[hodgesrm]

I kind of figured that happened when they lost the video. Still a really amazing accomplishment--the video of the boosters landing was like something out of a sci-fi movie. It's the best space launch since the first Space Shuttle in 1981.

[imjasonmiller]

In a press conference an hour or so ago, I think Elon mentioned that, if he had to pick one core that would experience “rapid unscheduled dissassembly”, it would have been the center one. I think he mentioned it was due to the boosters having the expensive titanium grid fins and also being reusable for future flights.

Regardless, it was absolutely wonderful to watch! I think the Youtube stream had 2,500,000 viewers at one point. I can’t wait for more footage of the launch the coming days.

[jacquesm]

Back when we did Shuttle launches on ww.com 10K or so was the maximum number of viewers we ever saw. It's absolutely incredible how far video delivery over the web has come since STS-87.

Keep in mind that we got kicked off the backbone because we were using too much bandwidth and 'the internet wasn't made for video' (which is why we moved to Canada to begin with).

[jlmorton]

The unspoken point in Musk's comment is that SpaceX doesn't actually care if they get these particular rockets back. They want to prove reusability, of course, but no matter the outcome they never plan to re-fly these cores. They will focus on the not-yet-flown Block 5 cores, and standardize on that going forward.

In this flight, the side boosters and center core were Blocks 3 and 4. So SpaceX definitely wants to recover the boosters, to perfect reusability, but they never intend to re-fly any of these boosters, so better to get back the one with the expensive and reusable titanium grid fins.

[kens]

> Block 5 cores

Why are rocket versions specified with the word "Block"? The Saturn launchers did the same thing, but it seems like a strange word to use.

[joezydeco]

It's a term carried over from the military/aerospace field.

https://www.f35.com/about/life-cycle/software

[perl4ever]

I boggle a little at what I read there, such as "With Block 3i, 89 percent of code required for full warfighting capability is flying". That's 89%? Not 88% or 90%?

[joezydeco]

You can be sure the specs for something like the F35 run into the hundreds of thousands of pages. Tagging exactly 89% of the features as making that milestone is probably the easiest part of the work.

[Eridrus]

Didn't they say these boosters had already flown before?

I'm also a bit surprised the grid find are so pricey, they seem pretty small? Not that I really know how much titanium costs to buy and machine.

[quasse]

They measure 4 by 5 feet, so we can estimate they are probably made from a solid chunk of titanium that was at least 20 cubic feet or almost 5,000 pounds. That would be nearly $150,000 in raw material and probably another 5x that in processing (guesstimating cost per cubic inch of titanium removal).

Either that or they were specially made castings, which are similarly expensive in low volume, if not more.

[larkeith]

Wouldn't you be able to recover most of the removed titanium, amortizing the majority of that guesstimated materials cost? Processing likely remains expensive, however.

[solarkraft]

I'd think so. They also 3D print a lot, but metal powder does seem expensive.

[stmfreak]

You are also dealing with low volume fabrication which means setup and tooling costs don't amortize across many components. I wouldn't be surprised if they cost $1M each.

[cryptoz]

The side boosters were flown before, and returned to Earth today for the second time. But they won't fly again.

[4minute]

They aren't reusing any more of the Falcons 9s we have seen. They are switching over to Block 5 of the rocket. They wanted to keep the fins, because I think those were Block 5 fins on them.

[Klathmon]

The video feed drops like that on every droneship landing.

[hodgesrm]

Do you know why that happens? This is the first time I've seen it live.

[wrigby]

The satellite antennas used to uplink a video feed like this have a very small beamwidth (around 1° depending on antenna size and the frequency they're using), so you need to keep them pointed precisely at a specific point in the sky. They rely on a sensitive IMU (accelerometers) and fast motors to actively track the satellite while the platform moves. They're quite impressive to watch in action[1], but I'm guessing they're no match for the shock and vibe of the rocket landing.

1: https://www.youtube.com/watch?v=k79vfwUkeYk

[Klathmon]

They use a satellite link on the barge, and the vibrations and pressure from the landing booster almost always cause the link to drop until things calm down.

They have said in the past that it's "solveable", but it's not exactly a high priority by any means as they can always retrieve the footage when they get to the barge.

[craftyguy]

According to the SpaceX media commentary folks that were talking as it was happening, it's because "intense vibrations are interfering with the antenna".

[mannykannot]

Meanwhile, in the background, a monitor appears to be showing smoke clearing from the deck of the barge, with no booster present.

https://twitter.com/Darkphibre/status/960990105581240321

[craftyguy]

Right, because the rocket ultimately didn't land on the ship. This does not invalidate anything they said about interference.

[eps]

It clearly does.

They both say Oh exactly at the moment when the smoke clears, meaning that they themselves are looking at the live feed while pretending it was lost.

Also the chances that Spacex doesn't have any other presence next to the droneship are zero. There in no reason for them to be beaming the data feed via a finicky satellite connection only.