Where will F9 flights 14 & 15 attempt "solid surface" landings?

[FutureSpaceTourist]

Elon saying maybe 50% chance of successful barge landing at first attempt sounds very positive to me.

He must be pretty confident in their landing accuracy and they've only had one successful test flight with grid fins. Really makes me curious about how accurate the two previous soft water landings were!

[Robotbeat]

BTW, that barge is huge... 300 feet long. If pointed into the waves, that means a wave height of ten feet will mean only 30 miliradians of an angle, less than 2 degrees of tilt! So it may be plenty steady enough even in moderately rough seas, as long as the natural frequency isn't too close to the wave frequency.

[Helodriver]

Its highly probable the barge will actually be two barges lashed tightly together to form a single rigid structure with a flush deck.

[Robotbeat]

Its highly probable the barge will actually be two barges lashed tightly together to form a single rigid structure with a flush deck.

That sounds mechanically unlikely to me (unless by "lashed" you mean bolted, riveted, or welded), but I trust you have it on a good source?

[Darga]

Sources tell me its being built at Conrad Shipyards, of Morgan City Louisiana.

Oh, if we google for Conrad Shipyards what could be found there?
Do you remember? 

It's "only" 200'x100'.
http://www.marinelink.com/maritime/CONRAD-SHIPYARDS

That guy is 300'x100' http://www.graybarge.com/sites/graybarge.com/files/julius_spec_shts_12mar14_0.pdf Conrad has the ability to create up to 350' length but I cannot find any info on width. Wonder if they will tie two together and put a deck on it or actually build the one big sucker.

[Kabloona]

Its highly probable the barge will actually be two barges lashed tightly together to form a single rigid structure with a flush deck.

That sounds mechanically unlikely to me, but I trust you have it on a good source?

I would tend to believe it. If you look at the Conrad website link above, they say they build all their vessels indoors, up to 350' length. But the big buildings don't look wide enough to handle a 170' wide barge. So maybe they build two 80' or so indoors, then take them outside and weld them together.

Yes, mechanically difficult because of the huge bending stresses in the middle, but with enough steel it should be possible.

[Robotbeat]

Its highly probable the barge will actually be two barges lashed tightly together to form a single rigid structure with a flush deck.

That sounds mechanically unlikely to me, but I trust you have it on a good source?

I would tend to believe it. If you look at the Conrad website link above, they say they build all their vessels indoors, up to 350' length. But the big buildings don't look wide enough to handle a 170' wide barge. So maybe they build two indoors, then take them outside and weld the, together.

Yes, mechanically difficult because of the huge bending stresses in the middle, but with enough steel it should be possible.

Welded, riveted, bolted I buy. I just questioned the word "lashed" since I'm imagining big ropes...

[Kabloona]

Yes, "lashed" made me think of Kon Tiki. But maybe they use really big steel cables instead.

[Lar]

Welded, riveted, bolted I buy. I just questioned the word "lashed" since I'm imagining big ropes...

The platform might have a seam and not need to be completely rigid. In that case big wire ropes are actually not such a bad engineering solution for keeping two vessels in close proximity, they allow some flex. Because of the overall size not a lot of flex is needed but I would expect welds to be torn to pieces in heavy seas more easily.

[Zed_Noir]

Welded, riveted, bolted I buy. I just questioned the word "lashed" since I'm imagining big ropes...

The platform might have a seam and not need to be completely rigid. In that case big wire ropes are actually not such a bad engineering solution for keeping two vessels in close proximity, they allow some flex. Because of the overall size not a lot of flex is needed but I would expect welds to be torn to pieces in heavy seas more easily.

It is a Catamaran barge.

[sghill]

Interesting they are apparently building one rather than renting. This implies that either they needed a custom design that doesn't exist on the market or that they plan on using it many times in the future, or both.

I'd opine that both your speculations are correct, and that even if they could find one to rent that fits the bill, the owners likely aren't enthusiastic about the possibility of a 14 story building dropping out of the sky and exploding on their boat. The security deposit probably doesn't cover that level of damage.

[Kabloona]

It is a Catamaran barge.

Ah, that explains it. Makes sense because a catamaran barge will have less wetted hull surface area and thus be easier to tow/propel. And it won't be carrying but minimal weight relative to its size, so large hull volume is not needed.

[Jet Black]

in the final landing fire of the engines, how much force is likely to be imparted on the barge?

[Robotbeat]

in the final landing fire of the engines, how much force is likely to be imparted on the barge?

Same as that exerted on the rocket. So to first order no more than about 65 tons, the thrust of one Merlin 1D.

[Jet Black]

where's the d'oh smiley?

thanks!

[Space Ghost 1962]

So we're back to the barge distraction, from the patent distraction, and somewhere back was the range safety distraction. You'll note we get no additional advisement on all of these. The most is learning of a barge being constructed, and its size.

So yes range won't countenance it until more precision landings. Perhaps they won't say. Which means an alternative.

That they have a barge under construction means little, because such a barge could prove useful for stage/BFR transport as well.

At this point, the key issue is to advance a landing that just doesn't topple over for a few minutes. Not necessarily stage recovery/reuse. Just something firm to land on. Hard for that to be precluded by patent license on the face of it.

[Kabloona]

That they have a barge under construction means little

You lost me there...Elon said categorically they will attempt several landings on the barge  in order to demonstrate repeatable precision landing to the Range.

That they have a barge under construction means it may be ready in time for CRS-5, and if not, it will be for future landing attempts.

Just to reiterate, here are some snippets from Elon's comments at MIT yesterday:

Before RTLS, need to show they can land with precision over and over again (on floating platform).
For upcoming launch (CRS-5), will attempt landing on the new barge.
Barge will not be anchored, but will have engines that keep it located at GPS coordinates.
50% chance of success landing CRS-5 booster on barge.
If successful, Elon says he thinks they will be able to refly booster.
If not successful, will continue attempts with upcoming launches.
80-90% chance that one of the upcoming launches will succeed in landing booster on the barge.

[mr. mark]

From the MIT discussion, Elon said that SpaceX most likely will have the barge ready for the CRS 5 launch. Take from that what you will.

[Space Ghost 1962]

That they have a barge under construction means little

You lost me there...Elon said categorically they will attempt several landings on the barge  in order to demonstrate repeatable precision landing to the Range.

Forgive me.

Means little to "infringement" on a patent.

Been trained to say fewest words.

add:
"We have a barge. Useful for many things. Like landing practice. No different than Grasshopper landing practice."

[Kabloona]

Ah, thank you for the clarification.

Yes, the barge means little to the patent issue until they actually land on it.