Author Topic: Refurbishment of Used Stages/Vehicles  (Read 210436 times)

Offline rpapo

  • Cybernetic Mole
  • Full Member
  • ****
  • Posts: 1185
  • Michigan, USA
  • Liked: 620
  • Likes Given: 473
Re: Refurbishment of Used Stages/Vehicles
« Reply #80 on: 01/03/2016 09:58 PM »
That's for the airframe. They were and probably are not yet sure how many reflights they can do with that. But there is the statement of Elon Musk about the engines. 40 cycles, which was assumed to be ignitions between refurbishments. But the engines have no meaningful limit of use. After 40 cycles some highly stressed components need to be replaced.
A wise man on this site (not Jim) once suggested that the Helium COPV bottles may be the items with the shortest useful life, both in time and cycles.  I tend to agree.
An Apollo fanboy . . . fifty years ago.

Offline joek

  • Senior Member
  • *****
  • Posts: 2931
  • Liked: 691
  • Likes Given: 368
Re: Refurbishment of Used Stages/Vehicles
« Reply #81 on: 01/03/2016 10:08 PM »
So on the one hand there's the idea that across multiple reflights, you keep the same engines in the same spots, using them in exactly the same way again and again. This means that the 3 engines used for multiple burns within a flight are a bit more suped up - particularly that central engine that gets used for landing.

Then on the other hand, there's the idea that you "rotate the tires" across multiple reflights - swapping the less used engines in place of the more used ones, so that they all get their fair share of wear and tear.

Which way is the better way out of those 2 approaches - and why? Are there any other approaches that might be better still? Why?

Early on SpaceX may be taking engines off at a much higher rate to validate empirically how they're doing, so let's ignore that for right now.

Once they have validated engine reliability, I'm not familiar with how airlines handle this but I would imagine that you would not remove an engine unless there is a reason you don't want it to fly on the next flight.

Over time you're going to end up with a mix of used engines, including the potential for some to be flown on new stages, so "rotating" them is not going to add much value, especially the eight outboard engines.

In general you do not remove a component unless there is reason to do so.  The reasons fall into three broad categories:
1. Hard time -- Limits based on aging or wear characteristics vs. time or cycles.  These are likely still to be established.[1]
2. Condition -- Inspection to identify aging or wear vs. standard.  These are likely nominally understood but with hard limits yet to be established.
3. Monitoring -- Operational data which indicates potential for additional wear or off-nominal conditions.

[1] edit: For flown components.
« Last Edit: 01/03/2016 10:12 PM by joek »

Offline Johnnyhinbos

  • Full Member
  • ****
  • Posts: 1373
  • Boston, MA
  • Liked: 1593
  • Likes Given: 222
Re: Refurbishment of Used Stages/Vehicles
« Reply #82 on: 01/03/2016 10:23 PM »
Though I've not seen any mention of it, from a reusable /refurb perspective, I wonder if it would make sense to get away from high pressure gas, and He altogether by going in some IVF path? Then you can drop the COPV He bottles and associated struts
John Hanzl. Author, action / adventure www.johnhanzl.com

Online Lars-J

  • Senior Member
  • *****
  • Posts: 4160
  • California
  • Liked: 3570
  • Likes Given: 2197
Re: Refurbishment of Used Stages/Vehicles
« Reply #83 on: 01/03/2016 11:37 PM »

The center engine is used in all burns. And as far as why you would use the same other two engines for multiple burns - we don't know - but it has been assumed, since when each engine has a its own supply of ignition fluids (TEA/TEB) it makes more sense to just give 3 engines more of it instead of giving all engines the same restart capability. (It is nasty dangerous stuff) But I could be wrong on the last point.

I am assuming something else. All engines are ground started from an external supply. So why would they not be air started by a common supply? It would be a pure software command, which engine restarts. That would make it possible to use the outer engines in turn. Only the center engine would need to be replaced/refurbished sooner. Unless there are other reasons in the geometry of the stage to always use the same engines.

You might be right. We don't know if there is a central source of TEA-TEB, or if the engines have their own supply.

