### Author Topic: SLS General Discussion Thread 2  (Read 424311 times)

#### oldAtlas_Eguy

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##### Re: SLS General Discussion Thread 2
« Reply #1240 on: 01/21/2018 04:16 am »
Cost of liquid engines only:

4 RL-10's \$80M
4 RS-25E's (\$55M each) \$220M

= \$300M

Now add two SRBs and tanks and ......

So the incremental cost is well over \$500M.

The pad costs are hopefully not more than the previously estimated \$800M/year (includes everything: processing, GSE, VAB, pad  - maintence, operations).

That puts the minimum absolute cost if you launched 2 a year at not less than \$1B each launch. At 1 per year it is about \$1.4B each launch. But in budget for the year launching two in 1 year requires a budget of \$2B but launching only 1 a year requires only a budget of \$1.4B.

#### AncientU

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##### Re: SLS General Discussion Thread 2
« Reply #1241 on: 01/21/2018 12:02 pm »
Cost of liquid engines only:

4 RL-10's \$80M
4 RS-25E's (\$55M each) \$220M

= \$300M

Now add two SRBs and tanks and ......

So the incremental cost is well over \$500M.

The pad costs are hopefully not more than the previously estimated \$800M/year (includes everything: processing, GSE, VAB, pad  - maintence, operations).

That puts the minimum absolute cost if you launched 2 a year at not less than \$1B each launch. At 1 per year it is about \$1.4B each launch. But in budget for the year launching two in 1 year requires a budget of \$2B but launching only 1 a year requires only a budget of \$1.4B.

That's before payload, of course.  Add an Orion and a ride-share DSG module each time for typical budgets.
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#### oldAtlas_Eguy

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##### Re: SLS General Discussion Thread 2
« Reply #1242 on: 01/21/2018 03:17 pm »
Cost of liquid engines only:

4 RL-10's \$80M
4 RS-25E's (\$55M each) \$220M

= \$300M

Now add two SRBs and tanks and ......

So the incremental cost is well over \$500M.

The pad costs are hopefully not more than the previously estimated \$800M/year (includes everything: processing, GSE, VAB, pad  - maintence, operations).

That puts the minimum absolute cost if you launched 2 a year at not less than \$1B each launch. At 1 per year it is about \$1.4B each launch. But in budget for the year launching two in 1 year requires a budget of \$2B but launching only 1 a year requires only a budget of \$1.4B.

That's before payload, of course.  Add an Orion and a ride-share DSG module each time for typical budgets.
It's the allowed budget level that is the real problem for SLS.

The budget would probably never get as high as \$1.5B / year just for the SLS LV line and any more than the \$800M / year for ground support. That gives a total of not more than \$2.3B which must also handle upgrades and future development costs. If launching 1 per year there is enough remaining to do significant development work for upgrades ~\$900M but launching at 2 per year development upgrades is starved.

But if you also consider Orion costs + DSG payloads and budget with this added to the total and the likely hood of all things SLS/Orion/GSE/DSG budget capped at no higher than \$3.5M, that \$900M margin disappears quickly in order to develop and build the DSG elements and for making improvements to the SLS/Orion and after EM-2 shouldering the complete cost of the SM manufacture for Orion.

The difficulties have only just begun for the program if the costs have grown for the basic incremental costs. Initially SLS's incremental cost was supposed to be (less EUS) ~\$300M but with just engines costing \$55M each for total of \$220M that figure may be difficult to reach! Which will starve payload (DSG) development and  ultimately SLS's purpose for being.

SLS
4 RS-25's (\$55M each) \$220M
2 SRB's (\$30M each) \$60M
Tank Core \$75M
Avionics \$25M (rad hard, commonality with EUS)
= \$380M

EUS
4 RL-10's (\$19M each) \$76M
Tank Core \$20
Avionics \$25M (rad hard)
= \$121M

SLS 1B = not less than \$501M (NOTE this is a very optimistic estimate)

This also shows why NASA is looking at ways to cut incremental costs of the EUS by using a different cheaper engine. A pair of BE-3U's (\$8M each, this actually is a high estimate and reality is likely to be lower) could save as much as \$60M.

#### Steven Pietrobon

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##### Re: SLS General Discussion Thread 2
« Reply #1243 on: 01/22/2018 05:30 am »
SLS 1B = not less than \$501M (NOTE this is a very optimistic estimate)

For a production run of 22 vehicles, I got a price of \$511M each using NASA cost models.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

#### AncientU

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##### Re: SLS General Discussion Thread 2
« Reply #1244 on: 01/22/2018 01:22 pm »
SLS 1B = not less than \$501M (NOTE this is a very optimistic estimate)

For a production run of 22 vehicles, I got a price of \$511M each using NASA cost models.

