 09:54 PM »
...
I used a lower per flt cost for SLS 2B in the hope that the cost per flt would go down with more use.
That is wishful thinking. Expect the SLS 2B to be more expensive than the SLS 1B, IMO. Also to get to the SLS 2B you need to restart RS-25 production and developed some flavor of advance booster. The advance booster is iffy considering the past with the STS's booster history.

And your table shows how noncompetitive the SLS is for assembling vehicle stacks in LEO in price. Of course the SLS will have a bigger payload fairing.
You are correct in that historically NASA costs have increased as the LV capability was expanded. But there is always hope that they would also do cost reduction work at the same time as creating a new version.

In the end LV selection could be just payload faring volume, cost being a secondary consideration. Bulky items SLS. Compact items commercial, such as propellant stages.

Offline whitelancer64

Re: SLS General Discussion Thread 2
« Reply #543 on: 08/06/2016 09:54 PM »
how the heck are they going to test a 10m diameter fairing? Where? Or even an 8.4m fairing?

At the Space Power Facility in Plum Brook Station, Ohio. The largest vacuum chamber there is 30 meters in diameter and 37 meters tall.
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Offline Zed_Noir

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Re: SLS General Discussion Thread 2
« Reply #544 on: 08/06/2016 09:57 PM »
how the heck are they going to test a 10m diameter fairing? Where? Or even an 8.4m fairing?

 :)
Live test on a commercial launcher with an adapter. After all the Atlas V got that 7.2 meter fairing option.
 :)

Offline A_M_Swallow

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Re: SLS General Discussion Thread 2
« Reply #545 on: 08/06/2016 11:42 PM »
how the heck are they going to test a 10m diameter fairing? Where? Or even an 8.4m fairing?

 :)
Live test on a commercial launcher with an adapter. After all the Atlas V got that 7.2 meter fairing option.
 :)

In which case I hope the dummy payload comes with telemetry so the engineers any problems the fairing has opening.

Offline PahTo

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Re: SLS General Discussion Thread 2
« Reply #546 on: 08/07/2016 02:18 AM »

I guess its once again time for my quarterly reminder that should SLS fly, or fly more than a couple-four times, the ultimate variation we'll see is 1B.  Having said that, I fully support SLS, and I bet the refined 1B will throw N. of 111T.



Offline Space Ghost 1962

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Re: SLS General Discussion Thread 2
« Reply #547 on: 08/07/2016 03:38 AM »
how the heck are they going to test a 10m diameter fairing? Where? Or even an 8.4m fairing?


"You don't understand the power of the dark ... wait ... cost plus prime force ..." ;)

And that one won't come cheap. Also, the Skylab one didn't "fair" so well...

add:

and


6.6m x 17.1m
« Last Edit: 08/07/2016 07:07 PM by Space Ghost 1962 »

Offline Robotbeat

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Re: SLS General Discussion Thread 2
« Reply #548 on: 08/07/2016 04:02 AM »
how the heck are they going to test a 10m diameter fairing? Where? Or even an 8.4m fairing?

At the Space Power Facility in Plum Brook Station, Ohio. The largest vacuum chamber there is 30 meters in diameter and 37 meters tall.
Oh, I know Plum Brook well. I've been inside it before. But even testing the 5m commercial fairings is cramped, let alone a much taller and wider 10m fairing. I'd argue there isn't enough room for a 10m by 30m fairing to be fully tested inside the space, since it needs room to actually separate, with all the mechanisms involved.

Heck, the doors are only 15m square. I don't see it realistically and fully being tested at Plum Brook, and I've never seen this realistically addressed.

10m fairings are a nightmare and likely to cost a fortune. How do you even transport them? Build them? Test them?

8.4m fairing even is a stretch (though isn't as absurd as 10m). My bet is SLS will fly only with Orion or the 5m fairing before being cancelled.
« Last Edit: 08/07/2016 04:06 AM by Robotbeat »
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline Coastal Ron

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Re: SLS General Discussion Thread 2
« Reply #549 on: 08/07/2016 06:15 AM »
Fiso podcast on SLS.

http://spirit.as.utexas.edu/~fiso/telecon/Sanders-Fuller-DaLee_8-3-16/

Costs aside there is lot to be said for being able to deliver 45t and 10m dia payloads direct to Mars , plus greatly reduce travel time for outer solar system robotic missions.

