Author Topic: SLS General Discussion Thread 2  (Read 224439 times)

Offline rayleighscatter

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Re: SLS General Discussion Thread 2
« Reply #600 on: 08/14/2016 03:42 PM »

Our best hope is that SpaceX simply shames or litigates the SLS into a quick retirement with the BFR and NASA has thouse funds freed up to purchase all transport services from SpaceX and develop actual mission hardware.

Since it requires constant reinforcement...

That's not how appropriations work. If SLS ends NASA does not keep the money.

Offline Robotbeat

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Re: SLS General Discussion Thread 2
« Reply #601 on: 08/14/2016 07:00 PM »

Our best hope is that SpaceX simply shames or litigates the SLS into a quick retirement with the BFR and NASA has thouse funds freed up to purchase all transport services from SpaceX and develop actual mission hardware.

Since it requires constant reinforcement...

That's not how appropriations work. If SLS ends NASA does not keep the money.
Sure, why not? Congress still wants jobs in those districts, NASA will just have to use the same workforce to build something different, like habs or asteroid grabbing robots or whathaveyou. SLS isn't the only thing that can provide that pork.
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Offline Proponent

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Re: SLS General Discussion Thread 2
« Reply #602 on: 08/15/2016 02:47 PM »
... back then a SDHLV appeared to be the best way to meet the lift needs of a BEO program.

Can you point to an engineering study backing up that conclusion?  Many appear to believe that Augustine reached this conclusion, but it did not.

My understanding is that the Augustine Commission basically said there are some missions that could benefit a lot from a super-heavy LV, but that you should only do so if you have a really definite need for one.  In other words, their recommendation (which we are currently almost exactly anti-observing) was that you should only build one if and when you need it, and only if it seems more economical to launch big pieces in fewer launches than launching a lot of pieces in a lot more launches.  Please correct me if I'm wrong about their conclusions, but that was what I took away from reading the report....

Augustine (report attached) very definitely concluded that super-heavy lift is needed for human exploration beyond LEO.  But its definition of "super-heavy" is "larger than the current 'heavy' EELVs, whose mass to low-Earth orbit is in the 20-25 mt range" [Sect. 5.2.1, p. 64].

More specifically,
Quote from: Augustine report, Sect. 5.2.1, p. 65
The Committee commissioned a detailed analysis of the reliability of missions that would require multiple launches of critical and less critical payloads.  It found that achieving reasonable probability of mission success requires either 90+ days of on-orbit life for the EDS, or a depot, and that at most three critical launches should be employed.  Since it is very constraining to balance mission components to always partition equally between launches, this strongly favors a minimum heavy-lift capacity of roughly 50 mt that allows the flexibility to lift two “dry” exploration elements on a single launch.

So, that's the short answer to the question.  Augustine goes on to compare Shuttle- and EELV-derived HLVs:
Quote from: Augustine report, Sect. 6.5.3, pp. 93-94
While there are technical differences between the two families [of launch vehicles: NASA-heritage and EELV], the Committee intended the principal difference to be programmatic.  The EELV-heritage super heavy would represent a new way of doing business for NASA, which would have the benefit of potentially lowering development and operational costs. The Committee used the EELV-heritage super-heavy vehicle to investigate the possibility of an essentially commercial acquisition of the required heavy-launch capability by a small NASA organization similar to a system program office in the Department of Defense.  It would eliminate somewhat the historic carrying cost of many Apollo- and Shuttle-era facilities and systems. This creates the possibility of substantially reduced operating costs, which may ultimately allow NASA to escape its conundrum of not having sufficient resources to both operate existing systems and build a new one.

However, this efficiency of operations would require significant near-term realignment of NASA. Substantial reductions in workforce, facilities closures, and mothballing would be required. When the Committee asked NASA to assess the cost of this process, the estimates ranged from $3 billion to $11 billion over five years. Because of these realignment costs, the EELV-heritage super heavy does not become available significantly sooner than the Ares V or Shuttle-derived families of launchers. The transition to this way of doing business would come at the cost of cutting deeply into a the internal NASA capability to develop and operate launchers, both in terms of skills and facilities.

