LEM : Not enough Fuel on Board to return

[blackbriar1]

This is the part i don`t get so i will make short verbiage of it.

I understand the enormous Saturn V rocket and mass fuel payload used to get out of earths gravity to outer space and all the complex math used to have it running a straight bee line for the moon once up in space given the earths rotational speed etc......etc...
Sorta point and shoot if you will at the right time.

The service module is orbiting the Moon, the LEM lets go and does a controlled decent to the Moons surface and burns off it`s first tank of hydrazine with ten seconds left to spare. and not landing exactly where planned, but they make it,....touch down.
Who`s doing all the new math in relation to where they don`t know exactly where they are at now sitting still on the moons surface and the Service module making an orbit every 25 minutes or thousands of miles per hour.

Now it`s time for lift off to break the Moons lesser gravity burning mass fuel to meet the orbiting service module going how many thousand miles per hour.

Are they going to crash head on, overshoot their trajectory, come from behind and miss it altogether without enough fuel to catch it because it`s speed is moving at constant velocity or even find the service module at all , way up there ? being no bigger in diameter than my own driveway trying to link up to a Metro sized bus?

Even with the 1969 computer and possible radar system ???
Like threading a needle from a mile away. Time....time becomes very fluid and difficult to handle in such a tight trigonometric calculation especially when there are no known controlled reference points to calculate the math off of or launch timing from the moons surface..

How they going to be able to link up, get into the same plane of orbit and have all this extra fuel on board the LEM to catch up and dock up with the Service Module? when they barley had enough to drop out of space and do a controlled decent.
Put it all together and the little amount of fuel the LEM carried on board in its second tank to do all this work with plenty left over ?

OH! Yea, who did the spacewalk and go out to the leg of the LEM after it was docked onto the service module and retrieve the film out of the camera?
You know the film roll that didn`t get damaged or melted from hydrazine burn nozzle, those low angle pictures with the leg mounted camera that recorded mankind's first step onto the moon without anyone else there taking the picture or moon dust on the lens?
If i remember that first prototype picture of the testing LEM on the earths surface, weren`t the leg footprints much further apart than the actual LEM`s to avoid the heat of the rockets main thrust nozzle?

Not sure how that leg mounted Hasslblad took all that close proximity heat and survived?
The LEM got dumped in space before coming home, so someone had to do a spacewalk to get the film or even if it was some kind of link video camera, did they have a small tv station on board? And again with the moon dust on the lens? What did they have? A remote controlled dust proof pop off lens cover to record the event? All mystifying.......chain of perfect events.....

I would love some input on this??

I`m no physicist or mathematician but i did manage a couple years college, at least enough to understand that triangulation and speed are a difficult thing to calculate when objects are moving.

[gillianren]

And isn't it a marvel that they worked it out? I certainly couldn't have.

[scooter]

For starters, the LM had two parts (stages),...the the descent module, the lower octagonally shaped part, which carried the fuel and engine to make the lunar landing. The vast majority of it's fuel was used in the landing, and this engine was not used again...the descent stages all still rest on the Moon today.

The ascent module, where the astronauts lived while on the Moon, also had it's own fuel supply and engine for the trip from the surface to the CM/SM (CSM) orbit for rendezvous. The engine and fuel were used to get it into the proper orbit to join the CSM, then the ascent stage's maneuvering (RCS) thrusters were used for fine tuning and stationkeeping with the CSM. The CSM performed the final docking maneivers.

[randombloke]

OH! Yea, who did the spacewalk and go out to the leg of the LEM after it was docked onto the service module and retrieve the film out of the camera?
You know the film roll that didn`t get damaged or melted from hydrazine burn nozzle, those low angle pictures with the leg mounted camera that recorded mankind's first step onto the moon without anyone else there taking the picture or moon dust on the lens?
If i remember that first prototype picture of the testing LEM on the earths surface, weren`t the leg footprints much further apart than the actual LEM`s to avoid the heat of the rockets main thrust nozzle?

All of this is wrong. Or at least based on a patently false premise.
Specifically; you don't normally get film out of a TV camera. So no-one performed your mysterious and unnecessary spacewalk. And neither did the non-existent film suffer any chance of being damaged by anything.

Also, no LEMs were ever tested on Earth. Individual component design prototypes might have been bench-tested, but no assembled LEM was ever fired up in 1g, for the simple reason that it would not have functioned correctly, what with being designed to function in a 1/6g vacuum at most.

What was flown on Earth were the training simulators affectionately known as the flying bedsteads, which were designed with a turbofan engine and uprated RCS thrusters to provide equivalent reactions to the controls but in full gravity. Those, of course, in no way physically resembled the equipment that landed, except for the controls themselves.

[blackbriar1]

Scooter,
Politely i understand your comment? i`m a bit rusty on the mechanical details of the ship itself but do remember now of the little craft blasting off the LEM module, however,

I understand the ability to triangulate from light waves, radio signals etc.. but in 1969 you have men on the ground using slide rules, men in the spacecraft using slide rules, an X= value of fuel quantity on board, trying to calculate some very complex algorithms and timing variables on slide rules and limited amount of time of life support, attempting a timed blast off plus thrust and vectoring variables trying to cross hairs with an orbiting vessel moving at thousands of miles an hour, hit or miss.
Not only did they miss their landing vector, but how did they know where their relationship was to this orbiting service module?

How does a quarterback hit his receiver? Judgment and experience, judging the receiver running speed and throwing the ball with enough thrust, lead angle, and leading the throw ahead of the receiver for everything to meet at the exact very moment......to much algorithmic calculation for a simple slide rule.

