Falcon 9 dimensions: measuring photos

[Hobbes-22]

I'm building scale models of the Falcon 9, for this purpose I'm trying to get reasonably accurate dimensions of the rocket.

This has proven non-straightforward, as SpaceX doesn't publish more than the total length and diameter, so no data for the individual stages.

I've measured several photos to get the following data, adding photos until I had a set that was reasonably consistent with each other. For the v1.2 data I used 4 photos.
I used simple software to get one reference dimension on the photo (the stage diameter, which is well-known at 12 ft), then derived other dimensions from the reference. I don't have access to photogrammetry software, which should be able to compensate for distortion. So that would be one avenue to improve on this data.

For F9 v1.2:
Total length: 70 m
first stage (full length of the stage incl. engines) 40,5 m
interstage 6,7 m
2nd stage 9,3 m (length of the outer skin visible on a stacked rocket, so excl engine)
These are ±0.5 m due to distortion in the photos I used.


For F9v1.1:
first stage (full length of the stage incl. engines) 41 m
interstage 6 m
2nd stage 8,3 m
Dragon trunk 2,8 m
These are ±1 m due to distortion in the photos I used.

For F9v1.0:
first stage (full length of the stage incl. engines) 31 m
interstage  6,4 m (although some flights used longer interstages)
2nd stage 4,6 m
These are ±1 m due to distortion in the photos I used.

Now, these data differ by several meters from the info found on Spacelaunchreport.

I've put this post in the SpaceX general section as the info may be useful for other purposes.

[meekGee]

I take it you measured that 12' diameter in several spots up and down the rocket, to determine the perspective and lens?

[Hobbes-22]

No. I just measured at one point, I don't know how to compensate for the distortion manually.

I did try to select the photos with the least distortion (e.g. photos taken from far away using a telephoto lens)

[meekGee]

No. I just measured at one point, I don't know how to compensate for the distortion manually.

I did try to select the photos with the least distortion (e.g. photos taken from far away using a telephoto lens)

That will help, but I can't tell you how much off you are...

Out of curiosity, what's the difference in the diameter between the lowest and highest point?

[Hobbes-22]

in one photo, the diameter measurements are 258 mm (just above the landing legs) and 289 mm (stage separation interface)

[meekGee]

And what is it midway in between (that'll tell you how linear the distortion is.)

[dglow]

Suggest you PM user okan170, who does many of NSF's excellent CG renders.

[DOCinCT]

There is also the large rendition off of the SpaceX Falcon 9 page
http://www.spacex.com/sites/all/themes/spacex2012/images/falcon9/falcon9-render.png
no perspective issues

[old_sellsword]

There is also the large rendition off of the SpaceX Falcon 9 page
http://www.spacex.com/sites/all/themes/spacex2012/images/falcon9/falcon9-render.png
no perspective issues

I wouldn't rely on that too heavily as it doesn't appear to be accurate, just look at the location of the grid fins in reference to the interstage.

[GWH]

Spaceflight 101 might have some helpful dimensions: http://spaceflight101.com/spacerockets/falcon-9-ft/

[Lars-J]

...I used simple software to get one reference dimension on the photo (the stage diameter, which is well-known at 12 ft), then derived other dimensions from the reference. ...

It's not quite that simple. Is 12 ft the interior tank diameter or the exterior? And does it include whatever exterior layers that are added on top of that? An inch here and there will skew your numbers.

[Hobbes-22]

Spaceflight 101 might have some helpful dimensions: http://spaceflight101.com/spacerockets/falcon-9-ft/

It looks like they use the same data as Spacelaunchreport, which doesn't agree with my measurements.

[Hobbes-22]

There is also the large rendition off of the SpaceX Falcon 9 page
http://www.spacex.com/sites/all/themes/spacex2012/images/falcon9/falcon9-render.png
no perspective issues

SpaceX's own renders were the first data point I tried to use and had to discard. For the v1.0 rocket, the renders were off by several meters.

[Hobbes-22]

...I used simple software to get one reference dimension on the photo (the stage diameter, which is well-known at 12 ft), then derived other dimensions from the reference. ...

It's not quite that simple. Is 12 ft the interior tank diameter or the exterior? And does it include whatever exterior layers that are added on top of that? An inch here and there will skew your numbers.

12 ft is the exterior diameter without insulation. The DragonLab factsheet shows the inner diameter of the trunk as 142".
Most of the photos I have don't have the resolution to measure down to 1", so I have to accept some noise in my measurements (hence the ±0.5 m).