In summary, the Committee considers the EELV-heritage super-heavy vehicle to be a way to significantly reduce the operating cost of the heavy lifter to NASA in the long run.  It would be a less-capable vehicle, but probably sufficiently capable for the mission. Reaping the long-term cost benefits would require substantial disruption in NASA, and force the agency to adopt a new way of doing business.  The choice between NASA and EELV heritage is driven by potential lower development and operations cost (favoring the EELV-heritage systems) vs. continuity of NASA’s system design, development and mission assurance knowledge and experience, which would provide higher probability of successful and predictable developments (favoring NASA systems). EELV-heritage launch systems, due to their lower payload performance, would require significantly greater launch and mission complexity to achieve the same total mass in orbit. The EELV option would also entail substantial reductions in the NASA workforce and closure of facilities necessary to obtain the expected cost reductions.

Augustine noted that the use of 50-tonne-class launch vehicles required the development of in-space refueling.  But it's interesting that NASA's recent Evolvable Mars Campaign breaks payloads down into 50-tonne chunks without refueling.  If LEO were used for rendezvous in addition to or in place of lunar DRO, then 50-tonne-class launch vehicles would suffice.  Whether such a thing would be desirable is another matter, but to my knowledge NASA has never officially even considered the possibility (unless you count the deeply flawed ESAS study of 2005: that's the one that claimed EELVs could not safely launch crews because of "black zones" and assumed a failure rate in excess of 1% for autonomous rendezvous and docking).

EDIT:  Added missing closing quotation mark to "black zones" in last sentence.
« Last Edit: 09/23/2016 09:18 AM by Proponent »

Offline Proponent

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Re: SLS General Discussion Thread 2
« Reply #603 on: 08/15/2016 02:54 PM »
... back then a SDHLV appeared to be the best way to meet the lift needs of a BEO program.

Can you point to an engineering study backing up that conclusion?  Many appear to believe that Augustine reached this conclusion, but it did not.
We both can point to studies that show our respective views on HLV or not debate. I'm not really interested in rehashing that debate. The sentence that you cherry picked was referring to an SDHLV being the majority consensus of the space flight engineering and planning community at that time, not necessarily the best option.

Could you please contribute references to the pro-HLV studies to which you refer to this thread.  I have been looking for such studies for a long time.

Offline Proponent

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Re: SLS General Discussion Thread 2
« Reply #604 on: 08/16/2016 11:00 AM »

Our best hope is that SpaceX simply shames or litigates the SLS into a quick retirement with the BFR and NASA has thouse funds freed up to purchase all transport services from SpaceX and develop actual mission hardware.

Since it requires constant reinforcement...

That's not how appropriations work. If SLS ends NASA does not keep the money.
Sure, why not? Congress still wants jobs in those districts, NASA will just have to use the same workforce to build something different, like habs or asteroid grabbing robots or whathaveyou. SLS isn't the only thing that can provide that pork.

It is in principle true that when one of its programs ends, NASA simply looses the money.  In practice, though, NASA's inflation-adjusted budget has been approximately constant for decades, even as big programs have come and gone (e.g., Constellation, ISS, the Shuttle, X-33, Hubble, JWST).  Though there is always a risk that next time will be different, in practice the forces that Robotbeat identifies seem to keep the cash flowing.

And with a NASA-managed launch vehicle, there are funding risks as the program moves from one phase to the next, as Blackjax pointed out some time ago in what I thought was a very interesting post.


Offline okan170

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Re: SLS General Discussion Thread 2
« Reply #605 on: 08/16/2016 09:02 PM »
I was looking at doing a SLS animation one day, when I came across this video on YouTube:


Now, at first, I was inclined to think it was a fan-created animation, but several angles and elements are identical to the EM-1 video that NASA posted.  To the level that I can't see it being done by anyone but the actual animation house that does the official NASA animations who has those scene setups already (one of them at least)...

I suppose if nothing else, its a preview of what we might see.

Offline Coastal Ron

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Re: SLS General Discussion Thread 2
« Reply #606 on: 08/16/2016 10:05 PM »
I think this is new, but if not remove:

NASA's Marshall Center - Done in 60 seconds: See a Massive Rocket Fuel Tank Built in A Minute



Not a fan of the music though - too "edgy"
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 russianhalo117

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Re: SLS General Discussion Thread 2
« Reply #607 on: 08/17/2016 12:05 AM »
I found this one that has also not been posted:

Offline woods170

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Re: SLS General Discussion Thread 2
« Reply #608 on: 08/17/2016 09:24 AM »
I think this is new, but if not remove:

NASA's Marshall Center - Done in 60 seconds: See a Massive Rocket Fuel Tank Built in A Minute
<snip>
Not a fan of the music though - too "edgy"
Is posted in the updates thread.
« Last Edit: 08/17/2016 09:25 AM by woods170 »

