Author Topic: SpaceX McGregor Testing Updates and Discussion THREAD 2  (Read 386268 times)

Offline adrianwyard

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #680 on: 05/06/2014 06:25 AM »
Yes, landing gear is dead easy compared to those challenges. But see the DC-X topple, and the Dream Chaser crash for failures they've caused.

I don't think anyone's advocating for extra legs, just some contingency planning for when the unlikely happens.

It occurred to me that gimballing all 9 engine bells might usefully shift the center of gravity too.

Offline Owlon

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #681 on: 05/06/2014 07:05 AM »
Yes, landing gear is dead easy compared to those challenges. But see the DC-X topple, and the Dream Chaser crash for failures they've caused.

I don't think anyone's advocating for extra legs, just some contingency planning for when the unlikely happens.

It occurred to me that gimballing all 9 engine bells might usefully shift the center of gravity too.

Keep in mind, though, that both of those examples were test vehicles.

How often does aircraft landing gear fail to deploy? (not a rhetorical question)

Offline darkenfast

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #682 on: 05/06/2014 08:33 AM »
Aircraft landing gear is designed to retract and deploy (sometimes multiple cycles in one flight due to training and go-arounds), and is more complex because of that. The better comparison would be the Space Shuttle's landing gear. It only had to work once, and always did.

Offline Nomadd

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #683 on: 05/06/2014 11:45 AM »

How often does aircraft landing gear fail to deploy? (not a rhetorical question)
On one SpaceX competitor I can think of, the gear has failed 100% of the time.
 But, the F9R gear is extremely simple. Plus, you don't have to worry about failure to deploy scenarios much, and can just hit it with full pressure at the start, since anything but proper operation would mean loss of the stage with no time to recover.
 I wonder what the protocol will be if sensors don't indicate a good deploy. Continuing the landing might be best since that would bring it down with the least damage to rocket and innocent bystanders. Or, if they can throttle that deep, maybe hover till fuel depletion.
« Last Edit: 05/06/2014 11:47 AM by Nomadd »

Offline meekGee

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #684 on: 05/06/2014 02:18 PM »
Aircraft landing gear is designed to retract and deploy (sometimes multiple cycles in one flight due to training and go-arounds), and is more complex because of that. The better comparison would be the Space Shuttle's landing gear. It only had to work once, and always did.
very true about the gear. nI think there are several 10,000 scheduled flights per day, and you hear about a gear up landing maybe once a year?  not sure if you hear about all of them though.
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Offline AncientU

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #685 on: 05/06/2014 02:32 PM »
Why does everyone seem to think it's so hard to make legs that are reliable enough you don't need the extra mass, cost, and complexity of extra legs?

They're just legs.  Surely a company that can send cargo into orbit and land it back safely on earth, and can do supersonic retro-propulsion to bring a hage stage back to a soft landing can manage getting legs to pop out.

Anyway, it's only the stage that has to be replaced if a leg somehow doesn't pop out.  There's no danger to cargo or passengers.
Assuming the landing pads are going to be designed for the occasional mishap, clean up the mess, patch concrete where needed, and get on with it.  We've been losing approximately one first stage per flight for fifty years.
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Offline TomNTex

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #686 on: 05/21/2014 04:01 PM »
Draft Environmental Assessment for Issuing an Experimental Permit to SpaceX for Operation of the Dragon Fly Vehicle at the McGregor Test Site, Texas, May 2014

http://www.faa.gov/about/office_org/headquarters_offices/ast/media/20140513_DragonFly_DraftEA(Public).pdf

http://www.faa.gov/about/office_org/headquarters_offices/ast/environmental/review/permits/

Offline Lars_J

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #687 on: 05/21/2014 04:22 PM »
Hmm, interesting information about the "DragonFly RLV" in that PDF:

 - up to four steel landing legs
 - weighs 14000 lbs unfueled
 - maximum proplellant load is 400 gallons

Four kinds of test flights expected:
 - propulsive assist landing (dropped from helicopter with chutes)
 - fully propulsive landing (dropped from helicopter)
 - propulsive assist hop (self launched, parachute deploys)
 - fully propulsive hop (like Grasshopper)
« Last Edit: 05/21/2014 04:25 PM by Lars_J »

Offline corrodedNut

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #688 on: 05/21/2014 04:27 PM »
Hmm, interesting information about the "DragonFly RLV" in that PDF:

 - up to four steel landing legs
 - weighs 14000 lbs unfueled
 - maximum proplellant load is 400 gallons

Four kinds of test flights expected:
 - propulsive assist landing (dropped from helicopter with chutes)
 - fully propulsive landing (dropped from helicopter)
 - propulsive assist hop (self launched, parachute deploys)
 - fully propulsive hop (like Grasshopper)

It's thread-worthy: http://forum.nasaspaceflight.com/index.php?topic=34800.0

Online Jarnis

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #689 on: 05/21/2014 04:31 PM »
Very interesting indeed.