[DOCinCT]

There is also the large rendition off of the SpaceX Falcon 9 page
http://www.spacex.com/sites/all/themes/spacex2012/images/falcon9/falcon9-render.png
no perspective issues

SpaceX's own renders were the first data point I tried to use and had to discard. For the v1.0 rocket, the renders were off by several meters.

There are some good side shots of F9 v1.1 from Vandenberg launch site, not too bad on perspective; and yes, those do show the correct positioning of the grid fins.
Also there are the large resolution images in the SpaceX gallery on their website

[edkyle99]

I'm building scale models of the Falcon 9, for this purpose I'm trying to get reasonably accurate dimensions of the rocket.

This has proven non-straightforward, as SpaceX doesn't publish more than the total length and diameter, so no data for the individual stages.

For what it is worth, I have been looking at this question, measuring multiple photos, looking at illustrations, etc., and have conjured the attached drawing which shows my current estimates for dimensions in inches.  Multiply by exactly 0.0254 to convert to meters.  Very much plus or minus, of course, especially on the lengths.  I've only focused on v1.2/Block 3 so far.

EDIT:  I'm removing this drawing from this message.  I'll provide updated drawings a subsequent message in this thread that will include v1.1 and, eventually, v1.0. 

 - Ed Kyle

[edkyle99]

A question to discuss.  I am attaching an image of the first stage/interstage connection area on a v1.2.  Where, I wonder, does the first stage upper LOX tank bulkhead attach to the cylindrical tank wall?  I've drawn some options.  I doubt it is right at the interstage connection (the line of fasteners), because I expect a "skirt" at the top of the stage itself, but I don't know.

 - Ed Kyle

[old_sellsword]

A question to discuss.  I am attaching an image of the first stage/interstage connection area on a v1.2.  Where, I wonder, does the first stage upper LOX tank bulkhead attach to the cylindrical tank wall?  I've drawn some options.  I doubt it is right at the interstage connection (the line of fasteners), because I expect a "skirt" at the top of the stage itself, but I don't know.

 - Ed Kyle

We've never seen a skirt at the top of a first stage tank, only at the bottom. Although I agree with you that putting all those rivets through the bulkhead connection sounds like a bad idea, I'm interested in what the solution is.

I've attached a couple pictures that might help. The first one is v1.1 stages in construction showing the metal skirts on the bottom of the tank. I'm not sure which end the second one is or even what version of F9 it is.

[cambrianera]

A question to discuss.  I am attaching an image of the first stage/interstage connection area on a v1.2.  Where, I wonder, does the first stage upper LOX tank bulkhead attach to the cylindrical tank wall?  I've drawn some options.  I doubt it is right at the interstage connection (the line of fasteners), because I expect a "skirt" at the top of the stage itself, but I don't know.

 - Ed Kyle

We've never seen a skirt at the top of a first stage tank, only at the bottom. Although I agree with you that putting all those rivets through the bulkhead connection sounds like a bad idea, I'm interested in what the solution is.

I've attached a couple pictures that might help. The first one is v1.1 stages in construction showing the metal skirts on the bottom of the tank. I'm not sure which end the second one is or even what version of F9 it is.

Second picture is F9 1.0: carbon composite skirt on the bottom of RP-1 tank.

[edkyle99]

Here's an image from Wiki of what are likely v1.1 stages at Hawthorne in 2014, showing the top part of the first stage.  I'm starting to believe that the tank wall is right up near where the interstage begins.

 - Ed Kyle

[Jim]

We've never seen a skirt at the top of a first stage tank, only at the bottom. Although I agree with you that putting all those rivets through the bulkhead connection sounds like a bad idea, I'm interested in what the solution is.

Either a little of the tank wall extends past the domes or the domes themselves have a lip.  That is how it is done.

[Lars-J]

Here's an image from Wiki of what are likely v1.1 stages at Hawthorne in 2014, showing the top part of the first stage.  I'm starting to believe that the tank wall is right up near where the interstage begins.

 - Ed Kyle

Good image there, based on the middle core, and the visible "racetrack bump" area (without cover), it looks like the tank extends almost all the way to the interstage. So in your tank top options listed here ( http://forum.nasaspaceflight.com/index.php?topic=41947.msg1647342#msg1647342 ), it looks like MIDDLE option is the accurate tank contour. Note how the red tape on the tank dome is shaded by a small tank wall lip.

