SpaceX, rapid reuse, and vertical rocket stacking (integration)

[meekGee]

It was already established, actually by people "from the business", that the long pole was processing the first stage itself - 9 engines, several sets of RCS, etc.

So first and foremost, I'm addressing the processing of landed first stages, and so none of the above contradicts anything.

Integrating the stages, (again under the premise of rapid reuse) will be a lot simpler than what you're used to today.  You basically keep imagining "how it's done today, only faster" and that's not the right way to think about it.

Shrug.  We'll find out eventually.

[douglas100]

... You basically keep imagining "how it's done today, only faster" and that's not the right way to think about it.

No, those who have argued against vertical integration have argued in terms of ease and safety of work. That it is safer to work at ground level than on high level platforms is a fundamental fact and has nothing to do with "how it's done today." That is is easier to handle long thin things in a horizontal position rather than in a vertical position is obvious. You might as well assert that people who predict that in the future car wheels will be circular are only "thinking how it's done today."

I don't think you have made the case for vertical integration over other means of handling. I don't believe it makes much difference to how quickly the vehicle can be turned around. The important point about rapid re-usability is not how the vehicle is handled but how much work has to be done on it to get it ready for the next flight.

[Robotbeat]

What if there's simply no work to do, just need to stack the stages, they "click" together? I.e. like docking or berthing?

Work on the first stage engines can be done at ground level before integrating the upper stage and payload. Obviously, this is what SpaceX did with Grasshopper between flights (as far as we can tell, since being put on the legs, the tank has never again been horizontal in 8 little flights, the later ones having about half to a third the burn time of a Falcon 9 first stage), so it's at least somewhat feasible and can't be THAT expensive.

[meekGee]

... You basically keep imagining "how it's done today, only faster" and that's not the right way to think about it.

...

That it is safer to work at ground level than on high level platforms is a fundamental fact and has nothing to do with "how it's done today."

That is is easier to handle long thin things in a horizontal position rather than in a vertical position is obvious.

 

No it isn't....  If the work platform reaches and conforms to the wall of the rocket, then it's safer than handling stuff overhead at ground level.  You walk up to an access cover at eye level, and that's that.

I can't see why handling a 9 engine cluster is easier when it's on its side, and you have to keep rotating the rocket for each specific engine.

The engines are man-sized.  If they're standing in front of you, and you have full-around access, it's a lot simpler than walking under the bottom-most engine and using step ladders to reach in between them.

The only good thing about the step ladders was that it allowed flexibility when the rocket and procedures kept changing from flight to flight.

[douglas100]

What if there's simply no work to do, just need to stack the stages, they "click" together? I.e. like docking or berthing?

Work on the first stage engines can be done at ground level before integrating the upper stage and payload. Obviously, this is what SpaceX did with Grasshopper between flights (as far as we can tell, since being put on the legs, the tank has never again been horizontal in 8 little flights, the later ones having about half to a third the burn time of a Falcon 9 first stage), so it's at least somewhat feasible and can't be THAT expensive.

Even rapid turnaround airliners need some work done on them.  But I agree with your general point that the key to rapid reuse is the amount of work needing done. That is more about the technology of the vehicle itself rather than what position it's processed in.

Grasshopper needs no work done on the top end between flights so there's no need to rotate it to the horizontal. The minute you put a second stage and payload on top we are back to the same choice being discussed. If we were talking about a squat SSTO vehicle like Delta Clipper or Roton then, yes, keeping the vehicle vertical makes sense. But for long thin multistage things, I still think horizontal is better.

@ meekGee: you made these arguments upthread. People who work in the industry disagree. This amateur votes with them. Both methods of processing are currently used. Either would work. You haven't convinced me vertical is better in principle.

You always reply, but I've said all I need to on this subject (unless you come up with a compelling new argument.)

[Jim]

No it isn't....  If the work platform reaches and conforms to the wall of the rocket, then it's safer than handling stuff overhead at ground level.  You walk up to an access cover at eye level, and that's that.

Wrong.  It is 10's of feet in the air and the platforms never really conform.  there is always a drop hazard.   And there is still a need for elevators and stairs.  To move ten feet in either direction on the vehicle, one must leave the area and to an elevator or stairs.

As for the engines, there is interference from the launcher and holddowns that reduces accessibility.

[Jim]

head at ground level.  You walk up to an access cover at eye level, and that's that.

I can't see why handling a 9 engine cluster is easier when it's on its side, and you have to keep rotating the rocket for each specific engine.

The engines are man-sized.  If they're standing in front of you, and you have full-around access, it's a lot simpler than walking under the bottom-most engine and using step ladders to reach in between them.

Several unqualified assumptions.

1.  9 engine cluster.  There is nothing that indicates this future vehicle will use this specific number.  9 was chosen for the F9 for performance and adaptability of an existing engine.  It has nothing to do with reuse.

2.  that there is no free access to the engines.  The vehicle will be sitting on the launcher platform.  There will be interference from holddown points, umbilicals, etc.   The engines will either be at ground level surrounded by support structure or elevated and will need access platforms. 

[guckyfan]

2.  that there is no free access to the engines.  The vehicle will be sitting on the launcher platform.  There will be interference from holddown points, umbilicals, etc.   The engines will either be at ground level surrounded by support structure or elevated and will need access platforms.

I am with you that much of the processing is better done horizontal. But Elon Musk made that statement that the SES-8 launcher was left vertical on the pad for easier access to the engines.

[Jim]

I am with you that much of the processing is better done horizontal. But Elon Musk made that statement that the SES-8 launcher was left vertical on the pad for easier access to the engines.

That is true when it is on the launcher/erector.  They would have had to go horizontal, roll back and demated from the launcher for access to the engines.  We are talking prelaunch. 

[sugmullun]

Not exactly on topic, but related:
On it's Vandenberg erector, can SpaceX actually put 53 mtons under a fairing, above the grapples and hoist it up OK with the present setup?

[RanulfC]

... You basically keep imagining "how it's done today, only faster" and that's not the right way to think about it.

...

That it is safer to work at ground level than on high level platforms is a fundamental fact and has nothing to do with "how it's done today."

That is is easier to handle long thin things in a horizontal position rather than in a vertical position is obvious.

 

No it isn't....  If the work platform reaches and conforms to the wall of the rocket, then it's safer than handling stuff overhead at ground level.  You walk up to an access cover at eye level, and that's that.

Work platforms are NEVER "confromal" they always have a gap though they can usually be "bridged" by some type of "soft" bumper, the bumpers are NOT load-bearing and more often than not they get torn up really quickly in regular use. And I'll point it out again, "ground-level" means maxium fall distance is the diameter of the booster, where as "vertical" means a lot of activity is going to be STACKED above each other with all the safety issues that entails.

Your description of checking an access panel leaves out quite a bit of effort btw: Step one, check out and don your fall protection harness and lanyard (required) Step two, enter and use elevator or stairs to gain access to correct level. Step three, attach fall protection lanyard to over-head rail and test fittings. Step four, move out onto work level platform and work your way around to inspection panel. Step five, carefully remove fastners on panel if they are "loose" you must bag them up along with the panel and secure them to the work platform, if the panel and fasteners are "attached" to the vehicle by a lanyard or other restraining device you have to ensure all the fasteners are secured to the panel and the panel is not going to come loose during the time you are working with it. (Nominally you'll use a piece of "flash-breaker" tape and attach it to the hull) Step six, do the inspection or perform the maintenance action. Step seven ensure all tools and parts are accounted for prior to closing the panel. Step eight, supervisor has to reveiw and inspect the tools and panel to ensure no parts are missing or loose. (Which means he has to don and use a safety harness and fall protection as well) Step nine, reseal the panel. Step ten, inspect surrounding area for tools and lose parts. (In any case where a part or tool falls either outside or inside the rocket all work must be stopped until the part or tool is found and any damage to the rocket hull or assemblies assessed and dealt with. This CAN include haveing to de-panel the entire side of the rocket to ensure that the part did not fall into the engine bay somewhere and get lodged or more) Step eleven, move back to elevator/stairs and detach fall protection system from overhead rail. Step twelve, return down elevator/stairs to ground level. Step thirteen, return fall protection lanyard and harness to storage.

Same "process" in a horizontal position? Step one, climb stairs to platform (12 feet does not require fall protection systems normally) walk down the hull until you reach the panel, unfasten the panel, if any parts or fastners fall off during this operation they can fall no further than 12 feet and since there is no one working below you they are not a danger. Since the rocket will be moved away after processing the parts can be "secured" any time a general clean up of the processing facility floor is done, (Worst case scenerio is a part falls INSIDE the rocket in which case panels along the lower "section" of the rocket may have to be removed to find and remove the loose part/tool.) Perform inspection and or maintenance and replace the panel. Move on to next job or climb down off the platform.

I don't think you're quite getting the amount of "infrastructure" for each process. Horizontally you would "require" at most two "long" platforms each the length of the booster from engine-bay to interstage adapter with a single platform capable of being used to access the engines and engine-bay but would also be usable at the "front" of the interstage adapter as well if need be.

Meanwhile a "vertical" set up would require from two to four "tower" set ups taller than the booster is. (Probably a LOT taller as you'd use the same set up to help with mating the interstage, 2nd stage and payload but at the very least the towers have to be tall enough to have a "top" level for inspection and maintenance of the interstage adapter AND the relevent fall protection system attachments over-head of that platform)

Then the towers would have to have the folding platform levels which for the moment we'll "assume" a platform every 10 feet so that's about 10 "platforms" maximum with a high probably of around three minimum assuming that the majority of the hull inspection can be done with a set of cameras. In addition the towers will have to have associated lights, ladders, stairs, ducting and HVAC systems attached as well as power generation systems and hydralics capable of lifting the booster so that the legs can be folded and in all likely hood the "towers" when closed up around the booster will be used to move the booster as well in place of a TE assembly.

Possible? Yes, I've worked on various equipment both horizontally and vertically, (Radar maintenance on the E3B AWACS which means I've had to lug stuff up to and into that big "saucer" on top as well as work inside the aircraft hull) "Texas-Towers" exist for getting people and equipment into place to do the work but they are specialized equipment and more expensive than the more numerous and easier to access "low" work platforms.

Drop a tool from the top of the aircraft hull (about 20 or so feet) and you MIGHT put dent in a panel, drop the same tool from 40ft and if you're lucky it won't put a hole in a panel. The former will give anyone not wearing a hard-hat a bruise, the latter will give them a concusion if they are lucky.

I can't see why handling a 9 engine cluster is easier when it's on its side, and you have to keep rotating the rocket for each specific engine.

You're assuming that "horizontal" and "ground-level" are litterally the same thing here when they are not. They DO use platforms to handle and interact with the booster when it is horizontal they are not however as tall as those that are required for vertical interaction. Work platforms have only to be as high as the TE and the Booster diameter but usually will only reach half the booster diamter as ladders and additional work stands can be easily brought up to reach all parts of the booster. In the case of the engines rotation is not neccessary as a single work platform with hydralic adjustment can reach all the engines without the need to rotate the booster.

The only specific time you'd have to "rotate" the booster is to reach panels that are normally "covered" by the TE supports, not to inspect or maintenance the engines.

Randy

[meekGee]

Hi Randy.   I appreciate the time you took to write this - I've read it carefully.  You clearly are familiar with the operation of the VIF, and I trust your experience.

I think the key is in how you build the VIF.  All the problems you describe are a result of the VIF being too "general purpose", or just having "heritage" features that get in the way.

You say "work platforms are NEVER conforming".  I have to ask - why not?   I'm discussing a vertical facility as I imagine it should be built, not as it is built today.   (I assume that by "NEVER" you mean you've never seen a conforming one , not that there's a fundamental problem building one).

I can't see a reason why at any level you want access, there'd be a fully conformal floor, that reach up to a few cm from the wall.  If the gap is small, the soft adapter can be strong enough to hold even a full person's load, even if that person could fit their foot in the gap.  At that point, not even a bolt can fall through. This must be a requirement for building the VIF.

If built like that, the maximum fall distance is irrelevant - do you worry about falling through the floor to the basement?  Definitely no lanyards should be necessary when the stage is in place, since the structure is as good as a regular building.

The ten steps you enumerated - they are basically the details of following procedures.  They would be the same on a HIF.  Count all your tools.  Count every piece of removable hardware.  Sure - but all of these steps are easier to perform at eye-level and side access than they are when you're working "upwards" with things over your head.  Don't drop bolts inside the rocket - that's a matter of how the rocket is designed - it's easily preventable.

I'd rather work on a sturdy floor than on a step-ladder, even if only 12' high.  You can't move sideways with a ladder.  It's not a natural body position, and you might still fall, with hardware in your hands.   In my imaginary VIF, there are indeed elevators to access each level, but parts and tools are already at those levels. You don't have to go up and down for every task.

I COMPLETELY agree with the observation about the amount of infrastructure.  A purpose built VIF is easily an order-of-magnitude more complex than an HIF.   That's why it doesn't make sense if you only fly once a month.  But if you want to do single-day turn-around like Musk wants, then time is money, and a dedicated VIF will pay for itself - provided you have the volume.  Musk won't go there before he has flight volume, since that's a classic mistake for start-ups - jump ahead of themselves and invest too much, too quickly, in infrastructure that only makes sense for markets that have yet to materialize. 

---

I attached the famous Maven/Atlas picture.  I think it is gorgeous, but it shows both the good and bad sides of the VIF.

The good:  The large number of connections at the perimeter of the bottom of the payload illustrates the advantage of vertical.  You can access all of them, all the time.  I'd rather access all nine engine bells like this at one level, all actuators and turbopumps (and start cartridges and what not) at a second level, Leg hinges and bottom RCS at third, Leg latches at a fourth, Upper RCS at a fifth, avionics at a sixth...   Each level has 8 access directions, and with an HIF, you can only access one at a time.

The bad: You mentioned lanyards.  This means that not all work platforms are indeed conformal.  The gantry should be built independent of the wind bearing walls, so it never moves.  There's a crane, and I don't like cranes.  If the rocket is of standard height, the payload (or second stage) should arrive on a dolly, be lifted up by an elevator, then rolled with the dolly at just the right height so that it can be set onto the second stage (or first stage) by lowering the dolly a few inches at most.  No risk, and alignment can be done by basically centering the dolly, so the load is pre-aligned when it is lowered.

---

In short - you're listing the real-life deficiencies of working on high gantries.  I think they can be overcome - I don't think they are inherent to a VIF.  The key is that it has to be a dedicated "tight" facility - basically a processing building that's purpose built to get a stage through the steps as quickly (hours) as possible, since it needs to fly again the next day.

If work on it resembles what you describe (lanyards, drop hazards, etc) then you're 100% right.  I just think it is possible to do much better.

[zodiacchris]

That is a great picture, and a setup like this definitely comes in under 'nice to have'. But look at the massive vertical integration bay, and the sheer amount of hardware for the different levels, which also have to partially retract to allow for removal of the integrated vehicle!

This is not KISS, and if a number of rollable horizontal platforms and a cherry picker can do the trick in a low and long hangar, why would a cost conscious mob like SpaceX do anything else??

Cheers,
Chris

[RonM]

That is a great picture, and a setup like this definitely comes in under 'nice to have'. But look at the massive vertical integration bay, and the sheer amount of hardware for the different levels, which also have to partially retract to allow for removal of the integrated vehicle!

This is not KISS, and if a number of rollable horizontal platforms and a cherry picker can do the trick in a low and long hangar, why would a cost conscious mob like SpaceX do anything else??

Cheers,
Chris

With horizontal integration, you can set up shop in what is basically a sheet metal warehouse. Vertical integration requires a complex structure with all the fiddly bits we see in the picture. Horizontal integration will be far cheaper.

Now I don't know which is faster, but turn around time shouldn't be a problem with multiple reusable rockets. You wouldn't want to rush refurbishing a rocket. That would lead to disaster. You're better off with a fleet and taking your time on each rocket.

[meekGee]

The image below does NOT try to equate the process of changing tires with reusable rocket stage re-processing.

What I'm showing is that once the volume of operations is high, "cheaper infrastructure" is no longer a figure of merit, and what becomes important is "Cost as amortized per launch" and "time to process".

Once we agree that for rapid operations (but not before that!) investing in expensive infrastructure does make sense, we can get back to which form of infrastructure (HIF or VIF) we want to invest in - which is a technical rather than financial discussion.

[Jim]

That is a great picture, and a setup like this definitely comes in under 'nice to have'. But look at the massive vertical integration bay, and the sheer amount of hardware for the different levels, which also have to partially retract to allow for removal of the integrated vehicle!

This is not KISS, and if a number of rollable horizontal platforms and a cherry picker can do the trick in a low and long hangar, why would a cost conscious mob like SpaceX do anything else??

Exactly.  And to make things even easier (which equates to cheaper and quicker), you design the vehicle so that the hardware that needs to be accessed is at less than shoulder height.  The Atlas booster is designed that way: all the booster avionics, harness, tubing, etc are in a fairing on the side of the vehicle that can be accessed from standing next to the vehicle.  See the photo, the worker is next to the fairing.  The bulk of the stage avionics is in the wider aft portion of the fairing.

Atlas only uses a VIF for 3 reasons and none of them have to do with ease of access, turn around expediency or cost.  The 3 reasons are:  1. vertical payload integration; 2. Centaur upperstage mate (balloon tank makes horizontal mate difficult if not impossible) and SRB installation. 

[joek]

That is a great picture, and a setup like this definitely comes in under 'nice to have'. But look at the massive vertical integration bay, and the sheer amount of hardware for the different levels, which also have to partially retract to allow for removal of the integrated vehicle!

This is not KISS, and if a number of rollable horizontal platforms and a cherry picker can do the trick in a low and long hangar, why would a cost conscious mob like SpaceX do anything else??

And as a point of reference... 2010 estimate for another Atlas V VIF at CCAFS $350M.  Reported estimates for SpaceX: CCAFS LC-40 (before F9v1.1 work) about $50M; for VAFB site nearly $100M; and for Brownsville Tx site $65-85M.

[meekGee]

That is a great picture, and a setup like this definitely comes in under 'nice to have'. But look at the massive vertical integration bay, and the sheer amount of hardware for the different levels, which also have to partially retract to allow for removal of the integrated vehicle!

This is not KISS, and if a number of rollable horizontal platforms and a cherry picker can do the trick in a low and long hangar, why would a cost conscious mob like SpaceX do anything else??

And as a point of reference... 2010 estimate for another Atlas V VIF at CCAFS $350M.  Reported estimates for SpaceX: CCAFS LC-40 (before F9v1.1 work) about $50M; for VAFB site nearly $100M; and for Brownsville Tx site $65-85M.

I never once said an HIF is cheaper... The starting point was that a VIF is more expensive.

However, there isn't any person on this board that has seen, or can give examples of what a rapid reprocessing facility looks like. The facilities mentioned above are built for assembly.  Stages arrive from the factory in a pristine condition, and are then put together towards a single launch, with a cycle time of several weeks.  This includes Atlas, Delta, and Falcon for the next several years.

They are absolutely not built for the tasks of:
- Accepting a just-flown stages
- Inspecting engines and related subsystems
- Inspecting landing gear, RCS, batteries, etc
- Possibly doing component maintenance (e.g. engine cleaning)
- Possibly doing component replacements

All with the intent of not keeping the stage on the ground for longer than necessary, since it has to fly ASAP.

A stage on the ground is a stage that's not bringing in revenue. If you settle for a slow re-processing cycle and many stages on the ground, then you're just looking at non-flying non-revenue-generating stock.

Perhaps I'm misleading the conversation by calling them VIFs or HIFs.  They are not "integration" facilities.  They are "reprocessing" facilities.

STS had reprocessing facilities, but they (and the vehicle design) were not rapid and were not cheap per flight - so not much we can learn from there.   

This is why extrapolating from the Delta and Atlas facilities as baselines is not the right way to look at things.

[joek]

...

Perhaps I'm misleading the conversation by calling them VIFs or HIFs.  They are not "integration" facilities.  They are "reprocessing" facilities.

STS had reprocessing facilities, but they (and the vehicle design) were not rapid and were not cheap per flight - so not much we can learn from there.   

This is why extrapolating from the Delta and Atlas facilities as baselines is not the right way to look at things.

My point in offering that information was that it provides reasonably concrete costs for two very different approaches.  In any case ...

Assuming some or all of the LV components are reused, there are still three basic capabilities required: (re)processing; integration; and launch.  I think we can say with certainty that launch requires a vertical orientation.  Beyond that, whether capabilities should be combined and their optimal orientation are closely related but different questions--although obviously optimal end-to-end flow depends on the answer to all question, not just one.

Rather than continue to debate whether one answer is better than another, it would be more instructive and constructive to quantitatively articulate the assumptions and model on which those answers are based.

[AJW]

I would think that the most important factor is that the cores are currently designed to be assembled and maintained horizontally, so all of the tools, procedures, and experience are all based on working on these cores in the horizontal position.  Switching to vertical will require new facilities, tools, processes, documentation, and training.  All of these introduce risk and a significant investment in time to develop, and the intent of going vertical should be to reduce time and risk.

The physical act of attaching a crawler-crane to the core and returning it to the PF should take no more than a few hours, but during this effort there will also be hours to offload fuel, purge lines, and safe the core before moving it indoors for inspection and maintenance.  I suspect that once reusability is proven over subsequent flights we will see significant improvements in turn-around, but building a VIF and creating all new procedures to save a few hours will not be the way to do this.

BTW, I should point out with the auto-jack example that at races, manual floor jacks are used on the track because they are significantly faster than raising the entire vehicle.