Talk:Apollo Lunar Module/Archive 1

Archive 1

Lunar lander redirect

Noted that Lunar lander redirected here. Perhaps it should go to Lunar Lander instead, or have some sort of disambig page? — Preceding unsigned comment added by 198.164.41.228 (talk) 14 September 2005

I've added some disambig notices to the top of the respective articles. Evil Monkey∴Hello 21:02, 14 September 2005 (UTC)

3, 4, or 5 legs?

This statement needs clarification:

"The initial design iteration had the LEM with three landing legs. It was felt that three legs, though the lightest configuration, was the least stable if one of the legs were damaged during landing. The next landing gear design iteration had five legs and was the most stable configuration for landing on an unknown terrain. That configuration was too heavy and the compromise was four landing legs."

Where did this information come from?

The initial LEM Statement of Work that went out to the 11 companies that bid on the LM is dated July 1962. It shows an LM with four legs. Of course, this was just a initial drawing, and NASA did not specify a preferred number of legs. The "Chariots for Apollo: A History of Manned Lunar Spacecraft" reference that is in the document states that Grumman started with 5 legs in 1963 and then went to four because of the shape of the descent stage and because it fit better in the adapter during launch. Cjosefy 17:09, 21 September 2006 (UTC)

This page specifically says:

...Grumman advised that, from the standpoint of landing stability, a five-legged LEM was unsatisfactory. Under investigation were a number of landing gear configurations, including retractable legs.

--62.243.82.106 (talk) 09:04, 25 February 2009 (UTC)

Landing legs manufacturer

I've heard a Canadian company built the landing legs. Anybody know which one it was? Trekphiler 15:13, 26 August 2007 (UTC)

Heroux-Devtek from Longueuil, Québec (south shore of Montréal) built the lander's landing gears.

http://www.herouxdevtek.com/

http://www.herouxdevtek.com/aboutus/history.php —Preceding unsigned comment added by 75.185.80.181 (talk) 00:02, 9 July 2008 (UTC)

Thanks so much. (My definitely includes ) TREKphiler 08:40, 9 July 2008 (UTC)

Consistency of numerals?

If we're aiming for consistency, shouldn't it be with the original? And didn't NASA use Roman numerals? (Which is why I changed it...) TREKphiler ^{hit me ♠} 16:47, 14 July 2008 (UTC)

Not sure what you mean by "the original"? As every other Wikipedia page about the Apollo missions uses Arabic numerals, I'm going to revert the one change you made so this page is consistent with the others. You're right in that NASA used Roman numerals for the Gemini missions, however they used Arabic for Apollo. Although, having said that, if you look at the mission patches, several of them use Roman, although they were designed by the astronauts, so it would be down to their personal taste. Hopefully this makes sense. --Whoosher (talk) 16:01, 15 July 2008 (UTC)

It do, & obviously I haven't seen enough of the NASA materials. The designators & patches I've seen have all been Roman numerals. TREKphiler ^{hit me ♠} 14:36, 17 July 2008 (UTC)

Grumman contract

I seem to remember that Grumman's bid for the LM was "cost plus $1". Can anyone reference that and add it to the article? Bubba73 (talk), 06:11, 6 February 2009 (UTC)

Where are they now?

Maybe I haven't read the article sufficiently well, but I can't see anything here which describes the fate of the LMs. Are they still in Lunar Orbit? —Preceding unsigned comment added by 150.101.31.57 (talk) 22:41, 1 April 2009 (UTC)

Why two engines?

I've been wondering why the LM had two engines, a descent and ascent engine, when one would do the job and save a lot of weight. Have it built into the ascent stage, of course, and in the sapce where the decent engine was just have an extension on the rocket bell. I've heard that NASA wanted some redundancy in the craft, hence two engines, but the CM only has the single engine, it was required to fire several times and it it failed then the astronauts would have been equally stranded anyway. Just curious. Billzilla (talk) 15:17, 20 July 2009 (UTC)

Studies indicated little weight difference between a one and two-engined lander. The two-engined design was chosen for redundancy. The descent engine had to be throttleable, which was a more complex design than the fixed-thrust ascent engine or service module engine. This increased the need for a redundant backup using the ascent engine. If the service module engined malfunctioned, there was time to troubleshoot. During a lunar landing with a single engine, there would be little time for that. Joema (talk) 16:58, 20 July 2009 (UTC)

