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Post by donnieb on May 28, 2007 8:07:45 GMT -4
Yeah I've been there 3 times I saw the ENORMUS Saturn V, my jaw dropped I could even talk I saw the inside of the LM and that cockpit was full of switches! Yes, it had a lot of dedicated controls. That's the way things were designed in those days, since small, mobile computers were pretty primitive. I just saw a TV documentary about the work that's being done on the Orion project (that's NASA's program to return to the Moon and beyond). Things will look quite a bit different in the new capsule. Many functions will be controlled using an array of touch screens, so only the controls needed at a given time will be visible. The pilots will be able to call up whatever controls they need. (There will still be some hardwired switches too.)
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Post by scooter on May 28, 2007 10:04:48 GMT -4
The Apollo days were the early days of computers, when slide rules were still in fashion, and pencil and paper calculations were commonplace. Many hoax believers seem to think that great engineering achievements were not possible without modern computers and the automation they provide. The 747 saw it's first flights in 1969, using many of the same sort of technologies from the space program. Yes, great aerospace accomplishments were possible using rudimentary computers and a lot of very smart folks. So much of it is just "big math". With the vast microchip revolution, and out current dependence on computers, I wonder how we would function without them today? We did quite well 40 some years ago. So many of the HBs don't understand the cultural, political, and technological realities of the 60s, seeing it as a murky ancient history that they can't understand. I remember those days quite fondly. Even watching the early flights of the shuttle...no laptops everywhere like today...things evolve so quickly these days. Yeah, the Saturn V display at KSC is breathtaking. It used the same VAB, launch pads and mobile launchers that they still use today, adapted for Shuttle.
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Post by JayUtah on May 28, 2007 10:08:38 GMT -4
Most of the LM switches were circuit breakers. They doubled in many cases as the on/off switches for the devices they controlled so that the designers didn't need to find a place for a separate switch intended for ordinary control. Even in glass cockpits you still need physical circuit breakers, but the configurable displays offer much better options for ordinary control. Configurable displays are combat-hardened nowadays and work quite well enough for manned space flight.
Panel real estate was a daunting problem for both the LM and CM. The designers simply didn't have room on the panels for every dial and switch the mission indicated. Ironically because of the flexibility of telemetry, the ground controllers often knew more about the condition of the spacecraft than the pilots. The Apollo 11 crew quickly diagnosed that their 120x computer malfunction correlated to a certain program meant to display a running descent rate. The ground controllers said to deactivate the program because they would monitor the descent rate using the telemetry. And similarly there was no switch to tell the LM it had landed: the LMP was meant to store a non-zero value in computer memory location 403 to tell the computer that, and he was to do it by punching a store command into the computer's console.
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Post by apollo13 on May 28, 2007 10:18:02 GMT -4
Why did'nt the LM have an emergency system because, all it had were ejection seats.
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Post by Grand Lunar on May 28, 2007 10:18:56 GMT -4
Pretty cool. Sounds something like what was depicted on the Enterprise-D.
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Post by JayUtah on May 28, 2007 10:26:34 GMT -4
Why did'nt the LM have an emergency system because, all it had were ejection seats.
You mean why wasn't there a way for the astronauts to bail out of the lunar module? Where would they go once they had left the ship?
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Post by HeadLikeARock (was postbaguk) on May 28, 2007 10:30:13 GMT -4
Why did'nt the LM have an emergency system because, all it had were ejection seats. I think your confusing the LM (Lunar Module that landed on the moon), with the LLTV (Lunar Landing Training Vehicle. The LLTV was used extensively by the pilots to gain experience in flying a craft in 1/6th gravity (it had a system in place to compensate for most of the Earth's gravity). The LLTV did have an ejector seat, which is just as well for Neil Armstrong since a valve failure caused him to lose control during one training session - he would almost certainly have been killed if he hadn't ejected at the last minute.
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Post by apollo13 on May 28, 2007 10:44:47 GMT -4
Yeah, thanks for the help, postbaguk!
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Post by JayUtah on May 28, 2007 11:09:08 GMT -4
I see -- you did mean the LLTV. Quite a different thing altogether than the LM.
The LLTV and its cousin the LLRV were never meant to be useful flying machines on their own. They were built for exactly one purpose; to teach the astronauts how to fly something that used a throttled rocket motor for lift and little rocket jets for control. Because that's all it was ever meant to do, the designers didn't put in a lot of extra features like cup holders. Or skin.
It may not be obvious unless you've studied aircraft design, but those training vehicles were kind of thrown together. It would be inexcusable to build a general-purpose aircraft that way, but the LLTVs were designed to be flown only by very experienced military test pilots over military airfields.
When Neil Armstrong crashed, it was because the LLTV broke. The steering jets stopped working so he had no control. On a regular, general-purpose aircraft there would have probably been some sort of backup steering system, or a more robust fuel system. But if they had been designed to those standards, it would have taken too long to design and build them, and they wouldn't have been ready. So Bell Aircraft (the designer) agreed with NASA that the vehicles weren't as safe as they could be if they could take more time to build them, so the ejection seat was provided to keep the pilot safe if one should malfunction.
