MacroFab Engineering Podcast #64
MacroFab Engineering Podcast #64
This week, Riley Hall of Fictiv joins the podcast to discuss how Fictiv connects engineers and designers to job and machining shops.
The US Mint Denver produces 30 million coins a day. Denes, the tooling department manager, discusses with us how production at this scale functions.
Stephen is on the hunt for the next step in his electrical engineering career and shares the shifts in the industry and what employers are looking for.
Figure 1: Sasha Maldonado
Figure 2: Paige Brown
Figure 3: SSI-48 Launch Group
Figure 4: The ballast system for the ValBal project
Figure 5: Mission Patch for the upcoming launch of SSI-52
Parker is an Electrical Engineer with backgrounds in Embedded System Design and Digital Signal Processing. He got his start in 2005 by hacking Nintendo consoles into portable gaming units. The following year he designed and produced an Atari 2600 video mod to allow the Atari to display a crisp, RF fuzz free picture on newer TVs. Over a thousand Atari video mods where produced by Parker from 2006 to 2011 and the mod is still made by other enthusiasts in the Atari community.
In 2006, Parker enrolled at The University of Texas at Austin as a Petroleum Engineer. After realizing electronics was his passion he switched majors in 2007 to Electrical and Computer Engineering. Following his previous background in making the Atari 2600 video mod, Parker decided to take more board layout classes and circuit design classes. Other areas of study include robotics, microcontroller theory and design, FPGA development with VHDL and Verilog, and image and signal processing with DSPs. In 2010, Parker won a Ti sponsored Launchpad programming and design contest that was held by the IEEE CS chapter at the University. Parker graduated with a BS in Electrical and Computer Engineering in the Spring of 2012.
In the Summer of 2012, Parker was hired on as an Electrical Engineer at Dynamic Perception to design and prototype new electronic products. Here, Parker learned about full product development cycles and honed his board layout skills. Seeing the difficulties in managing operations and FCC/CE compliance testing, Parker thought there had to be a better way for small electronic companies to get their product out in customer's hands.
Parker also runs the blog, longhornengineer.com, where he posts his personal projects, technical guides, and appnotes about board layout design and components.
Stephen Kraig began his electronics career by building musical oriented circuits in 2003. Stephen is an avid guitar player and, in his down time, manufactures audio electronics including guitar amplifiers, pedals, and pro audio gear. Stephen graduated with a BS in Electrical Engineering from Texas A&M University.
Special thanks to whixr over at Tymkrs for the intro and outro!
Welcome to the macrophage engineering podcast where your guests sash Maldonado,
and peach brown. And
we're your hosts, Parker Dohmen.
And Steven Craig, if you enjoyed listening to the Mac fab engineering podcast, please let others know about us. Tell a co worker, a loved one a friend or share it on social media, we might reward your love for sin with sending you a free koozie. So if you send us an email to podcast@mcafee.com and include the secret code word,
which we'll say sometime during the episode, along with your
address, then we'll send you a koozie. So keep your ears open for a secret code word. Oh, and
also, you did say the send a mailing address, correct?
That's right. Yes. Yeah. Include your address on that. Because we have got emails where it's just like, send me a koozie. No, just the code word. Yeah, just the code word. Yeah. So please send your address. We can't send you a koozie unless we have your address. So a few podcasts ago, I presented a design challenge and asked our listeners if they would like to participate.
And we've had astounding feedback on that. Yeah, we've actually
had a it was it was a really last minute thing for us. I kind of threw it together right before the podcast was just like, whatever, we'll put it in here. And it turned out really well. It seemed like the listeners liked it. So thanks a lot for all your submissions. We're going to talk about them in a future podcast every in two weeks. Yeah, we're gonna kind of dissect what, what other people have given in as the design challenge. And what's interesting so far with our submissions, or what we've heard from the listeners, I haven't seen two solutions that were even similar. Yeah, they're, they're really different. So it'll, it's gonna be fun. Cool. So our guests this week are Sasha Maldonado and Paige Brown of Stanford University. Sasha is a Stanford Junior major, majoring in electrical engineering. He is the now retired avionics lead of the Val Bell project, and has been with the project since its inception. Sasha is now one of the students space initiatives, also known as SSI, co president and working on electronics for an SSI build satellite payload. Paige Brown is a Stanford freshman majoring in chemical engineering. She is the mechanical engineering lead on the Val Bell project, and also helps manage flight control logistics. Outside of SSI, she works in an environmental engineering lab on phosphate pollution remediation in stormwater through chemical absorption,
you're way better at saying those words than me.