Vehicle unit cost or full operational cost?  How many vehicles per year launched?
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#### Ronsmytheiii

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##### Re: SLS General Discussion Thread 2
« Reply #1245 on: 01/22/2018 08:11 pm »
So was wondering why SLS kept the clean-pad design of the Ares I ML and tower vs moving the FSS to the Pad surface like Shuttle. The clean pad made sense for Ares as you had two separate LVs, but with SLS after EM-1/only Block 1A flight the vehicle should have a fixed height for umbilicals. By removing the Tower from the ML you free up a lot of space and most importantly weight on it.

#### AncientU

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##### Re: SLS General Discussion Thread 2
« Reply #1246 on: 01/22/2018 11:39 pm »
So was wondering why SLS kept the clean-pad design of the Ares I ML and tower vs moving the FSS to the Pad surface like Shuttle. The clean pad made sense for Ares as you had two separate LVs, but with SLS after EM-1/only Block 1A flight the vehicle should have a fixed height for umbilicals. By removing the Tower from the ML you free up a lot of space and most importantly weight on it.

The original concept was to have a shared pad with commercial launcher(s).
That seems to be on indefinite hold.
"If we shared everything [we are working on] people would think we are insane!"
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#### Jim

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##### Re: SLS General Discussion Thread 2
« Reply #1247 on: 01/23/2018 12:20 am »
So was wondering why SLS kept the clean-pad design of the Ares I ML and tower vs moving the FSS to the Pad surface like Shuttle. The clean pad made sense for Ares as you had two separate LVs, but with SLS after EM-1/only Block 1A flight the vehicle should have a fixed height for umbilicals. By removing the Tower from the ML you free up a lot of space and most importantly weight on it.

because it would increase pad time.  integration off pad with the umbilical tower makes more sense like Atlas V and Falcon 9.  The upper stages and spacecraft need to be checked  out with the umbilicals.  Spacecraft need to be connected to GSE once attached to the rocket.
Shuttle umbilicals were at the tail.  LH2 vent was the only connection at the pad.

#### Coastal Ron

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##### Re: SLS General Discussion Thread 2
« Reply #1248 on: 01/23/2018 12:47 am »
SLS
4 RS-25's (\$55M each) \$220M
2 SRB's (\$30M each) \$60M
Tank Core \$75M
Avionics \$25M (rad hard, commonality with EUS)
= \$380M

Where do you get \$60M per SRB set?

The last big SRM production contract that ATK Thiokol was awarded (in 2002) was \$2.4B for 70 SRM sets, or \$34.3M each or \$68.6M per set.

However that was for volume production of at least 5 sets per year, and the SLS is originally set up for no more than 1.5 launches per year. Plus the SLS SRM's are larger than the Shuttle SRM's.

Based on all of that I'd be surprised if a SLS SRM set cost less than \$100M per set.
« Last Edit: 01/23/2018 12:53 am by Coastal Ron »
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

#### Robotbeat

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##### Re: SLS General Discussion Thread 2
« Reply #1249 on: 01/23/2018 12:54 am »
Right, and the assembled whole is always more than all the pieces separately.

SLS is simply expensive. Just the hardware is expensive.

There's a way around this: Make SLS reusable. Flyback boosters AND the core. I'm aware of one such recent proposal, but it went nowhere, not even a pre-phase-A study.

(To make this feasible, it may be necessary to stretch the upper stage.)
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#### ncb1397

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##### Re: SLS General Discussion Thread 2
« Reply #1250 on: 01/23/2018 01:00 am »
SLS
4 RS-25's (\$55M each) \$220M
2 SRB's (\$30M each) \$60M
Tank Core \$75M
Avionics \$25M (rad hard, commonality with EUS)
= \$380M

Where do you get \$60M per SRB set?

The last big SRM production contract that ATK Thiokol was awarded (in 2002) was \$2.4B for 70 SRM sets, or \$34.3M each or \$68.6M per set.

However that was for volume production of at least 5 sets per year, and the SLS is originally set up for no more than 1.5 launches per year. Plus the SLS SRM's are larger than the Shuttle SRM's.

Based on all of that I'd be surprised if a SLS SRM set cost less than \$100M per set.

His model is assuming costs associated with high rate of SRM production but low rate of RS-25 production. All in all, you can call it a wash.

#### A_M_Swallow

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##### Re: SLS General Discussion Thread 2
« Reply #1251 on: 01/23/2018 01:04 am »
Right, and the assembled whole is always more than all the pieces separately.

SLS is simply expensive. Just the hardware is expensive.

