Author Topic: The infrastructure needed to support the BFR  (Read 16975 times)

Offline HeartofGold2030

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The infrastructure needed to support the BFR
« on: 03/17/2018 11:45 am »
I'm currently trying to wrap my head round how SpaceX plans to launch a full-stack BFR in the near future, it's not the rocket itself that's bothering me (as SpaceX have shown they can build rockets) but the infrastructure needed to support a BFR launch. Will the BFR fly from 39A? If that's the case, how will they modify it to cope? Are they even allowed to launch BFR from 39A, due to SpaceX's plan to land the booster on it's launching mounts? How will they actually get it upright on the pad, will they need to make a massive TEL, could they hire out the VAB and a crawler?.etc These are some of the questions I keep asking myself, is anybody able to shed some light on whether my fears are justified or not?

Offline docmordrid

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Re: The infrastructure needed to support the BFR
« Reply #1 on: 03/17/2018 12:47 pm »
I'm currently trying to wrap my head round how SpaceX plans to launch a full-stack BFR in the near future, it's not the rocket itself that's bothering me (as SpaceX have shown they can build rockets) but the infrastructure needed to support a BFR launch.
>

The most recent indication this is real is the recent NSF front page story. Everything else has to be part of this, or has already been addressed.

Quote
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SpaceX is also considering building their own new facilities, although this will not be a launch complex but rather a factory to build their future BFR vehicle. The company is talking with NASA and Space Florida about obtaining land for the new factory, likely be located near or right next to Blue Origin’s existing New Glenn factory.
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« Last Edit: 03/17/2018 12:54 pm by docmordrid »
DM

Re: The infrastructure needed to support the BFR
« Reply #2 on: 03/17/2018 01:27 pm »
They want to keep it simple. Minimal GSE. They want to achieve the lowest possible operational costs. Not only  they plan to have GSE simpler than what SLS or traditional SHLVs (no VAB for the full stack, no MLP etc) use but simpler than F9's.
I'm not an expert so I don't know how they plan to achieve this, but I'm confident the plan is to completely revolutionize LV operations.

They want to get rid of the TE altogether:
-The booster always remains vertical on the pad except for occasional maintenance (it only needs to be lowered/erected once in a while, every X launches);
-The launch/landing cradle supplies everything to both stages;
-The stacking is done directly on the launch mount.

The only things needed on the pad would be the crew access tower and a really big crane to mate the second stage and occasionally lower/erect the booster (or maybe something that serves both aims).

The question is: is this technically feasible, and how?

Another question is how they plan to operate the 50m, 85 ton second stage:
-Build a 50m high Refurbishment/processing building for it, use Vertical Integration and transport it vertically to the pad?

or

-Use horizontal integration; raise the BFS to its vertical position on the pad; only build a giant hangar for storage, processing and refurbishment shared by both the boosters and 2nd stages?




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Offline AncientU

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Re: The infrastructure needed to support the BFR
« Reply #3 on: 03/17/2018 01:33 pm »
I believe they will have a T/E to bring the vehicle to/from the pad to cover initial vehicle placement and return to hanger for maintenance.  This T/E will not be a TEL -- launches/landings are from/to the launch mount.  This same equipment could deliver and erect the BFSs in the same manner.  A crane has been shown moving the BFS from a side pad to mate to the booster.
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Offline su27k

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Re: The infrastructure needed to support the BFR
« Reply #4 on: 03/17/2018 01:37 pm »
39A is one of the options, see the end of this article for an educated guess on how to modify: https://www.nasaspaceflight.com/2017/07/installation-flame-deflector-sls-begins-39b/

(BTW, Chris promised a follow on article on BFR/39A, but I don't think it appeared yet)

Re: The infrastructure needed to support the BFR
« Reply #5 on: 03/17/2018 01:54 pm »
I believe they will have a T/E to bring the vehicle to/from the pad to cover initial vehicle placement and return to hanger for maintenance.  This T/E will not be a TEL -- launches/landings are from/to the launch mount.  This same equipment could deliver and erect the BFSs in the same manner.  A crane has been shown moving the BFS from a side pad to mate to the booster.

