 All the way at the top of the Apollo Saturn stack on top of even the launch escape tower is a tiny little silver ball Which I neglected to paint silver on this model, but this little silver ball played a huge role in Apollo launches This is what the Apollo command and service modules looked like before they launched on a mission to the moon or to low-earth Orbit if it was Apollo 7 or Apollo 9 the cylindrical service module held all the consumables for the mission And the command module is this gumdrop shaped module up top that was the only piece of the spacecraft to actually come back Through the atmosphere at the end of a mission on top of that was the launch escape tower or the launch escape system The launch escape system is this lattice like structure and the four solid rocket motors that would fire to pull the spacecraft away from an exploding rocket if anything went wrong in the initial phases of launch The four solid rocket motors actually had more power than the redstone rockets that launched the first two Mercury suborbital flights In the event of a launch anomaly these four rocket motors would fire and pull the spacecraft free of an exploding rocket and land the Astronaut safely in the ocean or if need be although it wasn't ideal they could land on land But pulling the spacecraft free of an exploding rocket during a launch abort wasn't enough There had to be some way of knowing exactly where the spacecraft was going and what angle it was flying That is where the little silver ball at the top of the launch escape tower comes in that little silver ball is bored with eight holes And they feed information to the cue ball the cue ball is similar to a pitot tube on an airplane a Pitot tube measures airspeed in flight and feeds that information into the flight computer where the pilot can see it The cue ball does something similar It doesn't measure airspeed, but it does measure air pressure and that's actually where it gets its name Pressure is sometimes referred to as cue so air pressure ball cue ball It's not just referenced to it looking like a bald man's head But the cue ball didn't gather data just for data's sake it gathered data for a very important reason for one It could actually help the rocket stay on course because the cue ball measured air pressure coming from all sides It could tell if the rocket was off its nominal trajectory by as little as an eighth of an inch It could actually tell the engines all the way down at the bottom of the first stage to Gimbal to correct for that off nominal trajectory But there was an even more important role that that cue ball played and that was in a launch abort In the event of a launch abort the cue balls measurement of air pressure on all sides would help determine Which way the spacecraft and the launch escape tower were flying making sure that the crew landed safely Away from the launch tower So this tiny little barely obvious silver ball at the very top of a Saturn Apollo stack played a huge role But if you look at it before certain launches in video or in images you might see it look a little bit bulbous That's because it had to be covered right until the last minute Just like pitot tubes are covered right before an airplane leaves the ground and with good reason if those holes Become blocked at all the data can be faulty and this can lead to big problems Insects building nests in pitot tubes have brought down full jets So the risk of something clogging those holes and having a real problem developed was significant The cue ball cover was two halves of a sphere held together by a two-inch rubber band with a razor blade Positioned behind the band pinched between the halves of the cover a wire rope was connected to the top and bottom of that razor blade and to both halves of the cover and that rope was then rooted through a Polly on the crane at the top of the launch umbilical tower and directed down a tube on the side of the structure It was connected to a weight housed inside that tube that in turn rested on a lever controlled by pneumatic valve The valve is actuated from the launch control center Rotating downwards and allowing the weight to drop down the tube pulling the wire that cut the elastic That separated the halves of the cue ball cover to expose the cue ball to the air This might sound like a super intense Over-engineered solution to the problem of covering the cue ball before launch after all airplanes just take off the cover manually before a flight But this couldn't happen with a Saturn launch to the moon Because the cue ball played at such an important life-saving role in a launch abort It had to be kept covered until the very last second It wouldn't do to manually uncover it before launch There's still a chance for something to block one of those holes The cover was only removed in the final five seconds before lift off And it had to be done remotely and it had to be sure that it would separate That's why the solution to the cover and separating it was so intense The cue ball as well as the entire launch escape structure as well as the boost protective cover over the command module Were jettisoned around the two-minute mark into the flight Once it was clear that there was no need for the launch abort system It was thrown away and the crew went off on their way to the moon a lot of you guys have asked me about the cue ball So I hope this answers your questions And this is the kind of question that I love so let me know what kinds of things you would like to see me dig Into in future episodes down in the comment section below and because I can already hear you guys asking Yes, this is a Pete t-shirt. I have limited edition Pete t-shirts now and I'm super excited I've got the links you need to buy one yourself in the description box down below So definitely check that out you guys love Pete you guys have asked for it So I gave you Pete merch Pete merch will be available for a limited time So definitely check that out sooner rather than later as always leave any other questions comments anything in the comment section below Be sure to follow me on Twitter and Instagram for daily vintage space content and with new episodes every single week Be sure to subscribe right here. So you never miss a video