Author Topic: Fairing reuse  (Read 511205 times)

Offline cambrianera

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Re: Fairing reuse
« Reply #280 on: 04/05/2016 07:46 PM »
-risk of tangling into payload (or between tethers, if more than one);
If you had three sided fairing, tangling potential could be maybe smaller, if there are three tethers connecting the corners. Hard to clear the rocket with two-halve clamshell fairing, would need extra pyro gear or something

True, but three sided fairings should call for more joints, more pushers, more mass overall.
But not a given, maybe interesting.
Tangling of the tethers still remain a possibility, and rejoining three pieces requires more effort.
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Offline cambrianera

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Re: Fairing reuse
« Reply #281 on: 04/05/2016 07:49 PM »

I get the convex/concave choices for managing shock and drag, but I am not sure a fairing (half) can maintain attitude control during re-entry, or during decent at terminal velocity.   Are you certain of the stability?  I do not know.   


Thinking to something like this, very light.
For first part, reentry, managing the shock
« Last Edit: 04/05/2016 07:53 PM by cambrianera »
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Offline CraigLieb

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Re: Fairing reuse
« Reply #282 on: 04/05/2016 08:21 PM »
How about the fairings split into 28.3 degree sections, sprout little wings,  with small jet engines that pop out, and fly themselves independently down to a specially designed run-way like a mini-shuttle?   ::)
Please no serious replies.  This was meant as a joke to point out how little value there is in trying to engineer a solution here.
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Online llanitedave

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Re: Fairing reuse
« Reply #283 on: 04/05/2016 11:37 PM »
Perhaps if we built a large, wooden badger...



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Offline sewebster

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Re: Fairing reuse
« Reply #284 on: 04/06/2016 02:13 AM »
Then you'd be taking it all the way up and as has been hashed and re-hashed above won't work because taking the current fairing along for the whole ride cuts your payload to orbit in half and you're talking about making it weigh more and then taking it to orbit.  And not only do you pay the mass penalty once going up but you've also added

Not that I'm advocating for taking the fairing to orbit, but does it really have a mass of half the payload? Do we know the mass? (maybe I just forget from upthread...)

Offline D_Dom

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Re: Fairing reuse
« Reply #285 on: 04/06/2016 02:22 AM »
The weight of the fairing must be overcome by burning rocket fuel. The mass of the fuel is dictated by the rocket equation. It is not that mass of the fairing is equal to half the payload, it is the tyranny of the rocket equation that cuts the payload mass if you carry the fairing further than absolutely necessary.
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Offline sewebster

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Re: Fairing reuse
« Reply #286 on: 04/06/2016 02:41 AM »
The weight of the fairing must be overcome by burning rocket fuel. The mass of the fuel is dictated by the rocket equation. It is not that mass of the fairing is equal to half the payload, it is the tyranny of the rocket equation that cuts the payload mass if you carry the fairing further than absolutely necessary.

Right, but presumably the worst case scenario is subtracting the fairing mass from the maximum payload mass (if you take the fairing to orbit)? In reality it isn't this bad, because you were already planning on taking the fairing up part of the way?

Offline savuporo

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Re: Fairing reuse
« Reply #287 on: 04/06/2016 02:53 AM »
Right, but presumably the worst case scenario is subtracting the fairing mass from the maximum payload mass (if you take the fairing to orbit)? In reality it isn't this bad, because you were already planning on taking the fairing up part of the way?
Its this bad, as fairing separates roughly after 1/3rd of the flight time. For the rest of the 2/3rd of flight, you are not trying to accelerate that weight.
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Offline OxCartMark

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Re: Fairing reuse
« Reply #288 on: 04/06/2016 02:48 PM »
In my opinion the combined productive benefit of the preceding 15 pages is about as useful to human endeavor as a parachute on a well driller.

Offline Lar

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Re: Fairing reuse
« Reply #289 on: 04/06/2016 04:26 PM »
Mod here: I've been trying to figure out how to split out the "what they could do" from "what we think... based on evidence, that SpaceX IS doing". I couldn't find a good set of posts to split out, but I'm trying.