So, if I understand correctly you are thinking about a single T/E that can be used alternatively to transport/erect the booster and the spacecraft.
Why not use a simple transporter and  erect both with the crane?
You need the pad crane from the beginning in any case (for stacking ops) and they already have the former orbiter transporter system that I think could already transport both the BFS and the booster.

This is ok for the booster that only has to be lowered occasionally, but a bit impractical for the BFS.
All things considered I think they may use this approach for the first few flights only. For mature operations I'm more and more convinced that completely vertical operation of the spacecraft is the way to go.
« Last Edit: 03/17/2018 02:09 pm by AbuSimbel »
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Offline envy887

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Re: The infrastructure needed to support the BFR
« Reply #6 on: 03/17/2018 02:08 pm »
I believe they will have a T/E to bring the vehicle to/from the pad to cover initial vehicle placement and return to hanger for maintenance.  This T/E will not be a TEL -- launches/landings are from/to the launch mount.  This same equipment could deliver and erect the BFSs in the same manner.  A crane has been shown moving the BFS from a side pad to mate to the booster.

So, if I understand correctly you are thinking about a single T/E that can be used alternatively to transport/erect the booster and the spacecraft.
Why not use a simple transporter and  erect both with the crane?
You need the pad crane from the beginning in any case (for stacking ops) and they already have the former orbiter transporter system that I think could already transport both the BFS and the booster.

This is ok for the booster that only has to be lowered occasionally, but a bit impractical for the BFS.
All things considered I think they may use this approach for the first few flights only. For mature operations I'm more and more convinced that VI of the spacecraft is the way to go.

Stabilizing a large heavy vehicle hanging on a cable to the precision required for stage mating is not easy. It's likely much simpler to lift the BFS from below with a transporter/erector. The same T/E could potentially move/erect the booster alone, or the full stack as well - allowing mating to be done in the HIF under more controlled conditions.

The only way a crane would be simpler if if the BFS lands close enough to the pad that they never have to break it over between flights, except for rare maintenance. SpaceX did show this in the P2P video last year, but I think that operational concept is somewhat further in the future. For the near term they will use what they learned with Falcon.

Re: The infrastructure needed to support the BFR
« Reply #7 on: 03/17/2018 02:17 pm »
I believe they will have a T/E to bring the vehicle to/from the pad to cover initial vehicle placement and return to hanger for maintenance.  This T/E will not be a TEL -- launches/landings are from/to the launch mount.  This same equipment could deliver and erect the BFSs in the same manner.  A crane has been shown moving the BFS from a side pad to mate to the booster.

So, if I understand correctly you are thinking about a single T/E that can be used alternatively to transport/erect the booster and the spacecraft.
Why not use a simple transporter and  erect both with the crane?
You need the pad crane from the beginning in any case (for stacking ops) and they already have the former orbiter transporter system that I think could already transport both the BFS and the booster.

This is ok for the booster that only has to be lowered occasionally, but a bit impractical for the BFS.
All things considered I think they may use this approach for the first few flights only. For mature operations I'm more and more convinced that VI of the spacecraft is the way to go.

Stabilizing a large heavy vehicle hanging on a cable to the precision required for stage mating is not easy. It's likely much simpler to lift the BFS from below with a transporter/erector. The same T/E could potentially move/erect the booster alone, or the full stack as well - allowing mating to be done in the HIF under more controlled conditions.

The only way a crane would be simpler if if the BFS lands close enough to the pad that they never have to break it over between flights, except for rare maintenance. SpaceX did show this in the P2P video last year, but I think that operational concept is somewhat further in the future. For the near term they will use what they learned with Falcon.

