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Apollo 13 LM upper stage.
On Mar 1, 6:31*am, Pat Flannery wrote:
On 2/28/2011 12:47 PM, Ken S. Tucker wrote: It was challenging enough to have the LM thrust the CSM load, something it was never designed for, or spec'd for, but Grumman put enough balls into the upper-LM stage to do it! It also had to sustain heavy loads on the docking collar then the CSM braked itself and the LM into lunar orbit. Pat my point was that if the upper LM had been detached at the same time the still attached LM was there was likely enough fuel to put the LM upper stage in earth orbit or heliospheric. I didnt say it was a good idea..... imagine though a museum display. here we have the apollo 11 LM upper stage, its lower half is still on the moon undisturbed/ Over here we have the apollo 13 LM upper stage from the flight with the explosion over here is the hubble space telescope, at its end of use nasa boosted it into a high stable orbit, it was recently retrieved by shutte 2. here we have snoopy, and a saturn booster that was lost in heliospheric orbit for over 80 years. sad most of this is impossible |
#12
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Apollo 13 LM upper stage.
On Mar 1, 8:07*am, " wrote:
On Mar 1, 6:31*am, Pat Flannery wrote: On 2/28/2011 12:47 PM, Ken S. Tucker wrote: It was challenging enough to have the LM thrust the CSM load, something it was never designed for, or spec'd for, but Grumman put enough balls into the upper-LM stage to do it! It also had to sustain heavy loads on the docking collar then the CSM braked itself and the LM into lunar orbit. Pat my point was that if the upper LM had been detached at the same time the still attached LM was there was likely enough fuel to put the LM upper stage in earth orbit or heliospheric. I didnt say it was a good idea..... imagine though a museum display. here we have the apollo 11 LM upper stage, its lower half is still on the moon undisturbed/ Over here we have the apollo 13 LM upper stage from the flight with the explosion over here is the hubble space telescope, at its end of use nasa boosted it into a high stable orbit, it was recently retrieved by shutte 2. here we have snoopy, and a saturn booster that was lost in heliospheric orbit for over 80 years. sad most of this is impossible after the LM was jettisoned could the ground seperated the upper stage and commanded a burn of its upper stage to send it heliospheric? this wouldnt of added any work onboard just wondering............. |
#14
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Apollo 13 LM upper stage.
On Mar 1, 3:31 am, Pat Flannery wrote:
On 2/28/2011 12:47 PM, Ken S. Tucker wrote: It was challenging enough to have the LM thrust the CSM load, something it was never designed for, or spec'd for, but Grumman put enough balls into the upper-LM stage to do it! It also had to sustain heavy loads on the docking collar then the CSM braked itself and the LM into lunar orbit. Pat "heavy loads", Not really, 1 inch / sec is an easy closing speed. (I can sim a soft landing on the moon doing that, so can automated landings). The LEM was between the descent stage engine and the CSM and the descent engine had a minimum thrust, obviously within specs. Ken |
#15
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Apollo 13 LM upper stage.
On 3/1/2011 6:31 PM, Ken S. Tucker wrote:
On Mar 1, 3:31 am, Pat wrote: On 2/28/2011 12:47 PM, Ken S. Tucker wrote: It was challenging enough to have the LM thrust the CSM load, something it was never designed for, or spec'd for, but Grumman put enough balls into the upper-LM stage to do it! It also had to sustain heavy loads on the docking collar then the CSM braked itself and the LM into lunar orbit. Pat "heavy loads", Not really, 1 inch / sec is an easy closing speed. (I can sim a soft landing on the moon doing that, so can automated landings). No, when the CSM with the LM attached to its nose entered lunar orbit, it used the big service module engine to do it. The service module engine produced 21,900 lbs. thrust. This would be pushing on the heavy fully-fueled LM's docking collar. When they fired up the LM descent engine on Apollo 13 its total thrust when running full-out was only 10,125 lbs. and they may not have run it at full thrust either. Push on it from the CSM side or from the LM side and the total stress on the docking collar assembly remains the same. Pat |
#16
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Apollo 13 LM upper stage.
