“Houston, We've Had a Problem” (1975) • Hacker News Board

Re: “Houston, We've Had a Problem” (1975)

#41

Post by 3JPLW » Sat, Jun 06, 2015, 4:40 PM UTC

gumby wrote: post #34

tdicola wrote: post #8

Although 13 was quite a near-disaster, I'm surprised that there isn't just as much attention to how much 11 very nearly was a disaster too. During 11's descent to the moon the LEM's computer was overloaded and started throwing alarms. In addition Neil Armstrong and Buzz Aldrin realized the craft overshot its intended landing spot and was heading for a field of rocks and boulders where landing would be impossible. Wha…

> Neil's landing is in my mind just as amazing as the recovery of 13. You're giving short shrift to Aldrin (and the training they all received) by calling it "Neil's landing". The whole team (Armstrong/Aldrin/Collins) were extraordinary. What made this clear to me was reading the transcripts of the LEM flight recorder (can't find them right now, just the audio, but they are on the NASA web site). I read Aldrin readin…

Here's the whole PDF[1] - the landing starts around page 160. Neil does ask for some readings, but not many. Really crazy to read through.

1. http://www.jsc.nasa.gov/history/mission_trans/AS11_CM.PDF

Re: “Houston, We've Had a Problem” (1975)

#42

Post by ams6110 » Sat, Jun 06, 2015, 5:59 PM UTC

tajen wrote: post #13

makeitsuckless wrote: post #12

Earlier quoted context omitted.

> "when people didn't know better" My god, what do you think 2001 was, the stone age?

When i hear "the startup bubble of 2001", I always take a moment to imagine what was a startup in 2001. I imagine an HTML 2 page with no Javascript and an ad banner at the top, inlined styles and tags... Like Altavista or Yahoo. So in truth, what were webpages before 2006?

Dynamic web apps in the first "bubble" era were generally either perl/cgi or ASP (without the .NET suffix, obviously). Javascript was used, but only for small things like required field validations. Databases would be SQL Server or Oracle or Sybase, typically. PHP and MySQL was also used. Servers were mostly either Sun or Microsoft (for ASP), though there was some Linux.

The main difference from today was that almost all dynamic content was generated server-side (of course we do still see that today also, but it's not "trendy"). Layouts were table-based and yes, styles were almost always in-line and not in separate stylesheets. Very little JavaScript, because it was common for browsers to not support it, there were significant quirky differences between browsers, and the CPU speeds of the day meant you couldn't do anything substantial with it anyway. If it was used, it was again typically in-line in an "onblur" or "onsubmit" handler.

Security of web apps at the time was laughable by today's standards. SSL had a significant impact on server performance and was mostly limited to use on the login page, if it was used at all. SQL injection was only beginning to be understood by most developers, many (most?) sites used SQL queries made with unescaped concatenated strings and were vulnerable.

If they were really on board with Microsoft technologies, they might have abstracted their logic into business objects likely written in VB6, running in a COM layer in Microsoft Transaction Server, which called stored procedures in SQL Server. Or they might have used Java and JSP and servlets

Almost nobody had broadband unless they worked at a university or tech company. Dial-up was the norm elsewhere so page assets had to be pretty minimal. Many people had screens that were 640x480 so most websites designed for that.

I still see a lot of code in languages like PHP that is quite similar to what was being written in 2000.

Re: “Houston, We've Had a Problem” (1975)

#43

Post by ams6110 » Sat, Jun 06, 2015, 6:02 PM UTC

keithpeter wrote: post #28

ColinWright wrote: post #17

Earlier quoted context omitted.

My site is still pretty much as I originally had it in the mid to late 1990s: http://www.solipsys.co.uk Didn't know better then, don't know better now. Still prefer content over style.

http://www.solipsys.co.uk/new/DistanceToTheMoon.html OK, I'm intrigued and will be thinking about that one when I'm getting my students into their exam on Monday... http://sohcahtoa.org.uk/ 1992 style. See html comments for the reasons...

I still see a lot of web pages like that among computer science academics, especially those who are of "pre-internet" generations. E.g http://www-cs-faculty.stanford.edu/~uno/

Re: “Houston, We've Had a Problem” (1975)

#44

Post by neurotech1 » Sat, Jun 06, 2015, 6:08 PM UTC

gumby wrote: post #34

tdicola wrote: post #8

Although 13 was quite a near-disaster, I'm surprised that there isn't just as much attention to how much 11 very nearly was a disaster too. During 11's descent to the moon the LEM's computer was overloaded and started throwing alarms. In addition Neil Armstrong and Buzz Aldrin realized the craft overshot its intended landing spot and was heading for a field of rocks and boulders where landing would be impossible. Wha…

> Neil's landing is in my mind just as amazing as the recovery of 13. You're giving short shrift to Aldrin (and the training they all received) by calling it "Neil's landing". The whole team (Armstrong/Aldrin/Collins) were extraordinary. What made this clear to me was reading the transcripts of the LEM flight recorder (can't find them right now, just the audio, but they are on the NASA web site). I read Aldrin readin…

All the Apollo astronauts were legendary test pilots (except Dr Harry Schmitt) [0]. Buzz and Neil are the ones everyone remembers, and they earned their place on that mission, however it took a huge team to get them there.

When Apollo 13 had the explosion, other astronauts including Ken Mattingly, and John Young, had a significant role in helping get them back home.

Astronauts were not just great pilots, but they knew how to work with a team. No astronaut would get selected if they were a great test pilot, but couldn't work as a crew. One particular test pilot (Chuck ..) who never became an astronaut is a classic example of that.