Offline woods170

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Re: SLS General Discussion Thread 2
« Reply #609 on: 08/17/2016 09:25 AM »
I found this one that has also not been posted:
<snip>
Older one. Also posted in the updates thread.
« Last Edit: 08/17/2016 09:25 AM by woods170 »

Offline Steven Pietrobon

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Re: SLS General Discussion Thread 2
« Reply #610 on: 08/17/2016 09:28 AM »
I was looking at doing a SLS animation one day, when I came across this video on YouTube:
youtube.com/watch?v=bK1foInKm00

Now, at first, I was inclined to think it was a fan-created animation, but several angles and elements are identical to the EM-1 video that NASA posted.  To the level that I can't see it being done by anyone but the actual animation house that does the official NASA animations who has those scene setups already (one of them at least)...

I suppose if nothing else, its a preview of what we might see.

One minor nit pick. The EUS should do a burn after core separation to get into LEO. The solar arrays then deploy, followed by TLI.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline okan170

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Re: SLS General Discussion Thread 2
« Reply #611 on: 08/17/2016 07:22 PM »
I was looking at doing a SLS animation one day, when I came across this video on YouTube:
youtube.com/watch?v=bK1foInKm00

Now, at first, I was inclined to think it was a fan-created animation, but several angles and elements are identical to the EM-1 video that NASA posted.  To the level that I can't see it being done by anyone but the actual animation house that does the official NASA animations who has those scene setups already (one of them at least)...

I suppose if nothing else, its a preview of what we might see.

One minor nit pick. The EUS should do a burn after core separation to get into LEO. The solar arrays then deploy, followed by TLI.

Yeah, the EM-1 video also doesn't follow the actual timing of events as they've shaken out. 

Apparently this IS an official animation:

Offline redliox

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Re: SLS General Discussion Thread 2
« Reply #612 on: 08/17/2016 07:33 PM »
While not relating to the EM-1 flight directly, news related to the Europa 'Clipper says the SLS is still their first choice, with Delta 4 and FH as alternatives.

http://spacenews.com/europa-mission-planning-for-possible-budget-cuts-in-2017/

It makes me wonder which version of SLS will be utilized; there's only one flight of the Block 1 version scheduled, for EM-1.  However, technically 2 Delta-derived upper stages were bought by NASA.  Most Europa presentations mentioning the SLS refer to Block 1 launchers.  I presume the Block 1B is the 'real' plan, but again I wonder if either version is possible.
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Offline Endeavour_01

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Re: SLS General Discussion Thread 2
« Reply #613 on: 08/18/2016 02:30 AM »
It makes me wonder which version of SLS will be utilized; there's only one flight of the Block 1 version scheduled, for EM-1.  However, technically 2 Delta-derived upper stages were bought by NASA.  Most Europa presentations mentioning the SLS refer to Block 1 launchers.  I presume the Block 1B is the 'real' plan, but again I wonder if either version is possible.

To get to Block IB the umbilicals and the ML have to be modified. EC is not going to be ready until 2022 or so at the earliest so the necessary mods would have to be delayed far longer than planned. That is not a smart strategy IMO. Plus depending on how adamant the Astronaut safety office is on having a IB launch before EM-2 (and how quickly EC is ready) the EC mission could get the first IB at the same time it would have gotten a Block I in your scenario.
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 ncb1397

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Re: SLS General Discussion Thread 2
« Reply #614 on: 08/18/2016 05:04 PM »

Our best hope is that SpaceX simply shames or litigates the SLS into a quick retirement with the BFR and NASA has thouse funds freed up to purchase all transport services from SpaceX and develop actual mission hardware.

Since it requires constant reinforcement...

That's not how appropriations work. If SLS ends NASA does not keep the money.
Sure, why not? Congress still wants jobs in those districts, NASA will just have to use the same workforce to build something different, like habs or asteroid grabbing robots or whathaveyou. SLS isn't the only thing that can provide that pork.

It is in principle true that when one of its programs ends, NASA simply looses the money.  In practice, though, NASA's inflation-adjusted budget has been approximately constant for decades, even as big programs have come and gone (e.g., Constellation, ISS, the Shuttle, X-33, Hubble, JWST).  Though there is always a risk that next time will be different, in practice the forces that Robotbeat identifies seem to keep the cash flowing.

And with a NASA-managed launch vehicle, there are funding risks as the program moves from one phase to the next, as Blackjax pointed out some time ago in what I thought was a very interesting post.