The thing is that having a T/E for the full stack completely disrupts BFR operations, not only for P2P. Why land on the cradle if you have to lower the booster and mate it with the BFS inside an hangar?
They have to design the system for vertical integration of the spacecraft on the pad from the beginning IMO, otherwise the concept doesn't make sense. And building a gargantuan TEL for a 110m, >100 ton SHLV just for the initial phase, only because you're afraid of the challenges of VI on the pad would be an error NASA can afford (see SLS' MLP), but not SX with their limited budget.
The question is: what are the technical challenges exactly?
« Last Edit: 03/17/2018 02:23 pm by AbuSimbel »
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Offline HeartofGold2030

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Re: The infrastructure needed to support the BFR
« Reply #8 on: 03/17/2018 02:19 pm »
So the general consensus seems to be, no matter what SpaceX decides to do in regards to launch infrastructure they will have to install a large crane. A while back I read an article about how the airforce had given a SpaceX a contract to install a crane on 39a for vertical integration of military payloads. Could this crane also be used in the future for assembling the BFR stack?
« Last Edit: 03/17/2018 02:19 pm by HeartofGold2030 »

Re: The infrastructure needed to support the BFR
« Reply #9 on: 03/17/2018 02:34 pm »
So the general consensus seems to be, no matter what SpaceX decides to do in regards to launch infrastructure they will have to install a large crane. A while back I read an article about how the airforce had given a SpaceX a contract to install a crane on 39a for vertical integration of military payloads. Could this crane also be used in the future for assembling the BFR stack?
Very good point. Unfortunately we haven't heard much about that project after the initial news. That crane was intended for FH/9. To me it's possible that SpaceX has ditched those VI plans for F9/H and moved them to BFR similarly to what happened to FH crew and dragon propulsive landing.
If a crane has to be designed and built on 39A it's likely it will be the BFR one, given how the planned timeframe for BFR on 39A is now 2020/2021. When would the first VI NSS mission have launched on falcon 9?
« Last Edit: 03/17/2018 02:38 pm by AbuSimbel »
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Offline speedevil

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Re: The infrastructure needed to support the BFR
« Reply #10 on: 03/17/2018 02:34 pm »
They have to design the system for vertical integration of the spacecraft on the pad from the beginning IMO.
The question is: what are the technical challenges exactly?

BFS/R are 'quite large' compared to falcon 9.

This means that some components may simply be ratable to a higher expected life before service, without much impact on payload.
It means that a lot more components are going to be large enough for a person to get between them and service them.
It means that instead of transporting it to the HIF, you climb in and pull an access panel on the floor of the cargo area and service stuff there.

It is also a rather newer rocket.
This means that monitoring will have been baked in even harder.
It is quite plausible to have several cameras for every single engine, for example. This means that if you see a data anomaly, the video may give you additional confidence in what to do about it - was it just a sensor issue that you can safely software patch.

This is even before you get into design for repairability/inspection as such, just things that are easily done, or come free with the scale of the vehicle that you couldn't consider before.

Quite a lot of space in there!

The fuel transfer pipes are 20cm or so in diameter, but the model seen so far contains no latching features/hold-downs/registration pins.

(The BFR of course will have lots less space at the bottom)

Offline rst

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Re: The infrastructure needed to support the BFR
« Reply #11 on: 03/17/2018 02:50 pm »
They want to get rid of the TE altogether:
-The booster always remains vertical on the pad except for occasional maintenance (it only needs to be lowered/erected once in a while, every X launches);
-The launch/landing cradle supplies everything to both stages;
-The stacking is done directly on the launch mount.

The only things needed on the pad would be the crew access tower and a really big crane to mate the second stage and occasionally lower/erect the booster (or maybe something that serves both aims).

The question is: is this technically feasible, and how?

Also, how soon? Your list represents SpaceX's current goals, as shown in their videos, but that may not all show up on the first launch.  For instance, even if their ultimate goal is landing on the launch cradle, there are all sorts of obvious reasons why they might have the first several launches targeting a cradle somewhere else, or just a landing pad with a set of (ultimately dispensable) landing legs on the booster.

