Author Topic: What would it take to change your mind on SLS/Orion?  (Read 9230 times)

Offline edkyle99

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Re: What would it take to change your mind on SLS/Orion?
« Reply #60 on: 08/11/2017 05:09 PM »
And yes, payload to LEO is the proper comparison, because most payloads go there, and all can be designed to depart from there to any destination with no relevant* loss in mission capabilities. 
SLS Block 1B is being designed to boost 32 metric tons (tonnes) trans-Mars.  Falcon Heavy Expendable is expected to lift 16.8 tonnes trans-Mars.  Falcon Heavy "recoverable" (first stage and boosters) would only lift about 4.9 tonnes trans-Mars.  These - or similar numbers to points beyond LEO - are the valid comparisons.  NASA has talked about starting with a Deep Space Gateway - not a LEO Gateway.

 The LEO-rendezvous Falcon Heavy alternative that you propose would require a new deep-space stage, a propellant depot setup, lots of LEO parking and propellant transfer capability that doesn't exist, etc. just to package a mission to the Deep Space Gateway - all of which would cost lots of cash.  SLS is being designed to go straight to the Gateway. 

Much of the LEO mass capability of a Falcon Heavy would be lost to "tare weight", propellant boiloff, parking orbit RCS propellant, etc.  Only about 60% of the liftoff weight of an HTV, for example, is actual cargo.

 - Ed Kyle
« Last Edit: 08/11/2017 05:17 PM by edkyle99 »

Offline tdperk

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Re: What would it take to change your mind on SLS/Orion?
« Reply #61 on: 08/11/2017 05:19 PM »
And yes, payload to LEO is the proper comparison, because most payloads go there, and all can be designed to depart from there to any destination with no relevant* loss in mission capabilities.
SLS Block 1B is being designed to boost 32 metric tons (tonnes) trans-Mars.  Falcon Heavy Expendable is expected to lift 16.8 tonnes trans-Mars.  These - or similar numbers to points beyond LEO - are the valid comparisons.

 The LEO-rendezvous Falcon Heavy alternative that you propose would require a new deep-space stage, a propellant depot setup, lots of LEO parking capability that doesn't exist, etc. - all of which would cost lots of cash.  Much of the LEO mass capability of a Falcon Heavy would be lost to "tare weight", propellant boiloff, parking orbit RCS propellant, etc.  Only about 60% of the liftoff weight of an HTV, for example, is actual cargo.

 - Ed Kyle

No, we are discussing travel in space.  The proper figure of merit is dV/lb/$, with the constraint the total dV is high enough.

"  The LEO-rendezvous Falcon ... is actual cargo. "  <--  Nothing you have said here is true and relevant, as you presume the use of non-optimal architectures which are easily avoided.  For that matter, even if your presumptions were true AND relevant, they'd have to amount to more than 11 tons to be to the good of the SLS in comparison solely on the basis of mass.

For example, I was quite pessimistic in allowing 4 months for the three FH launches.  SpaceX will within a few years have two pads built allowing FH launches.  With their already demonstrated turnaround time, the mission being thought of could be launched within a span of two weeks, with the minimal boiloff of a few hours time before departure for destination.
« Last Edit: 08/11/2017 05:28 PM by tdperk »

Offline edkyle99

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Re: What would it take to change your mind on SLS/Orion?
« Reply #62 on: 08/11/2017 06:23 PM »
"  The LEO-rendezvous Falcon ... is actual cargo. "  <--  Nothing you have said here is true and relevant, as you presume the use of non-optimal architectures which are easily avoided. 
What is the "optimal" alternative architecture?  How much does the currently non-existing hardware needed to make it work cost to develop, build, and fly?

 - Ed Kyle

Offline tdperk

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Re: What would it take to change your mind on SLS/Orion?
« Reply #63 on: 08/11/2017 06:49 PM »
"  The LEO-rendezvous Falcon ... is actual cargo. "  <--  Nothing you have said here is true and relevant, as you presume the use of non-optimal architectures which are easily avoided. 
What is the "optimal" alternative architecture?

The one that gets the job done for the least $.

 
How much does the currently non-existing hardware needed to make it work cost to develop, build, and fly?

Dunno, but if the 130+ tons one SLS will lift are instead lifted with FH's, you get up to $750mn saved from the Atlantic to work with.

And the TMI for an FH reusable is about 11.7 long tons to go by past history (I don't know where you are getting 4,900kg from), so you get to keep the rockets.  I'm generously (to ULA) calling the per launch FH cost to be $250mn per, where the quoted cost is $90mn.  I'm also generously presuming SLS costs don't rise further.

