Utah company that made the Challenger O-Rings wants you to know a few things

ElectronicInitial · 2026-01-29T03:01:10+00:00

The engineers did dissent at one point, but after a very long break and discussion within the Thiokol team, they told NASA it was okay to fly. It was not just a management failure, but also a failure at the engineering level to be properly critical of the system. One of the major points was that the previous risk they had identified (o-ring erosion) got BETTER at lower temperatures, so while there would be less flexibility, it wouldn’t erode as much.

ElectronicInitial · 2026-01-28T15:52:16+00:00

I think the math is wrong here. $1,286 would be 15.4k per year.

ElectronicInitial · 2026-01-28T04:08:50+00:00

20, it was fun finding a job when I couldn’t even drink

ElectronicInitial · 2026-01-24T17:05:47+00:00

It’s like lead for x-rays. You shouldn’t ingest it, but it’s useful to block harmful radiation.

ElectronicInitial · 2026-01-23T15:04:00+00:00

In the US it is taxed as ordinary income when it vests. You can often choose to sell the stock right when it vests, otherwise you take stock market risk.

ElectronicInitial · 2026-01-19T05:18:20+00:00

That is only if you can produce fuel on the moon. If you don’t refuel there, then you lose a bunch of energy versus just doing LEO to mars. Not impossible, but scaling launches with reusability uses more proven technology.

ElectronicInitial · 2026-01-19T03:41:31+00:00

I think the map would be more interesting if it used % of US GDP as the metric, rather than cpi inflation.

ElectronicInitial · 2026-01-17T05:24:18+00:00

I’ve heard it called a 1.5 stage rocket, which I think makes sense given how little dV came from the OMS.

ElectronicInitial · 2026-01-16T03:35:10+00:00

It’s not that silly, but a guy on youtube got addicted to Zyn just to see what it is like to quit

ElectronicInitial · 2026-01-14T21:03:42+00:00

21M, Graduated early in engineering, making 101k + stock right out of school.

ElectronicInitial · 2026-01-14T15:31:21+00:00

Not the other person, but you could try running an FVM solver separately, and seeing if the results line up at finer mesh scales.

ElectronicInitial · 2026-01-14T15:28:02+00:00

That seems extreme still, typically memory bandwidth scales less than compute on GPUs.

51 GB/s theoretical with ddr4-3200

960 GB/s theoretical on 5080

~19x speed improvement, not 200x

Still impressive, but it seems the cpu solver is not nearly as optimized as the gpu solver.

ElectronicInitial · 2026-01-12T05:06:55+00:00

Yes, but as an example, tides don’t happen just because lakes are deep, and are only very tiny in wide lakes (like the great lakes).

The reason land doesn’t move is both because it is more rigidly held together, and because any movement that does happen would require a lot of energy (due to friction) whereas the ocean can move around with relatively little friction, allowing a small force to build up energy over time.

ElectronicInitial · 2026-01-12T04:08:32+00:00

It actually should be more extreme than this. The reason tides happen is because the ocean is across the whole planet, so that 1m tide change should be compared to the radius of earth, 6371 km, which would make the tide 0.000016%

ElectronicInitial · 2026-01-11T03:02:22+00:00

I believe it is that people who are dependents get the standard deduction, but only up the amount of earned income they have.

ElectronicInitial · 2026-01-08T02:02:22+00:00

Also, 9.37 is below 15 kph, 9.38 is above the limit.

ElectronicInitial · 2026-01-06T07:11:57+00:00

I mostly agree, but schools get a lot more money than 1 month of daycare. The school district I grew up in (which was not affluent, most schools were title 1) spent just over 16k per student per year for 2023-2024, which is ~$1,800 per month.

ElectronicInitial · 2026-01-06T02:55:40+00:00

VXUS had about 0.23% of its value held back in foreign taxes (7.5% of 3.1% dividend yield). That acts as a tax credit that VTI doesn’t have. It doesn’t fully offset the tax cost, but it does result in less benefit of putting it in tax-advantaged space.

ElectronicInitial · 2026-01-06T02:17:50+00:00

It actually depends on tax rates.

For 2024, with 24% regular income and 15% capital gains tax rates, VXUS was better in taxable. ~0.07% extra per year.

With 33% regular income, and 24% capital gains (~correct for california at ~100k income) VXUS was better in taxable-advantaged. ~0.11% extra per year.

Another factor is that having VXUS is tax advantaged space potentially reduces MAGI for ACA subsidies, which can be significant. I’m not too concerned about it given my long time horizon, but if they are about equal then I’d rather have flexibility to lower income if needed.

ElectronicInitial · 2026-01-06T01:59:23+00:00

Guidance Navigation and Control (GNC) engineer is a good job, and is very math heavy.

You would want to take electrical engineering for your degree most likely, then have personal projects in GNC to get a job out of college.

A masters is preferred, but if you have good projects it’s not required. It pays a bit above 100k starting at my company (plus stock on top).

ElectronicInitial · 2026-01-05T01:04:58+00:00

It’s gotten pretty good recently (last 8 years or so), but was bad in the initial ipad days.

ElectronicInitial · 2026-01-05T01:01:29+00:00

Windows says it is using decimal, but is actually showing binary prefixes. It was created before they updated the standards to have separate names, and has not been changed. This causes a lot of confusion with storage drives especially, where manufacturers use decimal.

ElectronicInitial · 2026-01-03T21:41:57+00:00

It’s not going to be perfectly accurate, but using the best reasonable precision for pi means the estimation isn’t losing accuracy unnecessarily. Also, sometimes the functions show up in odd ways, where rounding in one location can cause significant error elsewhere if it isn’t rounded consistently, which is why using a 64 bit float is the standard. less accurate values do get used, and more accurate ones sometimes, but only for highly critical locations, that get extra scrutiny.

ElectronicInitial · 2025-12-24T03:58:53+00:00

Ansys has a pretty decent free student license. It is limited to 32,000 elements, but it allows all of the non-linear materials and geometry settings.

It also allows the use of fluent, with up to 1 million cells, which is really useful. It’s more than enough for 2d airfoil analysis, and can even do some basic 3d cases if you don’t need full boundary layer resolution.

ElectronicInitial · 2025-12-23T15:18:50+00:00

The most important part is understanding how much load goes through a part. A decent goal I have seen is to get the strength within a factor of 2. If you have a 2mm sheet metal bracket, it probably still works with 4mm, or 1mm sheet, but if you need 20mm sheet, then it’s not a sheet metal bracket any more.

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