Offline AncientU

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Re: The infrastructure needed to support the BFR
« Reply #12 on: 03/17/2018 03:57 pm »
So the general consensus seems to be, no matter what SpaceX decides to do in regards to launch infrastructure they will have to install a large crane. A while back I read an article about how the airforce had given a SpaceX a contract to install a crane on 39a for vertical integration of military payloads. Could this crane also be used in the future for assembling the BFR stack?
Very good point. Unfortunately we haven't heard much about that project after the initial news. That crane was intended for FH/9. To me it's possible that SpaceX has ditched those VI plans for F9/H and moved them to BFR similarly to what happened to FH crew and dragon propulsive landing.
If a crane has to be designed and built on 39A it's likely it will be the BFR one, given how the planned timeframe for BFR on 39A is now 2020/2021. When would the first VI NSS mission have launched on falcon 9?

There is a huge crane in a hut at Boca Chica...

I don't think they will ever do mating ops horizontally, but the integration facility will be a HIF, and the vehicles will be built and maintained horizontally -- not in a VAB or equivalent.  Info to date shows stacking at the pad.
« Last Edit: 03/17/2018 03:57 pm by AncientU »
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Online guckyfan

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Re: The infrastructure needed to support the BFR
« Reply #13 on: 03/17/2018 04:02 pm »
They will start test flights with BFS. They will get data on how precise they can land from these tests. If they are satisfied they can start with BFR as planned.

Offline envy887

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Re: The infrastructure needed to support the BFR
« Reply #14 on: 03/17/2018 04:38 pm »
I believe they will have a T/E to bring the vehicle to/from the pad to cover initial vehicle placement and return to hanger for maintenance.  This T/E will not be a TEL -- launches/landings are from/to the launch mount.  This same equipment could deliver and erect the BFSs in the same manner.  A crane has been shown moving the BFS from a side pad to mate to the booster.

So, if I understand correctly you are thinking about a single T/E that can be used alternatively to transport/erect the booster and the spacecraft.
Why not use a simple transporter and  erect both with the crane?
You need the pad crane from the beginning in any case (for stacking ops) and they already have the former orbiter transporter system that I think could already transport both the BFS and the booster.

This is ok for the booster that only has to be lowered occasionally, but a bit impractical for the BFS.
All things considered I think they may use this approach for the first few flights only. For mature operations I'm more and more convinced that VI of the spacecraft is the way to go.

Stabilizing a large heavy vehicle hanging on a cable to the precision required for stage mating is not easy. It's likely much simpler to lift the BFS from below with a transporter/erector. The same T/E could potentially move/erect the booster alone, or the full stack as well - allowing mating to be done in the HIF under more controlled conditions.

The only way a crane would be simpler if if the BFS lands close enough to the pad that they never have to break it over between flights, except for rare maintenance. SpaceX did show this in the P2P video last year, but I think that operational concept is somewhat further in the future. For the near term they will use what they learned with Falcon.

The thing is that having a T/E for the full stack completely disrupts BFR operations, not only for P2P. Why land on the cradle if you have to lower the booster and mate it with the BFS inside an hangar?
They have to design the system for vertical integration of the spacecraft on the pad from the beginning IMO, otherwise the concept doesn't make sense. And building a gargantuan TEL for a 110m, >100 ton SHLV just for the initial phase, only because you're afraid of the challenges of VI on the pad would be an error NASA can afford (see SLS' MLP), but not SX with their limited budget.
The question is: what are the technical challenges exactly?

I never said they would lower the booster every time. Once they perfect cradle landing, the BFS would be prepped in the HIF then rolled out on the T/E and placed atop the booster.

The T/E would not be "gargantuan", only about 30% larger than the FH TEL. FH is already 70 meters tall, 12 meters wide, and ~100 tonnes at rollout. The whole BFR stack is not that much larger.

Cranes have lower mass limits and more dynamic movement. And unless they land the upper stage within ~50 meters of the pad with the booster already on it, they need some way to move the BFS around on the ground, which is going to be difficult vertically. And they always have to use the HIF for loading cargo and satellites anyway.

Characterizing the use of horizontal operations as "afraid" of vertical ops is silly. SpaceX will use whatever they think is the fastest and lowest cost. So far, that is horizontal integration. For BFS/BFR, it will likely be a mix of horizontal and vertical.

