upvote

points

by ChicagoBoy111 days ago |
comments
upvoteby deepsun1 days ago|
next
[-]
And that's why it's harder (or easier?) to make the same landing again -- we taking way less chances. Today we know of way more failure modes than back then.
reply
upvoteby kevin_thibedeau1 days ago|
parent|
next
[-]
They sent people up in a tin can with the bare minimum computational power to manage navigation and control sequencing. It was barely safer than taking a barrel over Niagara Falls. We do have much more capable and reliable technology.
reply
upvoteby jvm___1 days ago|
parent|
[-]
Buzz Aldrin (?) was quoted as recalling holding a pencil inside the capsule as they were out in space and thinking "that wall isn't very thick or strong, I could probably jam a pencil through it pretty easily..."

Death being a layer of aluminum away changes your mind.

reply
upvoteby wat100001 days ago|
parent|
prev|
[-]
It's a miracle nobody died in flight during the program. Exploding oxygen tank, rockets shaking themselves to pieces during launch, getting hit by lightning on top of a flying skyscraper full of kerosene and liquid oxygen....
reply
upvoteby djmips1 days ago|
parent|
next
[-]
Gus Grissom, Ed White, and Roger Chaffee died on the Apollo program. I feel it's not polite to ignore that fact even if you add an 'in flight' qualifier.
reply
upvoteby vondur1 days ago|
parent|
[-]
And it's even more interesting in the fact that our rocket program started with the former rocket scientists from Nazi Germany who were brought over at the end of WW2 to work in the American rocket/missile program.
reply
upvoteby thinkingtoilet1 days ago|
parent|
prev|
[-]
Starting from the first test pilots, a lot of people died for us to get to the point to launch that flight. So while no one died on the flight, lots of people died just getting us there. If I recall, in The Right Stuff, it's mentioned that those early test pilots had something like a 25% mortality rate.
reply
upvoteby wat100001 days ago|
parent|
next
[-]
The early jet age was pretty nuts. Check the Wikipedia page for a random fighter from the era and you'll see figures like, 1,300 built, 50 lost in combat, 1,100 lost in accidents. And that's operational aircraft. Test pilots were in even more danger.
reply
upvoteby Quinner1 days ago|
parent|
next
[-]
Some were pretty bad, but none were nearly that bad. The B-58 Hustler lost 22% of its airframes, the F7U Cutlass 25%, the F-104 Starfighter in German service lost 33%. And those were outliers.
reply
upvoteby wat100001 days ago|
parent|
[-]
You're right, those numbers are from the F-8 but include non-total-loss accidents.

I don't think the numbers you quoted are outliers, though. The F-100 lost ~900 out of 2,300. The F-106 lost ~120/342. That's a pretty big list of planes with a 1/5-1/3 loss rate.

reply
upvoteby jaggederest1 days ago|
parent|
prev|
next
[-]
You should go back even a little further, the USPS air mail service lost 31 of the first 40 pilots.
reply
upvoteby mrguyorama1 days ago|
parent|
[-]
Back in the days where the plan was "So we've built literal signal fires and giant concrete arrows and well, good luck, it won't help"
reply
upvoteby ErroneousBosh1 days ago|
parent|
prev|
[-]
Have you ever listened to Robert Calvert's "Captain Lockheed and the Starfighters"?
reply
upvoteby ErroneousBosh1 days ago|
parent|
prev|
[-]
Think about the "failure mode" of the aircraft that won World War II, the Supermarine Spitfire.

There was a fuel tank mounted between the engine and cockpit so if it took enough of a hit to puncture right through (not hard, in practice) the failure mode was that the cockpit was now full of a 350mph jet of burning petrol.

Still, it did the job.

reply
upvoteby nativeit1 days ago|
prev|
next
[-]
Related topic on CuriousMarc and co.’s AGC restoration: https://news.ycombinator.com/item?id=47641528
reply
upvoteby russdill1 days ago|
prev|
[-]
"popularly described" and how it's currently understood are two different things. Because it's hard to explain to lay people, it's popularly described in a number of simplified ways, but it's well understood.
reply
upvoteby garaetjjte1 days ago|
parent|
[-]
Since we are on HN, I think it could be explained there (before it's all consumed by AI slop):

For complex reasons, available CPU time during landing was lower than expected (it was stolen by radar pointing peripheral). This caused regularly scheduled job to spawn before previous instance finished. As such, this caused two effects: job instances were suspended before finishing by new instances in the middle of the routine, and that pilling up of the old instances eventually exhausted resources and caused kernel to panic and reboot. Rebooting during landing sounds scary, but that actually was fine: such critical tasks were specifically designed to automatically restart from previously saved checkpoint data in the memory.

What was more dangerous, was the suspended tasks before restarts occured. First, it meant routine wasn't executing to the end, which in actual flight caused blanked displays (as updating the display was the last thing routine was doing). Any more CPU time stolen, and it could be interrupted even earlier, eg. before it sends the engine commands.

Another issue is that in case of fluctuating load, new instances could actually begin running to the end, and then previously suspended job instance could be resumed, potentially sending the stale data to the displays and engine.

And finally, while each job instance had it own core and VAC set properly managed by the kernel (think of it as modern kernel switching between task stacks), that particular routine wasn't designed to be reentrant. So it was using various global variables ("erasables") for its own purpose, that when interrupted in unluckly place might have caused very bad behavior.

How likely all of above is to occur, depends on the exact profile of fluctuating load caused by the confused radar peripheral. I guess that's why Mike Stewart is trying to replicate these issues with real CDU.

reply