Offline Coastal Ron

  • Senior Member
  • *****
  • Posts: 4151
  • I live... along the coast
  • Liked: 2821
  • Likes Given: 3594
Re: Refurbishment of Used Stages/Vehicles
« Reply #84 on: 01/04/2016 01:14 AM »
Though I've not seen any mention of it, from a reusable /refurb perspective, I wonder if it would make sense to get away from high pressure gas, and He altogether by going in some IVF path? Then you can drop the COPV He bottles and associated struts

They plan to do that with the BFR/MCT by using autogenous pressurization (i.e. engine supplied vaporized propellants for tank pressurization).

Falcon 9/Heavy is probably not going to change since that would take significant engineering resources for a product/system that is already "good enough".  Of course that assumes that the He pressurization system doesn't continue to be their Achilles Heal...
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 pippin

  • Regular
  • Senior Member
  • *****
  • Posts: 2560
  • Liked: 290
  • Likes Given: 39
Re: Refurbishment of Used Stages/Vehicles
« Reply #85 on: 01/04/2016 03:37 AM »
Umm, right now I doubt that structural issues will be the limiting factor for the number of reuses. Right now a significant number of their payloads need to use the margin they have for landing the stage so it can't be reused. Judging by their manifest that makes it unlikely they're going to get more than two or three reflights out of a core so the discussion is quite moot for F9.

I know, those here who haven't really done the maths on how much reuse saves (but that's another thread) think those payloads will go on a heavy but given the cost associated with that this is unlikely.

So... Nice theory exercise for MCT and BFR but not really relevant for F9...

Offline pathfinder_01

  • Full Member
  • ****
  • Posts: 1915
  • Liked: 68
  • Likes Given: 0
Re: Refurbishment of Used Stages/Vehicles
« Reply #86 on: 01/04/2016 04:13 AM »
Umm, right now I doubt that structural issues will be the limiting factor for the number of reuses. Right now a significant number of their payloads need to use the margin they have for landing the stage so it can't be reused. Judging by their manifest that makes it unlikely they're going to get more than two or three reflights out of a core so the discussion is quite moot for F9.

I know, those here who haven't really done the maths on how much reuse saves (but that's another thread) think those payloads will go on a heavy but given the cost associated with that this is unlikely.

So... Nice theory exercise for MCT and BFR but not really relevant for F9...

While 2-3 reflights maybe all that is possible, thoose 2-3 reflights could come at an higher profit margin to Space X if  refurbishment costs are not too great. The nice thing about the F9/FH is that the system is both reuseable and disposable.

Offline pippin

  • Regular
  • Senior Member
  • *****
  • Posts: 2560
  • Liked: 290
  • Likes Given: 39
Re: Refurbishment of Used Stages/Vehicles
« Reply #87 on: 01/04/2016 05:42 AM »
Sure. All I'm saying is the actual structural life time of the stage is probably no limiting factor.

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6758
  • Germany
  • Liked: 1791
  • Likes Given: 1768
Re: Refurbishment of Used Stages/Vehicles
« Reply #88 on: 01/04/2016 07:34 AM »
I know, those here who haven't really done the maths on how much reuse saves (but that's another thread) think those payloads will go on a heavy but given the cost associated with that this is unlikely.

Oh, well. It's only the concept of SpaceX and what do they know about reusability of the Falcon family.

Offline pippin

  • Regular
  • Senior Member
  • *****
  • Posts: 2560
  • Liked: 290
  • Likes Given: 39
Re: Refurbishment of Used Stages/Vehicles
« Reply #89 on: 01/04/2016 07:48 AM »
Their manifest says otherwise.
And no, it's not their concept to use heavy for everything. They have stated that they might eventually do that but everything beyond that is fanboy fantasy.

Heavy also reduces some of the advantages of reuse because it clearly has much higher refurbishment and handling cost than a single core.
« Last Edit: 01/04/2016 07:55 AM by pippin »

Offline guckyfan

  • Senior Member
  • *****
  • Posts: 6758
  • Germany
  • Liked: 1791
  • Likes Given: 1768
Re: Refurbishment of Used Stages/Vehicles
« Reply #90 on: 01/04/2016 10:21 AM »
Their manifest says otherwise.
And no, it's not their concept to use heavy for everything. They have stated that they might eventually do that but everything beyond that is fanboy fantasy.

