Author Topic: Fairing reuse  (Read 528203 times)

Online Robotbeat

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Re: Fairing reuse
« Reply #700 on: 03/25/2017 05:16 PM »
A Megawatt peak should be more than sufficient to carry a fairing halve with a multicopter video. A battery similar to what's in a Tesla.

Scales better electrically with more motors than simply bigger motors. So 60 motors, maybe?

Anyway, I doubt they'll pursue a custom flying fairing catcher, but it's fun to speculate.
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Offline georgegassaway

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Re: Fairing reuse
« Reply #701 on: 03/25/2017 06:40 PM »
Multicopters can fly pretty fast, and are very maneuverable (check out video of “Drone racing”.  I do not know what the record speed is, but some can fly over 100 mph).  And while they can be very maneuverable, they can also do very precise smooth maneuvering as well.

If there were some big custom multicopters used for air-snagging the parachute of a descending fairing half, I would expect that the single recovery barge (or ship with a very big deck) would be located at the sweet spot of where the fairings would likely splash down from their ballistic descent if they didn’t have chutes (not accounting for local wind variation). So, the multicopters would not have to travel too far horizontally, mainly climb to altitude, and then begin to home in on its assigned fairing/parachute.  Also, being designed to have the thrust to fly back with 1 ton underneath, it would be able to ascend crazy-fast without a payload (as well as fly very fast horizontally to catch-up to rendezvous for the air-snag maneuver).  After the snag,  not needing to fly very fast horizontally (mostly the issue of the drag and wobbling of fairing underneath while traveling horizontally). And ideally the whole thing would happen mostly directly above the barge (also thanks in part to the steerable parachute), so if the air-snag was say a mile up, it may have less than a mile to fly horizontally. 

This video (link below) by Casey Neistat gives info on the multicopter that was used for the Christmas video that he made.  16 motors, 16 props…..  a “HexaDecaCopter” (Hmm, with 8 x 2 layout I'd say more like a OctoCopter 2X, though I do get that hex + deca implies the number 16. An 8-armed multicopter  is called an OctoCopter).   By itself, it weighs 165 pounds. With Neistat, all the rigging, snowboard, total flying weight of about 365 pounds.  Max thrust of 1050 pounds. That info comes from this video he made about it:



It was made by three people, (two of whom are husband and wife) over a period of about a year. It is not known if they did this full-time as their one and only project, or a side project.  It is described as “home made”. So I suspect it was done as a side project. I suspect that if they were a small “mom and pop and friend” company that had the $ and time to do nothing else but this, they could have done it in far less time. Just as a hobbyist I may have a project that takes me 6 months to get done…. but that does not mean I put in 40 hours a week on it for 6 months, it’s a side project.  I do wish I knew more about them. Whoever they are, he trusted his life to them. For anyone who does not watch the whole thing, for the flying scenes he wore a harness with a cable running up one arm, hooked to the copter,  not just holding on by one hand.

One company that has made a “sit inside” passenger Multicopter prototype is Volocopter:

http://volocopter.com/index.php/en/

No CGI  and no photoshop stuff here,  their prototype really does exist and flies (youtube videos). I’m not suggesting that SpaceX would buy two of these and modify them, as for one they are probably not big enough to have enough thrust to handle a fairing half. But as an example of a yet larger configuration that actually does exist. It has 18 motors & props (thrust could be nearly doubled if it also had a lower set of motors/props  under the upper ones as the one Niestat used has, at a cost of about half the duration for the same battery. Still probably not quite enough thrust). So this generic multicopter scale-up of a scale-up could be….. scaled-up.  And we know SpaceX ain’t afraid of flying vehicles that have dozens of clustered motors…… :)

So, I do not expect they will do this. But it has potential. I do think that such a  one ton cargo carrying multicopter will exist someday.  Just a matter of how soon some company (or military branch) can justify doing it and make it happen.
« Last Edit: 03/25/2017 07:03 PM by georgegassaway »

Offline bstrong

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Re: Fairing reuse
« Reply #702 on: 03/25/2017 06:47 PM »
And don't forget that Elon's buddy Larry Page has not one, but two separate VTOL electric aircraft companies.

https://electrek.co/2016/10/25/first-picture-of-what-is-believed-to-be-larry-pages-electric-vtol-aircraft/

Offline Lar

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Re: Fairing reuse
« Reply #703 on: 03/26/2017 11:05 AM »
Referring to fate seems to indicate something experimental.

