I just watched a repeat of a documentary on the early Apollo missions, including the moon walk, and I was watching the film clips of the Mission Control guys at their ancient computer screens. What I wanna know is, how the hell did they know what was going on with the astronauts and the space capsule just by looking at a screen full of columns of numbers??? Even stranger, some of the guys had slide rules next to their workstations. I know, this was pre-calculator days, but if the computer was generating all these numbers for them, why bother with a slide rule?
I work in the aerospace biz, with a couple of friends who had a similar job with a normal satellite, not human spaceflight.
Lots and lots of practice. Seriously. They also only had their own specialty to worry about.
Just in case. I think it was more to have it there if something went wrong. That sure wouldn’t be the time to go looking for your slide rule. 
What makes you think they were looking at columns and numbers?
In the documentary For All Mankind, one of my favorites, they clearly show that the screens showed them things much like you’d think they would, ie. Position, Velocity, Azmuth, etc… Looked pretty normal to me.
I don’t know about manned spacecraft, but I’ve worked with a couple of satellites. When the satellite is in radio contact, it constantly transmits “housekeeping” data. This includes readings from temperature sensors, pressure sensors, voltmeters, gyroscope readings, valve status, computer status, error codes from computers, etc. Even on a small satellite, it takes half a dozen monitors to display all these numbers. If you have those numbers, you can tell exactly how much power is in each battery, which components are malfunctioning, which tanks are empty, etc.
But it’s guesswork from there. You usually wake up the guy who is supposed to know everything about the system in question, and ask him what could cause those symptoms. If the failed components are close together physically, it’s a good bet there was some physica damage such as an explosion. If they are scattered around but are connected to a common power source, it’s probably a problem with the power. Just like troubleshooting any complex system.
As for the slide rules - well, those consoles are not programmed for interactive work. They are not like spreadsheets - they display raw values and results of pre-programmed calculations (like unit conversions), but that’s about it. When something unexpected comes up and you need to do a quick calculation based on a few numbers on the screen, you don’t reprogram the computer, you take out a slide rule or pocket calculator
Sheesh, sorry about my sentence there.
I meant to say, they seemed pretty computer friendly. The views I saw didn’t have columns and whatnot, the screens showed things displayed logically, unless they were trying to compute fuel usage and whatever.
On further thought, after reading the above answers, I think I’ll stick with questions about my belly-button.
Chris has a point though, the ground computer does a lot of calculations to display data in a user-friendly manner. Graphical displays and all that. At least the NASA systems seem to, while the Japanese satellites I worked with use pure text displays. By the way, my reply was more of a “when something goes wrong, how do you know what happened.” Normally, you just monitor the various numbers and make sure they are what you expect.
The slide rule thing reminded me of the time I bought a train ticket here in Japan a few years ago. They have a sophisticated computer which tells the clerk which seats on which trains are reserved, which gets to Tokyo the fastest and all that. I bought one ticket, then another. He added the prices not on the computer, but on an abacus. I guess the more specialized the computer gets, the less flexible it becomes
Well, the entire computing power of NASA in 1969 is probably well matched–if not hugely exceeded–by the contents of the Best Buy down the street from you now.
The descent computer for the Lunar Excursion Module, Eagle, had less computing power than a Sony Playstation. It overloaded twice during Armstrong and Aldrin’s descent. Here’s how the guys in mission control addressed it:
'Quite unexpectedly, a yellow caution light winked at the astronauts from the computer control panel. It was identified as a 1202 alarm. They automatically asked the computer to define the problem. I am overloaded, it answered in its own code, I can’t handle all the jobs you’re giving me in the time available, and the data screen went blank…
'…Jack Garman, a “back room” boy supporting Bales from another console, remembered a similar problem had been tried out in a simulation only a week or so before, quickly reassured Bales: “It’s executive overflow; if it does not occur again, we’re fine.”