On Mar 2, 8:54 am, Pat Flannery wrote:
On 3/1/2011 6:31 PM, Ken S. Tucker wrote: On Mar 1, 3:31 am, Pat wrote: On 2/28/2011 12:47 PM, Ken S. Tucker wrote: It was challenging enough to have the LM thrust the CSM load, something it was never designed for, or spec'd for, but Grumman put enough balls into the upper-LM stage to do it! It also had to sustain heavy loads on the docking collar then the CSM braked itself and the LM into lunar orbit. Pat "heavy loads", Not really, 1 inch / sec is an easy closing speed. (I can sim a soft landing on the moon doing that, so can automated landings). No, when the CSM with the LM attached to its nose entered lunar orbit, it used the big service module engine to do it. The service module engine produced 21,900 lbs. thrust. This would be pushing on the heavy fully-fueled LM's docking collar. When they fired up the LM descent engine on Apollo 13 its total thrust when running full-out was only 10,125 lbs. and they may not have run it at full thrust either. Push on it from the CSM side or from the LM side and the total stress on the docking collar assembly remains the same. Pat Not quite sure your thesis holds Pat, cuz the CSM is quite a bit heavier than the Descent Stage, so the force = mass x acceleration would need to be all figured out. Ken |
#17
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Apollo 13 LM upper stage.
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#18
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Apollo 13 LM upper stage.
On 3/2/2011 12:02 PM, Ken S. Tucker wrote:
No, when the CSM with the LM attached to its nose entered lunar orbit, it used the big service module engine to do it. The service module engine produced 21,900 lbs. thrust. This would be pushing on the heavy fully-fueled LM's docking collar. When they fired up the LM descent engine on Apollo 13 its total thrust when running full-out was only 10,125 lbs. and they may not have run it at full thrust either. Push on it from the CSM side or from the LM side and the total stress on the docking collar assembly remains the same. Pat Not quite sure your thesis holds Pat, cuz the CSM is quite a bit heavier than the Descent Stage, so the force = mass x acceleration would need to be all figured out. CSM weighed 66,871 pounds; LM weighed 32,399 pounds. (Wikipedia) Since CSM weighs around twice as much as LM, but SM engine generates twice as much thrust as LM descent engine, stress on the docking collar would be nearly identical in both situations. And that assumes LM engine was run at full thrust. Does anyone know if that was the case in Apollo 13? They would get a lot better velocity control at LM engine shutdown if they ran it longer at lower thrust. Pat |
#19
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Apollo 13 LM upper stage.
On Mar 3, 3:41*am, Pat Flannery wrote:
On 3/2/2011 12:02 PM, Ken S. Tucker wrote: No, when the CSM with the LM attached to its nose entered lunar orbit, it used the big service module engine to do it. The service module engine produced 21,900 lbs. thrust. This would be pushing on the heavy fully-fueled LM's docking collar. When they fired up the LM descent engine on Apollo 13 its total thrust when running full-out was only 10,125 lbs. and they may not have run it at full thrust either. Push on it from the CSM side or from the LM side and the total stress on the docking collar assembly remains the same. Pat Not quite sure your thesis holds Pat, cuz the CSM is quite a bit heavier than the Descent Stage, so the force = mass x acceleration would need to be all figured out. CSM weighed 66,871 pounds; LM weighed 32,399 pounds. (Wikipedia) Since CSM weighs around twice as much as LM, but SM engine generates twice as much thrust as LM descent engine, stress on the docking collar would be nearly identical in both situations. And that assumes LM engine was run at full thrust. Does anyone know if that was the case in Apollo 13? They would get a lot better velocity control at LM engine shutdown if they ran it longer at lower thrust. Pat- Hide quoted text - - Show quoted text - vaguely i think course correction burns were pretty long which would indicate not full throttle... |
#20
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Apollo 13 LM upper stage.
On Thu, 03 Mar 2011 00:41:23 -0800, Pat Flannery
wrote: And that assumes LM engine was run at full thrust. Does anyone know if that was the case in Apollo 13? Remember, Aquarius fired its DPS engine three times: Free Return (MET 61:29:43), PC+2 (MET 79:27:39) and Course Correction (MET 105:18:28). According to Lovell's _Lost Moon_, the Free Return burn started at low throttle and then went up to 40%. The PC+2 burn was 5 seconds at minimum thrust, then 21 seconds at 40% thrust, and finally 4 minutes at full thrust. Lovell handled the throttle, the computer handled the timing. The Course Correction burn was at low throttle (10%). Brian |
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