Like i had mentioned in my post, threading a needle from a mile away in 1969 ?
And they only had one chance at it or they were finished.

I doubt that little space craft had enough fuel on board just to make it into orbit let alone find it`s mother. A blind deaf calf would have more success finding it`s own mothers single dry teet.

[LunarOrbit]

Mar 5, 2010 15:26:15 GMT -4 blackbriar1 said:

I doubt that little space craft had enough fuel on board just to make it into orbit let alone find it`s mother.

How much fuel did it have and how much was required? So far all I've seen from you is "I don't understand how it worked, therefore it must have been faked!"

[tedward]

As I understand it (and await the correction) you aim for where the moon will be, some orbital maths works out how fast and course corrections etc. These were done by some very experienced people and main frame computers back at mission control during the flight and course info sent up over the radio. They also did it all before to check and double check. The maths that is. Otherwise how would they have known they could get there?

So, on the way to where the moon will be. Nice big gravity thing as it is, it provide an object to use and abuse for landing or in the case of 13 a means to get home.

I would ask in stead of doubting the fuel, why not find out what was required?

Can you clarify your idea on the camera? I thought that the CM pilot did indeed retrieve film but that was from the service bay used when the others were on the surface. The landing shots of Armstrong were sent live.

[randombloke]

Why do you doubt it blackbriar? Just because you can't work it out doesn't mean nobody can. And what's wrong with slide-rules? They are fast and accurate - if they weren't, it would have been practically impossible to design the first computer, back in the 19th century. And as for calculating locations accurately; all you need is a reliable clock and angular measure, both of which were basically perfected before 1900. That is how GPS works, after all.

All you've posted so far is incredulity.* Care to try for some facts?



*Sorry LO, he hasn't even got as far as denying anything yet, though I don't doubt it's coming...

[blackbriar1]

RandomBloke,
I can accept your criticism now that scooter reminded all of us that the lower end of the LEM stayed on the moon, so there was no need for an unnecessary spacewalk to retrieve anything.
Thank-You for mentioning that fact.

I propose to you this concerning a damaged camera anything whether non-existent or real, some type of recording devise was mounted outboard on the LEMS landing leg to capture everything low level coming down the ladder stepping onto the moons surface.

I can`t imagine the LEM being no greater than 25 feet in diameter which radius value would be in the neighborhood of 12 to 15 feet from the center of the LEMS 10K lb. thrust nozzle burning liquid hydrazine fuel? The landing stage.

How could such a sensitive camera without a lens cap withstand the sonic reverberations from such a close proximity let alone the outward heat source?

I have read some of the theory's on thermal conductivity in a minus zero vacuum atmosphere which would indicate either hypothetically i could stick my bare hand into the cone of this raging fire and not get burned, or a sensitive camera 12 feet away could suffer some possible damage?? Actually, probably less than 12 feet at the cones most largest diameter outer ring?

[laurel]

Mar 5, 2010 15:52:09 GMT -4 tedward said:

I thought that the CM pilot did indeed retrieve film but that was from the service bay used when the others were on the surface. The landing shots of Armstrong were sent live.

The CMPs retrieved film from the panorama and mapping cameras, but that was only on the last three missions. And it was retrieved from the Service Module, not the LM.
history.nasa.gov/ap15fj/23day11_worden_eva.htm
history.nasa.gov/ap16fj/27_Day10_Pt2.htm

[laurel]

Mar 5, 2010 15:26:15 GMT -4 blackbriar1 said:

I doubt that little space craft had enough fuel on board just to make it into orbit let alone find it`s mother. A blind deaf calf would have more success finding it`s own mothers single dry teet.

It is worth mentioning that rendezvous was something the Americans first performed in 1965 with Gemini 6 and 7. Gemini 8, 9, 10, 11 and 12 all involved rendezvous with unmanned craft. The crews of Apollo 9 and 10 had tested the LM and practiced rendezvous and docking with it. I think it's safe to say that when it came to rendezvous in lunar orbit, the Apollo astronauts were well prepared and knew what they were doing.

[tedward]

Mar 5, 2010 16:28:44 GMT -4 laurel said:

Mar 5, 2010 15:52:09 GMT -4 tedward said:

I thought that the CM pilot did indeed retrieve film but that was from the service bay used when the others were on the surface. The landing shots of Armstrong were sent live.

The CMPs retrieved film from the panorama and mapping cameras, but that was only on the last three missions. And it was retrieved from the Service Module, not the LM.
history.nasa.gov/ap15fj/23day11_worden_eva.htm
history.nasa.gov/ap16fj/27_Day10_Pt2.htm

Ah. Got it, last few. Remember coming across this a while ago, knew it was the CM.
link

[blackbriar1]

"a reliable clock and angular measure, both of which were basically perfected before 1900. That is how GPS works, after all."

GPS wasn`t in 1969 and i highly doubt NASA would fly off a Seth Thomas and a yard stick with a plumb bob.

I doubt Apollo had either one on board when the were getting ready to supposedly leave the moons surface.

Incredulity and doubt ?, i haven`t heard a single comment that was anything other than that including void of any facts in relation to the comment or question.

[laurel]

If the Gemini spacecraft could rendezvous, why couldn't the Apollo spacecraft do it?

[blackbriar1]

Laurel,
I get that part of practice , practice, but those practices were not done thrusting off a stationary point moving past gravity and attempting to rendezvous or intersect with another vessel moving at what speed? and getting into it`s same plane of orbit, both a vertical and horizontal movement or complex interpolation.