posted 07-29-2010 10:31 AM               

I, when lecturing, explained it thus. If you have a car that starts first go 9 times out of 10, it is 90% reliable. If you have two cars that both start first go 9 times out of 10 then the pair taken together are not 90% reliable but 9/10 x 9/10 which is 81% reliable. For three cars the equation is 9/10 x 9/10 x 9/10 equalling a reliability of 72%.

posted 07-29-2010 10:39 AM               

Apart from the obvious proximity of the structure (or "Moose" as Mike Collins once called it), had one of the F1 first stage engines failed before the vehicle had cleared the tower, the remaining four engines would not have been powerful enough to maintain the upward motion and the rocket would have crashed back to earth! All down to physics I guess but that was never one of my strong school subjects.

By the time the tower was cleared, enough fuel had been consumed and weight shed to allow the vehicle to proceed on only four engines.

posted 07-29-2010 03:56 PM               

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Originally posted by Rick Mulheirn:
I discovered recently another significance of the term "Tower cleared" on a Saturn V launch.

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posted 07-30-2010 09:34 AM               

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Originally posted by spaced out:
It's difficult to see how such a huge effort in terms of budget, expertise and manpower would have been put together in such a short time if it hadn't been for the need to win the race to the moon against the USSR.

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posted 07-30-2010 01:15 PM               

Most here know that if that short would have occurred while Lovell and Haise were on the surface it would not have worked out. The same holds for anytime after the initiation of the descent to the surface, I would assume.

If it had happened after TLI, but earlier in the trip, could they have turned around with the DPS? Who knows? Could they have made it all the way around the moon? Probably not.

posted 08-01-2010 03:04 AM               

That each F-1 engine burnt 1 ton of kerosene and 2 tons of LOX every second.

posted 08-05-2010 05:40 PM               

That those lucky few applied 1960's communication technology to its best so that hundreds of millions would vicariously live the event;

posted 08-06-2010 12:54 PM               

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Originally posted by 328KF:
Along the lines of reliability (or odds, or probability), I am still amazed at the incredible good fortune of the Apollo 13 crew that the O2 tank let go when it did. How many times did they stir the tanks prior to that? How many times would they have done it later?

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Remember, too that the tank was originally installed on Apollo 10. What would have happened if, despite the dropping, it was reinstalled on that flight rather than 13?

posted 08-09-2010 05:51 PM               

The moon rocks were analyzed for signs of water bound to minerals present in the rocks; while trace amounts of water were detected, these were assumed to be contamination from Earth, because the containers the rocks came back in had leaked.

"The isotopes of oxygen that exist on the moon are the same as those that exist on Earth, so it was difficult if not impossible to tell the difference between water from the moon and water from Earth," said Larry Taylor of the University of Tennessee, Knoxville, who is a member of one of the NASA-built instrument teams for India's Chandrayaan-1 satellite and has studied the moon since the Apollo missions.

“We find that the moon rocks have 25 times the variability of terrestrial rocks,” said Sharp of the chlorine isotopes. “The only explanation is that the moon is anhydrous (waterless).”

Those rocks that have been reported, in recent years, to indicate the moon contains more water are not incorrect, said Sharp, but simply special cases. They probably do not represent the whole moon very well.

The discovery confirms, in a new way, what scientists found when they first looked at Apollo moon rocks: Every indication that the moon has always been a dry, dry place.

posted 08-09-2010 05:52 PM               

Your most amazing fact about Apollo

posted 08-10-2010 06:10 AM               

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Originally posted by Hart Sastrowardoyo:
What would have happened if, despite the dropping, it was reinstalled on that flight rather than 13?

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posted 08-10-2010 07:47 AM            

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Originally posted by moorouge:
Even more amazing is that the tank wouldn't have dropped if someone hadn't gone to lunch before completing the job.

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posted 08-10-2010 09:15 AM               

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Originally posted by Henry Heatherbank:
Huh, never heard that one before. What's the story?

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posted 08-11-2010 07:13 PM               

I have shook hands with 9 of the 12 moonwalkers and Naval Aviator #44 (retired in 1936). He had a pilot's license signed by Orville Wright.

posted 08-11-2010 08:00 PM            

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Originally posted by Robert Pearlman:
Then again, even more recent studies of the moon rocks now suggest the Moon's interior is bone dry.

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The key point about the Saal findings (which could only have been made in recent years because measuring equipment was not sensitive enough until recently) is that the water is in the centre of the glass beads and the concentration gets less and less towards the outside of the beads. That rules out contamination by water on Earth after the samples were returned and also rules out contamination by comet ice. The glass "beads" were thrown up from the Moon's interior by volcanic fire-fountains. As you have pointed out, Taylor acknowledges that this is a "special case" and probably not widely representative of the Moon as a whole.

The key point about the lack of water in most lunar samples, contrasted with the finding of water in the deep fire-fountain samples, is what this might tell us about the origin of the Moon.

Most lunar geologists now accept that the Moon coalesced out of a cloud of debris caused by an impact between a Mars-sized body and the Earth about 4.6 billion years ago. Harrison Schmitt has argued* that it is more likely that the Moon consists mostly of the impactor, with very little Earth material.