Relaunch of a first stage is experimental.
It's almost like you and iamlucky13 have no idea of who Musk is. When Musk is given an opportunity to double down, he does. No way he's just a referring to reflying a stage.

His ENTIRE CAREER has been one big giant parlay. So far he's been winning (and we all benefit).  That's off topic but I wanted to throw it out there. Because, ya, to Elon, this reuse is already routine, IMHO.

I don't think the "fate" comment applies to fairing reuse, unless we fanspies really blew it, as there isn't any gear on the "fairing" ship to speak of yet. I think it's the Xoomba, but we'll find out soon enough.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Online intrepidpursuit

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Re: Fairing reuse
« Reply #704 on: 03/26/2017 02:22 PM »
My original post implied that stage reuse was not experimental. They can't consider it very experimental since they have a paying customer's payload on top. No, Elon has something else planned, and I don't think the roomba is exciting enough to be it.

Online Robotbeat

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Re: Fairing reuse
« Reply #705 on: 03/26/2017 02:35 PM »
My original post implied that stage reuse was not experimental. They can't consider it very experimental since they have a paying customer's payload on top. No, Elon has something else planned, and I don't think the roomba is exciting enough to be it.
The Roomba is pretty dang exciting, because Musk probably wants to use it or things like it to do more crazy things. And they need to do similar crazy things on Mars.

Smart money is on the Roomba. Optimus Prime.
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Online LouScheffer

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Re: Fairing reuse
« Reply #706 on: 03/26/2017 02:56 PM »
Considering the technical problem only, and not cost, it seems like this is entirely feasible with existing technology.

(a) Fairing deploys a parachute.  There are many that can handle such loads (2 tonnes for a fairing half?)

(b) Two helicopters, taking off from a ship, catch the parachutes.  There are plenty of helicopters (not even the largest ones) that can handle this load (say Mi-8/Mi-17).  Range is not a problem since the ship is close to where the fairing comes down.

(c) The helicopters lower the fairings onto large airbags on the deck of a ship.  An internet search shows 15x15m airbags are stock items.  This should be gentle enough to not damage the fairing, and it never gets wet.

So now we have a working scheme, so the problem is to reduce the cost.  Perhaps they could put the airbags on the ASDS, and bring the fairings back with the booster.   Perhaps the helicopters can go out on the ASDS, take off before the booster lands, catch the fairings, then return to land unladen (the ferry range would indicate this might be possible.  Bahamas are about 400 km from landing zone.  Ferry range is close to 1000 km.   So the helicopter could use half its fuel making the catch, and still have enough to get to shore.).

Anyway, at an estimated cost of $3M per fairing, costs could be quite high and still worthwhile.

EDIT:  Added range to Bahamas, and ferry range.
« Last Edit: 03/26/2017 03:48 PM by LouScheffer »

Offline Lar

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Re: Fairing reuse
« Reply #707 on: 03/26/2017 09:41 PM »
Sorry for being diversionary but let's stick to fairing reuse here, not what the big surprise is. Mea culpa.
"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk
"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Offline Johnnyhinbos

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Re: Fairing reuse
« Reply #708 on: 03/26/2017 09:54 PM »
Humm - I'm going to be on a research vessel off Bimini, departing Miami April 3. I'll have to keep an eye out...
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Online Robotbeat

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Re: Fairing reuse
« Reply #709 on: 03/27/2017 12:21 AM »
A K-max helicopter should be capable of capturing the fairing half. It's $5m, plus operations. But they're relatively affordable to operate. If based from an ASDS, they wouldn't need to fly much.

