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.[/quote}You're lucky I couldn't figure out any good ways to intergrate some "War Stories" in there That surely would have crashed the forums QuoteI 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.Yes to the first part and both yes-and-no to the second. The only way you get a non "general-purpose" VIF is to size it to a SINGLE system. Otherwise you have to include the ability to deal with varying parameters for future and modified vehicles.QuoteYou 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). The easy answer is because rocket stages are easily damaged by impact and the only way to avoid that is to leave a good amount of space between where your "hard-structure" ends and your rocket hull begins.I actually HAVE seen "conformal" structures both used vertically and horizontally and the vertical ones tend to have to be "creeped" together in very small increments over a long period of time. Even then they never actually "touch" the structure and either use the "bumpers" I mentioned or in some cases inflated pillows.The "fundamental" issue in a VIF versus a HIF is that the VIF is less adjustable and able to deal with changes once built. Any changes usually take a major effort (and money) to make in order to handle different hardware.QuoteI 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.It would pretty much HAVE to be the requirements but then you're getting into some major structural work as well. I don't know if you've seen them but the majority of VIF work platforms don't have solid floors. They have gridded floors often covered with matting or something specifically to try and catch tools and parts before they fall. It doesn't work as often as we could wish. If you're 'gap' at the platform edge is ony a few cm you've now locked yourself into ONLY servicing a specific size vehicle and any change in diameter would require the removal and replacement of all the platforms. In a HIF the work-platforms can be adjusted by simply unlocking some wheels and moving it in or out. (Having said that I will note that the HIF facilities used by the AF have had their platforms replaced twice going from the MM-1 to the MM-3 which I think shows poor planning more than anythinig else )QuoteIf 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.If you're in a building with no fixed "rails" around a very long fall you still have to have fall protection, the same applies to the VIF as it has at least ONE side which is considered "open" The problem is safety regulations have to take into account the possibility of a fall no matter how low the odds. And tools and parts can and do "ignore" safety measures. Working with a "conformal" platform with the afore mentioned "bumpers" butted up against the aircraft I still managed to drop a socket-wrench that went right through the "sealed" gap between the bumpers. It missed the airframe and landed in another techs tool box that was working 40 feet below me. The "fix" for that was we were then required to use the inflatable bumpers instead of the normal ones. Even so another tech dropped a screwdriver which bounced off the inflatable and flew off the BACK side of the platform and wound up lodged in the roof of the supervisors van.QuoteThe 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.Sorry I thought I'd mentioned those steps in both scenerios, however the difference is that instead of working "above" other people and very far above the floor you are only working somewhere between 6 and 12 feet off the ground. You're not working "upward" nor "over-your-head" but at eye-level just with the booster on its side not vertical. I think this is the main stickinig point in the discussion as you seem to be assuming everythin is on the ground level when it doesn't (and usually isn't) have to be.For example:QuoteI'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.The "step-ladder" won't be 12' high, at most it would be six and more likely less than three. You'd have a "steady-floor" or a work platform next to the rocket that is probably no more than 6 feet off the ground putting you at "eye-level" with the middle of the rocket. In most cases you would simply rotate the rocket at set intervals to reach and interact with all the required maintenance and inspection panels without ever having to change "levels" on the platform.As a former tool-room tech and current parts attendant/equipment room tech I need to point out that having tools and parts on "every-level" of the VIF, (recall there could be anywhere between three and ten levels) is a LOT of stuff that has to be inventoried and accounted for at the begining and end of every shift! With a much increased chance of loosing or misplacing the same due to the high numbers.Really you'd have each tech issued a tool box he would move to the work site with the "common" tools and a more centerally located large tool bin that they would go to for more specialty tools. And they WOULD have to carry them from job to job I'm afraid.You would probably have the same in a HIF except you could place the larger tool bin on the platform (one for each side) and only need to move a maximum of around 6 feet (climb) and half way down the platform to reach them at any time.QuoteI 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. The thing is it would be much easier to expand an HIF as compared to doing the same with a VIF and there still doesn't seem to be a convincing reason to prefer VIF over HIF. Given the very nature of a processing facility that is trying to get down to single day processing the analog of assembly line structure would seem to beat out the idea of a "high-bay" structure.Though again it really comes down to WHAT you're imagining versus what the rest of us are seeing QuoteThe 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.See that's an "issue" right there, at the LEAST you could access two sides of the vehicle in a HIF. Again you're assuming that everything is accessed at "ground-level" while underneath the rocket and that's not how it's done.Another thing you miss but address as an "advantage" is the fact that you have "8-access-directions" which would then assume you have 8-crews per level so that you can access any of them at any time In reality you would in effect have only ONE (1) crew per level and they would have to pick up and move to each new location. Similarly to the way the crew is in the HIF though with more "steps" required to do the same work.QuoteThe 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.Lanyards and safety devices are a fact of life on high projects. Everyone hates them until they save your life, then you usually hate them a little less but still complain about them (Personal experiance, I fell off the wing during an aircraft wash and was saved by my harness and lanyard. Then again during an ice/snowstorm the same harness and lanyard failed to prevent me from falling off the wing while removing snow/ice and what saved me was the 5 feet of snow on the ground. The main difference being was that in the former case there was an actual fall protection system installed in the wash building, in the latter someone decided that simply having two people holding 40 foot ropes attached to the harness' would suffice. Note the aircraft wing is only about 12 to 15 feet off the ground at its lowest point. Note also that I had a perfectly good