My understanding (although this is a rather complex and esoteric subject possibly best left to experts like Schmitt, Taylor and Saal!) is that moisture is more likely to have evaporated from a cloud of debris which would have taken time to coalesce into the Moon.

On the other hand, if a large chunk of impactor survived to form the kernel of the Moon, that chunk is more likely to have retained some of its original water (some of which remained locked in the centre of volcanic glass beads).

In short, I believe the Saal findings remain valid, even if there is a valid debate about how much of a "special case" the findings are.

posted 08-11-2010 08:31 PM               

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Originally posted by Blackarrow:
I see nothing in the Larry Taylor findings to negate the Alberto Saal discovery of traces of water in Apollo samples of volcanic beads.

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I had intended only to comment on the "not until 2008" part of your post -- raising the circa 1970s findings that were dismissed as contamination.

posted 08-11-2010 09:49 PM               

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Originally posted by davidcwagner:
Anyone out there who has shook hands with both a Wright and a Moonwalker?

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posted 08-12-2010 12:03 PM            

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Originally posted by davidcwagner:
Anyone out there who has shook hands with both a Wright and a Moonwalker?

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The famous British astronomer Sir Patrick Moore (who has been presenting his monthly "Sky at Night" TV programme since April, 1957) met (and presumably shook hands with) both Orville Wright and Neil Armstrong (and probably all 11 other Moonwalkers). I have shaken hands with Sir Patrick, so I am also one handshake away from Kitty Hawk!

posted 08-12-2010 05:50 PM            

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Originally posted by Robert Pearlman:
Apologies, I muddled my own reply.

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posted 08-12-2010 06:22 PM            

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Originally posted by moorouge:
If you have a car that starts first go 9 times out of 10, it is 90% reliable. If you have two cars that both start first go 9 times out of 10 then the pair taken together are not 90% reliable but 9/10 x 9/10 which is 81% reliable. For three cars the equation is 9/10 x 9/10 x 9/10 equalling a reliability of 72%.

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I thought that the reliability of two vehicles which start and which each have a reliability of 90% is 1 - (1-0.9)*(1-0.9) = 1-0.01 = 99%, and the reliability of three vehicles which start and have the same reliability of 90% each is 1 - (1-0.9)*(1-0.9)*(1-0.9) = 1 - 0.001 = 99.9%.

posted 08-12-2010 06:34 PM               

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Originally posted by Robert Pearlman:
Then again, even more recent studies of the moon rocks now suggest the Moon's interior is bone dry.

"We find that the moon rocks have 25 times the variability of terrestrial rocks," said Sharp of the chlorine isotopes. "The only explanation is that the moon is anhydrous (waterless)."

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Carnegie Institute of Science: Moon Whets Appetite for Water:

Scientists at the Carnegie Institution's Geophysical Laboratory, with colleagues, have discovered a much higher water content in the Moon's interior than previous studies. Their research suggests that the water, which is a component of the lunar rocks, was preserved from the hot magma that was present when the Moon began to form some 4.5 billion years ago, and that it is likely widespread in the Moon's interior. The research is published in the on-line early edition of the Proceedings of the National Academy of Sciences the week of June 14.

"For over 40 years we thought the Moon was dry. The bulk water content of the Moon was estimated to be less than 1 ppb, which would make the Moon at least six orders of magnitude drier than the interiors of Earth and Mars," remarked lead author Francis McCubbin. "In our study we looked at hydroxyl in the mineral apatite -- the only hydrous mineral in the assemblage of minerals we examined in two Apollo samples and a lunar meteorite.

Summarizing his team's method and results, McCubbin explained, "In the lab of colleague Erik Hauri at Carnegie's Department of Terrestrial Magnetism, we used secondary ion mass spectrometry (SIMS), which can detect elements in the parts per million range and combining these measurements with models that characterize how the material crystallized as the Moon cooled during formation, we found that the minimum water content ranged from 64 parts per billion to 5 parts per million--at least two orders of magnitude greater than previous results."

That dry, dusty moon overhead? Seems it isn't quite as dry as it's long been thought to be. Although you won't find oceans, lakes, or even a shallow puddle on its surface, a team of geologists at the California Institute of Technology (Caltech), working with colleagues at the University of Tennessee, has found structurally bound hydroxyl groups (i.e., water) in a mineral in a lunar rock returned to Earth by the Apollo program.

Their findings are detailed in this week's issue of the journal Nature.

"The moon, which has generally been thought to be devoid of hydrous materials, has water," says John Eiler, the Robert P. Sharp Professor of Geology and professor of geochemistry at Caltech, and a coauthor on the paper.

"The fact that we were able to quantitatively measure significant amounts of water in a lunar mineral is truly surprising," adds lead author Jeremy Boyce, a visitor in geochemistry at Caltech, and a research scientist at the University of California, Los Angeles.

posted 08-12-2010 09:39 PM               

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Originally posted by minipci:
Am I missing something? Or is my probability wrong?

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If you only need one car to get around, you're good to go. But if you need your entire fleet to operate for mission success, you'll run into problems.