Author Topic: ASDS fly-back recovery  (Read 27809 times)

Offline Archibald

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Re: ASDS fly-back recovery
« Reply #40 on: 04/12/2016 05:39 pm »
Quote
Leasing a cargo ship that has an internal hold big enough for several F9s seems like a logical interim until the flight rate is multiple times per day. A shipboard crane could easily pick the S1 of the barge, drop it on blocks for delegging, and lower it into the hold where it would be protected from salt spray and even inspected and cleaned. A ship could travel 2-3 times faster than a barge while also carrying multiple F9s aboard, substantially increasing throughput over the towed-barge return scheme.

Or just buy Sea Launch command ship and converted oil rig.
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Online wannamoonbase

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Re: ASDS fly-back recovery
« Reply #41 on: 04/14/2016 01:25 pm »
What might SpaceX be doing to protect the booster from salt spray?  A tarpaulin around the engine area, or perhaps a spray coating that could be removed easily with no residue?  An exposure of several days might not be an immediate issue, but many such might have a cumulative effect.

I was thinking about that over the weekend.  I think after initial stabilization they can do the following to protect the engine section and some other cavities.

1) Install a flexible cover/bag over the engine area and seal it to the base of the vehicle.
2) Wheel up a portable diesel powered ECS air equipment (That also gets secured to the deck)
3) Connect flex duct to the cover as well as other flex ducts if needed.
4) Filtered air that pressurizes parts of the vehicle should be enough protection for a few days back to port.

All of this could be easily installed and obviously reusable.

A far more cost and hardware friendly option than flying a blunt ended vehicle back to port.  I think fly back recover, at least for the F9 is a non-starter, just based on subcooled propellants alone.

Future generation rockets with super reliable engines, perhaps.
Wildly optimistic prediction, Superheavy recovery on IFT-4 or IFT-5

Offline jeffkruse

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Re: ASDS fly-back recovery
« Reply #42 on: 04/14/2016 02:48 pm »
A far more cost and hardware friendly option than flying a blunt ended vehicle back to port.  I think fly back recover, at least for the F9 is a non-starter, just based on subcooled propellants alone.

Future generation rockets with super reliable engines, perhaps.

Why do they need to be subcooled for flyback?

Online envy887

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Re: ASDS fly-back recovery
« Reply #43 on: 04/14/2016 04:58 pm »
Has anyone put together a semi-comprehensive list of what needs to be done to a landed rocket for flyback?

Just to get it started:

1) Refill onboard TEA-TEB. Is there enough onboard TEA-TEB after landing for a pair of 3-engine starts and a 1-engine start, at minimum? Would refill be needed? Would a shipboard TEA-TEB connection be needed like at pad launch? Is there any way this could be stored onboard safely during landing?

2) Refuel LOX. Is there any feasible way this could be stored onboard safely during landing? Is the LOX tank accessible from deck?

3) Refuel RP-1. This could be stored onboard, in theory. How much LOX/RP-1 is needed for a 300-500 km hop?

4) Refill working fluids (He, grid fin hydraulic fluid, any others?). Can these all be safely stored aboard and loaded from the deck?

5) Install a nose cone. Has anyone calculated the performance hit from drag with an open interstage? What about potential for kabloomy if the stagnation pressure at Max-Q exceeds the interstage strength? This means the barge needs a crane and cherry picker, right? Can the nose cone be stored onboard during landing?

6) Put the stage up on a stand / Fold the legs. Can the legs survive aerodynamic loads on the way up and down? If not (and I can't imagine they would), then the stage has to be lifted. That means a bigger crane than nosecone installation... how big?

7) Setup GSE for relaunch. What's the minimum required support equipment for the actual launch? A portable stand with releasable hold-down ability seems required, if for nothing else than just to keep it upright. How about telemetry? TEA-TEB supply? Would it make sense to put a strongback on the barge? Is a engine health check before release necessary, or can it make the hop on 2 or even 1 engine?

Feels like this is barely scratching the surface of the challenges when relaunching.

