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Countdown to Apollo 11


Evan Burton

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23 May 69

With all the Apollo 10 crew now back in the CM, it was time to cast Snoopy adrift. The LM ascent stage would have its ascent engine started by remote control and run until depletion. This would provide valuable engineering data on engine performance. The engine burnt for 249 seconds and Snoopy was launched into a heliocentric orbit about the Sun. Of note, Snoopy is the only one of the flown LMs that survived. The others either burnt up in Earth orbit, or crashed into the lunar surface (this was done deliberately for some, to provide data for the seismic sensors on the lunar surface). The crew farewelled their spacecraft.

108 hrs 56 min GET

LMP: "Is he really going to the Sun?"

CAPCOM: "Well, he's going in that general direction."

LMP: "God, I feel sorta bad about that, because he's a pretty nice guy; he treated us well today."

As they passed behind the Moon on their 18th orbit, they packed away the spacesuits they had been wearing and squared away the cabin. The crew was tired after a long and busy day.

110 hrs 20 min GET

LMP: "And the crew status is tired, and happy, and hungry, and thirsty, and horny, and all those other things."

CAPCOM: "Roger, we copy everything, and we've got solutions or pills for everything except item 4 [sic]."

Houston informed the crew that they would be given an additional four hours of sleep time, given them about 11 hours. Final flight plan changes were made, and the crew settled down to sleep.

AS10-27-3873.jpg

When Houston called to wake the crew, they had already been awake for some time, getting an early start on the day. They were updated on their orbital parameters and told that Snoopy was now 23,000 miles away. Gene Cernan had an extensive consultation with Houston regarding the Hasselblad camera. He discussed how there were circumstances when the film pack appeared to jam, and then lens could not be removed. This was the same condition that had happened the previous day, when he reported that the camera batteries had died and / or the camera had malfunctioned. The cameras were very important to the mission; part of the Apollo 10 tasks were to take numerous photographs of the lunar surface, to further help with the selection of landing sites.

AS10-29-4324.jpg

There was also the continuing problem of the Mylar "snow", this time from part of the LM's insulating blanket. Although the LM was gone, the Mylar remained. The problems on Apollo 10 lead to the insulation being removed from the tunnel hatches of future CMs, and modification being made to the insulating blankets of LM5 and beyond. There were no further problems with the Mylar on future missions.

The CAPCOM brought the crew up to date with the latest news and sports, and of course... the horoscopes:

John Young (CMP) - Keep all operations above board. Confidential transactions are apt to blow up later with considerable embarrassment to all. Travel is better postponed; the people you would go to see are not yet set for the visit.

Tom Stafford (CDR) - Your natural tendency for moderate, sparse consumption serves you well. Your system is a little more sensitive to strange foods.

Gene Cernan (LMP) - Conditions are bewildering. There are so many odd and unfamiliar details. Just curb your impatience; question everything and put things into place, one at a time.

The photographs of the lunar surface continued, and preparations were made for a return to Earth. On the 26th orbit, after the spacecraft had passed behind the Moon, Apollo 10 came back with an interesting report. They saw a star they couldn't identify. They then realised it was in orbit with them. Eventually, they passed close enough to see it through sextant monocular and saw... the descent stage of Snoopy, left behind after staging. It would eventually crash into the lunar surface, but for the moment it was in orbit around the Moon.

A short day, and the crew once more entered a rest period before the following day's TEI burn; the Trans Earth Injection, the firing of the SPS that would propel Apollo 10 on its way back to Earth. If the SPS engine did not fire, however, Apollo 10 would remain in orbit around the Moon with no chance of rescue.

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24 May 69

131 hrs 59 min GET - Rev 29

The crew continued with the normal mission updates, including yet another report of the LM descent stage below them, tumbling end over end. Tom Stafford asked the FIDO (Flight Dynamics Officer) to once again examine the trajectory, to make sure there was no possibility of collision.

132 hrs 17 min GET

CDR: "Seeing what I saw, John, yesterday - but we sure don't like being around here playing footsy with that rascal."

CAPCOM: "Roger that. You treated him so bad on staging, he's out to get you."

They continued to take photographs of the Moon, discuss the position the LM descent stage, and report problems with spacecraft. They were taking so many photographs that they were nearly out of colour film. They still wanted to save some fir the voyage home, though.