Where do you think the many FH on the manifest come from? They plan to use it for everything too heavy for reusable F9.

Online abaddon

  • Full Member
  • ****
  • Posts: 1700
  • Liked: 1159
  • Likes Given: 1002
Re: Refurbishment of Used Stages/Vehicles
« Reply #91 on: 01/04/2016 01:54 PM »
Right now a significant number of their payloads need to use the margin they have for landing the stage so it can't be reused.
Shotwell has cited the main benefit of the F9FT is allowing a barge landing on flights that wouldn't have been able to in the past (GTO).  It has yet to be established just how heavy a payload the F9FT can throw to GTO and still carry legs and reserve propellant for a downrange landing.  A barge landing is estimated to require a ~15% performance margin.  I am guessing we won't really know for sure immediately as the next GTO payload (SES-9) is quite heavy.

According to Wiki the heaviest bird F9 has thrown to GTO was TurkmenAlem52E/MonacoSAT: https://en.wikipedia.org/wiki/TurkmenAlem52E/MonacoSAT at 4707kg.  According to Gunter's, SES-9 is 5330kg, so it will be the heaviest payload to GTO for F9 to date.

I threw together a quick table of upcoming flights and masses to get an idea of how many recovery flights might be possible over the next year or so.  I didn't spend a ton of time vetting these so some flights might have been delayed/canceled/whatever.  Masses are from Gunter's and I note when I am estimating based on a similar bird.  I categorized payload recovery as Yes, Probably, Possibly, and Unlikely based on mass and past history, and taking into account the ~33% payload increase to GTO that F9FT is supposed to provide.

Payload                        Mass     Dest   Recovery Possible?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jason-3                         533kg   LEO    Yes
CRS-8                             ?kg   LEO    Yes
CRS-9                             ?kg   LEO    Yes
SES-9                          5330kg   GTO    Possibly (based on evidence that a barge landing will be attempted)
SES-10                         5300kg   GTO    Possibly
Thaicom 8                      3100kg   GTO    Yes
ABS 2A, Eutelsat 117 West B   ~4000kg?  GTO    Possibly (based on ABS-3A, Eutelsat 115 West B mass)
JCSAT-14                      ~3400kg?  GTO    Probably (based on JCSAT-15 mass)
BulgariaSat-1                 ~3400kg?  GTO    Probably (based on JCSAT-15 mass, same SSL-1300 bus)
JCSAT-16                      ~3400kg?  GTO    Probably (based on JCSAT-15 mass)
KoreaSat-5                     4465kg   GTO    Possibly
Es'hail-2                     ~3000kg   GTO    Probably
CRS-11                            ?kg   LEO    Yes
CRS-12                            ?kg   LEO    Yes
Formosat-5                      525kg   SSO    Yes
Iridium NEXT 1                ~8000kg?  LEO    Yes (800kg x 9 + estimated adapter mass)
Iridium NEXT 2                ~8000kg?  LEO    Yes (800kg x 9 + estimated adapter mass)
Iridium NEXT 3                ~8000kg?  LEO    Yes (800kg x 9 + estimated adapter mass)
Iridium NEXT 4                ~8000kg?  LEO    Yes (800kg x 9 + estimated adapter mass)
Iridium NEXT 5                ~8000kg?  LEO    Yes (800kg x 9 + estimated adapter mass)

Based on this I count 15 likely recovery flights out of 20.  That's a far cry from "only a few flights" being possible for recovery.  And that's arguably conservative, as F9FT should have enough margin to recover anything that has previously flown on an F91.1 (up to 4707kg).

Corrections welcome, I am sure there is some stuff that will likely need to be fixed here.