But I think SpaceX could build their own, short-range electric drone capable of capturing a fairing half for about $1 million.
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Offline Jet Black

Re: Fairing reuse
« Reply #710 on: 03/27/2017 11:28 AM »
Referring to fate seems to indicate something experimental.

iirc this next launch is pretty far out on the edge of the envelope for a successful landing - where I include the rocket still being useable in successful.
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Offline CraigLieb

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Re: Fairing reuse
« Reply #711 on: 03/27/2017 03:10 PM »
We are beginning to see the designs of Elon, the evil genius...  (pinkie firmly planted in corner of mouth)

The fairing will deploy cold-gas thrusters and small pop-out grid fins to stabilize into a flyable aeroshell, navigating to a selected capture zone. At which point, the very large airship will open up it's large under slung cargo hold and the fairings will fly in and be caught in nets. The airship will then make its way to Elon's secret volcano lair ... which opens up it's hidden landing pad area, etc. Submarines or fast boats will return the shells to shore for additional processing.

 8)

 
Colonize Mars!

Offline oiorionsbelt

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Re: Fairing reuse
« Reply #712 on: 03/27/2017 07:39 PM »
A K-max helicopter should be capable of capturing the fairing half. It's $5m, plus operations. But they're relatively affordable to operate. If based from an ASDS, they wouldn't need to fly much.

But I think SpaceX could build their own, short-range electric drone capable of capturing a fairing half for about $1 million.
Or the fairing half is the drone.

Offline georgegassaway

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Re: Fairing reuse
« Reply #713 on: 03/27/2017 10:03 PM »
Or the fairing half is the drone.

I actually considered that idea.  But the added mass of the motors, props, various other hardware (including deployment mechanisms), and especially the batteries, would likely be so much that it would impact either the payload mass to orbit or reduce the orbit for the same payload mass. That presumes not short-changing the core's fuel to land itself, by burning a bit longer to make up for the performance hit of heavier shrouds.

Of course, adding a steerable chute also adds SOME mass too. Gut feeling is that it would be way less extra mass than a "Transformer" Shroud-Drone, but must admit I don't have a good mass estimate for what it would take.

Offline RobLynn

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Re: Fairing reuse
« Reply #714 on: 03/27/2017 10:48 PM »
A K-max helicopter should be capable of capturing the fairing half. It's $5m, plus operations. But they're relatively affordable to operate. If based from an ASDS, they wouldn't need to fly much.

But I think SpaceX could build their own, short-range electric drone capable of capturing a fairing half for about $1 million.
Or buy 6x robinson R22s or R44s for abut $2-3 million (less than a single k-max), implement autonomous control on them, and adapt the software these guys made to catch the falling fairing halves:
https://www.youtube.com/watch?v=oDyfGM35ekc?t=67

The helicopters can use long ropes to be 100's of meters away from the falling fairings, the nets can be pretty big so less precision is required, the net impacts can be very gentle, and apart from whatever modifications are needed to successfully re-enter almost no other add-ons or controls are needed on the fairings.
I'm a "glass is twice as big as it needs to be" kinda guy

Online Robotbeat

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Re: Fairing reuse
« Reply #715 on: 03/28/2017 03:56 AM »
More complicated, tho. I think they'd prefer to roll their own drone or use autonomous (or piloted, I suppose) K-Maxes.
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Offline Kaputnik

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Re: Fairing reuse
« Reply #716 on: 03/28/2017 06:56 AM »
Zero evidence for this, but splitting the fairing into four would simplify things a fair bit.
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Offline matthewkantar

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Re: Fairing reuse
« Reply #717 on: 03/28/2017 07:24 AM »
Zero evidence for this, but splitting the fairing into four would simplify things a fair bit.

The washering, flanging, and hardware for the joint adds a lot of weight.

Offline Kaputnik

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Re: Fairing reuse
« Reply #718 on: 03/28/2017 12:07 PM »
Zero evidence for this, but splitting the fairing into four would simplify things a fair bit.

The washering, flanging, and hardware for the joint adds a lot of weight.

Fair point. I can't t think of any LVs that use anything other than a two part clamshell.
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Online cscott

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Re: Fairing reuse
« Reply #719 on: 03/28/2017 12:11 PM »
Zero evidence for this, but splitting the fairing into four would simplify things a fair bit.
What's your reasoning?

It seems to me it would just multiply the complexity: four avionics packages, four parafoils, four joints, four ASDSes, four helicopters, four airbags, etc.

In fact, some folks spent a lot of time upthread trying to figure out how to reattach the fairing halves after separation to create *one* flyback item.  That also adds a lot of complexity.

Seems like two halves is the sweet spot.  But I'm interested to hear why you think four is better.

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