SpaceX now states the FH expendable payload to Mars is 16,800kg and the payload for reusables has generally been 70% of expendable.  Even if reusable launch payload drops to 60% of expendable and the price is that unrealistically high $250mn per, the FH still beats the SLS.
« Last Edit: 08/11/2017 07:01 PM by tdperk »

Offline Ictogan

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Re: What would it take to change your mind on SLS/Orion?
« Reply #64 on: 08/11/2017 07:00 PM »

Dunno, but if the 130+ tons one SLS will lift are instead lifted with FH's, you get up to $750mn saved from the Atlantic to work with.

And the TMI for an FH reusable is about 11.7 long tons to go by past history (I don't know where you are getting 4,900kg from), so you get to keep the rockets.  I'm generously (to ULA) calling the per launch FH cost to be $250mn per, where the quoted cost is $90mn.

A deep space tug/stage is required anyway.
SpaceX quotes the FH at than $90m up to 8000kg to GTO, suggesting that that is the cutoff point for triple core landings. Given that that is roughly the same as expendable F9, a similar TMI capacity as expendable F9 should be expected - F9 can do 4,020kg to TMI. So why do you think it can do 11.7 long tons?

Offline tdperk

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Re: What would it take to change your mind on SLS/Orion?
« Reply #65 on: 08/11/2017 07:29 PM »

Dunno, but if the 130+ tons one SLS will lift are instead lifted with FH's, you get up to $750mn saved from the Atlantic to work with.

And the TMI for an FH reusable is about 11.7 long tons to go by past history (I don't know where you are getting 4,900kg from), so you get to keep the rockets.  I'm generously (to ULA) calling the per launch FH cost to be $250mn per, where the quoted cost is $90mn.

A deep space tug/stage is required anyway.
SpaceX quotes the FH at than $90m up to 8000kg to GTO, suggesting that that is the cutoff point for triple core landings. Given that that is roughly the same as expendable F9, a similar TMI capacity as expendable F9 should be expected - F9 can do 4,020kg to TMI. So why do you think it can do 11.7 long tons?

(16,800kg to Mars expendable X 0.7 for reusability X 2.2 for kg to lbs conversion) / 2204 for pounds to long tons =~ 11.7

You seem to be presuming the all up Block 5 builds will have the same lower max velocity limits for return ability the current stages do.  Even if they do, it is at most about 40% of the vehicle cost being expended, since the side cores are certainly returnable.

I actually expect SpaceX will be successful at recovering all stages for the F9 and FH in the next several years.  There may well be for TMI and GTO, no practical way to recover the 2nd stage for most launch profiles of interest.  For TLI, a once around free return should be easy to arrange for almost every launch.
« Last Edit: 08/12/2017 12:09 AM by tdperk »

Offline ehb

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Re: What would it take to change your mind on SLS/Orion?
« Reply #66 on: 08/11/2017 09:57 PM »
(16,800kg to Mars expendable X 0.7 for reusability X 2.2 for kg to lbs conversion) / 2204 for pounds to long tons =~ 11.7

From (ugh) https://en.wikipedia.org/wiki/Ton

British [long] ton is 2240 lbs
US [short] ton is 2000 lbs
Metric (seems to be the primary measure used for rocket capabilities) ton [tonne, t (SI), MT (sic)] is 2204.6 lbs

To convert from kg to metric tons, just divide by 1k ;)

-e

edit: removed mT (in response to RonM's subsequent observation). 
« Last Edit: 08/12/2017 02:44 AM by ehb »

Online RonM

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Re: What would it take to change your mind on SLS/Orion?
« Reply #67 on: 08/11/2017 11:40 PM »
(16,800kg to Mars expendable X 0.7 for reusability X 2.2 for kg to lbs conversion) / 2204 for pounds to long tons =~ 11.7

From (ugh) https://en.wikipedia.org/wiki/Ton

British [long] ton is 2240 lbs
US [short] ton is 2000 lbs
Metric (seems to be the primary measure used for rocket capabilities) ton [tonne, MT] is 2204.6 lbs

To convert from kg to mT, just divide by 1k ;)

-e

Be careful with SI symbols, mT is millitesla. The correct SI symbol for tonne is lowercase t.

Online envy887

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Re: What would it take to change your mind on SLS/Orion?
« Reply #68 on: 08/11/2017 11:51 PM »

Dunno, but if the 130+ tons one SLS will lift are instead lifted with FH's, you get up to $750mn saved from the Atlantic to work with.