It has been approximately constant for decades, give or take a couple billion dollars. Removing SLS and/or Orion and NASA not keeping all or most of the money is entirely consistent with the waxing and waning of NASA's budget historically. For instance, in 1991, the 2014 inflation adjusted budget was 24,235. In 1994, it was 21,979. This represented a decrease of about 10%, which is about the portion of NASA's budget that is dedicated to SLS.

https://en.wikipedia.org/wiki/Budget_of_NASA

Offline Dante80

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Re: SLS General Discussion Thread 2
« Reply #615 on: 08/23/2016 12:23 AM »
Interesting interview with Bill Hill, manager of exploration systems development for NASA, about how much will SLS and Orion cost to fly.

http://arstechnica.com/science/2016/08/how-much-will-sls-and-orion-cost-to-fly-finally-some-answers

Some excerpts:

Quote
“My top number for Orion, SLS, and the ground systems that support it is $2 billion or less,” Hill told Ars. “I mean that’s my real ultimate goal. We were running at about three-plus, 3.6 billion [dollars] during the latter days of space shuttle. Of course, there again, we were flying six or seven missions. I think we’re actually going to have to get to less than that.”

(...)

Quote
During the space shuttle days, about 1,200 people worked at 40 stations to assemble the shuttle's external tank, which was a relatively simple design when compared to to the SLS core stage. Today, about 400 people with Boeing, the prime SLS contractor, work at a handful of stations to assemble the core stage. It represents a sign— a small but tangible one—that NASA might yet wrangle its big rocket and spacecraft costs into submission.
« Last Edit: 08/23/2016 12:23 AM by Dante80 »

Offline oldAtlas_Eguy

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Re: SLS General Discussion Thread 2
« Reply #616 on: 08/23/2016 03:06 PM »
Build rate!

Shuttle tank build rate was 6 per year. SLS build rate is 2 maybe. That is a factor of 3 difference and the main reason you see the 1200 personnel for Shuttle vs the 400 for SLS. Meaning the cost of the SLS core will be no more expensive "maybe" than the Shuttle ET.

In the end this is actually a good cost reduction accomplishment since lower build rate should have a higher manpower use per unit. So if the SLS core was manufactured at same rate as ETs, the manpower per SLS core should be less than an ET.

Offline Robotbeat

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Re: SLS General Discussion Thread 2
« Reply #617 on: 08/23/2016 06:53 PM »
SLS build rate is like half per year, not 1 per year.

If you're going by max rate, you'll have to compare with Shuttle's projected max (15, 20 per year? 40?). Shuttle achieved 9 missions one year and has a whole bunch of years where they achieved 7 or 8.
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Offline Robotbeat

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Re: SLS General Discussion Thread 2
« Reply #618 on: 08/23/2016 06:55 PM »
...
In the end this is actually a good cost reduction accomplishment since lower build rate should have a higher manpower use per unit. So if the SLS core was manufactured at same rate as ETs, the manpower per SLS core should be less than an ET.
Doesn't work like that because a lot of the absolute savings they're getting is by DRASTICALLY reducing the maximum production rate to just 2 per year (versus just about an order of magnitude higher for Shuttle).
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Offline Coastal Ron

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Re: SLS General Discussion Thread 2
« Reply #619 on: 08/23/2016 08:08 PM »
Build rate!

Shuttle tank build rate was 6 per year. SLS build rate is 2 maybe. That is a factor of 3 difference and the main reason you see the 1200 personnel for Shuttle vs the 400 for SLS. Meaning the cost of the SLS core will be no more expensive "maybe" than the Shuttle ET.

To a certain extent the number of personnel needed is not tied to the production rate.

For instance, the reason the Shuttle ET could be built in large quantities per year was due to tooling, not personnel specifically.  And the reason why the SLS is limited to being able to build less than two per year is partly due to tooling.

Also the SLS line is more automated than the Shuttle ET line was, so trying to draw conclusions from just staffing rates is not likely to yield useful information.

Quote
In the end this is actually a good cost reduction accomplishment since lower build rate should have a higher manpower use per unit. So if the SLS core was manufactured at same rate as ETs, the manpower per SLS core should be less than an ET.

Should be.  Although we also don't know the make-up & pay levels of the production staff required, so it could be a matter of comparing apples to oranges.

In general I hesitate to draw any conclusions or comparisons of the Shuttle vs the SLS, since they are more different than they are alike.
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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