Offline buraianto

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Re: ASDS fly-back recovery
« Reply #44 on: 04/14/2016 07:03 pm »
I don't think this is a problem.  There are no hold-downs for the second stage.  There are no hold-downs for the boostback burn.  There are no holddowns for the re-entry burn.  There are no holddowns for the landing burn.  So a lack of holddowns for the burn to launch from the ASDS is not going to make the whole system much more likely to lose a stage.  And no customer payload is at risk.

Without hold downs could you have a problem when launching with multiple engines if the engines don't start or throttle at the same rate before liftoff? Could you end up tipping the rocket over partially or fully?

How matched are the startups on F9 engines today?

Online meekGee

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Re: ASDS fly-back recovery
« Reply #45 on: 04/15/2016 03:12 am »
I posted this a long time ago...

You can have a complete launch pedestal hanging outboard, to allow for a full launch sequence with a hold-down.

You'd have a mobile platform that picks up the rocket (empty) where it landed, folds the legs, and shuffle over to an outboard structure like this, where it (the mobile platform) would clamp down.

This is where you can refuel, install a nose cap, and launch.

(During the landing, the mobile platform will be on the outboard shelf, so it's out of the way)
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Offline natebrau

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Re: ASDS fly-back recovery
« Reply #46 on: 04/15/2016 04:59 am »
Question- why does the F9 have to fly back on its own power?

After landing, why can't it be picked up with a Zeppelin, and gently flown back?

Advantages, minimal stress on the rocket, no stress on the engines.  Much faster than barge recovery, allows for faster barge reuse (land, cart off with Zeppelin, next one lands, and so on).  And also faster back to land.

Lock-Mart has a craft which can do it:
http://lockheedmartin.com/us/products/HybridAirship.html

It would be cheaper than a fleet of barges as well as cheaper than flying back (frankly).  Zeppelins are really efficient at moving big cargo, would burn less fuel as well as reduced wear on the rocket.

Offline chalz

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Re: ASDS fly-back recovery
« Reply #47 on: 04/15/2016 05:54 am »
Question- why does the F9 have to fly back on its own power?

After landing, why can't it be picked up with a Zeppelin, and gently flown back?

Advantages, minimal stress on the rocket, no stress on the engines.  Much faster than barge recovery, allows for faster barge reuse (land, cart off with Zeppelin, next one lands, and so on).  And also faster back to land.

Lock-Mart has a craft which can do it:
http://lockheedmartin.com/us/products/HybridAirship.html

It would be cheaper than a fleet of barges as well as cheaper than flying back (frankly).  Zeppelins are really efficient at moving big cargo, would burn less fuel as well as reduced wear on the rocket.

So thunderbird 2 should carry thunderbird 1 back to base? I like it.

Seriously I don't think this could happen until you can rent such a craft for a reasonable cost, which could be soon but isn't now. It is more complex (and expensive) than sailing back but much less complex than fly-back. Sadly the need for it is as unproven as the need for fly-back.

Online meekGee

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Re: ASDS fly-back recovery
« Reply #48 on: 04/15/2016 06:20 am »
Question- why does the F9 have to fly back on its own power?

After landing, why can't it be picked up with a Zeppelin, and gently flown back?

Advantages, minimal stress on the rocket, no stress on the engines.  Much faster than barge recovery, allows for faster barge reuse (land, cart off with Zeppelin, next one lands, and so on).  And also faster back to land.

Lock-Mart has a craft which can do it:
http://lockheedmartin.com/us/products/HybridAirship.html

It would be cheaper than a fleet of barges as well as cheaper than flying back (frankly).  Zeppelins are really efficient at moving big cargo, would burn less fuel as well as reduced wear on the rocket.

From that page:

Quote
Almost eight years ago, the team built and flew the technology demonstrator known as the P-791, which successfully demonstrated all the technologies needed to make this real.  Since then, the team has completed all required FAA certification planning steps for a new class of aircraft and they are ready to begin construction of the first commercial model and the completion of the FAA Type certification process."

So it doesn't exist yet.

