Author Topic: why was the usa the only one to go to the moon?  (Read 556258 times)

Offline JayUtah

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Re: why was the usa the only one to go to the moon?
« Reply #450 on: January 29, 2013, 09:29:29 PM »
Jay, what was the name of the program you did the desert photography segment for a few years back?

The Truth About The Moon Landings, although it was slightly retitled in each market.
"Facts are stubborn things." --John Adams

Offline Abaddon

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Re: why was the usa the only one to go to the moon?
« Reply #451 on: January 29, 2013, 09:34:35 PM »
For all his foolishness, alexsanchez got me thinking about a question I'm hoping Jay or some of the other aerospace expert types here can answer.

Assume that Eagle had some kind of catastrophic computer/electronic failure.  Would it be possible for a human being with Neil Armstrong's level of skill and training, assuming that the absolutely essential systems were still somewhat functional, to manually lift off and get into an orbit from which Collins could maneuver to a rendezvous?

One of the experts on here may know for sure, but I'm betting that either Armstrong or Aldrin could have done all the necessary calculations to give them the best chance of a successful docking, using only a pen and paper, including lift off time, burn time, and the timeline for pitchover and then manually flown the the LM into an orbit sufficiently close to have a chance of a successful LOR.

Of course, Mission Control would likely have done all the for them.
It's already been said. All the LM had to do was achieve orbit. After that, there was a simple matter (haha) of matching orbit with the CSM. Difficult, but not unattainable. Simply one more engineering challenge among many.

Offline dwight

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Re: why was the usa the only one to go to the moon?
« Reply #452 on: January 29, 2013, 09:44:51 PM »
I think from now on we need to explain being banned for bad behaviour via the use of finger puppets. Plain and simple english doesn't seem to work with Air Force Engineer types.
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Offline Bob B.

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Re: why was the usa the only one to go to the moon?
« Reply #453 on: January 29, 2013, 09:52:29 PM »
"Pitchover" is the beginning of a programmed set of attitudes that gradually deflect from the local vertical, aimed downrange, at various timed intervals designed to optimally achieve the proper altitude, direction, and downrange velocity.  Prior to pitchover, the program is "go straight up."  That's the terrain avoidance maneuver.  If the pilot had a working "eight ball" (and it could be zeroed manually) then Mission Control could read him a series of pitch angles to fly.

For my Lunar Module Ascent Simulation I had to derive a set of pitch angles by trial and error.  Surely my angles aren't the same as those actually used, but they have to be pretty close or else my simulation wouldn't have worked.

Offline onebigmonkey

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Re: why was the usa the only one to go to the moon?
« Reply #454 on: January 30, 2013, 12:28:58 AM »
For all his foolishness, alexsanchez got me thinking about a question I'm hoping Jay or some of the other aerospace expert types here can answer.

Assume that Eagle had some kind of catastrophic computer/electronic failure.  Would it be possible for a human being with Neil Armstrong's level of skill and training, assuming that the absolutely essential systems were still somewhat functional, to manually lift off and get into an orbit from which Collins could maneuver to a rendezvous?

One of the experts on here may know for sure, but I'm betting that either Armstrong or Aldrin could have done all the necessary calculations to give them the best chance of a successful docking, using only a pen and paper, including lift off time, burn time, and the timeline for pitchover and then manually flown the the LM into an orbit sufficiently close to have a chance of a successful LOR.

Of course, Mission Control would likely have done all the for them.

Possible the most obscure and geeky 'museum' site I've come across:

http://sliderulemuseum.com/Aerospace.htm

(parent site herehttp://sliderulemuseum.com/)

A little way down the page is Buzz Aldrin's flown slide rule with letter of authenticity. As I'm sure everyone here knows, Buzz's PhD was in orbital rendez-vous and he could probably have done the maths in his head.

There is, of course, the recently auctioned document from Apollo 13 showing the hand-written guidance re-calculations.

Offline JayUtah

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Re: why was the usa the only one to go to the moon?
« Reply #455 on: January 30, 2013, 12:36:46 AM »
A little way down the page is Buzz Aldrin's flown slide rule with letter of authenticity.