One of the problems was fuel cell No2, whose exhaust temperature was going up and down, causing the spacecraft MASTER ALARM to sound about every 5 mins. They weren't overly concerned about the fuel cell, but they could not afford to ignore an alarm, thinking it was the fluctuating fuel cell. The fuel cells were also responsible for spacecraft power, taking hydrogen and oxygen and mixing them together, giving electricity and water as the products. If one fuel cell was not operating correctly, a revision of the spacecraft power configuration for the TEI burn might be called for. Fuel cell No1 had a problem earlier, overheating and was kept functioning by disconnecting it when temperature limits were reached. Also, the waste water from No1 fuel cell could not be properly removed, and would shorten the fuel cell's useful life. For the moment, however, it was producing the required power. The No2 fuel cell later settled down, and things looked good for a nominal burn. Houston would continue to monitor the fuel cell problems. Later ground analysis would show the No1 fuel cell problems were caused by an extended hydrogen purge, and this procedure was dropped from future flights. The problem with the No2 fuel cell was not confirmed, although similar behaviour had been seen.

Final instructions were passed, and Apollo 10 passed behind the Moon on its 32nd orbit. The TEI - Trans Earth Injection - burn would take place behind the Moon. Houston waited for the expected AOS - Acquisition of Signal time.

At the appointed time, contact with the spacecraft was regained, and the crew reported a good burn; they were on their way home. Another TV broadcast was done, showing the Moon as Charlie Brown sped away.

137 hrs 50 min GET

CDR: "Houston, 10. I hope the Aussies have their sets tuned in because it's absolutely fantastic here."

CAPCOM: "Roger that Tom, I'm sure they're all watching."

The crew continued to make reports about the appearance of the Moon as they sped away at about 6000 feet per second. They began the PTC roll, and commenced the pre-sleep checklist. CDR Tom Stafford reported that all the crew were very tired, having been awake for over 22 hours. Now that the TEI burn had been successfully conducted, and systems check, all they wanted to do was sleep.

****************

After an all too brief 6 hour sleep, the crew of Apollo 10 was again awakened. While the crew were asleep, the spacecraft had stopped decelerating. The spacecraft had now slowed during the flight, but now at 187 300 miles away from the Earth, they began to accelerate again and were traveling at 4800 feet per second, and on course. The first planned mid-course correction was canceled.

As always, the latest news was passed to the crew: Thor Heyerdahl was leaving Morocco to cross the Atlantic aboard the Ra, a craft built of papyrus and based on designs from ancient Egypt. The Houston Astros baseball team beat the New York Mets, 7 to 0, with pitcher Tom Griffin striking out 13 batters. Boxer George Foreman signed up a manager and would make his professional debut as a boxer at Madison Square Garden in June. And the horoscopes?

LMP - Discussion fills much of the morning, and you'll learn a great deal that would never have come to your attention. That is, if you listen well.

CMP - Keep your attention focused on your own affairs Saturday. The necessary chores are quite enough for the time being, and leave the thrills for another time and place.

CDR - Problems tend to get out of hand, and logic is not quite enough. There is nothing to do but ride it out with a certain amount of leniency.

This was followed by another TV broadcast, where the crew explained that the spacecraft axis was actually aligned about 90 degrees to the direction of travel. They showed images of the Earth and the Moon as each passed by the spacecraft windows. The ground also had a procedure to rid the food bags of air bubbles, a problem which occurred when they added water:

147 hrs 54 min GET

LMP: "Go ahead with your procedure there, over."

CAPCOM: "Well good. I don't know if you wanted that or not. First off it's quite lengthy. It's a full page. I'll try to go through it slowly, and then we can talk it through and ask some questions. First off, fill the entire bag, both top compartment and bottom compartment, about half full of water. Then work the water and the gas to the lower compartment by either spinning it or by just kneading it down. Then after you get it all in the bottom, spin it up and then let it come to rest slowly; and if possible, squeeze the gas - if you have any gas in the upper compartment - squeeze the gas out of the upper compartment. Then, if the bubble is present in the lower compartment and top compartment is empty, add some more water to the approximate size of the bubble. Then you want to spin it again, as in step - well, as in step 3. Now, after you spin it up again, you should have gas in the top or partially gas in the top, and gas and water in the bottom, and repeat the procedure. Add more water to the approximate bubble size and spin it again. And by the time you get finished, you should have all the gas in the top and - compartment that is, and then the bottom compartment should be just about full of water. Now, if you fill it too full, so you've got the bottom full of water and the top full of water - partially full of water, then the only way you can get the bubble out of there then is to squeeze out the bubble and the water in the top compartment. The object is to get the bottom compartment completely full of water and the gas in the top compartment, and then you can vent it off by pinching off the lower compartment. If that sounds reasonable to you guys, you can try it. It's going to take a lot of spinning, but that's what they recommend in the back room after 3 days. Over."

LMP: "Hey Charlie. With all due respect, would you play back Glynn's tape recorder in there on his desk and listen to yourself, and then give us a call?"

CAPCOM: "Okay, I guess you couldn't understand that."

LMP: "No, we understood it."

CAPCOM: (Laughing) "I told you, you might not want this!"

LMP: "Listen babe, I'm glad that's all we've got to worry about at the moment!"