The specs say that when it will (exist), it will carry 21 tons, internally, and have a range of only 1400 nm in that configuration.  It also needs a runway, so it can't dead-lift it.

So it can't do the job, not even close.

Plus, everything looks nice and gentle in the demo, but when it's fighting wind to stay steady (and it has, by definition almost, a very low mass/area ratio), I don't know how gentle that lift will be.

Their literature doesn't show any kind of long line or winch lift.  I don't know that it can even station keep like a helicopter.  It can "hover" while empty, but I suspect that any gust of wind will move it a long way before the little motors can bring it back.
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Offline JamesH65

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Re: ASDS fly-back recovery
« Reply #49 on: 04/15/2016 08:51 am »
Question- why does the F9 have to fly back on its own power?

After landing, why can't it be picked up with a Zeppelin, and gently flown back?

Advantages, minimal stress on the rocket, no stress on the engines.  Much faster than barge recovery, allows for faster barge reuse (land, cart off with Zeppelin, next one lands, and so on).  And also faster back to land.

Lock-Mart has a craft which can do it:
http://lockheedmartin.com/us/products/HybridAirship.html

It would be cheaper than a fleet of barges as well as cheaper than flying back (frankly).  Zeppelins are really efficient at moving big cargo, would burn less fuel as well as reduced wear on the rocket.

From that page:

Quote
Almost eight years ago, the team built and flew the technology demonstrator known as the P-791, which successfully demonstrated all the technologies needed to make this real.  Since then, the team has completed all required FAA certification planning steps for a new class of aircraft and they are ready to begin construction of the first commercial model and the completion of the FAA Type certification process."

So it doesn't exist yet.

The specs say that when it will (exist), it will carry 21 tons, internally, and have a range of only 1400 nm in that configuration.  It also needs a runway, so it can't dead-lift it.

So it can't do the job, not even close.

Plus, everything looks nice and gentle in the demo, but when it's fighting wind to stay steady (and it has, by definition almost, a very low mass/area ratio), I don't know how gentle that lift will be.

Their literature doesn't show any kind of long line or winch lift.  I don't know that it can even station keep like a helicopter.  It can "hover" while empty, but I suspect that any gust of wind will move it a long way before the little motors can bring it back.

They do exist, now taken over by a firm in the UK. http://www.itv.com/news/anglia/story/2016-04-12/worlds-biggest-aircraft/

Offline timverhoeven

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Re: ASDS fly-back recovery
« Reply #50 on: 04/15/2016 09:00 am »
With viewing the recent overview movies on how SpaceX got to the successful drone ship landing, it struck me that both Grashopper and the F9RDev movies the stages lifted off completely self-standing. There was no support structures, umbilicals etc.
So it should be possible that a partly refueled stage on the drone ship can take of as is.

Two problems still remaining that I immediately think of is first, you need to have the needed fuels and supplies out in the ocean (LOX, RP-1, He, TEA/TEAB, ...). Those could be potentially stored on a seperate fuel ship.
Secondly, the extended legs will probably need to be retraced after takeoff for the hop from the drone ship to LZ-1. I'm guessing this would require some re-engineering of the leg mechanisms.

Online meekGee

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Re: ASDS fly-back recovery
« Reply #51 on: 04/15/2016 09:38 am »



So it doesn't exist yet.

The specs say that when it will (exist), it will carry 21 tons, internally, and have a range of only 1400 nm in that configuration.  It also needs a runway, so it can't dead-lift it.

So it can't do the job, not even close.

Plus, everything looks nice and gentle in the demo, but when it's fighting wind to stay steady (and it has, by definition almost, a very low mass/area ratio), I don't know how gentle that lift will be.

Their literature doesn't show any kind of long line or winch lift.  I don't know that it can even station keep like a helicopter.  It can "hover" while empty, but I suspect that any gust of wind will move it a long way before the little motors can bring it back.

They do exist, now taken over by a firm in the UK. http://www.itv.com/news/anglia/story/2016-04-12/worlds-biggest-aircraft/

They took over the tech demonstrator, and their spec sheet for the al10 has the same caveats:  20 tons, internally, while deriving 40% of its lift from forward motion.   When it's built, and they are crowd funding it.

