Author Topic: Landing the F9 V1.1 first stage  (Read 96049 times)

Offline meekGee

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Re: Landing the F9 V1.1 first stage
« Reply #300 on: 04/21/2015 09:18 PM »
New legs, that's the answer  ;)

Well Shirley you want a new rocket as well.
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Offline Joffan

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Re: Landing the F9 V1.1 first stage
« Reply #301 on: 04/21/2015 10:25 PM »
I'm not sure if we've had any discussion of adding control thrusters to the bottom of the stage or not, but it seems to me that if keeping the stage upright in the second before touchdown is key, then there might be a role for the instant thrust-independent capability of a set of radial-only thrusters down near the base of the stage.

Top not bottom:
The reason they have the thrusters on the top of the stage is because they have more control authority there than next to the main mass at the bottom of the stage.


In fact what I was suggesting was having thrusters both top and bottom, in order to make a paired system.

However you do identify the real reason my suggestion is poor: the stage mass distribution during landing. Side thrusters down near the engines will be very close to the centre of mass in that phase, so will not be effective at controlling attitude. Thanks.
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Offline Rocket Science

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Re: Landing the F9 V1.1 first stage
« Reply #302 on: 04/21/2015 10:37 PM »
I'm not sure if we've had any discussion of adding control thrusters to the bottom of the stage or not, but it seems to me that if keeping the stage upright in the second before touchdown is key, then there might be a role for the instant thrust-independent capability of a set of radial-only thrusters down near the base of the stage.

If Elon says - as he seems to be saying - his team can fix it all with improved Merlin control, I'm absolutely not going to contradict him. And like all options there are trade-offs in mass, cost, developmental focus, maintenance and approval steps, etc. But it looks to me like an extra set of control thrusters could be a viable solution to resolving the near-touchdown twin priorities of zeroing out lateral motion while delivering the stage upright to pad.
That's what I mean by vernier engines, see my post at the top of page 15....
« Last Edit: 04/21/2015 10:38 PM by Rocket Science »
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Offline cambrianera

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Re: Landing the F9 V1.1 first stage
« Reply #303 on: 04/22/2015 12:05 AM »
New legs, that's the answer  ;)

Well Shirley you want a new rocket as well.
Already in the pipe also, mr Serious  ;D
Oh to be young again. . .

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