I gave Apollo-model Picketts to my senior staff two years ago as Christmas presents.  They are still available if you know where to look.  My lead system administrator has a Curta from about 1958.  Amazing little device.

Yes. Buzz was passionate about orbital mechanics and rendezvous.  His nickname was "Dr. Rendezvous."
"Facts are stubborn things." --John Adams

Offline smartcooky

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Re: why was the usa the only one to go to the moon?
« Reply #456 on: January 30, 2013, 02:40:44 AM »
"Pitchover" is the beginning of a programmed set of attitudes that gradually deflect from the local vertical, aimed downrange, at various timed intervals designed to optimally achieve the proper altitude, direction, and downrange velocity.

My bad. I was using the term "pitchover" incorrectly

I was meaning that they would have no trouble calculating where they would have to begin to manually pitch the AS over from vertical to horizontal to make orbit, and at what rate they would need to do that.
If you're not a scientist but you think you've destroyed the foundation of a vast scientific edifice with 10 minutes of Googling, you might want to consider the possibility that you're wrong.

Offline ka9q

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Re: why was the usa the only one to go to the moon?
« Reply #457 on: January 30, 2013, 03:18:57 AM »
I was meaning that they would have no trouble calculating where they would have to begin to manually pitch the AS over from vertical to horizontal to make orbit, and at what rate they would need to do that.
But could they do that accurately enough by eye, without computers or (even more important) an inertial reference platform? Even with the LMP reading his watch and the attitude table to the CDR?

To get the launch azimuth and orbital plane right, you'd need a series of landmarks over which to fly by visual reference during the ascent burn. To get the correct perilune and apolune, both hopefully positive, you'd have to set up a pitch-vs-time table. You could start to fly it by sighting the horizon with the LPD marks on the commander's window. But the horizon would quickly move off the top of the scale, so you'd need some another sighting reference on the LM. There's the overhead rendezvous window, but it's very small and you couldn't get close to it under acceleration. You could roll over on your back and sight the earth if it's in the right place, but then you can't see your ground landmarks for azimuth steering.

It would be extremely difficult, but the only way to find out would be to have some astronauts try it in a simulator. That would be fun to watch. If one succeeded, you'd never hear the end of it.

Offline Zakalwe

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Re: why was the usa the only one to go to the moon?
« Reply #458 on: January 30, 2013, 04:04:45 AM »

Please explain this clip.  The astronaut is clearly hoisted up while trying to stand up.  (it's cued at 2:05)
http://www.youtube.com/watch?feature=player_detailpage&v=Zz9Bzi_GyD0#t=125s


Alex, Alex, Alex....come here and sit down, son. Haven't you learned anything about checking your sources before regurgitating them? Remember this post?

Regarding an AULIS pic I put up, after some graphic analysis I have come to the conclusion that the claim is unsubstantiated by the photos.
http://aulis.com/imagesfurther%20/compositevalley.jpg


Sheesh...you Air Force, aerospace engineers sure are hard of learning......

And by the way, remember that little bet that you offered out, that I took up? Any chance of a response to it? You don't have to post your details in the public forum (wouldn't want to jeopardise your precious anonymity, now would we?) Just PM the details to the other people that can verify them. I'm happy to accept their word that the details check out. Once that happens, you can let me know your charity of choice.
"The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that 'my ignorance is just as good as your knowledge.' " - Isaac Asimov

Offline Count Zero

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Re: why was the usa the only one to go to the moon?
« Reply #459 on: January 30, 2013, 04:15:51 AM »
You could start to fly it by sighting the horizon with the LPD marks on the commander's window. But the horizon would quickly move off the top of the scale, so you'd need some another sighting reference on the LM. There's the overhead rendezvous window, but it's very small and you couldn't get close to it under acceleration. You could roll over on your back and sight the earth if it's in the right place, but then you can't see your ground landmarks for azimuth steering.