They have an even gianter plan, but it too is not designed to hover and lift.

... And it's all off topic
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Offline RanulfC

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Re: ASDS fly-back recovery
« Reply #52 on: 04/15/2016 02:21 pm »
What might SpaceX be doing to protect the booster from salt spray?  A tarpaulin around the engine area, or perhaps a spray coating that could be removed easily with no residue?  An exposure of several days might not be an immediate issue, but many such might have a cumulative effect.

I was thinking about that over the weekend.  I think after initial stabilization they can do the following to protect the engine section and some other cavities.

1) Install a flexible cover/bag over the engine area and seal it to the base of the vehicle.
2) Wheel up a portable diesel powered ECS air equipment (That also gets secured to the deck)
3) Connect flex duct to the cover as well as other flex ducts if needed.
4) Filtered air that pressurizes parts of the vehicle should be enough protection for a few days back to port.

All of this could be easily installed and obviously reusable.

A far more cost and hardware friendly option than flying a blunt ended vehicle back to port.  I think fly back recover, at least for the F9 is a non-starter, just based on subcooled propellants alone.

Future generation rockets with super reliable engines, perhaps.

Just curious by why does everyone seem to be super-concerned with the engines being exposed to salt-air/spray? As I recall the Merlin is supposed to be robust enough they expected at one point to pluck them out of the ocean and re-use them. (Not sure if they ever actually tested that, but NASA did with the H1 back in the early 60's and found long-term exposure and minimum preservation didn't adversely effect the refurbishment cost or effort)

Seriously, throw a tarp over the engine when it cools down and get back to port, it's really about that simple. If you're REALLY concerned, spray the engine down with clear water and alcohol before you tarp it but really it's not needed so why bother?

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline RanulfC

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Re: ASDS fly-back recovery
« Reply #53 on: 04/15/2016 02:26 pm »
And why even consider fly-back? It's operationally and cost in-effective really. Hmmm, though if you really want to get it back to port ASAP install some hydrofoils on the barge, load some RP1/LOX tanks on the forward part of the barge, strap the F9 down with the engines pointed aft and light em up. :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Doesitfloat

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Re: ASDS fly-back recovery
« Reply #54 on: 04/15/2016 02:40 pm »
What might SpaceX be doing to protect the booster from salt spray?  A tarpaulin around the engine area, or perhaps a spray coating that could be removed easily with no residue?  An exposure of several days might not be an immediate issue, but many such might have a cumulative effect.

I was thinking about that over the weekend.  I think after initial stabilization they can do the following to protect the engine section and some other cavities.

1) Install a flexible cover/bag over the engine area and seal it to the base of the vehicle.
2) Wheel up a portable diesel powered ECS air equipment (That also gets secured to the deck)
3) Connect flex duct to the cover as well as other flex ducts if needed.
4) Filtered air that pressurizes parts of the vehicle should be enough protection for a few days back to port.

All of this could be easily installed and obviously reusable.

A far more cost and hardware friendly option than flying a blunt ended vehicle back to port.  I think fly back recover, at least for the F9 is a non-starter, just based on subcooled propellants alone.

Future generation rockets with super reliable engines, perhaps.

Just curious by why does everyone seem to be super-concerned with the engines being exposed to salt-air/spray? As I recall the Merlin is supposed to be robust enough they expected at one point to pluck them out of the ocean and re-use them. (Not sure if they ever actually tested that, but NASA did with the H1 back in the early 60's and found long-term exposure and minimum preservation didn't adversely effect the refurbishment cost or effort)

Seriously, throw a tarp over the engine when it cools down and get back to port, it's really about that simple. If you're REALLY concerned, spray the engine down with clear water and alcohol before you tarp it but really it's not needed so why bother?