Well of course if you ignore costs every capability looks great.  Unfortunately there IS a cost associated with each capability, and that will influence whether that capability is ever used.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline Zed_Noir

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Re: SLS General Discussion Thread 2
« Reply #550 on: 08/07/2016 08:41 AM »

I guess its once again time for my quarterly reminder that should SLS fly, or fly more than a couple-four times, the ultimate variation we'll see is 1B.  Having said that, I fully support SLS, and I bet the refined 1B will throw N. of 111T.
@Scotty disagree with you on the Clarification on SLS Block 1B Capabilities thread on the 111T+ guess. Presuming you meant metric tons.

Offline Oli

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Re: SLS General Discussion Thread 2
« Reply #551 on: 08/07/2016 01:46 PM »
I'd say slay the Orion, keep the SLS, and use commercial flights.  I could see the SLS easily flying an empty Mars or Lunar lander into LEO and whatever equipment, and then a smaller commercial launcher deliver the humans separately.  That would be the best compromise to me.

Orion won't come with the same fixed costs as SLS. Sure, given Orion's development cost I would say adding a hab/prop module to a commercial crew vehicle would have been the cheaper solution (or even a lunar taxi with propulsive capture).

With SLS you're looking at >$2bn per year for 2 launches. Starting at the end of the next decade. Until it flies at that rate it is going to cost another ~$20bn. All that while FH comes "for free" and SEP costs a fraction and is needed anyway.

Offline tea monster

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Re: SLS General Discussion Thread 2
« Reply #552 on: 08/07/2016 02:05 PM »
If they actually use the SLS on this 'Journey to Mars' and launch a load of new robot spacecraft to the outer solar system on high-speed trajectories, then brilliant.

The problem is that nobody believes that will happen. There has been little, if any interest in putting something on top of this rocket, as if everyone knows what is going to happen.

Offline the_other_Doug

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Re: SLS General Discussion Thread 2
« Reply #553 on: 08/07/2016 02:07 PM »
With SLS you're looking at >$2bn per year for 2 launches. Starting at the end of the next decade. Until it flies at that rate it is going to cost another ~$20bn. All that while FH comes "for free" and SEP costs a fraction and is needed anyway.

As opposed (adjusting to match projected timeframe dollars for SLS) to flying eight FH's for $2bn per year?  Or four Delta IV's?  Or three Vulcans?

And how in the world do you figure that FH comes "for free"?!  FH right now is being guesstimated at a cost per launch between $120 million and $250 million, depending on who you listen to.  Delta IV is already around a half billion per launch, Atlas V at around a quarter to a third of a billion, and I don't know anyone who is willing to bet that Vulcan will cost less than either of the other two ULA offerings available at present.

This is, pardon me for saying so, one of the stupidest examples of going way overboard on "SLS will cost so much, it's completely absurd!"  By trying to state that FH is "for free," you completely invalidate any argument you may have.

Face it -- there ain't no big launchers that aren't relatively expensive right now.  The difference between SpaceX and other providers is simply a matter of degree, at the moment.
-Doug  (With my shield, not yet upon it)

Offline Oli

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Re: SLS General Discussion Thread 2
« Reply #554 on: 08/07/2016 02:37 PM »
With SLS you're looking at >$2bn per year for 2 launches. Starting at the end of the next decade. Until it flies at that rate it is going to cost another ~$20bn. All that while FH comes "for free" and SEP costs a fraction and is needed anyway.

As opposed (adjusting to match projected timeframe dollars for SLS) to flying eight FH's for $2bn per year?  Or four Delta IV's?  Or three Vulcans?

And how in the world do you figure that FH comes "for free"?!  FH right now is being guesstimated at a cost per launch between $120 million and $250 million, depending on who you listen to.  Delta IV is already around a half billion per launch, Atlas V at around a quarter to a third of a billion, and I don't know anyone who is willing to bet that Vulcan will cost less than either of the other two ULA offerings available at present.

This is, pardon me for saying so, one of the stupidest examples of going way overboard on "SLS will cost so much, it's completely absurd!"  By trying to state that FH is "for free," you completely invalidate any argument you may have.