He could roll it on its side.  The vertical LPD axis would then line-up with the horizon.  He might still have azimuth errors, but he'd be in orbit and could finesse it from there, fuel allowing.
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Offline Glom

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Re: why was the usa the only one to go to the moon?
« Reply #460 on: January 30, 2013, 04:39:47 AM »
I'm pretty sure I've gotten into orbit when playing on space simulators through manual control. And that was launching from Earth.

Mind you, I'm not sure if I ever stuck around long enough to check if my perigee was really good enough.

Just get up to a decent altitude, point at the horizon, then burn until you can't burn anymore. It will be crude, but I'm counting on the CSM to come to the rescue.

The question whether the spacecraft will just go tumbling.

Offline Tedward

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Re: why was the usa the only one to go to the moon?
« Reply #461 on: January 30, 2013, 05:46:13 AM »
Slightly OT, I played a new demo a few years ago (it was new then and free, think it costs now). Kerbal space program? Not visited that game for a while but I found it tricky to get into orbit, not impossible but there in lies my problem. I only had on or two goes at it.

Offline ka9q

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Re: why was the usa the only one to go to the moon?
« Reply #462 on: January 30, 2013, 06:52:22 AM »
He could roll it on its side.  The vertical LPD axis would then line-up with the horizon.  He might still have azimuth errors, but he'd be in orbit and could finesse it from there, fuel allowing.
It might work. You'd have to estimate and control the angle between the LPD axis and the horizon, perhaps by using the small horizontal scale markings on the LPD; not sure what they were for. (Actually, this particular maneuver would be yaw, not roll. The LM axes were defined with respect to the astronauts' heads when in their flight positions, not with respect to the primary thrust axis.)

However, it would still be really important to control your launch azimuth. Otherwise you might well get into a stable orbit only to discover that your orbital plane is so far from the CSM's that you can't rendezvous with the available fuel. Even small plane changes can be very expensive in fuel, which is why the latitude of the launch site, the flight azimuth, and the launch time are all so important.

Perhaps you could do both by frequently yawing between heads down and heads to the side, or maybe even doing a continuous yaw that shows you the lunar surface, one horizon, the earth and the other horizon in sequence through the front windows.

The problem is that without a guidance system you'll have to continually compensate for the thrust vector not going directly through your center of mass. Note how even with a functioning guidance system all the LMs "wallowed" quite rapidly during ascent as the RCS engines were fired to compensate for this small unwanted torque from off-axis APS thrust. Come to think of it, a continuous yaw might help this problem too. Many satellite kick motors are fired with the satellite rolling around the thrust axis specifically to cancel out off-axis thrust.




« Last Edit: January 30, 2013, 07:03:46 AM by ka9q »

Offline Jason Thompson

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Re: why was the usa the only one to go to the moon?
« Reply #463 on: January 30, 2013, 07:57:46 AM »
So he had really good ankle strength?

Given the low gravity on the Moon, in any lifting exercise, including lifting his own weight, he had about six times the apparent strength in his muscles that he did on Earth.

While you're here, please explain how precisely the LM's lunar co-ordinates would need to be known in order to safely get into orbit and rendezvous with the CSM, and your claims to engineering expertise that don't match reality. Your earlier fake flounce does not absolve you of responsibility for those claims. They're still very much here on the table for discussion, and you have neither adequately defended nor retracted them.
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Offline Peter B

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Re: why was the usa the only one to go to the moon?
« Reply #464 on: January 30, 2013, 08:51:42 AM »
Please explain this clip.  The astronaut is clearly hoisted up while trying to stand up.  (it's cued at 2:05)
http://www.youtube.com/watch?feature=player_detailpage&v=Zz9Bzi_GyD0#t=125s
Did you keep watching? In the next clip the fake is supposedly achieved by filming at normal speed and then playing it back at half speed.

So which is it? Wires or half-speed film? Remember, in a single hour-long clip you can't switch between the two methods. (Someone on what's now Cosmoquest tried for something like that - reckoned that long shots were filmed in the desert while close-ups were filmed in a vacuum chamber, but didn't really have an answer for clips which contained both long shots and close-ups.)
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