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

[guckyfan]

From my experience - it's easier to slowly drop or raise a heavy (and delicate) components to place then to slide it sideways.

Elon Musk made the statement during the SES-8 launch campaign. They left Falcon vertical at the pad after the second scrub for easier engine maintenance.

Yet I am still convinced that transport and mating with a second stage is a lot easier done horizontal. They would probably do engine maintenance vertical at the landing pad after securing the stage in a strongback, then go horizontal for transport and mating with the second stage, then on to the launch pad. That's my opinion on optimized operations.


Edit: Or rather they take it horizontal, move it to a dedicated engine maintenance facility, going vertical there. Then go horizontal, move it to a hangar for mating with the second stage and payload. Then on to the launch pad. Changing between horizontal and vertical is just no issue of time and cost once the stage is secured in a strongback.

[Jim]

From my experience - it's easier to slowly drop or raise a heavy (and delicate) components to place then to slide it sideways. 

[llanitedave]

Not sure why processing vertical is faster or more natural. The things were assembled horizontally and that's how they're used to working on it. Removing and replacing a component would be a more complicated movement if it was vertical. You'd need an entirely different procedure as opposed to mainly using the same one you did for assembly at the plant. Same for putting the 2nd stage on. Why would they do it differently than they do for the first flight?

It's all upthread.

For example here:  http://forum.nasaspaceflight.com/index.php?topic=33430.msg1129579#msg1129579

and then Jason's comment about how in the plant they do it in the vertical orientation.


From my experience - it's easier to slowly drop or raise a heavy (and delicate) components to place then to slide it sideways.

I would think that all depends on the jig you're using.  Tooling is everything.

[meekGee]

Not sure why processing vertical is faster or more natural. The things were assembled horizontally and that's how they're used to working on it. Removing and replacing a component would be a more complicated movement if it was vertical. You'd need an entirely different procedure as opposed to mainly using the same one you did for assembly at the plant. Same for putting the 2nd stage on. Why would they do it differently than they do for the first flight?

It's all upthread.

For example here:  http://forum.nasaspaceflight.com/index.php?topic=33430.msg1129579#msg1129579

and then Jason's comment about how in the plant they do it in the vertical orientation.


From my experience - it's easier to slowly drop or raise a heavy (and delicate) components to place then to slide it sideways.

I would think that all depends on the jig you're using.  Tooling is everything.

... I didn't say impossible.   I said easier.

The problem with horizontal integration is that you typically have to "float" one of the components.  Also, adjustments perpendicular to the axis of the connection (motion and rotations) are more difficult to accomplish.

With vertical, gravity (which is now aligned with the axis of connection) has become your friend.   The load is supported against gravity, and can freely float in X-Y-theta.

Easier to void jamming, wedging, etc, and easier to avoid damage to the interface.

[Avron]

With vertical, gravity (which is now aligned with the axis of connection) has become your friend.   The load is supported against gravity, and can freely float in X-Y-theta.

Easier to void jamming, wedging, etc, and easier to avoid damage to the interface.

Was thinking vertical may be easier for some components but increase the level of danger by a few orders of magnitude.

Jim, did you not post during SES-8, that you observed the LV was horizontal

[meekGee]

With vertical, gravity (which is now aligned with the axis of connection) has become your friend.   The load is supported against gravity, and can freely float in X-Y-theta.

Easier to void jamming, wedging, etc, and easier to avoid damage to the interface.

Was thinking vertical may be easier for some components but increase the level of danger by a few orders of magnitude.

I suspect you mean "by a whole-number factor"....   "Few orders of magnitude" is anywhere between say 1000 and 1,000,000....

But even under the first meaning - how many payloads do you know of that were dropped off cranes in the past, say, 10 years?

[Avron]

With vertical, gravity (which is now aligned with the axis of connection) has become your friend.   The load is supported against gravity, and can freely float in X-Y-theta.

Easier to void jamming, wedging, etc, and easier to avoid damage to the interface.

Was thinking vertical may be easier for some components but increase the level of danger by a few orders of magnitude.

I suspect you mean "by a whole-number factor"....   "Few orders of magnitude" is anywhere between say 1000 and 1,000,000....

But even under the first meaning - how many payloads do you know of that were dropped off cranes in the past, say, 10 years?

Thinking humans, falling off a ladder 1000 falling from 30 M 1,000,000

[Garrett]

The problem with horizontal integration is that you typically have to "float" one of the components.  Also, adjustments perpendicular to the axis of the connection (motion and rotations) are more difficult to accomplish.
With vertical, gravity (which is now aligned with the axis of connection) has become your friend.   The load is supported against gravity, and can freely float in X-Y-theta.

