3 ms·

I feel if the 1st stage booster had an attitude control system toward the top like the BRAHMOS missile [1], the lean could've been corrected to at least have th

I feel if the 1st stage booster had an attitude control system toward the top like the BRAHMOS missile [1], the lean could've been corrected to at least have the rocket be upright when it impacted the platform. Although the choice to add an attitude control system would probably take up more space and add mass which is critical for a stage rocket. [1] http://i.imgur.com/5RWkvem.gif http://i.imgur.com/5RWkvem.gif

pbnjay 12y ago
It does (https://www.youtube.com/watch?v=DgLBIdVg3EM https://www.youtube.com/watch?v=DgLBIdVg3EM), it just ran out of hydraulic fluid in this case.
- 32faction 12y ago
  Those are just grid fins which are used more for steering than attitude control. If I kick the rocket over those fins won't do any thing because they can't correct the force I applied to kick the rocket over. An active thruster (an attitude control system) can recorrect the force of my kick and reorient the rocket vertically.
  - pbnjay 12y ago
    How are you going to kick a rocket falling from outer space? You don't need active thrusters (and all the extra weight that comes with it) when gravity and wind will do the job for you just as well.
    - 32faction 12y ago
      > How are you going to kick a rocket falling from outer space? I meant if there was some external force like a wind shear or grid fin/hydraulic line failure that pushes the rocket hard enough on descent to alter it's vertical orientation, those grid fins won't really do much to correct that force. > Gravity and wind will do the job for you You cannot control gravity or wind. You just have systems that manipulate those forces. Grid fins are a passive system in that they manipulate the fluid the rocket is in to steer it on course but not to correct drastic attitude alterations. But again, if the updates to the hydraulic lines work out, then they won't need the active thruster system. Adding an active thruster system is just engineering for worst case scenarios.
shasheene 12y ago
The Falcon 9 does have attitude control system towards the top: the nitrogen cold gas thrusters in the Reaction Control System is located in the interstage portion of the vehicle - right at the top of the first stage The gimballing engines give attitude control at the bottom, as far as I understand
- 32faction 12y ago
  Nitrogen cold gas thrusters don't give enough "oomph". Maybe if the rocket was inclined at angles x<10 degrees with respect to the vertical axis it would've been able to correct but this rocket was leaned over at what seems to be 20<x<=45 deg. In other words they wouldn't of have been powerful enough to correct that much of a drastic lean the Falcon had coming down. But I'm sure with the hydraulic fluid corrections a stronger control system won't be needed to fix large angles of attack but it would be nice to have as an emergency system. "Have it and not need it/Need it don't Have it" really doesn't work with rockets because of the mass requirements

pbnjay 12y ago

It does (https://www.youtube.com/watch?v=DgLBIdVg3EM https://www.youtube.com/watch?v=DgLBIdVg3EM), it just ran out of hydraulic fluid in this case.

32faction 12y ago
Those are just grid fins which are used more for steering than attitude control. If I kick the rocket over those fins won't do any thing because they can't correct the force I applied to kick the rocket over. An active thruster (an attitude control system) can recorrect the force of my kick and reorient the rocket vertically.
- pbnjay 12y ago
  How are you going to kick a rocket falling from outer space? You don't need active thrusters (and all the extra weight that comes with it) when gravity and wind will do the job for you just as well.
  - 32faction 12y ago
    > How are you going to kick a rocket falling from outer space? I meant if there was some external force like a wind shear or grid fin/hydraulic line failure that pushes the rocket hard enough on descent to alter it's vertical orientation, those grid fins won't really do much to correct that force. > Gravity and wind will do the job for you You cannot control gravity or wind. You just have systems that manipulate those forces. Grid fins are a passive system in that they manipulate the fluid the rocket is in to steer it on course but not to correct drastic attitude alterations. But again, if the updates to the hydraulic lines work out, then they won't need the active thruster system. Adding an active thruster system is just engineering for worst case scenarios.

shasheene 12y ago

The Falcon 9 does have attitude control system towards the top: the nitrogen cold gas thrusters in the Reaction Control System is located in the interstage portion of the vehicle - right at the top of the first stage The gimballing engines give attitude control at the bottom, as far as I understand

32faction 12y ago
Nitrogen cold gas thrusters don't give enough "oomph". Maybe if the rocket was inclined at angles x<10 degrees with respect to the vertical axis it would've been able to correct but this rocket was leaned over at what seems to be 20<x<=45 deg. In other words they wouldn't of have been powerful enough to correct that much of a drastic lean the Falcon had coming down. But I'm sure with the hydraulic fluid corrections a stronger control system won't be needed to fix large angles of attack but it would be nice to have as an emergency system. "Have it and not need it/Need it don't Have it" really doesn't work with rockets because of the mass requirements