Author Topic: Fairing reuse  (Read 333454 times)

Offline meekGee

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Re: Fairing reuse
« Reply #1160 on: 12/28/2017 11:37 AM »
Yup, exactly.
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Online AncientU

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Re: Fairing reuse
« Reply #1161 on: 12/28/2017 11:44 AM »
So, what colors are the balls going to be? ;)
« Last Edit: 12/28/2017 11:45 AM by AncientU »
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Offline Basto

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Re: Fairing reuse
« Reply #1162 on: 12/28/2017 03:39 PM »
What if the “bouncy castle” is just down on the deck and the line running across between the arms are meant to snag the parachute lines and then they drop tension on the lines and drop the fairing quickly onto the bouncy castle. That way the first line is out of the way when the second fairing half comes in and they repeat the process.

Offline meekGee

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Re: Fairing reuse
« Reply #1163 on: 12/28/2017 03:52 PM »
What if the “bouncy castle” is just down on the deck and the line running across between the arms are meant to snag the parachute lines and then they drop tension on the lines and drop the fairing quickly onto the bouncy castle. That way the first line is out of the way when the second fairing half comes in and they repeat the process.
Hmmm...  That's interesting too... 

The parachute system will then overtake the boat, flaring so that it flies horizontally, and intersect the wire.

I like any system that only requires an intersection of paths, not a bulls eye.  Leaves one DOF open for last minute corrections.

In your case  the fairing and its harness might just stay hung...
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Online FutureSpaceTourist

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Re: Fairing reuse
« Reply #1164 on: 12/28/2017 05:14 PM »
Quote
@NASASpaceflight Pics of Mr. Steven taken on the 24th by me, feel free to use em where ever :) ~6 hours after arrival into port, there were some workers around, but no fairing to be seen.

https://twitter.com/angrypackomeese/status/946431406825025536

Offline Oersted

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Re: Fairing reuse
« Reply #1165 on: 12/28/2017 07:36 PM »
I really doubt there will be any substantial "bouncy castle". Doesn't go well with the wind forces often encountered at sea. Count me in the "net" camp! (former navy guy)

Offline octavo

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Re: Fairing reuse
« Reply #1166 on: 12/29/2017 04:20 AM »
Net or bouncy castle, I think the funnel shape I drew earlier (very poorly) is still correct. I wonder why there are pulleys only from the top of the aft arms. I would guess they have to do with dropping the floor net onto the deck, perhaps to prepare for catching the second fairing.

Online Cheapchips

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Re: Fairing reuse
« Reply #1167 on: 12/29/2017 01:12 PM »

Apologies if I missed it somewhere in the thread - what time gap is possible between fairing landings?  They can presumably deploy at different altitude and have other options for varying glide range?

Online nacnud

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Re: Fairing reuse
« Reply #1168 on: 12/29/2017 01:18 PM »
I don't think anyone has run the numbers, you could give it a try and see what might be reasonable.

Online Cheapchips

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Re: Fairing reuse
« Reply #1169 on: 12/29/2017 01:41 PM »
I don't think anyone has run the numbers, you could give it a try and see what might be reasonable.

I'd love to.  Not remotely within my skillset though!

Online nacnud

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Re: Fairing reuse
« Reply #1170 on: 12/29/2017 01:52 PM »
https://skydivehigh.com/skydive-high/haho-intro/

A quick google gives a canopy time of 20 mins for a high altitude high opening parachute jump, so you could get 15 minutes between the fairings, provided you can design a parachute system that can open that high.

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Re: Fairing reuse
« Reply #1171 on: 12/29/2017 02:21 PM »
Well, a quick Google is within my skillset, just wasn't sure of that was providing the necessary depth of response. :)

15 minutes seems like a pretty short window to reset for the 2nd faring half, if a re-rigging of Mr Steven's grabber was required.

Did come across a brief bit of info that a Rogallo wing was considered and tested for 60's NASA capsules.  Without having chance to delve further atm, I thought some images were interesting:

link




« Last Edit: 12/29/2017 02:39 PM by gongora »

Online Johnnyhinbos

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Re: Fairing reuse
« Reply #1172 on: 12/29/2017 02:30 PM »
Personally I doubt they would do a high altitude opening (I have a Class A jump certification, but am certainly no authority).

Upper level wind is pretty high and often contrary to lowers. This leads to a loss of precision in the landing zone, even when using a steerable chute. Additionally, high altitudes in turn give low air density which in turn require larger strokes over longer times to effect control authority over the wing. Low density deployment also leads to higher spring recoil where the parachute can momentarily have a higher descent velocity than the payload.

Point being, I’d guess a later opening to pick up denser air with less variables re wind speed and direction.
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Online nacnud

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Re: Fairing reuse
« Reply #1173 on: 12/29/2017 02:37 PM »
Google is a nice place to start before breaking out the physics, :)

I think a ram air chute is more likely than a Rogallo wing these days, like that used with the X38.