And the TMI for an FH reusable is about 11.7 long tons to go by past history (I don't know where you are getting 4,900kg from), so you get to keep the rockets.  I'm generously (to ULA) calling the per launch FH cost to be $250mn per, where the quoted cost is $90mn.

A deep space tug/stage is required anyway.
SpaceX quotes the FH at than $90m up to 8000kg to GTO, suggesting that that is the cutoff point for triple core landings. Given that that is roughly the same as expendable F9, a similar TMI capacity as expendable F9 should be expected - F9 can do 4,020kg to TMI. So why do you think it can do 11.7 long tons?

SpaceX was planning to attempt 3-core recovery on Red Dragon missions, which would require sending around 10 tonnes through TMI. I don't think 8,000 kg to GTO is at all near the limit for FH with 3-core recovery.

I think this capability will be demonstrated with the lunar Dragon mission. And that that point it will get a bit more difficult to convince me that SLS is worthwhile.

Offline edkyle99

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Re: What would it take to change your mind on SLS/Orion?
« Reply #69 on: 08/12/2017 05:45 AM »
"  The LEO-rendezvous Falcon ... is actual cargo. "  <--  Nothing you have said here is true and relevant, as you presume the use of non-optimal architectures which are easily avoided. 
What is the "optimal" alternative architecture?

The one that gets the job done for the least $.
That could very well be SLS/Orion.  NASA's goal is $1.5 billion per year for one to two SLS/Orion launches.  The fully-recoverable Falcon Heavy/Dragon cost for the ten flights we've been discussing would exceed $1.8 billion.

 - Ed Kyle

Offline guckyfan

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Re: What would it take to change your mind on SLS/Orion?
« Reply #70 on: 08/12/2017 06:10 AM »
That could very well be SLS/Orion.  NASA's goal is $1.5 billion per year for one to two SLS/Orion launches.  The fully-recoverable Falcon Heavy/Dragon cost for the ten flights we've been discussing would exceed $1.8 billion.

 - Ed Kyle

How do you get to $180 million per 3 core reusable FH flight? No way that would be more than $100 million with a healthy profit.

Edit: added 3 core reusable
« Last Edit: 08/12/2017 06:11 AM by guckyfan »

Offline Proponent

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Re: What would it take to change your mind on SLS/Orion?
« Reply #71 on: 08/12/2017 08:17 AM »
Metric (seems to be the primary measure used for rocket capabilities) ton [tonne, t (SI), MT (sic)] is 2204.6 lbs

To be really, really technical and persnickety, the tonne is not an SI unit, though it and the associated symbol 't' are recognized by the International Bureau of Weights and Measures (BIPM).

Offline edkyle99

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Re: What would it take to change your mind on SLS/Orion?
« Reply #72 on: 08/12/2017 12:26 PM »
That could very well be SLS/Orion.  NASA's goal is $1.5 billion per year for one to two SLS/Orion launches.  The fully-recoverable Falcon Heavy/Dragon cost for the ten flights we've been discussing would exceed $1.8 billion.

 - Ed Kyle

How do you get to $180 million per 3 core reusable FH flight? No way that would be more than $100 million with a healthy profit.

Edit: added 3 core reusable
I am comparing cost of launch vehicle and payload.

 - Ed Kyle 

Online AncientU

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Re: What would it take to change your mind on SLS/Orion?
« Reply #73 on: 08/12/2017 12:28 PM »
"  The LEO-rendezvous Falcon ... is actual cargo. "  <--  Nothing you have said here is true and relevant, as you presume the use of non-optimal architectures which are easily avoided. 
What is the "optimal" alternative architecture?

The one that gets the job done for the least $.
That could very well be SLS/Orion.  NASA's goal is $1.5 billion per year for one to two SLS/Orion launches.  The fully-recoverable Falcon Heavy/Dragon cost for the ten flights we've been discussing would exceed $1.8 billion.

 - Ed Kyle

Did you just say that without a wink?

Development costs for SLS/Orion alone will be $2B/flight if amortized over the first 20 flights (which will never actually be flown).  NASA's goal... sure, I believe that. ;)
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Online envy887

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Re: What would it take to change your mind on SLS/Orion?
« Reply #74 on: 08/12/2017 02:15 PM »
That could very well be SLS/Orion.  NASA's goal is $1.5 billion per year for one to two SLS/Orion launches.  The fully-recoverable Falcon Heavy/Dragon cost for the ten flights we've been discussing would exceed $1.8 billion.

