5 ms·

The Vehicle Assembly Building is an amazing sight, but is it also an example of how infinite budgets lead to non-optimal solutions? SpaceX, who tend to be a lo

by hugh3 16y ago

The Vehicle Assembly Building is an amazing sight, but is it also an example of how infinite budgets lead to non-optimal solutions? SpaceX, who tend to be a lot more budget-conscious, assemble their rockets lying down and then hoist them to vertical, thusly: http://www.youtube.com/watch?v=XrAr4ovtf9Q&feature=related http://www.youtube.com/watch?v=XrAr4ovtf9Q&feature=relat... That seems a lot easier and cheaper. I'm tempted to think that maybe there's some factor that makes it more difficult to engineer a rocket that can handle sideways stresses as well as vertical stresses, but... heck, it's a rocket, they shouldn't be that fragile, should they?

gambling8nt 16y ago
The launch vehicles themselves may not be that fragile, but payloads often are. Multimillion-dollar satellites can be damaged or completely non-functional from effects as small as being dropped 1 meter (see http://www.spacetoday.net/Summary/2230 http://www.spacetoday.net/Summary/2230 , for example).
- hugh3 16y ago
  Dropping 1m onto a hard floor is a lot worse than being slowly hoisted from horizontal to vertical. If you disagree, I'll ride on the hoist and you can fall 1m headfirst onto concrete.
  - gambling8nt 16y ago
    If the bolts holding the payload in place shear away under the lateral force of supporting the payload, the payload may fall and hit the hard inside of the launch vehicle, making the two events quite similar. (Indeed, the original drop I linked to occurred when the satellite was not correctly bolted to a table on which is was going to be tipped to one side in order to verify that it could withstand the stress of being in that physical orientation.) That said, ugh's comment suggests my reasoning (as an explanation for vertical assembly) is either incorrect, incomplete, or both.
    - InclinedPlane 16y ago
      If your erection system fails it doesn't matter how it works, "bad things" are a likely outcome.
      - wsbail29 16y ago
        that's what she said
- ugh 16y ago
  Ariane rockets are also assembled vertically [1]. Since assembly and adding the payload are two discrete steps, done in two different buildings [2], both of the times vertically, that tells me that there is more to it than the payload. [1] http://www.arianespace.com/spaceport-ariane5/launcher-integration.asp http://www.arianespace.com/spaceport-ariane5/launcher-integr... [2] http://www.arianespace.com/spaceport-ariane5/final-assembly-building.asp http://www.arianespace.com/spaceport-ariane5/final-assembly-...
  - gambling8nt 16y ago
    This does indeed suggest that there may be other factors at work. I could try tossing out other ideas, but they would be little more than hypothesis. (Bending during the tipping process damaging the joints in multi-segment launch vehicles? This might explain the difference with SpaceX's Falcons, which I believe do not have joints with O-rings.)
  - InclinedPlane 16y ago
    The main reason is merely tradition (really). Most systems are designed as evolutions of older systems, if the first system used vertical assembly, then so will the latest. Note that the Russians have been doing horizontal to vertical launch vehicle assembly for decades (with manned and unmanned launches). There's no engineering reason why you must prefer one method or the other, it's a choice. http://www.globalsecurity.org/space/world/russia/images/ustanovka-rn-proton-na-pu.jpg http://www.globalsecurity.org/space/world/russia/images/usta...
rbanffy 16y ago
IIRC Russian rockets are also taken lying down to the launch platform and are rotated into vertical position. You can see a couple pictures of that happening at http://www.darkroastedblend.com/2007/11/rare-photos-of-russian-buran-space.html http://www.darkroastedblend.com/2007/11/rare-photos-of-russi... http://www.energia.ru/english/energia/launchers/vehicle_n1-l3_l.html http://www.energia.ru/english/energia/launchers/vehicle_n1-l...
- hugh3 16y ago
  I did a bit more googling and Delta rockets are also built horizontally and raised. A Delta IV is bigger (or at least taller) than the space shuttle launch system, so size isn't the issue.
  - rbanffy 16y ago
    I think payload integration with the Deltas is done with the vehicle standing in launch position. But my knowledge on this matters is, too, very much reliant on what Google can find me. That's one career switch I would consider seriously.

by hugh3 16y ago

gambling8nt 16y ago

The launch vehicles themselves may not be that fragile, but payloads often are. Multimillion-dollar satellites can be damaged or completely non-functional from effects as small as being dropped 1 meter (see http://www.spacetoday.net/Summary/2230 http://www.spacetoday.net/Summary/2230 , for example).

hugh3 16y ago
Dropping 1m onto a hard floor is a lot worse than being slowly hoisted from horizontal to vertical. If you disagree, I'll ride on the hoist and you can fall 1m headfirst onto concrete.
- gambling8nt 16y ago
  If the bolts holding the payload in place shear away under the lateral force of supporting the payload, the payload may fall and hit the hard inside of the launch vehicle, making the two events quite similar. (Indeed, the original drop I linked to occurred when the satellite was not correctly bolted to a table on which is was going to be tipped to one side in order to verify that it could withstand the stress of being in that physical orientation.) That said, ugh's comment suggests my reasoning (as an explanation for vertical assembly) is either incorrect, incomplete, or both.
  - InclinedPlane 16y ago
    If your erection system fails it doesn't matter how it works, "bad things" are a likely outcome.
    - wsbail29 16y ago
      that's what she said
ugh 16y ago
Ariane rockets are also assembled vertically [1]. Since assembly and adding the payload are two discrete steps, done in two different buildings [2], both of the times vertically, that tells me that there is more to it than the payload. [1] http://www.arianespace.com/spaceport-ariane5/launcher-integration.asp http://www.arianespace.com/spaceport-ariane5/launcher-integr... [2] http://www.arianespace.com/spaceport-ariane5/final-assembly-building.asp http://www.arianespace.com/spaceport-ariane5/final-assembly-...
- gambling8nt 16y ago
  This does indeed suggest that there may be other factors at work. I could try tossing out other ideas, but they would be little more than hypothesis. (Bending during the tipping process damaging the joints in multi-segment launch vehicles? This might explain the difference with SpaceX's Falcons, which I believe do not have joints with O-rings.)
- InclinedPlane 16y ago
  The main reason is merely tradition (really). Most systems are designed as evolutions of older systems, if the first system used vertical assembly, then so will the latest. Note that the Russians have been doing horizontal to vertical launch vehicle assembly for decades (with manned and unmanned launches). There's no engineering reason why you must prefer one method or the other, it's a choice. http://www.globalsecurity.org/space/world/russia/images/ustanovka-rn-proton-na-pu.jpg http://www.globalsecurity.org/space/world/russia/images/usta...

rbanffy 16y ago

IIRC Russian rockets are also taken lying down to the launch platform and are rotated into vertical position. You can see a couple pictures of that happening at http://www.darkroastedblend.com/2007/11/rare-photos-of-russian-buran-space.html http://www.darkroastedblend.com/2007/11/rare-photos-of-russi... http://www.energia.ru/english/energia/launchers/vehicle_n1-l3_l.html http://www.energia.ru/english/energia/launchers/vehicle_n1-l...

hugh3 16y ago
I did a bit more googling and Delta rockets are also built horizontally and raised. A Delta IV is bigger (or at least taller) than the space shuttle launch system, so size isn't the issue.
- rbanffy 16y ago
  I think payload integration with the Deltas is done with the vehicle standing in launch position. But my knowledge on this matters is, too, very much reliant on what Google can find me. That's one career switch I would consider seriously.