Update: I've updated SES-9 and 10 to "possibly" based on news that an application for barge landing has been filed.  That means that, theoretically, all of the upcoming launches will allow for recovery.
« Last Edit: 01/04/2016 04:11 PM by abaddon »

Offline LouScheffer

  • Full Member
  • ****
  • Posts: 1866
  • Liked: 2420
  • Likes Given: 269
Re: Refurbishment of Used Stages/Vehicles
« Reply #92 on: 01/04/2016 02:55 PM »
Right now a significant number of their payloads need to use the margin they have for landing the stage so it can't be reused.
...  It has yet to be established just how heavy a payload the F9FT can throw to GTO and still carry legs and reserve propellant for a downrange landing.  A barge landing is estimated to require a ~15% performance margin.  I am guessing we won't really know for sure immediately as the next GTO payload (SES-9) is quite heavy.

According to Wiki the heaviest bird F9 has thrown to GTO was TurkmenAlem52E/MonacoSAT: https://en.wikipedia.org/wiki/TurkmenAlem52E/MonacoSAT at 4707kg.  According to Gunter's, SES-9 is 5330kg, so it will be the heaviest payload to GTO for F9 to date.
From back-of-the-envelope calculations of the four improvements (cooled fuel, full thrust, bigger second stage, better ISP of second stage), and Musk's comments about staging velocity, ( https://forum.nasaspaceflight.com/index.php?topic=34077.msg1463298#msg1463298 ) it's possible SES-9 could be recoverable, particularly if they are willing to accept an 1800 m/s deficit to GEO (apogee at GEO, no inclination reduction). 

Online abaddon

  • Full Member
  • ****
  • Posts: 1700
  • Liked: 1159
  • Likes Given: 1002
Re: Refurbishment of Used Stages/Vehicles
« Reply #93 on: 01/04/2016 03:03 PM »
From back-of-the-envelope calculations of the four improvements (cooled fuel, full thrust, bigger second stage, better ISP of second stage), and Musk's comments about staging velocity, ( https://forum.nasaspaceflight.com/index.php?topic=34077.msg1463298#msg1463298 ) it's possible SES-9 could be recoverable, particularly if they are willing to accept an 1800 m/s deficit to GEO (apogee at GEO, no inclination reduction).
Right.  I originally classified the SES payloads as "possible", but I decided to be a little more conservative instead.  I do think it is possible we see legs on SES-9, which would have interesting repercussions...

Offline Dante80

  • Full Member
  • ****
  • Posts: 885
  • Athens : Greece
  • Liked: 806
  • Likes Given: 502
Re: Refurbishment of Used Stages/Vehicles
« Reply #94 on: 01/04/2016 03:05 PM »
I think that SES would love to be part of the party, but they also would love Falcon to give SES9-10 a super-synchronous orbit like SES8 (if it could manage it).

Lets see how this unfolds..

edit: barging may be on the schedule... https://apps.fcc.gov/oetcf/els/reports/STA_Print.cfm?mode=initial&application_seq=69076&RequestTimeout=1000

660km away for this one.
« Last Edit: 01/04/2016 03:26 PM by Dante80 »

Online rsdavis9

Re: Refurbishment of Used Stages/Vehicles
« Reply #95 on: 01/04/2016 03:51 PM »
Geez at this rate they are going to need a lz-2 in the bahamas. :)

Or maybe bernuda. Don't know if thats too far. Definitely in the wrong direction for gto. Maybe the center booster of falcon heavy?
With ELV best efficiency was the paradigm. The new paradigm is reusable, good enough, and commonality of design.
Same engines. Design once. Same vehicle. Design once. Reusable. Build once.

Online oldAtlas_Eguy

  • Senior Member
  • *****
  • Posts: 3458
  • Florida
  • Liked: 1864
  • Likes Given: 223
Re: Refurbishment of Used Stages/Vehicles
« Reply #96 on: 01/04/2016 04:35 PM »
The increase in performance of the F9FT should be able to at least barge land every currently manifested payload with RTLS for all but the heaviest that also wants to have higher energy orbit than what they would have gotten on F9v1.1.