‘26 year old Steve Bales recalled that fateful moment: “I had just started to relax a little bit, if you can call it relaxing, and I heard the program alarm, and quite frankly, Jack, who had these things memorised said, ‘that’s okay’, before I could even remember which group it was in… I was frantically trying to look down…by the time I looked at the group and saw which one the alarm was in, Jack said it’s okay, I remembered yeah, that’s one of those we said it’s okay, I looked up, the rest of the computer looked good, so I said ‘Lets go!’ It took us a long time. In the Control Center any more than three seconds on descent is too long… and it took us about ten to fifteen seconds.”’
–from http://www.tip.net.au/~jsaxon/Apollo11.htm
Fifteen seconds to troubleshoot a computer from 250,000 miles away is not too shabby. Supposedly, another specialist rifled through an endless printout of binary code until he spotted the string of ones and zeros that didn’t look right. He pronounced the problem non-threatening.
And don’t underestimate the slide rule: I never could beat my father at fairly complex mathematical problems armed with a TI calculator against his trusty slide. NASA control room folks never trusted to a computer what they could verify with the Mark I instead.
I’d be shocked if the descent computer had anywhere near the computing power of a Sony Playstation. My guess is that it had less computing power than my programmable calculator.
As I recall, even as late as the space shuttle, the onboard computers were about as powerful as an early IBM PC, which would be perhaps 1/100 the power of your typical home computer today.
The slide rules were there to check that the computers were right. My dad’s high school math teacher went to NASA in '66-'67 to work on the calculations for the Apollo project…with a slide rule.
[side note]Mission control’s actually pretty small, about 20x30 feet. They use wide-angle lenses and stuff to make it look bigger in the movies, but it’s really small and cluttered. [/note]
Back when I worked for DEC on the Ultrix O/S, we got the contract to update all of Ground Control in Houston for the Space Shuttle controllers. We spend lots of time validating and verifying the software, major headache, and they ended up with older technology and software, but of course that’s the way things must be.
The controllers there were incredibly impressed that they could now get any information at any of the workstations. The old system was all hardwired so you could only see the data meant for that workstation. It’s absolutely amazing what they did with what they had.
Since we’ve sort of evolved into talking about the actual control center, why is it in Houston? I’ve never understood why we launch spacecraft in Florida and control them in Texas. I understand that Florida has geographical advantages in launches, but wouldn’t it have been easier to build the Johnson Space Center in Florida also? Is JSC in Texas just because LBJ was from Texas?
Drum God, I wonder the same thing. I think maybe they just like to spread the spending around to different states to get more political support.
Drum God, you’ve guessed right. Johnson lobbied heavily to have NASA headquartered in Texas. There were also senators lobbying to have other parts of the space pie, so that’s why we have Cape Canaveral, FL, and Huntsville, AL space camp, plus parts being built in California, Washington, and so on. The more states that got some money out of the space program, the easier it was to justify the spending.
As to the distance, well, since you’re monitoring something tens of thousands of miles away, it doesn’t matter if you’re close to the launch site or not.
Also note that there’s not just one Mission Control-- There’s at least four, in at least three different cities. There is, in fact, one in Florida that handles the flight up until something like 20 seconds after launch, and then Houston takes over. Meanwhile, Goddard SFC in Maryland is on standby, in case something happens at Johnson, and there’s another complete Mission Control room one floor below the standard one (viewable by the public) for use with secret DoD missions. This way, if some disaster strikes one city, they can still complete the mission sucessfully. There’s also several possible landing sites (Edwards AFB, White Sands Missile Range, and KSC), and I think even one alternate launch site (I don’t know where), for similar reasons.
Until launch exactly, in fact. If you ever watch NASA TV, you will note that the voice of the PAO (Public Affairs, the person who talks to the public) changes after the Kennedy PAO says “Ignition, liftoff” and whatever PR thing he/she says. Until launch, pictures of Mission Control are from Kennedy; after launch they are shown from Houston. The CapCom also changes from Kennedy to Houston. (CapCom is the person–and generally the only person–at MCC who speaks to the astronauts, and by tradition is an astronaut himself or herself.)
Not to mention something like a dozen emergency landing sites around the world.
LL