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<p>[QUOTE=&quot;Skyman, post: 3615164, member: 28299&quot;]July 20, 1969, one of the Great days in human history.&nbsp; On that day, 50 years ago today, humans landed on the Moon for the first time. While I realize that for the human race it was the walking on the Moon that made it all seem real, you&#039;ll note that I didn&#039;t say walk, because for the people involved, landing on the Moon was the tough part.&nbsp; Walking on the Moon was basically a victory lap. </p><p><br /></p><p>I&#039;ve been able to meet and talk with both Buzz Aldrin and Michael Collins.&nbsp; Of perhaps more interest, and information, than that to me was meeting, working with (in a volunteer capacity) and talking with Charlie Duke multiple times.&nbsp; Charlie was the CapCom in Mission Control when Apollo 11 landed on the Moon (and he became the 10th person to walk on the Moon during Apollo 16).</p><p><br /></p><p>Mission Control was, and is, in many regards the heart and soul of manned spaceflight.&nbsp; In it&#039;s most basic form, it is the engineers and technicians who work with the astronauts of a mission both in preflight simulations, and during the actual flight.&nbsp;&nbsp; Located in Houston, Mission control during Apollo 11 had three 8 hour shifts to cover the flight.&nbsp; While each of these shifts were considered co-equal, the &quot;top&quot; shift was scheduled for the Moon landing.&nbsp; This shift was headed by Gene Kranz as Flight Director. </p><p><br /></p><p>Hierarchically, there is a Flight Director with assorted subordinates that are the head of specific technical sections (such as the flight dynamics officer, nicknamed FIDO, or guidance officer, nicknamed GUIDO) dealing with the flight.&nbsp; The Flight director and the assorted section leaders are located in the main room of the building.&nbsp; This is the room you&#039;ve all seen pictures of.&nbsp; The section leaders are located in front of the flight director, and in the aggregate have nicknamed themselves, &quot;The Trenches&quot;, as they are the people who have to do the grunt work to make sure the mission succeeds. Each of these section leaders has an audio link to his section&#039;s workers in the backrooms, one room for each section. He/She can access these workers greater specific knowledge if they need it.&nbsp; In turn these workers in the backrooms can contact the contractors who built the actual spacecraft and brainstorm with them if it becomes necessary.</p><p><br /></p><p>Basically what happens in a time critical situation is the section leader gives the flight director a go/no go call.&nbsp; The flight director can then either say go/no go depending on what he thinks, and at that point the CapCom communicates this call to the astronauts.&nbsp; CapCom is a contraction of Capsule Communicator. Back in the day (and nowadays too), the spacecraft was shaped like a capsule, hence the name CapCom.&nbsp; The capcom is always an astronaut, as it is thought that an astronaut can talk better to the astronauts in the mission, and better understand what they are asking of Mission Control.</p><p><br /></p><p>According to Duke, the Apollo 11 crew took about 6 hours to prepare the LM <i>Eagle</i> for undocking from the CSM <i>Columbia</i>.&nbsp; At undocking something occurred that no one was aware of at that point in time. There was some residual air left in the tunnel between the LM and the CSM, so when they undocked the air rushing out acted as a small rocket for the LM, increasing it&#039;s speed.&nbsp; The affect this would have would occur later, when it pushed the LM further downrange from it&#039;s expected landing area. </p><p><br /></p><p>After undocking and a brief mutual visual checkout of both spacecraft the LM fired it&#039;s engine to put it into a lower orbit, with a low point of 47,000 feet.&nbsp; It descended towards the Moon around the backside of the Moon.&nbsp; When it returned to the front side of the Moon, and thus in communication with Mission Control, it was supposed to initiate a roughly 14 minute long burn that would drop it from roughly 3,000 mph at 47,000 feet to a landing.</p><p><br /></p><p>At this point things started going wrong.&nbsp; When the <i>Eagle</i> came into Earth view, the communications link was poor, due to the attitude of the spacecraft with regards to the Earth and the Sun.&nbsp; Under mission rules, if mission control could not get at least 50% of the spacecraft&#039;s information (speed, engine info etc. etc.) then the landing would be called off.&nbsp; While rotating the LM somewhat improved communications it was a very dicey affair, and communications continued to be iffy during the whole descent.</p><p><br /></p><p>Buzz Aldrin was nicknamed Dr. Rendezvous, because he has a Ph.D. dealing with rendezvousing in space. Prior to landing, the computer was configured to take in radar information dealing with height above ground and speed of approach.