There's a way around this: Make SLS reusable. Flyback boosters AND the core. I'm aware of one such recent proposal, but it went nowhere, not even a pre-phase-A study.

(To make this feasible, it may be necessary to stretch the upper stage.)

Getting Orion to a space station in low lunar orbit may also require a stretched upper stage.

#### Robotbeat

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##### Re: SLS General Discussion Thread 2
« Reply #1252 on: 01/23/2018 01:20 am »
Right, and the assembled whole is always more than all the pieces separately.

SLS is simply expensive. Just the hardware is expensive.

There's a way around this: Make SLS reusable. Flyback boosters AND the core. I'm aware of one such recent proposal, but it went nowhere, not even a pre-phase-A study.

(To make this feasible, it may be necessary to stretch the upper stage.)

Getting Orion to a space station in low lunar orbit may also require a stretched upper stage.
Low lunar orbit isn't a very good place for a space station, tho.
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

#### A_M_Swallow

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##### Re: SLS General Discussion Thread 2
« Reply #1253 on: 01/23/2018 02:07 am »
Low lunar orbit isn't a very good place for a space station, tho.

Ion thrusters can keep a spacestation in low lunar orbit. It is a good place to store and refuel the lander between missions.

#### Coastal Ron

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##### Re: SLS General Discussion Thread 2
« Reply #1254 on: 01/23/2018 02:30 am »
SLS
4 RS-25's (\$55M each) \$220M
2 SRB's (\$30M each) \$60M
Tank Core \$75M
Avionics \$25M (rad hard, commonality with EUS)
= \$380M

Where do you get \$60M per SRB set?

The last big SRM production contract that ATK Thiokol was awarded (in 2002) was \$2.4B for 70 SRM sets, or \$34.3M each or \$68.6M per set.

However that was for volume production of at least 5 sets per year, and the SLS is originally set up for no more than 1.5 launches per year. Plus the SLS SRM's are larger than the Shuttle SRM's.

Based on all of that I'd be surprised if a SLS SRM set cost less than \$100M per set.

His model is assuming costs associated with high rate of SRM production but low rate of RS-25 production. All in all, you can call it a wash.

The term "high rate" when talking about the SLS as it stands today is more than one but less then two flight-sets per year.

And any costing exercise has to assume the same number of complete assemblies, otherwise the numbers being discussed/debated aren't meaningful.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

#### Steven Pietrobon

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##### Re: SLS General Discussion Thread 2
« Reply #1255 on: 01/23/2018 06:38 am »
For a production run of 22 vehicles, I got a price of \$511M each using NASA cost models.
Vehicle unit cost or full operational cost?

Vehicle unit cost.

Quote
How many vehicles per year launched?

The model does not take that into account, but I would assume at least two vehicles per year.

]Low lunar orbit isn't a very good place for a space station, tho.

An LLO space station is not necessary. The station we want is on the Moon, not LLO.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

#### A_M_Swallow

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##### Re: SLS General Discussion Thread 2
« Reply #1256 on: 01/23/2018 08:50 am »
]Low lunar orbit isn't a very good place for a space station, tho.

An LLO space station is not necessary. The station we want is on the Moon, not LLO.

We get both. The LLO space station is used to build the lunar base. Landing the big heavy bits from LEO without refuelling is difficult.

#### AncientU

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##### Re: SLS General Discussion Thread 2
« Reply #1257 on: 01/23/2018 12:02 pm »
Right, and the assembled whole is always more than all the pieces separately.

SLS is simply expensive. Just the hardware is expensive.

There's a way around this: Make SLS reusable. Flyback boosters AND the core. I'm aware of one such recent proposal, but it went nowhere, not even a pre-phase-A study.

(To make this feasible, it may be necessary to stretch the upper stage.)

If you want a reusable rocket, take out a blank sheet of paper and design one.
It will look nothing like SLS with reusable bits.
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-- SpaceX friend of mlindner

#### MATTBLAK

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##### Re: SLS General Discussion Thread 2
« Reply #1258 on: 01/23/2018 12:18 pm »
Flyback core? No - not that and have maximum payload delivery. I would agree that in a perfect world; the boosters would be flyback LOX/Hydrocarbon, the corestage would have 5 and not 4 RS-25's and the upper stage would have stronger engines and a slightly higher propellant load.

But that's not what we're getting. For better or worse, SLS is not going to be changing much.
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#### speedevil

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##### Re: SLS General Discussion Thread 2
« Reply #1259 on: 01/23/2018 12:18 pm »
If you want a reusable rocket, take out a blank sheet of paper and design one.
It will look nothing like SLS with reusable bits.
Unless you're congress.
I just had the nightmare that the response to increasing commercial competition on SLS would be to try.

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