As for the 15 mins between faring landings I think it's feasible but you'd want to try and avoid too much labour on deck between landings. I'm imagining something like
1) Catch fairing in net
2) Deal with parachute (I like the idea of the magic disappearing curtain from the Dragon 2 reveal, start at 3:30)
3) Lower fairing to deck and temporarily secure
4) Reset net, it could be the same net but using a different one might be easier
5) Repeat.
« Last Edit: 12/29/2017 02:38 PM by nacnud »

Online nacnud

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Re: Fairing reuse
« Reply #1174 on: 12/29/2017 02:42 PM »
Personally I doubt they would do a high altitude opening...

Me too but I was trying to find an upper boundary for possible time between fairings, what would you suggest? 5 mins?

Online Johnnyhinbos

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Re: Fairing reuse
« Reply #1175 on: 12/29/2017 02:51 PM »
Personally I doubt they would do a high altitude opening...

Me too but I was trying to find an upper boundary for possible time between fairings, what would you suggest? 5 mins?
I think perhaps they might open around the same time but follow different plight profiles to dump altitude as needed.

Generally speaking however - I think this entire endeavor is amazing. It's a really tricky problem and I love that SpaceX is actively tackling it!
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Offline john smith 19

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Re: Fairing reuse
« Reply #1176 on: 12/29/2017 06:14 PM »
This thread asked what the specific heat of PICA-X was, I don't think an answer was ever found.
https://forum.nasaspaceflight.com/index.php?topic=36039.0

I would suspect it was rather high but?

( High specific heat means more heat energy is needed per unit mass to raise the temperature of a material by one degree so it makes a better defense against heat energy. If the thermal conductivity is low that's a good thing too (while defending). This is a place where low density kind of works against you on heating up, but for you on cooling down again. Same with thermal conductivity... low works for you on heating and against you on cooling)
The balance in the process is quite subtle. Lower density --> Lower SHC but Lower density --> poorer thermal conductor (Historically AVCOAT was quite a good conductor and was about 2x heavier than 1st generation PICAX).

AFAIK the parameter that brings things together is known as the "Thermal Diffusivity" and is loosely described as  measure of how heat spreads through a material, where things like SHC tend to be bulk properties, assuming the whole thing is at a certain temperature, or thermal conductivity, which assumes a constant temperature gradient.

But that about exhausts my HS level physics.
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Offline Steve D

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Re: Fairing reuse
« Reply #1177 on: 12/30/2017 01:31 AM »
My money is on them eventually having 2 boats out there. Just catching 1 fairing half during the test phase then setting up a second ship when they go into normal recovery operations. KISS principle at work

Offline ClayJar

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Re: Fairing reuse
« Reply #1178 on: 12/30/2017 03:22 AM »
My money is on them eventually having 2 boats out there. Just catching 1 fairing half during the test phase then setting up a second ship when they go into normal recovery operations. KISS principle at work

Two boats seems the pragmatic approach.  I'm not sure I'd want to bet $5 million on everything going right without any glitches.  (Or would that be $2.5 million, since you'd only have to wave goodbye to the second half?)

If I were trying to find ways to make things more efficient, the first thing I'd have to wonder is whether I can consolidate something *other* than fairing catching.  Can I, perhaps, get a fairing catcher that can also tow an ASDS into position?  Saves me the same number of boats, but doesn't require perfect timing.  (Not saying a fairing catcher can be a ASDS towing craft, but you get the general idea.)
« Last Edit: 12/30/2017 03:23 AM by ClayJar »

Online deruch

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Re: Fairing reuse
« Reply #1179 on: 12/30/2017 07:02 AM »
My money is on them eventually having 2 boats out there. Just catching 1 fairing half during the test phase then setting up a second ship when they go into normal recovery operations. KISS principle at work

Two boats seems the pragmatic approach.  I'm not sure I'd want to bet $5 million on everything going right without any glitches.  (Or would that be $2.5 million, since you'd only have to wave goodbye to the second half?)

If I were trying to find ways to make things more efficient, the first thing I'd have to wonder is whether I can consolidate something *other* than fairing catching.  Can I, perhaps, get a fairing catcher that can also tow an ASDS into position?  Saves me the same number of boats, but doesn't require perfect timing.  (Not saying a fairing catcher can be a ASDS towing craft, but you get the general idea.)

It may be wrong that both fairing halves are equally valued.  The active half may be worth significantly more.  IMO, the best argument for investing the effort to catch the fairings at all is that it saves the large capital expenditures needed to make a whole lot more fairings, and thereby enables SpaceX's goal of a much higher flight rate.  Catching just 1 could be enough to meet their short term needs and so we won't see anything else until they start getting closer to their limiting rate.
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