Highlighting in red by me to point out the contradiction.No matter what orientation, there is always a need to "float" components.

Also, the "axis of connection" is not necesarily vertical. I imagine there could be many engineering reasons for it to be slightly off-vertical, or even horizontal. SSME's didn't seem to be "connected" along the principal orbiter axis (see photo by Jim above)

Finally, vertical integration requires access to heights of the order of the stage length or entire rocket length. Horizontal integration only requires access to heights on the order of the stage/rocket diameter.

[meekGee]

The problem with horizontal integration is that you typically have to "float" one of the components.  Also, adjustments perpendicular to the axis of the connection (motion and rotations) are more difficult to accomplish.
With vertical, gravity (which is now aligned with the axis of connection) has become your friend.   The load is supported against gravity, and can freely float in X-Y-theta.

Highlighting in red by me to point out the contradiction.No matter what orientation, there is always a need to "float" components.

Also, the "axis of connection" is not necesarily vertical. I imagine there could be many engineering reasons for it to be slightly off-vertical, or even horizontal. SSME's didn't seem to be "connected" along the principal orbiter axis (see photo by Jim above)

Finally, vertical integration requires access to heights of the order of the stage or entire rocket. Horizontal integration only requires access to heights on the order of the stage/rocket diameter.

No contradiction...

When you hang something from above, you naturally get high rigidity in Z, and low rigidity and friction in X-Y-Theta, which is exactly what you want.   This is because gravity is pointing along Z.  Even if you lift from below, it is easier to get to this result.

When you hold something with a lift, or hang it from above, and try to mate horizontally, you now have an issue since you have high stiffness along the Z axis (which is counteracting gravity).  It's solvable, but is a pain.

Doing a combined move where the engine is horizontal, but you mate it vertically is problematic too, since naturally you want it to mate as it moves "into" the rocket, so that X-Y-Theta (in the frame of the rocket) can be positioned accurately. 

...  and Space'X comments make it seem they believe so too.

[meekGee]

BTW - just in case you think horizontal integration is risk free:

[Jim]

BTW - just in case you think horizontal integration is risk free:

Bad example and supports the opposite. 
It was vertical.  That was the issue.  It was unsafe condition in the vertical configuration.  It would have fallen over even if they tried moving the base to another location in the work area.

[meekGee]

BTW - just in case you think horizontal integration is risk free:

Bad example and supports the opposite. 
It was vertical.  That was the issue.  It was unsafe condition in the vertical configuration.  It would have fallen over even if they tried moving the base to another location in the work area.

It shows that handling (as in attaching to fixtures, tilting, etc) has risks no matter what you do.

I wasn't arguing that "you need to go vertical to reduce risk".

I was pointing out that "vertical is risky because cranes" is not a good argument.

[Garrett]

It shows that handling (as in attaching to fixtures, tilting, etc) has risks no matter what you do.

That is a given and not something being argued.

I wasn't arguing that "you need to go vertical to reduce risk".

Seemed like you were. Especially in light of your previous posts in this thread.

[Nomadd]

 Being free to float doesn't make precision insertion easier. Gravity isn't some enemy force to overcome. Random motion is.

[meekGee]

It shows that handling (as in attaching to fixtures, tilting, etc) has risks no matter what you do.

That is a given and not something being argued.

I wasn't arguing that "you need to go vertical to reduce risk".

Seemed like you were. Especially in light of your previous posts in this thread.

The discussion about risk started with a comment that Horizontal integration is many times safer.

I was pointing out that as far as I know, no spacecraft or stage was dropped from a crane, but actually I can show an example where a spacecraft was dropped under the kind of handling you'd expect when tilting stages up and down.

Overall, keeping the rocket vertical reduces the amount of handling.

However, this was not the main argument of the thread, it's just an offshoot. In both cases, the rick of incident can be reduced enough so it's not an overriding concern.

[Jim]

Overall, keeping the rocket vertical reduces the amount of handling.

No, quite the opposite.  That is the main benefit of horizontal.   Delta uses no cranes until the vehicle gets to the pad.  The core is built, shipped and assembled on the same set of GSE. 

[Elmar Moelzer]

I don't know about the US, but in Austria unionized workers get paid higher salaries if they have to work in great heights.

[meekGee]

Overall, keeping the rocket vertical reduces the amount of handling.

No, quite the opposite.  That is the main benefit of horizontal.   Delta uses no cranes until the vehicle gets to the pad.  The core is built, shipped and assembled on the same set of GSE.

Never mind Delta - it's an expendable, the components arrive horizontal anyway, and no engine cluster.


With FH for example, the starting point is 3 cores, each with 9 engines, already standing vertical on their legs.