 - Ed Kyle

How do you get to $180 million per 3 core reusable FH flight? No way that would be more than $100 million with a healthy profit.

Edit: added 3 core reusable
I am comparing cost of launch vehicle and payload.

 - Ed Kyle

You're comparing 1 Orion to 10 Dragons?

Offline edkyle99

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Re: What would it take to change your mind on SLS/Orion?
« Reply #75 on: 08/12/2017 02:20 PM »
That could very well be SLS/Orion.  NASA's goal is $1.5 billion per year for one to two SLS/Orion launches.  The fully-recoverable Falcon Heavy/Dragon cost for the ten flights we've been discussing would exceed $1.8 billion.

 - Ed Kyle

How do you get to $180 million per 3 core reusable FH flight? No way that would be more than $100 million with a healthy profit.

Edit: added 3 core reusable
I am comparing cost of launch vehicle and payload.

 - Ed Kyle

You're comparing 1 Orion to 10 Dragons?
Yes, as a placeholder.  There has to be some type of smart payload on top of each rocket.  Something to maneuver the cargo in orbit, etc.  Each payload and its integration has a cost.

 - Ed Kyle

Offline tdperk

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Re: What would it take to change your mind on SLS/Orion?
« Reply #76 on: 08/12/2017 03:28 PM »
"  The LEO-rendezvous Falcon ... is actual cargo. "  <--  Nothing you have said here is true and relevant, as you presume the use of non-optimal architectures which are easily avoided. 
What is the "optimal" alternative architecture?

The one that gets the job done for the least $.
That could very well be SLS/Orion.  NASA's goal is $1.5 billion per year for one to two SLS/Orion launches.  The fully-recoverable Falcon Heavy/Dragon cost for the ten flights we've been discussing would exceed $1.8 billion.

 - Ed Kyle

But three FH flights duplicate one SLS for at most half the cost.  1/4 the cost is plausible.

And no, there has to be something smart enough and with enough fuel or refuel-able on orbit at the top of one rocket.  Your presuming otherwise is you presuming sub-optimal architectures.
« Last Edit: 08/12/2017 03:35 PM by tdperk »

Offline edkyle99

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Re: What would it take to change your mind on SLS/Orion?
« Reply #77 on: 08/13/2017 12:01 AM »
But three FH flights duplicate one SLS for at most half the cost.  1/4 the cost is plausible.

And no, there has to be something smart enough and with enough fuel or refuel-able on orbit at the top of one rocket.  Your presuming otherwise is you presuming sub-optimal architectures.
The Falcon Heavy upper stage batteries die after several hours at most and there is no means for recharging them.  The stage has no ability to rendezvous or dock with other orbiting objects.  There is no auto docking system for the stage.  There is no propellant transfer system once docked.  You pretend that all of these non-existing capabilities have no cost when, in fact, the cost to develop and test and fly such systems would be quite large.  Dragon can fly in space, rendezvous, and dock, making it a good surrogate for such costs.

 - Ed Kyle
« Last Edit: 08/13/2017 12:01 AM by edkyle99 »

Offline tdperk

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Re: What would it take to change your mind on SLS/Orion?
« Reply #78 on: 08/17/2017 06:30 PM »
But three FH flights duplicate one SLS for at most half the cost.  1/4 the cost is plausible.

And no, there has to be something smart enough and with enough fuel or refuel-able on orbit at the top of one rocket.  Your presuming otherwise is you presuming sub-optimal architectures.
The Falcon Heavy upper stage batteries die after several hours at most and there is no means for recharging them.  The stage has no ability to rendezvous or dock with other orbiting objects.  There is no auto docking system for the stage.  There is no propellant transfer system once docked.  You pretend that all of these non-existing capabilities have no cost when, in fact, the cost to develop and test and fly such systems would be quite large.  Dragon can fly in space, rendezvous, and dock, making it a good surrogate for such costs.

 - Ed Kyle

And you are honestly positing these are show stoppers?  That remedying them will cost significantly more than has been SpaceX's history to date of being 1/10th the cost of Old Space to get the same job done innovatively?

Also, the Upper Stage would just deorbit--it's capabilities are not at issue at all.
« Last Edit: 08/17/2017 08:41 PM by tdperk »

Offline Lar

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Re: What would it take to change your mind on SLS/Orion?
« Reply #79 on: 08/17/2017 06:58 PM »
Arguing about tons vs tonnes? Stale and boring.

This is a thread about what would change your mind. Maybe some out of the box thinking is needed. The pricing and payload discussions are also stale and boring.

Let's try to up the level shall we?
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

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