F9v1.1 [no landing] -> F9FT [RTLS or with a higher energy orbit a Barge landing]
F9v1.1 [Barge landing] -> F9FT [RTLS even with a higher energy orbit]
F9v1.1 [RTLS] -> F9FT [RTLS with additional burn for even slower reentry]

The other item here is the current costs of this refurbishment processing to the point of full duration static fire.
 Total work days from recovery is at 14 days so far with 6 days (weekends + holidays) as probably no work = 8 work days of single shift crew.

Question becomes how many average crew over the period 10,20,50 100? My guess is at 20 only so far and almost all of them part of the LC39A new crew except a few experienced hands (technicians and engineers) from other pads, McGregor and Hawthorne leading the inspection and handling teams for both discovery and training in handling.

That would be a current balance for refurbishment cost at 8 days X $740 per day X 20 workers + $50,000 in equipment charges and other charges = $168,400 so far.

1 month at 50 workers + other charges [except equipment replacement part costs] would be only about $420,000.

2 months of labor plus additional misc cost for 150 workers would be about $3M. That is the size of the entire pad crew working on just this core for 2 months!! I do not think that this will be the case for this core and probably most cores. More like the 50 workers for 1 month ~$500K.

Now how many parts if any would be replaced (avionics, actuators, valves, TEA/TEB, complete engines, COPVs, etc)? That looks to be the main driver for refurbishment costs not the number of personnel to refurbish.

Refurbishment labor costs (1 to 2 months of 50 crew)+misc costs $.5-1M
Replacement parts? $0-10M [largest ticket item are engines]

3 engines swapped out is only a charge of $3-4.5M plus $1M in other parts brings a probable refurbishment cost to a range of $1.5M to $6.5M.

This seems to indicate that refurbishment charges are not going to be a lot and on average could be very small. In fact if they are estimated for a stage to be above a certain value the stage may be junked for parts.

also it may be cheaper to discard an engine not easily refurbished (a refurbishment cost for the engine at no more than $500K) since a brand new one has a cost of as low as $1M. If an engine needs that much rework it is not a good engine and refurbishment probably would not make it a better engine. most likely are engines that fail in-flight. They would be engineering and QC articles to discover what went wrong but probably not an engine slatted for reflight.

Offline OxCartMark

  • Full Member
  • ****
  • Posts: 1071
  • Michigan
  • Liked: 828
  • Likes Given: 887
Re: Refurbishment of Used Stages/Vehicles
« Reply #97 on: 01/05/2016 02:35 AM »
Total work days from recovery is at 14 days so far with 6 days (weekends + holidays) as probably no work = 8 work days of single shift crew.

Question becomes how many average crew over the period 10,20,50 100? My guess is at 20 only so far

Outside of cleaning the soot off the tanks {and maybe one thing that shall not be mentioned} there isn't much to base the case on that there has been or will be any refurbishment.  As far as I can see its in the new building because the building is empty and they don't want bird poo to accumulate on the stage.  Elon knows what is happening in the building and he said its ready to fire.  You don't know what is happening in the building and I think you've done a lot of imagining or at least shuttle based assuming.

Offline john smith 19

  • Senior Member
  • *****
  • Posts: 7547
  • Everyplaceelse
  • Liked: 1155
  • Likes Given: 7717
Re: Refurbishment of Used Stages/Vehicles
« Reply #98 on: 01/05/2016 08:03 AM »

That would be a current balance for refurbishment cost at 8 days X $740 per day X 20 workers + $50,000 in equipment charges and other charges = $168,400 so far.

Refurbishment labor costs (1 to 2 months of 50 crew)+misc costs $.5-1M
Replacement parts? $0-10M [largest ticket item are engines]

3 engines swapped out is only a charge of $3-4.5M plus $1M in other parts brings a probable refurbishment cost to a range of $1.5M to $6.5M.
Thanks for this OAG. My only real figure for staff costs was the average figure full up cost for a full time employee on the Shuttle programme at around $128k each. That $740/day figure will come in handy.

I'm going to have to break out support hardware and replacement parts in new headings for my costing game. Version 6 here it comes.<sigh>

What I wonder is how many people realize you are "thinking out loud" when you mention numbers for some of these things. IE What they might be and how good, or bad they may be.

I will note 3 things.

