SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident • Hacker News Board

Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#261

Post by Retric » Fri, Nov 22, 2019, 3:29 PM UTC

ncmncm wrote: post #256

JshWright wrote: post #252

Earlier quoted context omitted.

Many of the "no attempt" 2018 missions were because they were reflights of older models of cores (pre-Block 5) that weren't worth keeping around. Expendable launches for Block 5 boosters are far less common.

Right, if you can throw away an obsolete rocket stage as part of profitably launching a much bigger load than you would have done with a re-usable one, it's hard to justify not doing it, and just selling it for scrap instead.

They are also removing new rockets. SpaceX is simply going to prioritize older ones for destruction assuming they can handle the payload.

Remember while the first stage is significantly more valuable, it's not just a question of fuel the upper stage is destroyed with both approaches. So, combined with significantly lower payloads the cost per kg does not drop as much as you might think.

Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#262

Post by missosoup » Sat, Nov 23, 2019, 5:43 PM UTC

ncmncm wrote: post #249

missosoup wrote: post #217

Earlier quoted context omitted.

There wouldn't be much to 'leak'. The nuclear material in weapons is relatively safe to handle as long as you don't ingest it. It's the post-explosion fission products that are nasty. Also with nuclear weapons, as much engineering has gone into safety as into weapon design itself. It's astronomically improbable for a modern nuclear weapon to detonate prior to arming even if the explosive lens is set off. The reentry…

The word "safety" in connection with nukes has been redefined to mean "it blows when you push the button". So the DOE's responsibility to maintain the "safety" of the arsenal sounds much better than it is. Not blowing up when you don't push the button doesn't have a name. When they actually dropped a pair by accident from a B-52, both got very far into their ignition sequence before something failed. Questions were A…

You're talking about an incident involving a mark-39 bomb which was built in the 1950s, the same time period when USA ran reactors with a man wielding an axe to cut rope to drop control rods as an emergency shutdown measure.

We have come a long, long way since then in nuclear safety both in weapons and reactors.

Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#263

Post by ncmncm » Sat, Nov 23, 2019, 7:11 PM UTC

missosoup wrote: post #262

ncmncm wrote: post #249

Earlier quoted context omitted.

The word "safety" in connection with nukes has been redefined to mean "it blows when you push the button". So the DOE's responsibility to maintain the "safety" of the arsenal sounds much better than it is. Not blowing up when you don't push the button doesn't have a name. When they actually dropped a pair by accident from a B-52, both got very far into their ignition sequence before something failed. Questions were A…

You're talking about an incident involving a mark-39 bomb which was built in the 1950s, the same time period when USA ran reactors with a man wielding an axe to cut rope to drop control rods as an emergency shutdown measure. We have come a long, long way since then in nuclear safety both in weapons and reactors.

Who is "we"?

Does it include Rick Perry? You are aware that the supposed secret "nuke launch code" was seventeen zeroes?

Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#264

Post by labawi » Sun, Nov 24, 2019, 3:18 PM UTC

Roark66 wrote: post #231

tinco wrote: post #213

Earlier quoted context omitted.

Maybe they did both things, and the weld still failed. The rocket's being engineered, which means they make it as weak as possible without it blowing up. Those welds might be perfect in the x-rays, they might've done all sorts of destructive analysis, and still the thing might fail in staging. Of course, they might also be on a deadline, and just went ahead and built it to spec and test it. But I don't think you can…

>Maybe they did both things, and the weld still failed. The rocket's being engineered, which means they make it as weak as possible without it blowing up. Those welds might be perfect in the x-rays, they might've done all sorts of destructive analysis, and still the thing might fail in staging. Yes, that is also a possibility. I'm not sure how likely is it that a pressure vessel would fail along a weld if that weld w…

AFAIK, during early development they are using a different, simpler welding process, including more welds and thicker off-the-shelf steel plates to compensate strength.

The welding process probably isn't optimized or fully inspected and the weakest parts would expectedly be the welds.

Re: SpaceX's Starship Mk1 just blew off its bulkhead in a pressurization accident

#265

Post by missosoup » Mon, Nov 25, 2019, 2:51 PM UTC

ncmncm wrote: post #263

missosoup wrote: post #262

Earlier quoted context omitted.

You're talking about an incident involving a mark-39 bomb which was built in the 1950s, the same time period when USA ran reactors with a man wielding an axe to cut rope to drop control rods as an emergency shutdown measure. We have come a long, long way since then in nuclear safety both in weapons and reactors.

Who is "we"? Does it include Rick Perry? You are aware that the supposed secret "nuke launch code" was seventeen zeroes?

The code you're talking about is the final step in a long sequence of events that requires positive authorisation from 6+ individuals from the president down.

By the time you've punched in the code, whether it's an OTP or seventeen zeroes, you've already committed a missile to a target and you're already 100% going to go through with the launch because two missile combat crew members turned their keys.

Russia doesn't even bother with these kinds of codes. Their second strike capability is fully autonomous and will launch even if all of c&c infra is destroyed.

This also has absolutely nothing to do with the mechanical intrinsic safety of the actual nuclear weapon during a fire or the RV that carries it. Which is the original topic at hand. The code is just an extra step to arm the weapon. The physical safeties are there to 99.999% guarantee that the weapon will not detonate unless armed. Even if you try really really hard to detonate it.

More thinking has gone into each tiny element of this process including the kind of paint used on bombs, than you have given to the topic as a whole.