Good answer, thanks for that. Billzilla (talk) 03:20, 21 July 2009 (UTC)

"Successors" section breaks the flow

I think documenting the details of the Altair lander here is inappropriate and breaks the flow of the article. It especially may be moot now that Our Genius President has seen fit to assassinate the program. I have no objection to including a brief reference to it with a link to the article, under a section titled Proposed Successors (remember Wikipedia Is Not a Crystal Ball) if there is concern about the Altair article being orphaned (as the President seems to want to do to the actual program.) :-)

I also think the Apollo Telescope Mount needs to be moved up with the LM Truck into a separate section titled Proposed Derivatives since these were both not actually implemented, and the ATM wasn't really used as such in the real Skylab (the paragraph also needs to be revised slightly for accuracy.)

I think the article progresses nicely up until the LM Truck section and then it's slowed to a crawl. If I hear no objections, I will implement this soon. JustinTime55 (talk) 16:56, 18 February 2010 (UTC)

LLRV

The History section's description of the LLRV is incorrect (or at least incomplete and misleading.) The LLRV (later LL Training V) was a vehicle the astronauts actually flew around in, not a crane, designed and built at Edwards AFB and operated at the Houston MSC. The Langley article states NASA used a crane-mounted "LM mockup" to conduct landing simulations there. JustinTime55 (talk) 15:02, 1 March 2010 (UTC)

That was the "flying bedstead" rig, yes? The one Neil crashed? TREKphiler ^{any time you're ready, Uhura} 21:52, 1 March 2010 (UTC)

Yes, that's the one. If you look at the article, it says that three of the five crashed (implying it was risky to fly), but apparently all pilots (including Armstrong) ejected safely. I considered mentioning this in the article. What do you think? JustinTime55 (talk) 14:42, 2 March 2010 (UTC)

I'd put it in. It wasn't risky, as I understand, as much as damn difficult (which may amount to the same thing ;p). I've heard it compared to flying a helo, but harder. The difficulty suggests the level of skill in putting the LEM down safely, & emphasises Neil's fine control in skating across the surface on short fuel. As an aside, I have a vague recollection a similar rig was used to train Harrier pilots; if true, it may merit a mention by way of comparison. TREKphiler ^{any time you're ready, Uhura} 16:21, 2 March 2010 (UTC)

Helium pressures

Does anyone know where to find verification of the true helium pressures? Where did the ones given in the article come from? The ascent stage value was given as 21 MPa which is 3000 psi; sounds about right. But the descent stage value was given as 10.7 kPa which is only 1.555 psi, which doesn't sound right at all. I just guessed it was supposed to be MPa too, but 1,555 psi is still only about half the APS value. ??? JustinTime55 (talk) 21:56, 3 March 2010 (UTC)

Apollo 13 did not explode

The accident on Apollo 13 was a violent rupture of the O2 tank, not an explosion, and such was determined by NASA in its review of the incident. The Apollo 13 article corrects this long-standing mis-impression, as supported on its discussion page.

Most people probably think the Space Shuttle Challenger disaster was an explosion also, but notice that article careflully explains the similarly misunderstood event and says the craft broke up or disintegrated, not "exploded". JustinTime55 (talk) 20:44, 15 March 2010 (UTC)

Thrust figures

Thrust is incorrectly converted to metric units in both AS and DS, you are missing a factor of ten. The thrust to weight ratio is related to the weight on earth which does not make sense, and should read 2.1:1 as the initial AS weight on the moon is only about 7600 N while thrust is 15600 N. Please correct. —Preceding unsigned comment added by 84.73.51.121 (talk) 17:13, 1 April 2010 (UTC)

I corrected the thrust to weight; whoever produced the original number must have been confused. But I don't see what you mean about the thrusts; they all look correct in pounds, and I calculate 2.12 as thrust-to-weight.