I'm just reading, like, as verbatim as I can hear. No, no, we tend to do that with our guests. It makes it a little bit more fun to have it like that. So Did we miss anything from those descriptions? Guys?
Think we're good. Sounds great. sums it up about right.
So that was a mouthful. Let's let's kind of let's kind of unpack what's in there.
So what is the vowel vowel project?
So kind of the kind of the purpose behind the vowel project is to control the altitude of a latex balloon. So, you know, the latex balloons that we're talking about are a lot bigger than your average party balloon. So that when they're when they're blown up on the ground, they actually stand about, like seven feet eight feet tall, that is big wrap, you know, cross. So these are huge balloons. And usually, these high altitude balloons are sent up to collect high altitude data, but they go up, they pop, and they come back down in about three hours. So not really much range for altitude data collection.
helium balloons.
Yes, yes, they're filled with helium. Yeah, so what we decided is that we wanted to have something that could go for not just three hours, not just 30 hours, but maybe even 100 plus hours, up high in the atmosphere, flying along with the wind currents and collecting data as it goes. And we also wanted to have it be low cost since latex balloons are low cost, especially compared to other balloons, like super pressure balloons. Those can range like hundreds of 1000s of dollars. That's what like Google loon uses. It's not really an option for researchers.
How much is the balloon that they found that area 51
It's made of aluminum foil. They broke it apart and made hats out of it right? Yeah.
It's probably yes. Free first come first serve.
Oh, yeah.
Anyway, so the reason it's called the bow Bell project is because it uses a valve and ballast to control the altitude and to accomplish those long duration flights. So there's a valve on the Bottom of the blue neck that opens and closes, releasing helium, when you want to, when you want to go down and prevent the balloon from rising further, so you can calibrate. And then on the bottom of the payload is a huge container of ballast and we use, we use biodegradable BB pellets that we drop out the bottom as ballast. And by reducing the mass of the payload, you can go back up again. So you can fly along at about 14 kilometers up just above where airplanes fly. And you can do that for quite a long time, actually. So recently, we we flew Val Val in November, and it actually broke a world record for the longest duration flight by latex balloon.
Nice. Cool. So I got a question on that the ballast and Valve setup is how, like, when you like how fast is a change in terms of like altitude, like what's the tolerance on your altitude that you can keep.
Um, so we typically have, it can vary by flight, but we typically set the upper altitude limit at about 15 kilometers and then lower altitude limit at about 13 kilometers. But the way that the control algorithm works, it allows it to go. Like it slows it down as it's approaching the those altitude bounds. So it starts taking actions, like as it's approaching, to try to try to stay within those bounds. So the the reason that we keep these bounds is number one, because the FAA told us that we can't fly. So we have to stay at bars. 12.25 kilometers? Um, oh, wait, wait,
there's one question I have from something you said earlier, you have a ballast full of bees. And the FAA is okay with you just randomly dropping babies from a really high altitude
we did, we did the math are not going to hurt anyone.
It actually, it actually works out so that the kinetic energy of dropping one of those BB pellets from about 14 kilometers is the same as taking a tennis ball about an inch above your head, dropping it, so it's not going to kill anyone. Um, so yeah, the so the upper limit is kind of set by the ozone layer, because we don't really want to fly in the ozone layer. Because it it does quite a number on our latex balloons, it starts breaking down the latex polymers.
Oh, is that why most balloons explode when they go up high?