&nbsp; Unbeknownst to Mission Control, and TO THE BEST OF MY UNDERSTANDING NOT on the checklist, when Aldrin was configuring the radar and the computer for landing he added that the radar and computer should also keep track of the CSM in case an abort was needed. </p><p><br /></p><p>One thing you need to remember about the Apollo computers is that by today&#039;s standards they were laughably weak.&nbsp; The ENTIRE computer capacity of the Saturn V and Apollo spacecraft was on the order of the KEY FOB in your pocket.&nbsp; On the way down to the Moon, unbeknownst to Armstrong, Aldrin and Mission Control, the addition of keeping track of the CSM was overloading the computer, and a 1202 alarm was called by Aldrin.&nbsp; In Mission Control most people thought that they had lost the landing.&nbsp; With no quick response from Mission Control, Armstrong even asked what the 1202 alarm means, and, to put it mildly, to have Armstrong express concern, you&#039;d just about have to have a complete disaster on your hands.</p><p><br /></p><p>One thing you need to remember about Mission Control during Apollo is that all these guys were VERY young. The people in the Trench were generally in their mid-twenties. The guys in the back rooms were even younger. Gene Kranz was an old man of 36. These were the people who had to make the split second decisions affecting men&#039;s lives and multimultimillion dollar missions, with, at the back of their minds realizing that the whole world was watching the Apollo 11 mission.&nbsp; Jack Garman, a 24 year old, in the guidance backroom figured out that the 1202 alarm was basically an overflow of the system.&nbsp; The computer was continuing to do it&#039;s highest priority tasks, e.g. ranging dealing with speed and height for the landing, and dropping lower priority tasks, e.g. tracking the CSM, off of the list.&nbsp; Garman contacted his boss in the front room, Steve Bales (26), who was the guidance officer (GUIDO), who gave the GO call to Kranz. In conversation with Duke, he says he was so excited by this time that he didn&#039;t wait for Kranz to say go, but said it himself to the LM.&nbsp; In actuality it had taken a very short period of time to make the call, it was just the stressed nature of the moment that had made it seem longer.</p><p><br /></p><p>There were a couple more 1202 and 1201 alarms (1201 was they same type as a 1202 alarm) on the way down. At this point, Mission Control noticed that something was going wrong with the expected descent profile of the LM. Instead of continuing down in a braking parabolic curve to the Moon&#039;s surface it was flattening out and keeping the same speed.&nbsp; Fuel available was running out.&nbsp; Unbeknownst to Mission Control, the LM, due to the undocking issue mentioned above, was landing down range, out of the planned relatively flat and clear area. Specifically it was going to land in a football field sized crater that was surrounded with car size boulders.</p><p><br /></p><p>Duke kept giving information to Armstrong.&nbsp; If you look at movies of mission control during the Apollo 11 landing you&#039;ll see seated next to Duke a gentlemen in a red shirt, Deke Slayton.&nbsp; Slayton was the head of the astronaut office, and an old pilot himself.&nbsp; According to Duke, Slayton at this point leaned over to Duke and told him to shut up about everything, except for the fuel remaining.&nbsp; First it was 60 seconds of fuel remaining.&nbsp; Then it was 30 seconds of fuel remaining.&nbsp; When Aldrin finally called out, &quot;Contact lights (there were ~ 6 foot long probes at the base of the foot pads), Engine Stop&quot;, there were 17 seconds of fuel remaining in the LM.</p><p><br /></p><p>After a few comments by Aldrin about &quot;safing&quot; various LM systems, Armstrong called out, &quot;Tranquillity Base here, the <i>Eagle</i> has landed&quot;. </p><p><br /></p><p>Here are two pieces from my collection.&nbsp; The first is signed by four of the Flight Directors:</p><p><br /></p><p>Chris Kraft, Gerry Griffin,</p><p>Glynn Lunney, Gene Kranz.</p><p><br /></p><p>[ATTACH=full]968431[/ATTACH] </p><p><br /></p><p><br /></p><p>A postcard of the famous visor shot, signed by Neil Armstrong.</p><p><br /></p><p>[ATTACH=full]968432[/ATTACH] </p><p><br /></p><p><br /></p><p>If you want to relive the powered descent to the lunar surface, here&#039;s a good video.&nbsp; It&#039;s about 15 minutes long.</p><p><br /></p><p>[MEDIA=youtube]RONIax0_1ec[/MEDIA]</p><p><br /></p><p>In all films of the landing the camera is located in Aldrin&#039;s LM window.&nbsp; We do not see what Armstrong saw.&nbsp; Here&#039;s a roughly 4 minute long video that blends what Aldrin saw along with a video simulation of what Armstrong was seeing from his window as he approached the landing site.</p><p><br /></p><p>[MEDIA=youtube]ScFJBcLfasQ[/MEDIA][/QUOTE]</p><p><br /></p>

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