A Space & astronomy forum. SpaceBanter.com

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » SpaceBanter.com forum » Space Science » Policy
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

Falcon 9 Delivers Dragon Into Orbit, Flubs Landing



 
 
Thread Tools Display Modes
  #11  
Old December 7th 18, 08:03 PM posted to sci.space.policy
Fred J. McCall[_3_]
external usenet poster
 
Posts: 9,817
Default Falcon 9 Delivers Dragon Into Orbit, Flubs Landing

Jeff Findley wrote on Fri, 7 Dec 2018
07:17:04 -0500:

In article ,
says...

Niklas Holsti wrote on Thu, 6 Dec 2018
19:01:58 +0200:

On 18-12-06 13:06 , Jeff Findley wrote:

Also, the stage managed to land very well on the ocean (as can be seen
in a video posted by an observer on social media). SpaceX also released
the on board camera footage from the stage which showed that once the
landing burn started, the engines were able to negate the roll caused by
the stuck grid fin.

I thought the landing uses only one engine, therefore probably the
center engine -- then how can the engine control roll? I don't understand.


The same way any other single engine booster controls roll, I would
think. The engine gimbals.


That would be a neat trick.


Or not.


On Falcon 1, that version of Merlin had a gimbal on the turbo-pump
exhaust for roll control. As far as I know, they deleted that feature
on Merlins used for Falcon 9 since the extra complexity wasn't needed
anymore.


Wiki indicates that the ability to gimbal was removed as of the Merlin
1C engine. Everything else I find, including the Payload User's
Guide, indicates that the Merlin 1D engines on a Falcon 9 do indeed
still have the ability to gimbal and gimballing is used to control
pitch, yaw, and roll for the first stage.


--
"Now I'm hiding in Honduras.
I'm a desperate man.
Send lawyers, guns and money.
The **** has hit the fan."
-- "Send Lawyers, Guns, and Money", Warren Zevon
Ads
  #12  
Old December 7th 18, 10:12 PM posted to sci.space.policy
Jeff Findley[_6_]
external usenet poster
 
Posts: 1,761
Default Falcon 9 Delivers Dragon Into Orbit, Flubs Landing

In article ,
says...

Jeff Findley wrote on Fri, 7 Dec 2018
07:17:04 -0500:

In article ,
says...

Niklas Holsti wrote on Thu, 6 Dec 2018
19:01:58 +0200:

On 18-12-06 13:06 , Jeff Findley wrote:

Also, the stage managed to land very well on the ocean (as can be seen
in a video posted by an observer on social media). SpaceX also released
the on board camera footage from the stage which showed that once the
landing burn started, the engines were able to negate the roll caused by
the stuck grid fin.

I thought the landing uses only one engine, therefore probably the
center engine -- then how can the engine control roll? I don't understand.


The same way any other single engine booster controls roll, I would
think. The engine gimbals.


That would be a neat trick.


Or not.


On Falcon 1, that version of Merlin had a gimbal on the turbo-pump
exhaust for roll control. As far as I know, they deleted that feature
on Merlins used for Falcon 9 since the extra complexity wasn't needed
anymore.


Wiki indicates that the ability to gimbal was removed as of the Merlin
1C engine. Everything else I find, including the Payload User's
Guide, indicates that the Merlin 1D engines on a Falcon 9 do indeed
still have the ability to gimbal and gimballing is used to control
pitch, yaw, and roll for the first stage.


I agree that the center engine can gimbal. But during the final phase
of landing, only the center engine is firing. So how can you generate a
torque in the direction of the vertical axis of the rocket when the
center engine is located on that same vertical axis?

Jeff
--
All opinions posted by me on Usenet News are mine, and mine alone.
These posts do not reflect the opinions of my family, friends,
employer, or any organization that I am a member of.
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
SpaceX video showing Falcon 9 stages and Dragon performing avertical landing David Spain Policy 14 October 15th 11 09:51 PM
SpaceX video showing Falcon 9 stages and Dragon performing avertical landing Space Cadet[_1_] Policy 7 October 6th 11 09:00 PM
Dragon/Falcon 9 Update [email protected] Policy 16 October 7th 09 04:42 PM
No escape tower on Dragon / Falcon 9 [email protected] Policy 0 September 30th 08 03:43 PM
ESA flubs Titan Landing show Ken Amateur Astronomy 36 January 19th 05 09:00 PM


All times are GMT +1. The time now is 10:20 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright 2004-2018 SpaceBanter.com.
The comments are property of their posters.