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Post by apollo13 on May 28, 2007 11:33:53 GMT -4
Well Neil, was really close to death. Why could'nt NASA make a new emergency system after Neil was almost killed?
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Post by scooter on May 28, 2007 11:43:28 GMT -4
They probably could have, but they found the cause of the failure pretty quickly. There was a reason they had test pilots as astronauts. What we consider dangerous, they see as almost a routine. Armstrong was an old X-15 pilot, also a dangerous job. He quickly recognized the problem, realized he was no longer in control, and ejected...just part of the job, as difficult as that is to imagine for the rest of us. Astronauts had an "interesting" job, with skills to match.
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Post by apollo13 on May 28, 2007 11:46:50 GMT -4
Thanks for the response, scooter!
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Post by JayUtah on May 28, 2007 11:50:43 GMT -4
First, it's safe to say Armstrong knew what he was doing. Ejection seats are meant to work at low altitudes, and he was a test pilot experienced in how to use them safely and how to deal with aircraft that break when you're flying them. So while the film footage of the crash scares the willies out of you and me, it's not all that scary to test pilots. That's what they do.
The crash was investigated, naturally. But the cause was deemed unlikely to occur again, so they just added a preflight check to look more carefully at the attitude control fuel fittings next time. And although there were other LLTV accidents, none of them was because of that same problem. One of the other accidents, for example, was because the wind picked up during the flight -- you could only fly the thing in still weather.
NASA could have improved the design, but it's not always wise to achieve better safety that way. Sometimes you don't have to change the machine in order to operate it safer; you just have to pay closer attention to certain details before you start it up. When you add something to a machine that you intend to be a safety feature, it sometimes actually makes things worse. So to keep from changing the way the machine works and making it less predictable, you leave the design alone and instead just look more carefully for signs of danger, like leaky fuel fittings.
Clearly NASA doesn't want its highly-trained astronauts killed in training missions, but the LLTV flew literally hundreds of times with only a few accidents. That's not as good as a passenger airliner, but it was good enough. NASA didn't want a perfectly safe vehicle because it would have taken too long and cost too much. They just wanted one that was safe enough. That's where the skill of the engineer lies: in making something that is just good enough.
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Post by JayUtah on May 28, 2007 12:19:22 GMT -4
That reminds me of when my friend Matt and I were flying a light plane a few years ago. We were out near the former Wendover Air Force Base in Nevada, mostly because even a klutz like me can land on those luxurious B-29 runways. We were taking turns flying and photographing.
The roll trim started to get wonky on the way home, and I figured out it was because one wing tank was being emptied faster than the other. Matt switched the fuel system from BOTH to LEFT in order to pull fuel from the left tank only and even out the weight. Within seconds the engine started to sputter and lose power. Not what you want to hear at 7,000 feet.
Panic? No, not at all. Matt is an excellent and experienced pilot, and I know my way around a cockpit too. First and foremost -- fly the plane. As pilot-in-command that duty fell to Matt. His only order to me was, "Get my engine back."
Now we really weren't in any danger since we were over the salt flats. No shortage of places to land in an emergency.
First order of business was to switch the fuel supply back to the setting we know worked. That improved things a bit, but there was a telltale whine -- the unmistakable noise of a cavitating pump. The fuel pump was sucking air. "Left tank fuel line blockage; air in the fuel line." That also explained why the left tank hadn't been draining at the same rate. "Dive a bit, I wanna mess with your power setting." I had hoped that changing the throttle setting would vary the pressure in the fuel lines enough to close the air bubbles around the pump. The dive was to maintain airspeed at low power.
No luck. Matt asked for the most power I could give him because he wanted to try something else. He went through a series of abrupt roll excursions to slosh the fuel around the tanks. If the blockage was in the tank, sloshing the fuel around might dislodge it. No help.
Finally we hit on a combination of mixture and throttle that gave us controlled straight and level flight and we landed safely at Salt Lake International. Although the mechanic couldn't reproduce the cavitation problem, he did notice that the left fuel tank screen had some material stuck to it.
There's really no way to remedy that in flight, but that's why the aircraft in question has two largely independent fuel systems. The fuel pump can deliver adequate fuel pressure and flow even while cavitating, and the system is built around redundant plumbing. There's no real design improvement I would recommend. The fuel screen is meant to trap coarse debris in the tank that would otherwise clock the pump or other more delicate parts of the engine.
But you can operate that design more safely by flushing the fuel lines and tanks between each flight and fueling the aircraft under more controlled circumstances than a desert airport normally offers.
And the other point is that neither of us was particularly worried. We were both experienced operators of aircraft who had confidence in our combined ability. The worst-case scenario we contemplated was having to land on the salt flats and be out of cell phone range. There are far more experienced pilots who can remain similarly calm in far more exigent circumstances. A few of them became astronauts.
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Post by apollo13 on May 28, 2007 13:29:23 GMT -4
Cool, you're the only pilot I know who would'nt panicin a severe emergecy.
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