Your choices are:

A. Move them on their legs, and have access to all part of the rocket at the same time, then re-mate in the same attitude.

B. Cradle them on the pad, rotate to horizontal, then spin 8 times to access only one engine at a time, mate horizontally, then re-rotate to vertical.

A is simpler and faster.
B is more flexible when you're making changes

[Jim]

A. Move them on their legs, and have access to all part of the rocket at the same time, then re-mate in the same attitude.

B. Cradle them on the pad, rotate to horizontal, then spin 8 times to access only one engine at a time, mate horizontally, then re-rotate to vertical.

A is simpler and faster.
B is more flexible when you're making changes

 Unsupported claims. 

a.  No data the legs will not be strong enough for transport loads and attaching some mode of a transporter to each leg is not trivial.    Also logistics of working the legs into facility doesn't interfere with the structure or umbilical tower.

b.  no need to spin that much, Just like now,the vehicle is less than 4m wide.  Simple rollup platforms and manlifts can aid access. 

Never mind engine access, you are grossly overstating it and wrongly fixating on it. 
Spacex does it all the time in the current configuration before going vertical.  It was done at the pad for SES-8 for mostly for the spacecraft (the spacecraft would have to have been disconnected from AC and comm for roll back.  I bet if it was a Dragon, they would have rolled back.

Just grab the vehicle, retract gear, break it over and transport.  Just the opposite of mobile TEL's

Also, the nine engines is not a given for that far into the future nor is the diameter.

Here are an easy and simple, safe, efficient methods for access. 

http://upload.wikimedia.org/wikipedia/commons/3/30/The_First_Stages_of_Saturn_IB_in_Final_Assembly_-_GPN-2000-000043.jpg

http://history.nasa.gov/MHR-5/fig348t.jpg

[meekGee]

A. Move them on their legs, and have access to all part of the rocket at the same time, then re-mate in the same attitude.

B. Cradle them on the pad, rotate to horizontal, then spin 8 times to access only one engine at a time, mate horizontally, then re-rotate to vertical.

A is simpler and faster.
B is more flexible when you're making changes

 Unsupported claims. 

a.  No data the legs will not be strong enough for transport loads and attaching some mode of a transporter to each leg is not trivial.    Also logistics of working the legs into facility doesn't interfere with the structure or umbilical tower.

b.  no need to spin that much, Just like now,the vehicle is less than 4m wide.  Simple rollup platforms and manlifts can aid access. 

Never mind engine access, you are grossly overstating it and wrongly fixating on it. 
Spacex does it all the time in the current configuration before going vertical.  It was done at the pad for SES-8 for mostly for the spacecraft (the spacecraft would have to have been disconnected from AC and comm for roll back.  I bet if it was a Dragon, they would have rolled back.

Just grab the vehicle, retract gear, break it over and transport.  Just the opposite of mobile TEL's

Also, the nine engines is not a given for that far into the future nor is the diameter.

Here are an easy and simple, safe, efficient methods for access. 

http://upload.wikimedia.org/wikipedia/commons/3/30/The_First_Stages_of_Saturn_IB_in_Final_Assembly_-_GPN-2000-000043.jpg

http://history.nasa.gov/MHR-5/fig348t.jpg

Supported by the logic upthread.

If the legs can take the landing+margin, they can take a rollout on a taxiway between the pad and the hangar. 
No data?  SpaceX is the one designing them - if they choose to go that route, they'll design them accordingly.

Nothing easier than attaching gear to a leg with a 1-2" lift.  A simple over-center cam will do it even for something like a first stage.  The stage can take the misalignment as you attach the gear one leg at a time.

Specifically, the lead wheel is aligned with the tow bar, the two side gears are locked parallel the direction of travel, and the back gear is free-rotating (caster).  The stage will follow the tractor, no problem.

Travel at 5-10 km/hr, be back at the facility in 10 minutes.

The legs won'd interfere with anything, since again - SpaceX is designing it, so if they go that route, they won't forget to leave clearance... 

and there's no "just" break it over.  It's easy to tilt a stage once it's on a strongback.  But to pick it up without damaging it, from a concrete pad, outdoors (night, rain, wind) is not so trivial.  Conditions are not controlled as well as in a service hangar, and if you do it rapidly, 4 times per flight, it's a concern.  Towing it "as-is" is a lot safer.


I am not over-stressing engine access.  You're the one that stated (many times) that rapid reuse is impossible because just engine rework will take too long.  So vertical access increases your access to the engines - you can access all 9 in parallel, and in parallel to other components of the stage.


The key emphasis here is on processing of the first stage.  That's the most amount of work in the re-flight cycle, and so needs the most attention.