[edkyle99]

Here's an image from Wiki of what are likely v1.1 stages at Hawthorne in 2014, showing the top part of the first stage.  I'm starting to believe that the tank wall is right up near where the interstage begins.

 - Ed Kyle

Good image there, based on the middle core, and the visible "racetrack bump" area (without cover), it looks like the tank extends almost all the way to the interstage. So in your tank top options listed here ( http://forum.nasaspaceflight.com/index.php?topic=41947.msg1647342#msg1647342 ), it looks like MIDDLE option is the accurate tank contour. Note how the red tape on the tank dome is shaded by a small tank wall lip.

Thanks.  I've updated my original drawing accordingly, upthread.

 - Ed Kyle

[ashamedpedant]

Is the Falcon Heavy center core, photo linked below, the same length as the F9 cores? I ask because in the Red Dragon render the central core's grid fins were mounted slightly higher up.

http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=39181.0;attach=1343334;image

[edkyle99]

Is the Falcon Heavy center core, photo linked below, the same length as the F9 cores? I ask because in the Red Dragon render the central core's grid fins were mounted slightly higher up.

http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=39181.0;attach=1343334;image

For me, this is all very much TBD.  I won't know what to believe until I see good images of the rocket stacked on the pad.  What I can say is that Falcon 9 illustrations on the SpaceX web site vary in appearance from the actual hardware.

This wind tunnel model may serve as a decent predictor of Falcon Heavy appearance.
http://i.imgur.com/ZJfbZzz.jpg
http://i.imgur.com/wzy8ooH.jpg

 - Ed Kyle

[alang]

I'm building scale models of the Falcon 9, for this purpose I'm trying to get reasonably accurate dimensions of the rocket.

This has proven non-straightforward, as SpaceX doesn't publish more than the total length and diameter, so no data for the individual stages.

For what it is worth, I have been looking at this question, measuring multiple photos, looking at illustrations, etc., and have conjured the attached drawing which shows my current estimates for dimensions in inches.  Multiply by exactly 0.0254 to convert to meters.  Very much plus or minus, of course, especially on the lengths.  I've only focused on v1.2/Block 3 so far.

 - Ed Kyle

Is that a typo on the v1.2 upper stage with fairing. On the upper stage upper tank you've got the bottom as 2222 and the top as 2238 - only 16* inches. Presumably the 2222 is meant to be 2022 or something else?*

*Fixed own typos

[edkyle99]

Is that a typo on the v1.2 upper stage with fairing. On the upper stage upper tank you've got the bottom as 2222 and the top as 2238 - only 16* inches. Presumably the 2222 is meant to be 2022 or something else?*

*Fixed own typos

Thanks!  It should have been 2022 and I have updated accordingly.

 - Ed Kyle

[IanThePineapple]

I made a model from AXM paper space models, and I'm trying to add a second stage engine to it. Problem is, I can't find any good pics of the upper part of the engine, only the engine bell.

Does anyone have a good picture of the top portion of the engine?

[old_sellsword]

I made a model from AXM paper space models, and I'm trying to add a second stage engine to it. Problem is, I can't find any good pics of the upper part of the engine, only the engine bell.

Does anyone have a good picture of the top portion of the engine?

Here's the best picture of a recent version.

[IanThePineapple]

I made a model from AXM paper space models, and I'm trying to add a second stage engine to it. Problem is, I can't find any good pics of the upper part of the engine, only the engine bell.

Does anyone have a good picture of the top portion of the engine?

Here's the best picture of a recent version.

Thanks!

[edkyle99]

I made a model from AXM paper space models, and I'm trying to add a second stage engine to it. Problem is, I can't find any good pics of the upper part of the engine, only the engine bell.

Does anyone have a good picture of the top portion of the engine?

Here's the best picture of a recent version.

Thanks!

The attached SpaceX illustration seems generally consistent with the photo.  I've scaled this to 1 pixel = 1 inch, -ish.

 - Ed Kyle

[jgoldader]

Maybe OT, but I'm trying to get the "width" of the new strongback for LC-39A (thinking of building it to go with my 1/144 F9).  Is there an image showing the "back" of the strongback (see attached) while holding a Falcon 9, so I can get the width? I know it's about the diameter of the stage, but a little bigger vs. a little smaller matters.  Thanks!

