SpaceX Falcon 9 : Hispasat 30W-6 (1F) : March 6, 2018 - DISCUSSION

[Formica]

The legs are probably worthless if Block 5 uses a new design. But I am really perplexed about the fins.

I am as well. I interpreted their presence - as did many others - as a sign of how confident SpaceX was in the recovery attempt. As recently as FH the fins were among the most valuable recoverable components of the rocket. They supposedly take a very long time to make, and it has been hypothesized they have three sets of them at most.

Are they cranking titanium fins out now? Based on the press kit timeline, they don't appear to be doing a burn-to-depletion for maximum supersync. Are they counting on a soft water landing and pulling the fins off at sea? Is this all to meet a contractual deadline? This launch just keeps getting more and more unusual.

[whitelancer64]

What is worth more to them, an ASDS or a Block V booster?

The ASDS is obviously easier to reuse, but....

You mean block IV, don't you? I don't think that is an either/or option. Most likely in that rough sea condition they would loose both.

What I don't understand is why not remove grid fins and legs? Significant cost savings even though performance increase is not required and it would have the benefit of increased performance margin.

The legs are probably worthless if Block 5 uses a new design. But I am really perplexed about the fins.

If they had time to take them off, I'd bet they would.

[lrk]

Maybe they consider the entry data more valuable that this particular set of fins?  It could be that the entry is expected to be hot enough to melt the aluminum fins, and they really want more hot landing experience using a less-valuable core. 
Alternatively, they could just be out of aluminum fins, and planning all future launches to use titanium ones, although I rather doubt that this is the case. 

[Norm38]

Abandoning the landing attempt because of rough seas is tolerable for now. But the economics of Block 5 won’t allow for a stage to be abandoned early in its life. They’ll have to delay missions. Especially if they plan to shutdown the F9 production line. Almost seems best to get customers used to the idea now.

[CyndyC]

For some perspective on the sea state off Cape Canaveral yesterday, and why the fleet couldn't be out there or en route, meteorologists in Jacksonville were previewing our weather by watching the buoys 130 miles off the Cape, and the wave height was 22'. There would not only have been a high risk for the landing & to OCISLY, but to human life.

[envy887]

Abandoning the landing attempt because of rough seas is tolerable for now. But the economics of Block 5 won’t allow for a stage to be abandoned early in its life. They’ll have to delay missions. Especially if they plan to shutdown the F9 production line. Almost seems best to get customers used to the idea now.

If that's the case they probably aren't charging enough for flights on Block 5.

[Nomadd]

What is worth more to them, an ASDS or a Block V booster?

The ASDS is obviously easier to reuse, but....

A booster costs a whole lot more to build, but since lack of an ASDS could cost them several boosters, the barge is worth is a lot more than the money you spend building it.

[gongora]

Elon called this "Falcon 9 Flight 50" in a tweet, but of course this is the 51st Falcon 9 stacked for launch. 

 - Ed Kyle

And the 50th that will fly (if nothing goes wrong).

[rickl]

So if the stage comes down in the ocean and sinks, would it make economic sense to take a submersible down there to recover the titanium grid fins?  Is that even possible?

I've never rented a submersible so I don't know how much it costs.

[IanThePineapple]

So if the stage comes down in the ocean and sinks, would it make economic sense to take a submersible down there to recover the titanium grid fins?  Is that even possible?

I've never rented a submersible so I don't know how much it costs.

The ocean at the landing point is likely a mile or more deep, so it would be near pointless to do that.

Also, the fins could get damaged from the stage popping as it hits the water.

[MATTBLAK]

So if the stage comes down in the ocean and sinks, would it make economic sense to take a submersible down there to recover the titanium grid fins?  Is that even possible?

I've never rented a submersible so I don't know how much it costs.

Can they be removed on the launchpad; before propellant loading?

[Robotbeat]

Elon called this "Falcon 9 Flight 50" in a tweet, but of course this is the 51st Falcon 9 stacked for launch. 

 - Ed Kyle

So Musk was correct, in other words.

If you want to count number of Falcon 9s stacked on the pad, this would be the 52nd.

[gongora]

Elon called this "Falcon 9 Flight 50" in a tweet, but of course this is the 51st Falcon 9 stacked for launch. 

 - Ed Kyle

So Musk was correct, in other words.

If you want to count number of Falcon 9s stacked on the pad, this would be the 52nd.

"Flight 50" seems misleading to me.  I would prefer "flight 50" without the capital "F".  This would be F9-51 using the original method we used to track these things. 

 - Ed Kyle

"Flight 50" might not tell the whole story but it's not technically wrong.  On my SpaceX Manifest I have it as the 51st F9 mission (numbered 52 because I included FH in the numbers, need to decide sometime if that's the right way to do it.)  You don't seem to have counted the AMOS-6 incident in your calculations for the F9 v1.2 reliability stats since it was technically in testing instead of flight, choosing instead to put the failure in a footnote.  Calling it the 50th is a little strange to me also but it will be the 50th to take off (hopefully).

[Nomadd]

 God forbid an F9 blows up at ignition, or this argument will never die. Maybe we could establish a section just to debate semantics. The "sort of a planet Pluto" endless back and forth could go there.

[jjyach]

So if the stage comes down in the ocean and sinks, would it make economic sense to take a submersible down there to recover the titanium grid fins?  Is that even possible?

I've never rented a submersible so I don't know how much it costs.

Can they be removed on the launchpad; before propellant loading?

In this case at least there was not enough time to allow it.

[JoerTex]

Is any of this worth the effort to type it?  Fifty Smhifty.

[sewebster]

Stage 1 not re-orienting immediately after stage sep?

[speedevil]

Stage 1 not re-orienting immediately after stage sep?

It's only if they're doing boostback burns that there is any urgency in doing the reorienting quickly.
For very maximum launch energies, they would not do that, but only an entry burn, with the drone-ship stationed quite a ways off shore, then a landing burn.

[CyndyC]

This is the first launch I've thought of looking for from my house near downtown Jacksonville Florida, and I saw it easily, about 10-15 seconds before MECO.

[LouScheffer]

Staging at 8232 km/hr = 2286 m/s.  Normal for block 4.

Roughly 22 second entry burn.  Also pretty close to previous, so not much change due to new fins.