set of insulated pants, uniform pants and my keester ripped open by the row of "flow-seperators" along the aft edge of the wing when I yanked the guy who was supposed to be "belaying" me off his feet. 14 stiches and suddenly it wasn't so "important" to clean the snow/ice off the wings anymore. )The mating sequence you point out is as I understand it pretty much how it is done in the HIF.QuoteIn 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.Above a certain hight off the "ground" some of these ARE going to be inherent simply because of the process and safety needs. Some can be mitigated and avoided by careful design yes, but the same can be said for an HIF and it won't have the inherent issues involved in the VIF. I go back again to the question of what each of us is "seeing" when we say "HIF/VIF"?QuoteIf 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.Possible? Of course, but the question is WHAT is the "better" you see compared to what I and others are seeing?How about this, this is what I "see" as the "process" for a "fast" turn around F9R (yes Jim we know this is probagbly NOT going to be the vehicle but we'll work with it for an example at this point )Ok, F9R lands and is safed by a ground crew. During that time the TE vehicle is moved into place near the landing pad and readied to retrieve the vehicle. Once safed, the TE backs to within a few feet of the F9R and clamps are secured at the top and bottom and either the TE or a dedicated lift vehicle raises the F9R so that the legs can be folded and locked. The TE completes mating with the F9R and then lowers it into a horizontal transport position and proceeds to the processing facility. TE is dropped off at enterance to the HIF processing facility where it is pulled into the "dock" and work-platforms placed on both sides of the vehicle. Processing begins on both sides of the vehicle as well as from underneath, meanwhile the upper "leg" is extended, inspected and maintenance done. If it needs to be replaced this is done so with the overhead crane. (The F9R will be rotated a total of four times but only needs two rotations for full processing) Any engine changes or major maintenance will be performed using the overhead crane and an aft "engine" platform.Once processing is done the TE is towed "forward" to have an interstage and associated processing done, meanwhile another F9R is already being towed into position to begin the processing stage. ONce the interstage is attached and checked out the TE is towed foward again into position where the second stage and payload have already been intergrated and checked out. Mating of the F9R and second stage takes place and all-up vehicle check out is done. (Second F9R is getting its interstage attached and checked out while a third F9R is begining being processed)At this point the "all-up" F9R vehicle TE is towed from the facility to a launch pad and erected for pre-launch check out and fueling prior to launch. Meanwhile another F9R has landed and is being safed for pick up by another TE.Randy
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.
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.
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.
However, there isn't any person on this board that has seen, or can give examples of what a rapid reprocessing facility looks like.
So, a question based on this discussion...What is the maximum rate that SpaceX can integrate boosters (units/month) given the technique they use now?And if they move to vertical integration (however unlikely) what rate would they be able to achieve? I recall some comment earlier that said Soyuz was launching at the rate of around 1/week.
People were saying that ("it's a GOAL, it's something to keep in mind for 10 years from now") about reusability too. Yet F9R will fly this year, and maybe even be recovered. Fast turn-around is more complex, since you need both technology and demand. Market demand is an elusive thing. It hides for 20 years, then one day it pops up and suddenly there's a new reality. In this case, I think SpaceX itself will be part of making the market happen, since they will become their own customer on the way to Mars.Irrespective of this though, what I'm describing is "How I think a reprocessing system for rapid reusable rockets should be designed". Fair? If it doesn't happen, it doesn't happen....
For first stage processing, you also have to add (in your example) not only 4x as many rockets, but also 4x as much ground infrastructure.
I have followed this conversation with interest. After reading all the concepts and counter concepts and delays inherent in reuse, I am concerned that fuel depots on orbit will never happen simply because it takes way to much inspection, repair and time delay between docking and fueling. I mean, why would it work any different on orbit than it works on the ground and why would it work differently on the ground than it (hypothetically)works in orbit?There will be either a considerable process to launch a recovered stages and never a refueling depot in space, or there will be gas and go for recovered stages, and gas and go on orbit. JMO
I think that MCT will be powered by a collection of center cores that are attached together in orbit. Why build fuel depots when you are already sending up a big tank that conveniently also comes with propulsion. The SpaceX reusable video also shows a moveable nozzle skirt extension which would indicate an engine that can be efficient both at launch and in vacuum. Launch a bunch of center cores, link them together and attach the crew module. Send fuel to top off the tanks and then send up the crew/colonists. This is why I listed fuel to MCT rather than to a depot. Depots will exist at some point, but I think the short-term goals can be met without them.
With airplanes, a typical jet liner doesn't need anything between maintenance checks, which are tens of flights apart. Here, we don't know. Is the rocket truly gas-and-go? My intuition says that no, and some level of inspection is necessary after each flight, even if it's only 1 hour's worth. But who knows.
Quote from: meekGee on 12/27/2013 04:49 am With airplanes, a typical jet liner doesn't need anything between maintenance checks, which are tens of flights apart. Here, we don't know. Is the rocket truly gas-and-go? My intuition says that no, and some level of inspection is necessary after each flight, even if it's only 1 hour's worth. But who knows.Early airliners were subject to frequent 'inspections' involving disassembly, intrusion... and airlines had component (e.g. radios, instruments, etc) replacements based solely on age.... millions upon millions of man hours were expended in the name of 'safety...However, subsequent airline and FAA analysis revealed that many/most failures and accidents were caused by the human intervention/inspections... e.g. mistakes in reassembly, contamination, inadvertent damage... and that proven parts were more reliable than new ones subject to installation errors and infantile failure...that the inspections and scheduled replacements were counter-productive..In modern systems (like jet engines), manual inspections are replaced by automated monitoring/logging of operating temps/pressures/vibrations/g forces... identifying trends, out of bounds conditions, and pending failures..SpaceX has all this airline/aircraft experience and technology to draw from...