Offline geza

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Re: The infrastructure needed to support the BFR
« Reply #15 on: 03/18/2018 03:48 pm »
Landing precision is the main issue determining the BFR ground infrastructure.
Falcon 9 first stages land with precision of a few meters. Intuitively, it seems to be a fantastic achievement. Not long ago we were quite happy when the stages missed the barge by a few tens of meters only. However, the few meters precision is probably not enough for the BFR landing: it risks the outer engines to collide with the cradle accepting the outer skin of the rocket. What kind of precision we can envision? If it is e.g. 0.5 meter, then we need a way to take care of that 0.5 meter.

Offline niwax

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Re: The infrastructure needed to support the BFR
« Reply #16 on: 03/18/2018 04:03 pm »
Landing precision is the main issue determining the BFR ground infrastructure.
Falcon 9 first stages land with precision of a few meters. Intuitively, it seems to be a fantastic achievement. Not long ago we were quite happy when the stages missed the barge by a few tens of meters only. However, the few meters precision is probably not enough for the BFR landing: it risks the outer engines to collide with the cradle accepting the outer skin of the rocket. What kind of precision we can envision? If it is e.g. 0.5 meter, then we need a way to take care of that 0.5 meter.

The BFR likely won't have to perform a hoverslam that aggressive. On early Grasshopper flights they had it hover and move sideways. The issue right now is that F9 has so much thrust it has to get its position right early in the approach because it won't get a chance to slow down and correct later on.
Which booster has the most soot? SpaceX booster launch history! (discussion)

Offline speedevil

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Re: The infrastructure needed to support the BFR
« Reply #17 on: 03/18/2018 04:15 pm »
What kind of precision we can envision? If it is e.g. 0.5 meter, then we need a way to take care of that 0.5 meter.
F9 has underpowered cold gas thrusters as its only active way of controlling the position of the stage without gimballing the main engines.
This leads to an unavoidable undesirable tension between correcting orientation so it lands vertically, and correcting position so it lands in the right spot.
To move left, you have to gimbal right moving the bottom of the stage right, allow the stage to fall left, gimbal neutral, allow the stage to move left, gimbal left to cancel out motion, gimbal neutral at the right spot.
Much like balancing a broomstick on one hand - you have poor control and it all interacts.

BFS, and presumably BFR has high powered (relatively) metholox thrusters, with the capability to fire for very small amounts of time.
This means it doesn't need to do all of the above, gimballing can be to only perform the coarsest movements, whereas the thrusters keep the vehicle in a rigid orientation for the last several meters.

Add to this that the scale of BFR means it is somewhat less affected by the same velocity of wind as F9, and the fact they will surely have upgraded local windspeed measurements to get live information of the wind in the last several seconds - something that F9 class accuracy doesn't require - and very good indeed landing accuracy is possible.

BFS of course is nice in that it is an identical diameter platform that can be test landed in precisely the same way you would a BFR - just on flat concrete.
Being able to try the landing software out many dozen times at least before committing to an actual physical cradle enormously eases development.

Initially, there is likely to be large amounts of margin available for landing fuel.

But, it is unclear that avoiding a hoverslam by burning fuel actually helps - if you have the control authority to actually keep your rocket vertical over the desired landing spot while descending.

Offline rakaydos

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Re: The infrastructure needed to support the BFR
« Reply #18 on: 03/18/2018 04:27 pm »
To the first order, about how heavy would BFR booster be if the 42 raptors were not installed into the octoweb until after the booster is vertical in the launch clamps? Would it be comparable to an unfueled BFS?

Offline speedevil

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Re: The infrastructure needed to support the BFR
« Reply #19 on: 03/18/2018 04:36 pm »
To the first order, about how heavy would BFR booster be if the 42 raptors were not installed into the octoweb until after the booster is vertical in the launch clamps? Would it be comparable to an unfueled BFS?

That would seem rather odd to do.
It's not an Octoweb anyway - would the correct term be AdamsWeb? (42)
:)

It seems unlikely that an unfueled BFR would hit BFS unfuelled weight - assuming 150:1 T/W of everything engine-related that would need to be installed, it's in the range of 30 tons.

Not enough lightening to count for anything meaningful, as well as being massively complex to do on the pad if you don't have to.
Is this to avoid a slightly larger crane?

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