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.
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.
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.
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.
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.htmlIt 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.
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."
Quote from: natebrau on 04/15/2016 04:59 amQuestion- 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.htmlIt 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.
Quote from: meekGee on 04/15/2016 06:20 amSo 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/
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.
Quote from: pmonta on 04/10/2016 04:45 pmWhat 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.
Quote from: wannamoonbase on 04/14/2016 01:25 pmQuote from: pmonta on 04/10/2016 04:45 pmWhat 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
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 not launching from its own legs in the video.
Quote from: RanulfC on 04/15/2016 02:21 pmQuote from: wannamoonbase on 04/14/2016 01:25 pmQuote from: pmonta on 04/10/2016 04:45 pmWhat 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?RandyRandy,I'm concerned that your lack of concern is concerning.