Face it -- there ain't no big launchers that aren't relatively expensive right now.  The difference between SpaceX and other providers is simply a matter of degree, at the moment.

"For free" in this context means NASA doesn't have to pay for development or all the fixed cost. It is a rocket that will fly no matter what. I think FH plus SEP could approximately half the price per kg to cis-lunar space compared to SLS (assuming $200m for FH). Moreover it could save billions of development cost.

That said, I am not a die-hard SLS opponent. Congress wants to pay for it, so be it.

Offline the_other_Doug

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Re: SLS General Discussion Thread 2
« Reply #555 on: 08/07/2016 03:23 PM »
I keep getting irritated by the oft-repeated rubric that NASA is wasting money by developing a rocket that has no funded missions in the offing.

Development of a launch capability is never done (with the exception of during Apollo, and even then was not initiated by a funded mission) because a series of funded flights require that capability.  You need to have the capability in place before you can start to fund the missions that will take advantage of it -- again, unless you want to repeat the heady go-for-broke days of Apollo.

Just as a reminder, the F-1 engine originally went into development in 1955, based upon a perceived need by the Air Force to eventually be able to orbit large payloads.

Nineteen-fifty-five.  Two years before anyone, anywhere had even demonstrated the capability of orbiting anything.  At all.

If there was a funded mission that required an F-1 engine in 1955, I'd love to see the funding appropriation for it.

And, to be honest, I don't believe it would have been possible to seek funding for Apollo if there was not an F-1 class engine already under development.  If the U.S. had been forced to try and design Apollo without the F-1 having been under development for five years already, I don't think anyone would have bitten the bullet and committed to it.  One of the reasons Apollo was considered within the realm of possibility in 1961 was the fact that the F-1 engine was scheduled to become available by 1965 or so.

Again, unless you're running a crash program like Apollo, you don't start funding your missions until the rocket needed is designed and nearly ready to go.  And I will remind y'all that, in 1966, the only Apollo crewed missions that were specifically funded were AS-204 and AS-276.  All other Apollo missions funded in that time period were unmanned tests of the vehicles. 

While the only crewed mission to fly on SLS currently funded is EM-2, at a similar point in Apollo (which was a crash program in which all elements were being designed and built all at once) there was no funding specific to any crewed Saturn V launches, much less for actual lunar landing missions.  They weren't going to happen in the next fiscal year, and as such none of the funding was specific to any such missions.

In the case of SLS/Orion, I will also point out that two of the major elements of future crewed BLEO missions -- SLS and Orion -- are in development at the same time, and targeted to come online at the same time.  And there is funding now, this year, for early stages of DSH development.  So, it's not even as if we're building a rocket that has no crewed elements under development.

When y'all toss around the complaint "no funded missions," please recall Congress only funds things one fiscal year at a time (when they bother to do so at all and we don't just get stuck with a mess of CR's).  Apollo didn't have funded crewed lunar landing missions until fiscal 1969.  NASA had a longer-than-one-year plan for Apollo, and Congress appropriated for the new fiscal year based on what NASA told them were their needs to accomplish that plan.  That doesn't differ from what's happening right now, as NASA refines their DRA for Mars and presents funding requests based on accomplishing it without many "balloon" years needed to do so (i.e., with mostly flat budgets).  Congress has given them funding for the pieces they think they need to develop in the next fiscal year.

Now, you can complain that the DRA doesn't realistically define needs for new start funding on various vehicles and preliminary missions.  But that's a far different discussion than just continuing to insist SLS must die because there are no funded missions.

Rant mode off... ;)
-Doug  (With my shield, not yet upon it)

Offline A_M_Swallow

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Re: SLS General Discussion Thread 2
« Reply #556 on: 08/07/2016 05:19 PM »
how the heck are they going to test a 10m diameter fairing? Where? Or even an 8.4m fairing?

At the Space Power Facility in Plum Brook Station, Ohio. The largest vacuum chamber there is 30 meters in diameter and 37 meters tall.
Oh, I know Plum Brook well. I've been inside it before. But even testing the 5m commercial fairings is cramped, let alone a much taller and wider 10m fairing. I'd argue there isn't enough room for a 10m by 30m fairing to be fully tested inside the space, since it needs room to actually separate, with all the mechanisms involved.