I used the units conversion template for thrusts and weights (and double-checked them against a hardcopy reference), so the Newton values should be correct (I don't happen to have the pounds-to-Newtons conversion factor at hand.) Are you sure you weren't multiplying the kilograms weight by the thrust-to-weight? I know the Newtons/kilograms conversion is about 9.8 (close to ten.) (That's an advantage of the English system; as long as you ignore the difference between mass and weight and use pounds instead of the actual mass unit, thrust-to-weight is easy to calculate.) JustinTime55 (talk) 18:10, 1 April 2010 (UTC)

Okay, I see the problem (coded lb for pounds-mass instead of lbf pounds-force) and someone corrected it in the infobox. However it was missed in the article body, and I just corrected that. JustinTime55 (talk) 19:31, 1 April 2010 (UTC)

Weight reference in lead

I wonder about the clause in the lead section pointing out the CSM was "approximately twice as heavy." Is that factoid relevant to the lead section? (Mass, of course, is more significant in microgravity than weight to begin with). RadioBroadcast (talk) 02:41, 29 April 2010 (UTC)

Yes, I think it is. Three points:

• I added the brief description of the CSM to the lead because the LM can't fly its intended mission without it. Do you really think four words bloat the lead?

And as it happened, being twice as heavy (massive) turned out to be relevant on Apollo 13, when the LM's RCS had to be used to control the attitude of the complete CSM/LM stack. Captain Lovell described it in Lost Moon as "trying to fly while holding a dead elephant [the CSM] over your head." (You may remember Tom Hanks saying this line in the movie.) The reasons for this have to do with center of gravity and moment (physics), which puts the CG closer to the CSM's RCS than the LM's because of the difference in weight (mass). Under normal conditions, the lighter LM didn't "feel like a dead elephant" to the CSM's RCS. It might be a good idea to mention this in the body of the article where Apollo 13 is mentioned.

• I think it would be pedantic to insist on a strict distinction between mass and weight in this context. The difference is only significant if you're doing flight dynamics calculations of the craft in space. By definition there's a one-to-one correspondence between a pound mass and a pound weight on Earth, and it's intuitive for most laymen to think that way. It's perfectly reasonable to talk about spacecraft weights which is common practice. Every pound of mass sent into space is a pound of weight that the launch vehicle had to lift off of Earth.
• This is parenthetical to the point, but you happen to be repeating a common mistake in using the word factoid this way. Most people probably mistakenly assume the "-oid" suffix means little, but android refers to a robot designed to look like a man, rather than to a male dwarf; and humanoid refers to an extraterrestrial being with characteristics similar to a human, rather than to a child.

Therefore the suffix "-oid" really refers to something that looks like something else, but really isn't. So a factoid is actually not a piece of trivia, but an unverified (probably untrue) statement that looks like a fact but isn't (necessarily), which of course we're all trying to keep out of the Wikipedia. JustinTime55 (talk) 16:57, 30 April 2010 (UTC)

Thank you for your characterization of my use of factoid; however, I would refer you to the Wikipedia definition, which notes "the word can sometimes mean, instead, an insignificant but true piece of information." RadioBroadcast (talk) 04:22, 2 May 2010 (UTC)

I changed heavy to massive in the lead; it may be true that many readers do not care about the difference but that is no reason to use the less accurate term when both are easily understood. Some easily understood description of the proportions between the two craft is important; I don't know if the lead is the best place or not. Jminthorne (talk) 05:55, 2 May 2010 (UTC)

Reason for change from LEM to LM

Aha -- so that explains it. Sounds logical; do you have a citation, to keep it strictly kosher? JustinTime55 (talk) 20:09, 11 May 2010 (UTC)

Fuel reserve technique on Extended class missions

Do we have a source for the Service Module Powered Descent Initiation tactic? (I don't remember it being advertised at the time.) Also, did the CSM keep the 50,000 ft. pericynthion for its scientific observations? I would think they would have wanted to go back to the circular orbit for the rendezvous, and it would have had to at least done some kind of separation burn to avoid following the LM to its pericynthion, for safety sake. JustinTime55 (talk) 21:35, 7 June 2010 (UTC)

"Confusion" over Lunar Module Pilot title

O'Dea: Explicitly describing the function was not what I was calling non-encyclopedic. If you want to describe the pilots' (plural) functions, that's fine. I was thinking of the tone or style of phrases like "confusingly", or "despite his title".