For the next 15 minutes, the crew tried the procedure without success. They eventually gave up. Spacecraft commander Tom Stafford then discussed the staging problem they had with the LM, recognising they had accidentally put the mode switch into the wrong position. There was also some initial debriefing about the performance of the LM's steerable antennas.

At 152 hrs 21 min GET, Apollo 10 was 168 375 nautical miles from the Earth, and speeding along at 5000 feet per second. Yet another TV broadcast, yet more medical and radiation reports, and the crew prepared for sleep. In two days they would be home.

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Evan,

Let me bring you down to earth for a moment, since you are indeed awake and apparently at the wheel, I'd like to know why you or Kathy or John G. or any of the moderators have not responded to the half-dozen or more posts by a forum member that should be violations - making up bizarre quotes and attributing them to another forum member, stepping on threads with no contributing information, endlessly repeating the same things over and over again, and attempting to get me fired from an imaginary job for an imaginary reason.

While you can classify this as just a nut case, it is threatening to me if he is trying to get me fired - and he is known to have violently assaulted another researcher in the past.

The answer, as the forum's leader has suggested, is not to make me a moderator, but to make those who are supposed to be moderators to do their jobs.

This is my third or fourth protest, and I've never protested anything like this before.

Bill Kelly

bkjfk3@yahoo.com

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(I’ll combine the days until the end of the flight, as I’ll be away for the next couple of days)

25 May 69

Today was a day with a twist: the crew of Apollo 10 gave a wakeup call to Houston! First was the song “Come fly with me” followed by a chipper and DJ-like “Geno” Cernan:

162 hrs 54 min GET

LMP: “Good morning, good morning! This is Tom, John and Gene from WAP-10, broadcasting again from approximately 140,000 miles out into the universe. It’s a beautiful day out here, and it appears that it might be a beautiful day down in Mother Earth country. For those of you who are not just ready for work or are just getting up: GET UP LAZY BONES! It’s time you got up! A big day ahead! And the thought for the day is: Remember – National Secretary’s Week was last month!”

CAPCOM: “Good morning Apollo 10! You managed to wake everyone up early down here, and thank you for your brief program. And we’ll be giving your advice due consideration down here. And we’ve got a little bit of music for you…”

(Plays: Zippity Do Dah)

(Applause from spacecraft)

CAPCOM: “Roger. Thank you for the applause. And watch out for migratory bird season!”

LMP: “That was a couple of seals up here.”

CAPCOM: “You might have recognized Deke Slayton, as solo, on that song we just sent up, 10”

(Deke Slayton was the Chief Astronaut, often referred to – by the astronauts and not in his presence – as “Mother Slayton”. He was a primary force in crew assignments)

CDR: “Roger.”

LMP: “If he’s eating that food, he’s zippity-do-dahed all right!”

As per normal – and looked forward to every day by the Apollo 10 crew – was the horoscope:

LMP – This Sunday may find you in some quandary over home conditions. There should be some help available. Don’t make smart remarks about Marines.

(Gene had been making jokes about Marines to CAPCOM Jack Lousma during the flight. Jack subsequently flew on Skylab 3 and shuttle mission STS-3)

CMP – Your money has to be spent today on institutions and the use of them for various purposes. Take the time to check everything out before doing anything drastic. Finding out the “why” in a situation may be more important than any other determination.

CDR – Your relatives and neighbours expect to see you this Sunday. Do the amenities gratefully. Make the rounds; there are gifts for you here and there. Then seek solitude. Reprimand all those in your command who make smart remarks about Marines.

This was followed by the news, and updates on the weather in the recovery area. The weather would be the determining factor; there was a prime recovery area chosen, but NASA had to have contingency plans in case the weather was unsuitable. This meant an additional 2 or 3 areas, each requiring a suitable recovery force of US Navy ships and aircraft.

At 164 hrs 33 min GET, Apollo 10 was about 130,000 miles from the Earth and travelling at a speed of 5700 feet per second. Their course (with a mid-course correction) put them on a re-entry angle of 6.52 degrees, almost exactly in the middle of their corridor. The “nominal” corridor was between 5.4 and 7.4 degrees. (Even without a mid-course correction, they were headed for an angle of 6.95 degrees).

The flight continued with the day-to-day routine of spaceflight: reports on radiation, oxygen and fuel remaining, flight plan updates or corrections, and word of the “unemployed philosopher”, who continually gave his (or her) update on the effect of Apollo 10’s colour television broadcast on the world. This wavered between a return to B&W television because of the crew’s appearance, through to the current report: colour TV was making a comeback. It would make a real splash around here soon! The crew also reported that a new fangled invention called ‘shaving’ was working well aboard the spacecraft, and they all expected to look good upon splashdown…. but did they?

The crew concentrated on discussing spacecraft performance reports, and passing visual reports of the Earth. Because of the important re-entry to Earth’s atmosphere, the crew asked for an early wake-up call… and an order of bacon & eggs. What’s a CAPCOM to do?