Firstly when NASA eliminated the White top coat from the ET they saved 100s of Kg of mass that went straight to orbiter payload. Thin layers over enough skin area multiply up.  :(

Secondly the obvious solution is something like an industrial sized hot air paint stripper with an "air knife" attachment, possibly with a GO2 feed down stream of the heater/blower.

Properly adjusted this starts the process of burning the HC residues down to CO2 and water without triggering the underlying ablative to start boiling off, restoring the pristine flight weight surface.  IRL I'd want a big fume extraction systems pointed at it and running full blast as I value my lungs  :(

Thirdly is an idea that occurred to me was that a lot of the potential stage inspection/refurbishment tasks could be described as :-
1)Clamp stage to a rotating base.
2)Have a guide way parallel to the stage carrying platform on an extensible arm to hold various sensors or tools.
3)Have the platform travel on the guide way moving in and out to track the stage and avoid its legs.

In fact if you called the platform a headstock, the guide way the bed and the platform a Saddle you'd be talking about a really big lathe.

Obviously "speeds and feeds" for it are a bit different than most peoples experience (less RPM and more MPR, with say 5m/hr along the bed) but such machines (and the companies that can build them) do exist.
« Last Edit: 01/05/2016 08:06 AM by john smith 19 »
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

Offline john smith 19

  • Senior Member
  • *****
  • Posts: 7547
  • Everyplaceelse
  • Liked: 1155
  • Likes Given: 7717
Re: Refurbishment of Used Stages/Vehicles
« Reply #99 on: 01/05/2016 08:14 AM »
Falcon 9/Heavy is probably not going to change since that would take significant engineering resources for a product/system that is already "good enough". 
True. One thing we know is SX really does not like to retain 2 different versions of something. Once Raptor is ready and the BFR is ready the question becomes "Retain RP1 and install CH4 piping or go CH4 for everything?"
But I doubt that will happen for another 8-10 years.
Quote
Of course that assumes that the He pressurization system doesn't continue to be their Achilles Heal...
That's a bit harsh.

COPV have had excellent safety records. The GHe ones on the SSME's ran to 4000psi and I'm not sure if they were ever  replaced (a Jim question?). The downside is their damage potential is measured in terms of Kg of TNT, due to their stored energy. An interesting question would be would the range safety people (usually the USAF?) let the certification on these tanks they did for the original launch carry over to further launches? If not then SX will have to do the process all over again.  :(
That would probably be enough to start them looking at "IVF like" (as IVF is covered by patents) options.

That said AFAIk none of them were inside a cryogenic tank, although the Saturn 1 & Saturn V ones were. However I think they were Titanium. Interestingly an upgrade project on Saturn was looking at replacing them with pressure stretched stainless steel with the same weight at 1/13 of the cost.

The mounting hardware on the other hand...

The center engine is used in all burns. And as far as why you would use the same other two engines for multiple burns - we don't know - but it has been assumed, since when each engine has a its own supply of ignition fluids (TEA/TEB) it makes more sense to just give 3 engines more of it instead of giving all engines the same restart capability. (It is nasty dangerous stuff) But I could be wrong on the last point.

I am assuming something else. All engines are ground started from an external supply. So why would they not be air started by a common supply? It would be a pure software command, which engine restarts. That would make it possible to use the outer engines in turn. Only the center engine would need to be replaced/refurbished sooner. Unless there are other reasons in the geometry of the stage to always use the same engines.

You might be right. We don't know if there is a central source of TEA-TEB, or if the engines have their own supply.
True. Theoretically a central system adds flexibility and saves weight.

The downside is a)It's a single point of failure. That tank leaks and all engines have a problem b)Engine change out now includes breaking the connections of a line carrying a very nasty chemical. That means staff on the pad in SCAPE suits rather than coveralls, gloves and visors. c)The Merlin Vac needs a standalone engine starter anyway. While people keep saying the Merlin Vac is much  more than a stock Merlin with a big nozzle this would represent more unique parts that SX have to build/test/store/install/troubleshoot/repair.

SX have shown themselves well aware of the cost of storing more complex inventories than they need to.
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

Tags: