SpaceX long-term stage processing goal = 48 hour turnaround

[wardy89]

Would it be impractical to put dollys under the ends of the legs and roll it around? Not back to a building, but to a strongback at the edge of the landing pad, where they could detank and drop to horizontal.

I have been wondering the same sort of thing, although in the form of a strongback that could be taken to the rocket. Capable of recovering the stage back to horizontal, practical enough to allow for inspection, 2nd stage integration and payload integration then launch without the 1st stage having to be lifted off the strongback.
My thinking is that it would reduce the number of times you have to lift and load a stage, reducing the number of steps between landing and relaunch.

Taking the current F9 design and looking at pictures of the recovered stage i imagine a strongback capable of lowering a recovered stage to horizontal would need to be narrower than currently used at launch, so it fits between the extended legs and leaves room for them to retracted back to the closed position or be taken off.
 

[bstrong]

Taking the launch strongback all the way to the landing pad doesn't sound like a great idea to me. If you had a "stage manipulator" that can grab a stage, move it, and change it's orientation without requiring any manual rigging, you'd save a ton of labor and time, and it would be useful for other purposes as well (grabbing the stage off a truck, sticking it into a storage slot, etc).

I'm reminded of how forklift drivers shuffle around 40ft yachts in dry-stack storage like it's no big deal. If you had to use cranes, the whole business wouldn't work due to the extra time and labor. You need the equivalent for rocket stages (including the big storage shed with stacked slots for stages).

Edit: The piece of equipment I was imagining is called a reachstacker and is commercially available in sizes large enough to handle a stage (see attachment 2). Some have ability to tilt the payload. You just need a custom grappler. You could put one on the barge once you're confident enough that you're not going to set it on fire.

[Jim]

The first stage is too long for handlers such as those.  Also, rigging is required because built in attach points on the front end of the stage would add a lot of mass (the aft end with the thrust structure has ready made attachments )

[rpapo]

I think that a lot of people in this forum don't quite get just how BIG that stage is.  That forty foot yacht is only a quarter as long, and many times less weight, despite the fact that the stage is very light for its size.

[bstrong]

I think that a lot of people in this forum don't quite get just how BIG that stage is.  That forty foot yacht is only a quarter as long, and many times less weight, despite the fact that the stage is very light for its size.

I wasn't saying you could actually grab it with a forklift. Just using that example of efficiently shuffling around large items (in timeframes measured in seconds, not hours) using equipment that doesn't require rigging.

You can buy a reachstacker with 100,000 lb capacity (forklifts, too), which is more than enough for a stage, I believe. You couldn't use the one in the photo I attached unmodified, but with a 3x longer crossbeam and some custom grapplers on the ends that close to hold the stage in the same way as the rotisserie rings, I don't see why it couldn't be done. These companies crank out customized equipment all the time.

My point is that you have to stop thinking about handling stages one at a time and treating them like they're priceless artifacts. To support the flight rates that justify 48 hour processing, you'll have a large industrial facility with storage for 10-20 stages (probably racked vertically, somehow) and the capacity to process several in parallel. You'll be shuffling them around constantly, and you'll use techniques that more closely resemble the way large objects are shuffled around in other high-throughput industrial settings than what they're doing today.

[AncientU]

Each leg has three structural attach point (all ball joints), and maybe gas lines or electric connections. (I hope each leg has its own internal bottle).

Saving 12 demate/mate operations like that is a major time saver IMO.  The legs are heavy and awkward to handle.

I hope to see them folded on the spot.

I hope that too.

However presently the means of transporting the stage requires the legs gone. That's necessary for size restrictions when transported on public highways. It would not be required for moving in the cape area, even from the present mooring location of the ASDS. But new methods of transporting the stage would be needed. I don't know if an ASDS could land the stage at Vandenberg? Probably not because the west coast ASDS is not homed there. So at the west coast the legs would need to be removed for transport on barge landing.

Yes - in-place leg folding goes hand I  hand with never leaving the cape.

Once a Retriever engages the stage and supports its weight from the Octoweb, the legs can physically be retracted.
I suspect that a vacuum pump-out of the actuating gas could be the motivating force to pull legs back up along the stage -- after the latches are released, that is.  When legs are locked in place, the stage is moved to horizontal (using the above strongback) and driven back to hanger/HIF.  In the hanger/HIF, the stage is rigged with slings and bridge cranes as a new stage would be, except a legs-on method would be needed for the aft end.  Actuating gas is recharged along with other expendable fluids.

This type of retrieval, with legs on, could go from landing/safeing to hanger/HIF in a couple hours.

[Jim]

1.  You can buy a reachstacker with 100,000 lb capacity (forklifts, too), which is more than enough for a stage, I believe. You couldn't use the one in the photo I attached unmodified, but with a 3x longer crossbeam and some custom grapplers on the ends that close to hold the stage in the same way as the rotisserie rings, I don't see why it couldn't be done. These companies crank out customized equipment all the time.

2.  My point is that you have to stop thinking about handling stages one at a time and treating them like they're priceless artifacts.

3.  To support the flight rates that justify 48 hour processing, you'll have a large industrial facility with storage for 10-20 stages (probably racked vertically, somehow) and the capacity to process several in parallel. You'll be shuffling them around constantly, and you'll use techniques that more closely resemble the way large objects are shuffled around in other high-throughput industrial settings than what they're doing today.

1.  The stages are too long to be handled that way.   Would require a huge building just for maneuvering. Towing/movement lengthwise will be SOP no matter what the flight rate. 

2.  Wrong.  One ding and that takes the stage out the flow and maybe out of the fleet. 

3. Nonsense.  7 or so is enough.   And they won't be stacked like cordwood.  Stored stages don't make money.   A low hangar with as many bays as needed.  Doors  will be on each end of the bays, so stages can towed/driven through.

[DAZ]

4 small motorized self-propelled lifting units, one for each leg.  Lifting units attach themselves to the bottom of each leg.  Cable is then attached between the lifting units (one cable to each unit left and right) and cables are then snubbed tight.  Lifting units then lift the stage legs off the ground several inches.  Because of the cables the stage can no longer sag.  At this point the stage can even be leveled by adjusting the cable lengths.  This arrangement would seem to be faster and safer than using large aircraft jacks.

The same arrangement could be used on the ASDS.  On the barge the units would move and attach themselves to pad eyes for transport back to shore.  On the landing pad the units would move to a fixed Detanking/safeing and lowering unit.  Think simplified fixed strong back.  The legs would then be removed and the stage lowered.  It could then be easily loaded onto a standard F9 Road transporter.  A similar arrangement could be used dockside for the barge.  This too would seem to be to me much faster and safer than using a crane.

[bstrong]

1.  The stages are too long to be handled that way.   Would require a huge building just for maneuvering.

A facility that supports multiple launches a day is going to be enormous, no matter what. And besides, Elon loves huge buildings. Across all his companies, he has quite a collection of buildings that seemed unreasonably large when he built or acquired them.

Towing/movement lengthwise will be SOP no matter what the flight rate. 

I agree. Load it onto a flatbed truck for movement. No need to design a new vehicle that can both grab and drive long distances.

2.  Wrong.  One ding and that takes the stage out the flow and maybe out of the fleet. 

Everything may be need to be robotic if human operators aren't up to the task. That negates my argument for off-the-shelf equipment, but not the broader point that a large number of cores are going to be in constant motion, and it's best to be able to grab and manipulate them, even if it requires huge machines to do it.

3. Nonsense.  7 or so is enough.   And they won't be stacked like cordwood.  Stored stages don't make money.

The economics of re-use say flight rate trumps cost of a few additional cores. To maximize flight rate, you need to have some spares, so that you never miss a launch window if processing is delayed on a vehicle and also to account for both routine and unscheduled maintenance that takes longer than the normal processing time (e.g., an overhaul every 30 flights).

The number of extra cores you need depends on what fraction of the time cores are either undergoing maintenance or waiting to undergo it, just like the number of extra aircraft an airline needs to maintain. It's an interesting unknown number.

A low hangar with as many bays as needed.  Doors  will be on each end of the bays, so stages can towed/driven through.

With a large number of cores in the facility and a hanger the height of the HIF's (how or why would you make it lower?), you're going to get an enormous building that way, too. Sounds plausible, though. I guess it depends on how much land you have to work with.

I've defended this idea more than it really deserves, so I'll stop now.

[AncientU]

The 'strongback' could be the extended sections of a hydraulic crane, with a clamp like on the TEL upper end.  The stage is strong enough to support its own weight (stages always seen with support on each end, nothing in the middle), so the 'strongback' merely needs to lower and guide the upper end of the stage into a horizontal cradle.  Bulk of stage weight is at octoweb end,  so the upper end of the stage wouldn't need massive support.  The octoweb end, which is strong enough to support a fully-fueled vehicle, would easily handle the full stage weight when the stage is lifted for leg retraction.

I don't see this as a difficult rigging problem to solve.  Predict that the cranes and slo-mo landed vehicle handling will be replaced this year by a custom retriever.

[darkenfast]

Or maybe...just maybe....you stick with the simpler, tried-and-true method of hiring a local specialty crane outfit to safely lower your stage and put it on the transporter.  The thing is long and awkward and can only be handled at certain points.  They have this method down.  They use it in Texas all the time.  I would guess that they took longer than usual this time because it is the first time, and they are being very careful.   

[guckyfan]

Or maybe...just maybe....you stick with the simpler, tried-and-true method of hiring a local specialty crane outfit to safely lower your stage and put it on the transporter.  The thing is long and awkward and can only be handled at certain points.  They have this method down.  They use it in Texas all the time.  I would guess that they took longer than usual this time because it is the first time, and they are being very careful.

In McGregor they had no choice. It was put on top of the tripod until very recently. The handling is tricky. As you said it can be handled only at certain points in a certain way. I am not sure they will let a local crane crew handle it, I would expect they flew in the crew from McGregor. A special design for the purpose is at least a possibility IMO.

[AncientU]

Or maybe...just maybe....you stick with the simpler, tried-and-true method of hiring a local specialty crane outfit to safely lower your stage and put it on the transporter.  The thing is long and awkward and can only be handled at certain points.  They have this method down.  They use it in Texas all the time.  I would guess that they took longer than usual this time because it is the first time, and they are being very careful.

It took 48 hours to get the first landed stage to the hanger -- the operation was cumbersome and slow.  I suspect that the division of time in the target 48 hours for processing will be a small allocation to retrieval (maybe 10%/4.8hrs), and most time to ground checks and reintegration of the stage in the HIF(90%).

[DaveH62]

Moving to 48 hour turn around will be a journey, identifying and solving hundreds of critical path issues one at a time. A crane may be ok for now, but eventually they will need a built to suit system. A modular strongback with the louvered base section a permanent part of the launch and landing pad and a upper strongback, stage connection section, able to disconnect from the base. Once the strongback is raised at the landing pad, it connects to the rocket, is lowered to a transport and moved to a hanger for inspection. Once complete, the same strongback stage connection section could be moved to the launch pad.

[AncientU]

Moving to 48 hour turn around will be a journey, identifying and solving hundreds of critical path issues one at a time. A crane may be ok for now, but eventually they will need a built to suit system. A modular strongback with the louvered base section a permanent part of the launch and landing pad and a upper strongback, stage connection section, able to disconnect from the base. Once the strongback is raised at the landing pad, it connects to the rocket, is lowered to a transport and moved to a hanger for inspection. Once complete, the same strongback stage connection section could be moved to the launch pad.

Why use the same strongback?   The TEL is special purpose tooling and would be impractical to run it down to the landing pad.  The LC-39A version runs on railroad tracks as well as having umbilicals, etc. which would be useless at landing pad. 

Also, if the strongback is run down to the landing pad, it could not be integrating the next vehicle, could not be refurbished from the just completed launch, would have to have core offloaded in hanger for integration, etc.  Too many issues... if you want fast turn-around, make special tooling that does each job efficiently.

Nope, there will be special apparatus built for retrieving.

Edit: The TEL strongback is also too long to retrieve first stage plus interstage.  It is designed for a mated pair of stages.

[rcoppola]

I look at how they customized the Marmac's to become ASDS's. (Including modifications as they gained experience.)

I suspect the same will apply here and they may have already started a customized landed stage Vertical to horizontal/transporter at some undisclosed sub-contractor location. Or at the least, are working on final designs to facilitate such. With the potential of as many returned cores as they may have for 2016, they'll want to streamline this process as efficiently as possible heading into the 3rd & 4th quarters of 2016.

"LZ-1, the Falcon has landed. Landing operators move to procedure 11.100 Section 3 on LZ 1 B-Net..." I suspect they'll be amending their post landing procedures constantly through to the stage being returned to HIF.

They have a lot of TE experience at this point having designed and built multiple variations. As well as a lot of crane and customized flat bed experience in moving cores around. So I don't think it's a stretch to think they can take all that experience and create a customized and efficient hybrid de-erector/transporter.

[john smith 19]

I just discovered this thread and have now read through all of it. I have a few points.

1) People have said where think the time is going but the first real task would be plot on a time line where it actually goes.

2)Special purpose stage (not complete rocket) handling machines (probably adapted versions of commercial vehicles or the existing TEL) will be needed at the implied flight rates that need such fast turnaround.

3)To maintain this flight rate you are going to need "buffer stocks" of stages in a storage facility to cover the delay from ocean recovery --> transport to McGregor and McGregor --> Refurb site and Refurb  site --> launch site. So IRL the next booster comes from the refurb store while the last is just landing on the ASDS for transport back to port. That "Buffer store" will be pretty big.
Faster refurb --> smaller store.
Faster return to port --> smaller store.
Faster test firing --> smaller store.

The poster boy for this is the "Single digit press tool changeover" in the auto industry, pioneered by (IIRC) Toyota.  Key fact was that in principal it could have been done any time since about the 1930's if the incentive had existed for it to happen.

[Paul_G]

3)To maintain this flight rate you are going to need "buffer stocks" of stages in a storage facility to cover the delay from ocean recovery --> transport to McGregor and McGregor --> Refurb site and Refurb  site --> launch site.

I know that the FH boosters were taken back to McGregor for a test fire, but am not sure if the other reuse cores have been taken back - I *thought* the East Coast cores were refurbished at KSC / CCAFS and were not hauled back and forth to McGregor.

[stcks]

The only reused F9 (not FH) to go back through McGregor was 1021

[john smith 19]

The only reused F9 (not FH) to go back through McGregor was 1021

Then that buffer stock holding area just got smaller.