Or is it the pressure thing. So if you fill up a lit up party balloon, or even or one of our bigger weather balloons filled up with helium, it will rise and rise and rise. And eventually it will the pressure difference, the amount of like force of the gas inside trying to push against the atmosphere is going to get bigger than the amount of pressure that the blink of a stand, the balloons stretch and burst. So the first thing we tried to just to first get some extra length on our flights was just put on a valve. So before we had a ballast system, just to let out gas as we were going up, because you want to you it's it's really hard to wait the balloon properly so that it will level off automatically. Because the amount of lift you have as you go up varies. And so if you keep it low, you can actually if you get really lucky if you get really lucky or measure really well how much gas you put in the balloon, you can get your blood to level off naturally. Like right before the latex bursts. There's this one point where it suddenly becomes stable. Or the latex like stops stretching. And so you stop getting extra lift and trying to go up and you'll level off. But that's really hard to hit. And it's particularly hard to hit if you're trying to carry a lot of weight underneath, like you're trying to carry a scientific experiment, or oh batteries to last a couple of days.
Because it kind of oscillate around that position.
You can get it to if so people of the people who held the previous world record, what they did was they basically made one PCB with a solar cell on one side and a packet radio on the other side. And when they happen to be facing the sun and happened to be in range of a ground station, they would like send one ping saying, Hey, you were alive. Yeah, the whole their whole payload was you know, a couple 100 grams. And the way they did this was they got a really massive balloon. And they put a really as little gas into it as they could and still let it rise. So it rose really slowly. And they wound up stopping really high in the atmosphere like double our altitude, but the balloon naturally leveled off. They're like they managed to get everything to work just right. So the balloons
naturally weren't like that. was 25 kilometers there
were 2530, somewhere in that range. So that's pretty good. Yeah, above a lot of the ozone, which meant that they were really fighting with ultraviolet because it just breaks down latex. Says Paige mentioned earlier, we tried to fly below the ozone layer, because that, in theory should extend the lifetime a lot both being below meaning that you don't get the UV and then not in it, because with the one time we tried flying, like towards the bottom edge, the ozone was clearly doing a number on the balloon.
So how many times don't take to figure out that it was the ozone eating your balloon? Or Did y'all kind of know that down the road.
So it was kind of it was kind of like reactive, we noticed that the balloons were popping, and we noticed that, especially like, we were able to recover one of our balloons, actually from the world record launch. And the latex is it's all stretched out. And it's actually more brittle. And so we we did some research into, like, what is up there that could be affecting it. And one of those, one of those, one of those compounds is ozone. And what happens is the ozone, it's a natural process called ozone cracking. And this happens, like the car tires and stuff, and like latex seals, you know, anything you leave outside, or like around a source of ozone. And the ozone like breaks the crosslinks in the latex polymers. So they start kind of becoming more brittle, they don't stretch as easily, they break more easily. And then that's how you have a balloon popping. So we're we're trying to work on figuring out ways to modify the balloon maybe coated in some sort of compound, looking into graphene, but that's still up in the air
being balloon, that would be awesome.
But that's kind of the bell Bell Material Science Division. We're gonna try to try to get a longer duration out of our modified latex balloons, but still in the cylinder works. I
think we should throw some numbers on it. So the the previous world record said that the superlight payload was 57 hours and change. We actually back in last June, we hit 70 hours and change on one of our balloons. And then as paid mentioned earlier, back in November, we hit 80 hours. Wow. Well done.
Yeah, and y'all have? Sorry, I said y'all will have another launch coming up this Saturday, right? Yeah, that's correct. Yeah. I already know you looking forward to hitting this time.
Um, so actually, the way that the trajectory is heading for this launch, it's going to be flying down across the southern United States. And then after about two days, it's gonna cross it over to the Atlantic Ocean, down near South Carolina. Really far, then. Yeah. So after three days, which is, you know, about where about where our last world record was a little over three days, it'll end up in the middle of the Atlantic Ocean. So we're going to have to make the call during the flight if we, if we think that it's valuable to get the data and let it fly over the ocean, because once it flies out over the ocean, it's not likely that we're going to get it back. It's likely going to y'all don't have a
drone ship right. Now,
we, we know some people
attention. But if it looks if the predictions change, and it looks like we have enough ballast to make it over the ocean, we might let it let it continue flying. If it if it makes it over the ocean, it'll land in Morocco.
