Falcon Heavy core booster lost at sea • Hacker News Board

Re: Falcon Heavy core booster lost at sea

#61

Post by solarkraft » Wed, Feb 07, 2018, 12:54 PM UTC

larkeith wrote: post #43

quasse wrote: post #36

Earlier quoted context omitted.

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.

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.

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

Re: Falcon Heavy core booster lost at sea

#62

Post by joezydeco » Wed, Feb 07, 2018, 1:27 PM UTC

perl4ever wrote: post #59

joezydeco wrote: post #38

Earlier quoted context omitted.

It's a term carried over from the military/aerospace field. https://www.f35.com/about/life-cycle/software

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%?

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.

Re: Falcon Heavy core booster lost at sea

#63

Post by mabbo » Wed, Feb 07, 2018, 2:45 PM UTC

sehugg wrote: post #41

mabbo wrote: post #31

SpaceX hasn't failed a landing of a booster in two years (correct me if I'm wrong). I hope a lot of data was collected as to why and how it failed. SpaceX's biggest advantage is that they iterate quickly. Hopefully next iteration fixes whatever problem they had today. Those boosters aren't cheap.

Musk attributed it to low levels of triethylborane—a hot-burning propellant that essentially acts as rocket engines' starter fluid—in the center booster. The center core is a special structurally enhanced model, so I'll give them a pass since they're flying a new bird. I'm sure they'll get it right.

That makes a lot of sense. The center core had to ignite for liftoff, then either scale back or stop entirely during the main lift phase, then re-ignite when the side boosters detached, then reignite for the boostback, entry AND landing burns. That's a lot of re-ignition!

I hope they post a very high quality video of that booster having its unplanned disassembly. May not be great for PR, etc, but it sure would be entertaining.

Re: Falcon Heavy core booster lost at sea

#64

Post by effie » Wed, Feb 07, 2018, 4:29 PM UTC

mariuolo wrote: post #57

eps wrote: post #55

Earlier quoted context omitted.

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 .

> Also the chances that Spacex doesn't have any other presence next to the droneship are zero. Would you keep manned boats in the area where a rocket is coming down?

Not a manned boat, but it seems obvious that they would want to have another unmanned boat with instruments recording the landing event. This could be much smaller and thousands of meters away from the landing site so there would be very little risk of it getting inoperable by the landing rocket.

Re: Falcon Heavy core booster lost at sea

#65

Post by bpizzi » Wed, Feb 07, 2018, 5:07 PM UTC

Flemlord wrote: post #46

deadA1ias wrote: post #30

Earlier quoted context omitted.

For anyone who has not yet read of the books from The Culture series, I highly encourage you to do so. They are an amazing - agnostic - version of what our far future selves could be. Iain M. Banks had quite the mind (no pun intended).

Yes, great books! I recommend starting with 'The Player of Games', not the first book in the series but the best. They are only loosely connected, you won't miss anything.

While 'Excession' being the most complex to me. But gosh, how I enjoyed it.

Re: Falcon Heavy core booster lost at sea

#66

Post by woodandsteel » Wed, Feb 07, 2018, 7:35 PM UTC

eps wrote: post #55

craftyguy wrote: post #54

Earlier quoted context omitted.

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

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 .

Besides, I am sure the rocket itself had radios that were reporting on what was going on. When they all stopped sending signals at the very point the rocket should be touching down, that was a pretty sure signal it had crashed.

Re: Falcon Heavy core booster lost at sea

#67

Post by 4minute » Wed, Feb 07, 2018, 7:41 PM UTC

imjasonmiller wrote: post #12

hodgesrm wrote: post #2

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.

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 a…

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.

Re: Falcon Heavy core booster lost at sea

#68

Post by Mithaldu » Thu, Feb 08, 2018, 10:17 AM UTC

mariuolo wrote: post #57

eps wrote: post #55

Earlier quoted context omitted.

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 .

> Also the chances that Spacex doesn't have any other presence next to the droneship are zero. Would you keep manned boats in the area where a rocket is coming down?

From previous crashes we know they keep observers nearby.

Re: Falcon Heavy core booster lost at sea

#69

Post by stmfreak » Thu, Feb 08, 2018, 4:18 PM UTC

quasse wrote: post #36

Eridrus wrote: post #29

Earlier quoted context omitted.

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.

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.

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.

Re: Falcon Heavy core booster lost at sea

#70

Post by cjsawyer » Thu, Feb 08, 2018, 8:52 PM UTC

solarkraft wrote: post #61

larkeith wrote: post #43

Earlier quoted context omitted.

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.

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

Printed metal has huge issues with heat, and they just switched from aluminum gridfins to titanium because of the heat. I seriously doubt that they’re usung additive techniques here.