Maybe the way to go is to start a new thread that focuses only on the evidence, and stays narrowly focused, and leave this thread for those folks that want to come up with ever wilder schemes.... (not me, so much, I'm more interested in the kremlinology around what SpaceX appears to actually be doing)  I will continue to try to find a way to split but if not, will lock this, and start two threads.
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Offline dorkmo

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Re: Fairing reuse
« Reply #290 on: 04/06/2016 10:27 PM »
known spacex advances:
thrusters to control orientation
go pros to record fall
possible extra recovery ship
a few statements about recovery intentions
?

i vote for one thread to speculate at will. its not perfect but we dont have much to go on in the first place.
(says the guy that thinks they could dock the two halves together lulz)
« Last Edit: 04/06/2016 10:33 PM by dorkmo »

Online llanitedave

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Re: Fairing reuse
« Reply #291 on: 04/06/2016 10:42 PM »
Maybe we need a fairing Bingo thread.
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Offline wannamoonbase

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Re: Fairing reuse
« Reply #292 on: 04/07/2016 12:28 AM »
known spacex advances:
thrusters to control orientation
go pros to record fall
possible extra recovery ship
a few statements about recovery intentions
?

i vote for one thread to speculate at will. its not perfect but we dont have much to go on in the first place.
(says the guy that thinks they could dock the two halves together lulz)

This whole development is exciting and interesting.  They'll likely proceed incrementally and slowly and we won't know how far they are until they succeed.  I'd bet they start with recovering one half first.

With all the developments they have going on, if they try hooking one in the next year that would be pretty quick in my opinion.
 
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Online cscott

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Re: Fairing reuse
« Reply #293 on: 04/07/2016 02:45 PM »
I like the two thread idea.  It's obvious (to me) that SpaceX is recovering the fairing halves individually, and is experimenting with RCS mechanisms to stabilize them.  The outlandish clamshell and tether ideas here have no evidence supporting them -- putting aside completely the question of their practicality, superiority, etc.  Sign me up for the low-volume thread discussing actual *evidence* and theories grounded in that evidence.  I have no problem with folks continuing to try to "build a better mousetrap"... I'm just not personally interested in following that thread.

Ob. Fairing news: in the ASDS thread we've noticed that Go Searcher, who has gone out for recovery attempts involving fairings, is staying in port for the dragon launch (which doesn't involve a fairing).  We'll see if this pattern holds, but it's beginning to look like evidence for a "fairing recovery" role for Go Searcher.

Offline D_Dom

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Re: Fairing reuse
« Reply #294 on: 04/07/2016 04:09 PM »
Huge benefit to people unfamiliar with the statement "space is hard" is that on this site you can ask any questions you like and expect a responsible answer. Agreed that some of the topics on this thread defy all the known laws of physics, so be it. Also thinking of channeling Jim for one word responses if only just to increase the number of replies I have time for. Not at all offended by having to wade through the outlandish ideas to consider the "evidence". My humble opinion is leave it as one thread, cultivate the signal, address the noise (respectfully) and we may all learn something about this most interesting aspect of re-usability.
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Offline Space Ghost 1962

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Re: Fairing reuse
« Reply #295 on: 04/07/2016 04:16 PM »
... and do your own reading/searching/research on the substantial body of what has been attempted already.

For example, Kistler K-1 was to be a TSTO 100% reusable vehicle, which had ... a kind of fairing that was reused.

Also, keep in mind that some conceived ideas change as you take a concept and put it into action. For example, Dragon's solar panels were encased inside the trunk and a complex articulation of booms deployed them - never flown - they chose to mount them on the side for a simpler deploy with jettisoned fairings.

Ask yourself "why" these decisions were/are made first. Think of the trades for each.

Offline D_Dom

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Re: Fairing reuse
« Reply #296 on: 04/07/2016 04:27 PM »
In my opinion the combined productive benefit of the preceding 15 pages is about as useful to human endeavor as a parachute on a well driller.

Having jumped out of perfectly good airplanes before I can see the advantage of "dropping in" heavy equipment to a remote site. just saying...
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Offline manoweb

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Re: Fairing reuse
« Reply #297 on: 04/08/2016 11:15 PM »
Today at the press debriefing Mr. E. Musk mentioned they are pursuing fairing reuse, because it costs several million dollars.

Offline Mader Levap

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Re: Fairing reuse
« Reply #298 on: 04/08/2016 11:17 PM »
Today at the press debriefing Mr. E. Musk mentioned they are pursuing fairing reuse, because it costs several million dollars.
Wouldn't that be first official mention of fairing reuse?
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Offline mlow

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Re: Fairing reuse
« Reply #299 on: 04/08/2016 11:20 PM »
The way I heard it, sounded like he was referring to couple mil each.

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