Oh, that'd be cool. How many days will it take to get there?
About five days? So that'd be pushing it a little?
Sounds like that sounds like a shattering of a world record.
Yeah. Yeah, we would, if it landed in Morocco, we get not only the duration, world record, but also the distance.
So what is the distance record then? Also, Morocco?
It turns out from to the our cheat leading competitors, you can say are the group here called the California inner space project. So they are the ones who built the little solar cell radio balloon. And they hold
the cheater balloon, right?
I mean, it's it's there a lot of flame wars. Yeah. It's a flame war. I'm sorry.
I know that. The flame wars already happened on Hackaday. There are a lot of people who
are is there like people in different camps in the different Yeah. Like the people in the SpaceX people.
There are different people in like, do trying to do different things with balloons. So there are a lot of people trying to set records and so you'll get different people who build like these crazy tiny like 20 gram balloon payloads, but they strap them to like special mylar balloons and they can fly them around the world for like weeks on end. But now they all they pretty much all they do is say hey, I'm here. I'm a balloon and keep orbiting we're trying to do we'll talk a little bit more about later, what we're trying to do is what we're trying to do is build out something that can actually fly experiments actually, like it has like a sizable amount of mass, you can just swap in or out and put, you know, a useful scientific experiment on board and get data out of it.
Again, with the, the numbers just kind of explained more. So the our payload without any, any ballast in it is about, like 1.5 to two kilograms. And then we typically add between four and five kilograms of ballast. So that's that's about how to achieve that for, like, what it can carry.
What's the speaker and the weight? What's the limit for a space of a balloon like that? Under was an FCC, FCC.
FFA regs, fa fa 101?
Fa is the farmers one?
Yeah. Sorry, go ahead. Fa one on one. So you're exempt from the rule. If you are below six pounds, I want to say we are. We're not below six pounds. So we that's why we deal with the FAA. But okay, they've they sign off on our flights, we tell them where the balloon is we're going along. We don't we don't we can't carry like a full radar transmitter, like a full black box, like you see on planes. But we have good enough position data and a way of distributing it. And the FAA is happy.
Okay, awesome. So I actually set you all apart from what most people doing then
most people fly again, fly a lot lighter. So they're doing cool things like they go way longer. And they still fly around the world multiple times. But we're hoping to be able to fly and then do something cool when it lands.
And the other thing is, the other thing is the cost. Since the latex balloons are only about like a few $100 and our our system itself, Val, Val costs about a few $100 for all of the parts that go into, like manufacturing it and electronics and ballast and just all the consumables, it ends up being a couple $100 So this is this is very low cost in the world of like high altitude ballooning, I guess isn't a very
big thing could be a new hobby. Like eccentric hobbyists. High altitude balloonists.
I mean, you already do see that you see the people sending like cake to space that people sending like, tweets to space.
I think it was a meat pie. Yeah, pretty simple sent up. Awesome. On the on the I was gonna say something about the cost. I can't remember anymore. Well, I got distracted by meat pie.
I got a quick question about the your balance mechanism? Because I don't know, I think that's kind of cool. So we you have a limited amount of of ballast, right? So once that's consumed, it's it's game over. Right?