Randy

Randy,
I'm concerned that your lack of concern is concerning.  :)


Offline Lars-J

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Re: ASDS fly-back recovery
« Reply #55 on: 04/15/2016 05:45 pm »
With viewing the recent overview movies on how SpaceX got to the successful drone ship landing, it struck me that both Grashopper and the F9RDev movies the stages lifted off completely self-standing. There was no support structures, umbilicals etc.
So it should be possible that a partly refueled stage on the drone ship can take of as is.

No. Grasshopper could do it - with a small propellant load - because it had a VERY beefy leg structure. But look at all the F9R-Dev1 flights (with the current leg designs) - they all took off from a support structure, even on the shortest hops. It can't be repeated enough it seems: The legs just cannot support the rocket with a propellant load for even a short hop.

Look at this video, starting at 1:18, to see how F9R-Dev1 flights were done. Note how it takes off from a support structure that is very similar to what the stage is sitting on top of right now in Port Canaveral. It is not launching from its own legs in the video.

« Last Edit: 04/15/2016 08:20 pm by Lars-J »

Offline timverhoeven

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Re: ASDS fly-back recovery
« Reply #56 on: 04/15/2016 06:49 pm »
No. Grasshopper could do it - with a small propellant load - because it had a VERY beefy leg structure. But look at all the F9R-Dev1 flights (with the current leg designs) - they all took off from a support structure, even on the shortest hops. It can't be repeated enough it seems: The legs just cannot support the rocket with a propellant load for even a short hop.

Look at this video, starting at 1:18, to see how F9R-Dev1 flights were done. Note how it takes off from a support structure that is very similar to what the stage is sitting on top of right now in Port Canaveral. It is not not launching from its own legs in the video.

I stand corrected, but it wasn't that clear in that video. I was only visible for a very short moments. Thanks for the clarification  ;)

Offline RanulfC

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Re: ASDS fly-back recovery
« Reply #57 on: 04/15/2016 09:33 pm »
What might SpaceX be doing to protect the booster from salt spray?  A tarpaulin around the engine area, or perhaps a spray coating that could be removed easily with no residue?  An exposure of several days might not be an immediate issue, but many such might have a cumulative effect.

I was thinking about that over the weekend.  I think after initial stabilization they can do the following to protect the engine section and some other cavities.

1) Install a flexible cover/bag over the engine area and seal it to the base of the vehicle.
2) Wheel up a portable diesel powered ECS air equipment (That also gets secured to the deck)
3) Connect flex duct to the cover as well as other flex ducts if needed.
4) Filtered air that pressurizes parts of the vehicle should be enough protection for a few days back to port.

All of this could be easily installed and obviously reusable.

A far more cost and hardware friendly option than flying a blunt ended vehicle back to port.  I think fly back recover, at least for the F9 is a non-starter, just based on subcooled propellants alone.

Future generation rockets with super reliable engines, perhaps.

Just curious by why does everyone seem to be super-concerned with the engines being exposed to salt-air/spray? As I recall the Merlin is supposed to be robust enough they expected at one point to pluck them out of the ocean and re-use them. (Not sure if they ever actually tested that, but NASA did with the H1 back in the early 60's and found long-term exposure and minimum preservation didn't adversely effect the refurbishment cost or effort)

Seriously, throw a tarp over the engine when it cools down and get back to port, it's really about that simple. If you're REALLY concerned, spray the engine down with clear water and alcohol before you tarp it but really it's not needed so why bother?

Randy

Randy,
I'm concerned that your lack of concern is concerning.  :)

Obviously I have SOME concern or I would have pointed out the extreme water-skiing opportunities involved :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Online envy887

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Re: ASDS fly-back recovery
« Reply #58 on: 04/17/2016 02:38 am »
Instead of an airship, how about flying it back under a Mi-26 helicopter? They can lift 25,000 kg and have about 2000 km of range.

Offline Dante2121

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Re: ASDS fly-back recovery
« Reply #59 on: 04/17/2016 03:12 am »
There's no need to fly the rocket back to speed up launch cadence.

More likely there will be a fleet of seven or so F9s - one launches each day.  This gives you a week to bring it back and get it ready before it is needed again.

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