[ethan829]

Maybe OT, but I'm trying to get the "width" of the new strongback for LC-39A (thinking of building it to go with my 1/144 F9).  Is there an image showing the "back" of the strongback (see attached) while holding a Falcon 9, so I can get the width? I know it's about the diameter of the stage, but a little bigger vs. a little smaller matters.  Thanks!

This is the best one I could find, but it looks like it's still at a slight angle.

[old_sellsword]

Maybe OT, but I'm trying to get the "width" of the new strongback for LC-39A (thinking of building it to go with my 1/144 F9).  Is there an image showing the "back" of the strongback (see attached) while holding a Falcon 9, so I can get the width? I know it's about the diameter of the stage, but a little bigger vs. a little smaller matters.  Thanks!

Here's a new picture from SpaceX, it appears that the rocket is just ever so slightly larger than the (bottom half of) the TE.

[Lars-J]

Maybe OT, but I'm trying to get the "width" of the new strongback for LC-39A (thinking of building it to go with my 1/144 F9).  Is there an image showing the "back" of the strongback (see attached) while holding a Falcon 9, so I can get the width? I know it's about the diameter of the stage, but a little bigger vs. a little smaller matters.  Thanks!

Here's a new picture from SpaceX, it appears that the rocket is just ever so slightly larger than the (bottom half of) the TE.

No, to me it seems like the TE is ~1 pixel wider on each edge. (most noticeable on the lighter/sunny side) So taking the perspective into account, the thin part of the TE is at least 3.75m wide, probably closer to 3.8m.

[OneSpeed]

Adding my estimated dimensions for Block 1.

This is a great resource. For the imperially challenged amongst us, I've taken the liberty of converting the diagram to metric.

[Lars-J]

Adding my estimated dimensions for Block 1.  Plus or minus about 6 inches, if not more.

SpaceX and press at the time gave all kinds of conflicting dimensions.  Height was reported as 154 feet (1,848 inches), 47 meters (1,850.4 inches), 157 feet (1,884 inches), 48.1 meters (1,893.7 inches) and even 180 feet (2,160 inches).  The latter height was obviously for the 17 foot fairing, which never flew atop a Block 1.  The 154 feet height may have been for the first launch only, which carried a straight adapter between the second stage and non-deployed capsule rather than a trunk and adapter.  I'm showing the operational CRS configuration.  I may add the inaugural flight version later.

 - Ed Kyle

That's a great job, a great reference resource! 

But I see a discrepancy... For block II the fairing is 525 inches tall, but for block III the fairing is 517 inches tall. I'm not aware of any fairing size change, how do you explain it?

[edkyle99]

But I see a discrepancy... For block II the fairing is 525 inches tall, but for block III the fairing is 517 inches tall. I'm not aware of any fairing size change, how do you explain it?

These are clearly imperfect estimates.  They're based on analysis of multiple photographs, combined with bits and pieces of published dimensional information, including illustrations.  I agree that the fairings should be the same.  In fact, I expect that they are actually longer than 525 inches (SpaceX drawings circa 2008-9 show them at 546 inches), but these are the numbers I ended up with from photos.  I hope to improve on these as more information becomes available, and I urge others to contribute their own estimates.

 - Ed Kyle

[edkyle99]

Here's an update.  I think I've corrected the fairing dimension issue.  (Updated April 21, 2017)

 - Ed Kyle

[OneSpeed]

And a metric update. One minor note, the block 2 CRS Dragon has 2331" marked as the vertical dimension in two places. Perhaps the upper one should be 2431" ?

[edkyle99]

And a metric update. One minor note, the block 2 CRS Dragon has 2331" marked as the vertical dimension in two places. Perhaps the upper one should be 2431" ?

Yes.  Thanks.  I'll have to fix that, but it won't be until later today.  EDIT:  Drawing updated, upthread.

 - Ed Kyle

[dmc6960]

One additional thought, lower and define the center engine (a negative value perhaps?).  It is certainly lowered a little bit with respect to the other eight, pretty hard to measure though.

[edkyle99]

One additional thought, lower and define the center engine (a negative value perhaps?).  It is certainly lowered a little bit with respect to the other eight, pretty hard to measure though.

I'll try to get to that.  My thinking right now is to reset the "zero" vertical reference point to the plane where the rocket actually sits on the launch stand.  That would be where the hold down posts and/or T-0 umbilicals connect to the rocket.  Dimensions would be positive up and negative down from that point.  That would roughly be the plane now shown as +86 inches.

 - Ed Kyle