Yeah. So that's actually one of the limiting aspects for our flight duration. And that's what we what what ended our flight. That was the last world record. It ran out about us and we couldn't control the altitude any longer, we had to just drop down and he couldn't correct for that. So we're actually working on on making a more efficient algorithm, so that it uses less ballast over the course of the flight. Because there's actually in optimum balance usage. It's, it's limited, but there's, there's an optimum usage, because you need every night because when the sun goes down, the temperature drops. And so the buoyancy of the balloon also drops when the gas compresses. So you have to drop 10% of your weight every single night, in order to stay flying. And then correct for that in the morning. By venting, but as as you properly ascertain, the limiting factor is the ballast. And so that means that, at minimum, at maximum, we can go for however many days it takes to use up 10% of our system weight in ballast every night. But currently, we're not we're not at that optimal level. And there's a lot of random corrections during the day if it overshoots when events you got to correct with using ballast, if it gets caught in some turbulence gets into a weird oscillation, you have to correct a ballast. And so that that is limiting our our flight length and we want to get to optimal balance usage so that we can fly longer,
because it's okay. All right.
Oh, it's about a week. Like
you could make it to Morocco if everything was optimal.
Or we could make it to make it to like the Middle East. I think it landed in like but Last time we ran the predictor for that long it laid in, like Lebanon or something.
And what do you use for simulation?
Um, we have a set of predictor utility online,
some hubhub.org. I want to say it's a group actually based out of Cambridge University and sort of their balloon team, they built a tool that looks at NOAA weather data, because they just wind data at different altitudes. And does this cute little simulation. You know, each point in time, it looks at what is the local prevailing wind? And that'll let you track your distance, like track your trajectory, and it'll project out a couple of days.
Alright, cool. One thing I was I just remembered what I was talking about the the payload hardware that you said it was a couple $100, right, is what's the chance of that, you know, becoming reusable.
So it's actually pretty high. And in the world of research, That's chump change. And it's, it's also has the potential to drop in cost. You know, as manufacturing techniques improve, as we like, reduce the number of parts make everything simpler. But it's right now it's about a couple $100, we're actually working on towards a goal of having a kit Val Val available. So so we make all the parts and it's just you assemble it, you put your scientific experiment in, and then you launch it. So that's kind of the ultimate goal for for this sort of project is making this accessible to to any researcher.
If you take the earlier vows are very, let's say bespoke. You know, handmade, kind of clutching in parts. And as we figured out what works, you know, we have a nice, we've been steadily reducing the part count, sort of like taking out things that don't need to be there or merging pieces together to make one bigger piece.
Yet, for instance, the ballasts mechanism. The ballasts dispenser housing used to have, I think it was 16 Different flat acrylic parts that fit together, it was a nightmare to assemble. And we recently replaced that ALL with ONE 3d printed part. So it's, it's just it takes a lot less time to assemble out and just overall. Better.
Yeah, so it's three, it's three. So how does the mechanism work then?
Is this like a gumball machine?
Okay. Yeah, it was it was let's say this just shoot one pellet out at a time, or, or was it just a, you know, a dump valve, but I figured the one at a time is a lot more accurate for y'all.
Yeah, rotating wheel that catches one ballot, one, one pellet, each time, it rotates, and then suddenly drops them.
And it's nice, because again, because we can basically drop single pellets, we have super fine controlling our weight, because each of these pellets is like a quarter of a gram. So we can and it's a surprisingly small number of them will get you a surprisingly large change in like the rate at which you're going up and down. Because we're operating so close to the point of just like floating along being neutrally buoyant, that if you drop, you know, if you drop below that buoyancy point, you're going to start going down, even if it's really slowly you're gonna start going down. So I put the librium point is razor thin, right? Yeah. So so which means that if you look at our trajectories, we do oscillate. But we do balance between sort of the bottom of where we want to fly and the top where we want to fly.
Do you know what that distance is?
It's about two kilometer. Yeah, down. Okay.
But so we get more and more efficient, the slower these Bobs are. So you know, if we, if, if we're bobbing up once every hour, no, that's we're wasting a lot of gas and a lot of ballast, because every time we go up, we have to bend gas. And every time we go down, we have to drop ballast. So we can just get like a really gradual,
you can either fall Yeah, I guess your optimal would be if you can stretch that over the entire day. So yeah, exactly.
Yeah.
So I had a buddy who was telling me about some some balloon technology, where instead of having ballast that you inject, it was actually a compressed tank, that would just it was a closed loop system that would just fill the balloon or pump it back into the Compress tank based off. Have you guys heard of it before?