At 177 hrs 18 min GET, Deke Slayton came on the comm channel to quickly talk to the crew before the crew slept for the final night in space. At 177 hrs and 50 min, the crew said goodnight and went to sleep.

26 May 69

A little over 6 hours later, the crew of Apollo 10 was awakened with a bugle call. Today, the return to Earth would be a big day. Firstly, the course of the spacecraft would be checked. Too shallow and it would bounce off the atmosphere, with no hope of recovery. Too deep and the capsule would go through excessive heating, burning up the capsule despite the heatshield.

After the Service Module (SM) had been jettisoned, the Command Module (CM) would only have very limited ability to change course. There was only a corridor of 2 degrees for a safe re-entry.

The capsule would enter the atmosphere, slowing down and generating tremendous amounts of heats. A little know fact was that the CM would then actually change its attitude and climb, further slowing and reducing the heat generated. It would then pitch back towards the Earth and once again re-enter the atmosphere.

Weather reports for the recovery area were discussed. The prime recovery area looked good. Before the re-entry, the crew of Apollo 10 recounted the achievements of the mission.

After 7 days 23 hours and 33 minutes from liftoff, Apollo 10 jettisoned the service module. The CM, no longer connected to the SM fuel cells, had a limited time on its internal batteries. Apollo 10 was on its way home. The spacecraft now started its descent. As they fell, the force of Earth’s gravity exerted its force. Last reports were passed: about 2 miles from their target point. Plasma began to envelope the capsule, blocking communications.

Mission control waited anxiously for the first reports, either from the capsule or the helicopter from the recovery force.

.

.

.

8 days, 3 minutes and 25 seconds from launch, Apollo 10 splashed down.

ap10-S69-21036.jpg

Apollo 10 after splashdown

ap10-S69-20549.jpg

The crew of Apollo 10 aboard the recovery vessel USS PRINCETON

Apart from a minor switch problem with the LM, Apollo 10 was a success. Everything was in place for the next attempt: Apollo 10 was a green light for a lunar landing of Apollo 11. Less than 2 months later, man would be walking on the Moon – or have died trying.

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  • 1 month later...

I'm going to be away during the Apollo 11 period (at an Apollo 40th anniversary celebration) so I won't do a day-by-day for Apollo 11. If you are on Twitter, you can get an excellent coverage of Apollo 11:

http://twitter.com/ApolloPlus40

I will, however, cover two points regarding Apollo 11 that always get asked: The Program Alarms and the LM fuel.

The Program Alarms

During the descent, you can hear a call of "Program Alarm 1202" and "1201". This meant that the LM's Primary Guidance and Navigation System (PGNS) was reporting an "Executive Overflow". Simply put, it was saying "I've got too much to do! I'm going to dump everything except my primary stuff".

The first question was do we need to abort? In the Mission Operations Control Room everyone looked at Steve Bales, who was responsible for that section of the spacecraft. This was not an alarm they usually encountered or practiced for. Bales, however, did recognise it. During a simulation run it had occurred and they had aborted the landing. In the debrief the SIMSUP (Simulator Supervisor) had berated the controllers for that decision. As long as the alarm was not continuous, they could still land. Bales had felt very embarrassed during that simulation and not forgotten the lesson.

"We're... we're GO on that alarm!" he reported.

Despite a similar event (the 1201) occurring later, the landing could go ahead. But what caused it?

It turned out to be an unexpected switch setting. The LM rendezvous radar - used for an ascent - was on, where it was supposed to be according to the checklist. It was decided to leave it on, ready for an abort situation. Since the radar was not actually transmitting, this would not be a problem. This was not quite the case though. The computer programme was still trying to calculate the rendezvous parameters. Since the radar was not on, some of the parameters it was using for these calculations (an angle and distance) were zero. The computer was trying to divide by zero... an impossible task, and one which was taking up a majority of the computer resources. This was resolved in subsequent missions by amending the switch setting.

The Fuel Quantity

There is a lot of confusion about this, with people believing they only had seconds of fuel left when they landed. That's not true. To begin with, there was a little more fuel they they thought; the fuel sloshed around in the tanks and the sensors got a false reading. This was corrected in later versions by putting baffles inside the tanks (my old P-76 had the same problem, the fuel gauge used to move around a fair bit!). So when the fuel quantity light came on, there was actually more fuel than they thought. The quantity light call started a 94 second countdown. You can hear Mission Control call "60 seconds" and "30 seconds". This was NOT fuel remaining though; it was a countdown to what is known as a 'Bingo' fuel call. They were counting down to a decision point, where they had to land within 20 seconds or abort now. So there was the 30 second call, and they landed 13 seconds later; they had 17 seconds before they needed to make an land-or-abort call and were not running out of fuel.

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