Heck, the doors are only 15m square. I don't see it realistically and fully being tested at Plum Brook, and I've never seen this realistically addressed.

10m fairings are a nightmare and likely to cost a fortune. How do you even transport them? Build them? Test them?

8.4m fairing even is a stretch (though isn't as absurd as 10m). My bet is SLS will fly only with Orion or the 5m fairing before being cancelled.

A 10m fairing can be moved by building it in three 120 parts. Assemble inside the vacuum test chamber.

How to environmentally test a payload that needs a 10m fairing is a different but related problem. New extra large test chamber?

Offline Coastal Ron

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Re: SLS General Discussion Thread 2
« Reply #557 on: 08/07/2016 08:16 PM »
I keep getting irritated by the oft-repeated rubric that NASA is wasting money by developing a rocket that has no funded missions in the offing.

Not only funded, but no defined long-term need.  And by that I mean our political leadership has agreed to a goal that requires so much mass moved to space that a sustained need for an HLV is merited, and existing commercial capabilities cannot satisfy the goal.  None of that thinking has taken place or been agreed to.

Quote
Development of a launch capability is never done (with the exception of during Apollo, and even then was not initiated by a funded mission) because a series of funded flights require that capability.  You need to have the capability in place before you can start to fund the missions that will take advantage of it -- again, unless you want to repeat the heady go-for-broke days of Apollo.

No, the U.S. Government does not engage in that type of $B speculation without at least some sort of indication of demand, regardless how accurate or well done the study is.  And moving mass to space is now a mature industry, with the private sector here in the U.S. the master of this capability, not the U.S. Government.

So why does Congress want NASA to create a U.S. Government capability?  If there is a real need, it should be easy to quantify.

Quote
Just as a reminder, the F-1 engine originally went into development in 1955, based upon a perceived need by the Air Force to eventually be able to orbit large payloads.

Nineteen-fifty-five.  Two years before anyone, anywhere had even demonstrated the capability of orbiting anything.  At all.

From Wikipedia about the F-1:

"The F-1 was originally developed by Rocketdyne to meet a 1955 U.S. Air Force requirement for a very large rocket engine."

So there was need.  And just to be clear, the military spends money differently than the civilian side of the government, so comparing the SLS to military rocket is apples-to-daisies.

Quote
In the case of SLS/Orion, I will also point out that two of the major elements of future crewed BLEO missions -- SLS and Orion -- are in development at the same time, and targeted to come online at the same time.

Well of course, they were created from the same source - the cancelled Constellation program.  Which still doesn't address what they are to used for, especially since the Orion is limited to going to the Moon for 21 day missions - and that is not a critical path requirement for going to Mars (i.e. the supposed prime destination NASA is focused on).

Quote
And there is funding now, this year, for early stages of DSH development.  So, it's not even as if we're building a rocket that has no crewed elements under development.

A Deep Space Habitat does not require an HLV.

And bottom line, what many people see is that "stuff" is being built to justify the SLS, not to address critical path items that are keeping us from getting to Mars (or whatever is NASA's top priority).

And if you have a capability that has to launch every 12 months (i.e. NASA's minimum safe flight cadence), then that means 70-130mT of "stuff" has to be in the funding pipeline years in advance.  It take years, and sometimes over a decade, for NASA to build space "stuff", and here we are just 6 years away from the SLS being operational - and there is a lack of "stuff" in the funding pipeline.

If the SLS truly was needed at this moment in history, you'd think we'd see more evidence of that need.

My $0.02
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline rayleighscatter

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Re: SLS General Discussion Thread 2
« Reply #558 on: 08/07/2016 08:45 PM »

So why does Congress want NASA to create a U.S. Government capability?  If there is a real need, it should be easy to quantify.
Like a manned space program?

Offline Coastal Ron

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Re: SLS General Discussion Thread 2
« Reply #559 on: 08/07/2016 11:24 PM »

So why does Congress want NASA to create a U.S. Government capability?  If there is a real need, it should be easy to quantify.
Like a manned space program?

We have that today without an HLV.

There are NASA studies that show we could, if needed, go to Mars without an HLV - and studies that say an HLV would be an asset.

The deciding factor will be what the next President and Congress envision for NASA...
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

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