I don't think you have any basis to conclude that confusion over the meaning of "pilot" is widespread. The term is used generically to refer to anyone in the business of flying (or controlling a boat), as well as to the person actually steering. The person in the right-hand seat of a commercial plane lists his/her profession as pilot, even though the other guy is "the pilot". Most real-world writers don't seem to have had a problem with NASA's use of the word in their crew position titles over the last four or five decades (e.g., Gemini: Command Pilot / Pilot, Apollo I: Command Pilot / Senior Pilot / Pilot; etc.)

I'm going to leave in the crew descriptions, but remove the second-guessing of NASA's titles. JustinTime55 (talk) 21:04, 6 August 2010 (UTC)

Problems with Design Phase edit

The following edit made by Edgy01 has several major problems:

"An additional design problem was discovered by RCA engineers when due to convenient design the steering rockets of the LM impinged upon the LM rendezvous radar beam. When the rockets were firing to maneuver, you couldn't depend upon the radar. Additionally the Ryan landing radar, a precision altimeter, was poorly designed by being located beside the huge landing thruster. The effects of the rocket plasma upon the radar veracity were disasterous. Although RCA warned NASA about this discovery during testing, NASA operations shrugged it off. It was later learned during Apollo 11 how significant this problem was as Astronaut Neil Armstrong had to land the clumsy vehicle visually and kinesthetically, using up nearly all of their fuel in so doing. For Armstrong, the Ryan landing radar proved to be useless. The antenna was moved onto outriggers for subsequent moon shots, which improved the problem greatly, but introduced some parallax, for future flights."

• It is unsourced. This cannot stand, especially given the controversial claim that NASA ignored vendor engineers.
• It makes a dubious conclusion (WP:OR?) that the Apollo 11 landing problem was due to this alleged radar problem, when it was known that a guidance computer programming error was taking them downrange of the intended landing target.
• It makes an editorial judgement ("clumsy") about the LM (WP:BALANCE).
• It's not specific enough; exactly what testing is supposed to have revealed the problem to the RCA engineers?
• It is out of place here; the intent of this section is to track the evolution of the design configuration of the LM; operational problems found in development would belong somewhere later on.

Also, the writing style is poor (ex.: "due to convenient design"; "you couldn't depend on the radar"; redundancies "for subsequent moon shots", "for future flights"), and parallax should be wiki-linked.

I'm reverting the change. You are welcome to try again, if you have a citation and can write it in a more neutral manner, in the appropriate section. JustinTime55 (talk) 17:29, 22 December 2010 (UTC)

LM was not an SSTO

Category:SSTO says it is intended "for SSTO spaceplanes". This is stretching the definition beyond its intent. Since it was successfully demonstrated in 1969, it obviously was not that difficult to design a rocket-powered vehicle to take off from the Moon and reach orbit in a single stage, given the one-sixth gravity and no atmospheric drag, compared to doing the same thing on Earth, which as far as I know has yet to be demonstrated. Overcoming these challenges is what defines a "spaceplane", a term which cannot properly be applied to any lunar vehicle. This change should be reverted. JustinTime55 (talk) 17:01, 25 January 2011 (UTC)

Langley Research Center prototype

I just added the image at right to Apollo Lunar Module#History. It is an experimental prototype; the image is from NASA and was taken in May 1963 at Langley Research Center.

What's also needed is an update to the history section incorporating the details behind that prototype and what influence (if any) it had on the program. 67.101.6.172 (talk) 22:37, 1 March 2012 (UTC)

I believe you are misinterpreting what this is. If you read the Description NASA page link on this picture, you see the words "Subject category: Simulators, Lunar Module". This is not a prototype design of the real LM, but probably a proposed simulator for training the astronauts on Earth how to land the LM on the Moon. (An open glass, Earthbound helecopter cockpit on the Moon, really?) Reading the History text makes it clear that by March 1963 the actual LM design was pretty mature.

There is an Astronaut training section already in the article; if this picture belonged anywhere, it would be there. But reading the text makes it clear that this prototype would have been beat out by the LLRV in 1964. We really should have a picture of that here. It might be interesting to mention the other prototype as a side note (moot, anyway, unless we can find a textual source for verification of exactly what this is), but adding this picture would probably just crowd the section. JustinTime55 (talk) 14:56, 2 March 2012 (UTC)