I must say that freefall until 5sec before splat and "suicide burn" to soft touchdown sounds to be positively brown-pants grade stuff. Can't wait for the videos!

Online docmordrid

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #690 on: 05/21/2014 05:07 PM »
Time to re-stock the popcorn :)

Sounds like the initial Grasshopper hop shouldn't be too far off, what with the pad abort coming up.
DM

Offline wannamoonbase

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #691 on: 05/21/2014 05:23 PM »
Well that is exciting indeed.

Sounds like good engineering and good viewing.

Things are getting more interesting.  What an intense development period:
Learning to fly F9V1.1
F9R,
F9H,
F9R-Dev1,
F9R-Dev2,
Raptor,
Launch Abort Tests,
DragonFly

SpaceX has a LOT going on.
Jonesing for a copy of 'Tales of Suspense #39'

Offline ImUtrecht

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #692 on: 05/21/2014 07:02 PM »
And Falcon Heavy...

Offline Hauerg

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #693 on: 05/21/2014 07:56 PM »
And Falcon Heavy...
Ahem. That would be the "F9H" in the above list.

Online mme

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #694 on: 05/21/2014 08:28 PM »
And Falcon Heavy...
Ahem. That would be the "F9H" in the above list.
Not to be too pedantic, but Falcon Heavy should be abbreviated FH (or, tongue in cheek, F27). No?
Space is not Highlander.  There can, and will, be more than one.

Offline mvpel

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #695 on: 05/24/2014 07:42 PM »
I'm going to be down in McGregor late afternoon June 12 and on June 13 - does SpaceX publish their planned schedules for the local community so they know which loud noises are expected vs. unexpected? Or do I just need to keep my fingers crossed and hope for the best?
"Ugly programs are like ugly suspension bridges: they're much more liable to collapse than pretty ones, because the way humans (especially engineer-humans) perceive beauty is intimately related to our ability to process and understand complexity. A language that makes it hard to write elegant code makes it hard to write good code." - Eric S. Raymond

Offline Llian Rhydderch

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #696 on: 05/24/2014 11:36 PM »
I'm going to be down in McGregor late afternoon June 12 and on June 13 - does SpaceX publish their planned schedules for the local community so they know which loud noises are expected vs. unexpected? Or do I just need to keep my fingers crossed and hope for the best?

Apparently not.  "Joe Science" (Joseph Abbott) at the Waco Tribune has been covering the local happenings with SpaceX pretty well.  If you look through his old posts/articles, you'll see a few "heads up" type notices that SpaceX has given him but it's usually just a "louder test than usual" (e.g, a 9-engine stage test) and happening "next week" or some other very approximate date/time.

Still, very glad you'll be down there.  Maybe you'll pull something interesting up.  Keep camera handy!   :) And let us all know what you find.

Me, I'm kind of interested to hear if they have permanently closed off one or more of the local (previously public) roads as SpaceX has acquired more land for their rocket test facility.  Google Maps still shows all the roads as public, I believe.  (and the authorities always were closing some roads temporarily during the biggest engine tests).

Also, if you meet a well-positioned local landowner, ... I think it'd be kind of cool for ten or twenty of us to go in on a web cam arrangement from a nearby pole, and rent some bandwidth from the farmer's internet connection to broadcast an updated photo once in a while.   ;D
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Offline mvpel

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #697 on: 05/25/2014 12:20 AM »
What's a little creepy stalking among friends, right? ;D
"Ugly programs are like ugly suspension bridges: they're much more liable to collapse than pretty ones, because the way humans (especially engineer-humans) perceive beauty is intimately related to our ability to process and understand complexity. A language that makes it hard to write elegant code makes it hard to write good code." - Eric S. Raymond

Offline ImUtrecht

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #698 on: 05/25/2014 01:10 AM »
And Falcon Heavy...
Ahem. That would be the "F9H" in the above list.
Not to be too pedantic, but Falcon Heavy should be abbreviated FH (or, tongue in cheek, F27). No?

Yes my mistake...
EM uses FH
F27 is also nice... reminds me of the Fokker Friendship, revolutionary because of it's glued wings...  ;)

Offline mvpel

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Re: SpaceX McGregor Testing Updates and Discussion THREAD 2
« Reply #699 on: 06/12/2014 09:50 PM »
I'm driving towards the stand and they appear to have the booster on the stand. More so
"Ugly programs are like ugly suspension bridges: they're much more liable to collapse than pretty ones, because the way humans (especially engineer-humans) perceive beauty is intimately related to our ability to process and understand complexity. A language that makes it hard to write elegant code makes it hard to write good code." - Eric S. Raymond

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