[0] http://en.wikipedia.org/wiki/Harrison_Schmitt

Re: “Houston, We've Had a Problem” (1975)

#45

Post by JesperRavn » Sat, Jun 06, 2015, 6:57 PM UTC

jonsen wrote: post #16

venomsnake wrote: post #10

Earlier quoted context omitted.

I have read the selection process that was described in Lost Moon (the book of appolo 13). The NASA were literally recruiting superhumans back then. The smartest, healthiest, toughest and on on ... So I am not at all surprised that he managed to pull it off. https://www.countbayesie.com/blog/2015/2/18/hans-solo-and-ba...

And at the interview they could fly any spacecraft on a whiteboard.

We are allowed to consider national hero's the "smartest". They get an exception to the usual PC rules. Software Engineers aren't allowed to be considered super smart because that would hint at biological determinism (not saying that one directly implies the other, but any connection is enough). Therefore any interview process that is designed to select for intelligence (rather than other qualities) is going to be regarded as illegitimate.

Re: “Houston, We've Had a Problem” (1975)

#46

Post by pdonis » Sat, Jun 06, 2015, 7:54 PM UTC

Someone wrote: post #15

tdicola wrote: post #8

Although 13 was quite a near-disaster, I'm surprised that there isn't just as much attention to how much 11 very nearly was a disaster too. During 11's descent to the moon the LEM's computer was overloaded and started throwing alarms. In addition Neil Armstrong and Buzz Aldrin realized the craft overshot its intended landing spot and was heading for a field of rocks and boulders where landing would be impossible. Wha…

"In fact when they tried to test it on Earth, it very nearly killed him [...] Without Neil Armstrong Apollo 11 very likely would have ended with Richard Nixon reading this somber message" Not necessarily. It can be argued that Neil Armstrong should have aborted the landing, rather than risk it with so little safety room. After all, if he couldn't reliably do it on earth, how can you argue that it was purely his intel…

Of course they had luck (and more than a bit). But aborting safely would have required luck too. They were already off their pre-planned trajectory, which meant initiating an abort would have put them off of the pre-planned abort trajectory. So a successful abort would probably also have required manual control, and not just for the minute or so required to land, but for an extended period of time while they tried to figure out the right trajectory to get back up into lunar orbit and rendezvous with the command module.

Given that choice, I'm not surprised that Armstrong elected to attempt the landing.

Re: “Houston, We've Had a Problem” (1975)

#47

Post by TheLoneWolfling » Sat, Jun 06, 2015, 9:17 PM UTC

FlannelPancake wrote: post #39

> With the wisdom of hindsight, I should have said, "Hold it. Wait a second. I'm riding on this spacecraft. Just go out and replace that tank." That's crazy. I didn't realize the tank was acting funny before they even took off. To me, the risk-adverse non-astronaut, that seems like something that would've triggered big ominous "DANGER" signs going off in my head. I guess that's the benefit of hindsight, though.

Anything that complex always will have things acting funny.

Re: “Houston, We've Had a Problem” (1975)

#48

Post by FlannelPancake » Sat, Jun 06, 2015, 9:54 PM UTC

TheLoneWolfling wrote: post #47

FlannelPancake wrote: post #39

> With the wisdom of hindsight, I should have said, "Hold it. Wait a second. I'm riding on this spacecraft. Just go out and replace that tank." That's crazy. I didn't realize the tank was acting funny before they even took off. To me, the risk-adverse non-astronaut, that seems like something that would've triggered big ominous "DANGER" signs going off in my head. I guess that's the benefit of hindsight, though.

Anything that complex always will have things acting funny.

Heh, that's fair.

Re: “Houston, We've Had a Problem” (1975)

#49

Post by Nomentatus » Sat, Jun 06, 2015, 10:05 PM UTC

The Apollo 13 explosion turned out to be a magnificent example of "false redundancy". By packing the three (supposedly redundant) fuel cells tightly together, NASA actually tripled the chance of losing all power. They now had three fuses that might be the wrong wattage. (As I remember what I've read, someone got but never read a memo that the fuse wattage had been changed in the fuel cell design - the memo was found speared with many others in an unread pile after the accident.) Reading the details of Musk's designs his team really does seem to understand what redundancy is and is not. It's all too easy to get wrong.

Re: “Houston, We've Had a Problem” (1975)

#50

Post by Nomentatus » Sat, Jun 06, 2015, 10:12 PM UTC

pdonis wrote: post #46

Someone wrote: post #15

Earlier quoted context omitted.

"In fact when they tried to test it on Earth, it very nearly killed him [...] Without Neil Armstrong Apollo 11 very likely would have ended with Richard Nixon reading this somber message" Not necessarily. It can be argued that Neil Armstrong should have aborted the landing, rather than risk it with so little safety room. After all, if he couldn't reliably do it on earth, how can you argue that it was purely his intel…

Of course they had luck (and more than a bit). But aborting safely would have required luck too. They were already off their pre-planned trajectory, which meant initiating an abort would have put them off of the pre-planned abort trajectory. So a successful abort would probably also have required manual control, and not just for the minute or so required to land, but for an extended period of time while they tried to…

Mission control would have had the trajectory back up calculated and in hand, but separating from the lower lander stage and engaging the (different) return rocket at low altitude, outside of normal flight parameters, with an ongoing computer problem of (then) unknown origin - I would agree, that sounds still dicier. Plus, a manual landing was practiced in computer-governed simulators; it wouldn't feel the same, but otherwise the task would be quite similar - except for the dust perhaps.