Wayne Hale

https://waynehale.wordpress.com/2012/11/12/after-ten-years-a-few-words-from-admiral-gehman/

> I need to give you the issue from the NASA point of view so you can understand the pressures that they were under. In a developmental program, any developmental program, the program manager essentially has four areas to trade. The first one is money. Obviously, he can go get more money if he falls behind schedule. If he runs into technical difficulties or something goes wrong, he can go ask for more money. The second one is quantity. The third one is performance margin. If you are in trouble with your program, and it isn’t working, you shave the performance. You shave the safety margin. You shave the margins. The fourth one is time. If you are out of money, and you’re running into technical problems, or you need more time to solve a margin problem, you spread the program out, take more time. These are the four things that a program manager has. If you are a program manager for the shuttle, the option of quantity is eliminated. There are only four shuttles. You’re not going to buy any more. What you got is what you got. If money is being held constant, which it is—they’re on a fixed budget, and I’ll get into that later—then if you run into some kind of problem with your program, you can only trade time and margin. If somebody is making you stick to a rigid time schedule, then you’ve only got one thing left, and that’s margin. By margin, I mean either redundancy—making something…

I use Feedly / NetNewsFire for feeds, rather than newsletters, but in reality they're the same, just different consumption methods. Just interesting to see NNW was in HN recently. These are the most interesting things I keep in Feedly.

acoup.blog - A Collection of Unmitigated Pedantry - frequently linked to HN already. He's a great history writer, covering everything from Roman logistics, to analysis of current games and movies - eg. LotR battles.

https://www.youtube.com/channel/UC364qOwWXAzgRruHhhFMhVg - Croker vs Rover. A New Zealand guy restoring a 70s Land Rover. It's a Youtube channel, but both hilarious and informative. Infrequent too, so easy to cruise through at leisure.

Atlas Obscura - https://www.atlasobscura.com/ - interesting history/geography mix.

https://www.numberphile.com/ - Mathy easy-access but complex topics - mostly videos on Youtube. Very accessible, but interesting for a mostly non-math person to see real math at work.

https://waynehale.wordpress.com/ - Wayne Hale - NASA flight controller. Interesting views and analysis of current space / incident management topics vs how it was done for the shuttle, along with some other commentary. Infrequent and interesting.

https://computer.rip/ - Deeply geekly telco / 50s-70s computer history with some cold-war fun. Pretty in-depth, and a fun read.

https://www.cringely.com/ - Cringley - weekly-monthly tech posts on bigger tech strategy with an Appleish focus. He's been around SV for years. Was early at…

> But no RS-25 has ever failed during flight

There was near miss though:

>By about T-3 seconds, all engines were up and operating at 100% of rated power level. Exactly when it happened is not clear, but on the right engine, the gold plated pin from LOX post 32 in row 13 came shooting out. [...] Now two scary things could have happened. First, the LOX post, which was pinned for a reason, could have failed allowing LOX to pour into the engine cavity where the hot hydrogen was introduced. [...] Failure of the LOX post was considered a CRIT 1 failure [...] How close we were to disaster has never been determined. [...] Second, the nozzle extension could have failed. [...] Someone had calculated that if 5 adjacent cooling tubes split or were otherwise ruptured, there would not be enough local area cooling and a burn through would occur, causing a cascading failure of the nozzle and ... a CRIT 1 failure. [...] The bullet shaped LOX post pin hit the side of the right engine nozzle extension about two thirds of the way to the end with great force. Just by sheer luck, three nozzle tubes were breached.

https://waynehale.wordpress.com/2014/10/26/sts-93-we-dont-need-any-more-of-those/ https://www.youtube.com/watch?v=u6rJpDPxYGU

I recently went through the HN posts I upvoted/saved this year and maybe someday will get around summarizing the ones that taught/inspired me the most...here are two technical ones that stuck out for me:

SiteChat: a postmortem. Or, the rise and fall of a society.
http://burakkanber.com/blog/sitechat-a-postmortem-or-the-rise-and-fall-of-a-society/
This to me was the epitome of a great HN post: the author decides he wants to learn how to build Chrome extensions and implement WebSockets and builds a chat app from scratch. It becomes a runaway hit and he leaves it alone, only to rediscover later that it developed into its own online civilization of sorts.

How We Nearly Lost Discovery
http://waynehale.wordpress.com/2012/04/18/how-we-nearly-lost-discovery/
A former NASA engineer describes how Discovery nearly ended up as tragedy, and "how I found out that we were never really as smart as we thought we were."

Thanks! You might find Wayne Hale's (Space Shuttle Program Manager or Deputy for 5 years, a Space Shuttle Flight Director for 40 missions) 10-year retrospective on the Columbia crash interesting:

https://waynehale.wordpress.com/category/after-ten-years/

Also, I recall reading somewhere that the chairman of the Columbia Accident Investigation Board, Admiral Harold Gehman, decided to conduct a test to see if the piece of foam seen hitting the leading edge could have broken it. As, at the time, it had not been decided to end the shuttle program, this was not an easy decision, as it meant sacrificing an essentially irreplaceable spare part. What finally convinced Gehman to go ahead was the fact that a great many NASA engineers firmly believed it could not possibly have been the cause.