So what Google is doing, yeah, and we, as
I was about to ask was like, Yeah, that's what I'm about to ask is, you know, what made y'all go with this design decision versus a system a more complex sounds more complicated, you know, recompressing gas, or just, or just having an onboard tank that can refill what you've rented, instead of a solar system?
Yeah. So we have we have considered that and it may still be possible in the future to switch to that since it it is kind of the more optimal system in terms of a ballast usage, but the problem is it takes a lot of energy to compress gas. Correct. So if we did we have batteries on board for powering electronics. But I, it's hard to it's hard to get enough power to just compress. Yeah. And maybe so maybe if we pair it that addition with like solar panels to run it might be possible. It's it's definitely a more complex system to work out and we'd have to also kind of just yeah, like it would increase the weight. But actually, yeah, if you're increasing the weight, but you don't have if you have unlimited ballasts, it doesn't really matter.
One of the cat we did one of the, one of the big catches we looked at when we looked at this previously is the scale. So Google the balloons, for example, the Google loon uses carry, like 80 kilograms of payload. So the onboard, all the onboard equipment is a lot heavier. But it means that they can have, you know, a big pump, because they have, it's not that big of a fraction of their weight. Because we're a lot lower and getting a functional pump at the weights we want that could actually move gas in and out of the balloon at a rate that would quickly. Yeah, that's the big thing is that, you know, the scale of the balloon, the payload is pretty large, you know, there's a lot of
that dictates a huge amount of the design and getting a pump
in the right size. In addition to get the power in addition to powering it, it's getting a pump in the right size, and the right weight is really hard. Yeah.
I cool. So while you're working on this project, like was there, I know that UV stuff was probably an ozone was probably unexpected. But was there anything designing like electron like actually, this go into electronics that are actually on no more electrical engineering podcast? So let's talk about the electronics a bit that's on the board. If y'all can.
Yeah, so we're actually built around. Because this is built by a bunch of people. Background is all in hobby electronics. We started out with an Arduino. Yeah, started. We started. So we now we now sport a teensy. I don't know if you're familiar with that. It's it's Arduino compatible. The cute, they're really nice. And we actually so we used to buy a dev boards and like solder them in. We have a stack of custom made circuit boards. We do our PCBs custom, now with macro fab. But we've been making our own circuit boards for a while now. And used to just solder these teensy development boards in bought them online. And now we actually took the reference design, basically took all the parts from it and soldered them straight in, like embedded the Teensy into the system, got a couple extra IO pins, because they're not broken out nicely on the dev board. So in interfacing with that at the core, which is it, you know, it's pretty beefy, as a processor goes it, you can run up to like almost 100 megahertz on it. It's an ARM Cortex M four, so it does quite a bit for us.
Those are pretty efficient. And terms. Yeah, how many MIPS you get?
Mm hmm. So, you know, that's a that's at the core, we've got a couple of motor drivers for the valve and ballast, which are, they're just at this point that actually just DC motors used to do servos, and an encoder, rather motor and an encoder on the balance side. But now they're new DC motors, because we have characterize them well enough that we don't really need the feedback.
That makes it a lot lighter as well. Yeah,
that's a lot of empirical data gathering in order to characterize a DC motor.
I mean, it's, it's, they've, we've sent something like we've dropped, I want to say 100,000, help balance pellets in flight, without, without jamming, like without a terminal jam, the wheel reverses every couple seconds that doesn't like build up a gym, but we haven't seen it lock out in flight. That's cool. And we there's enough of a range on the valve. Like mechanically, there's enough of a range that even we do entirely by time at this point. And even with just going off with the time it takes to open the valve, we get it open and close, like sufficiently open and sufficiently closed, that it the fact that we don't have any good position feedback on it isn't a huge deal. Right. So we have motor drivers, we monitor the current going into everything to guard against short circuits because we can disable things if they're looks like they've short circuited. We have an Iridium modem onboard. So the I don't know if you're familiar with the Iridium constellation. Yeah, that's the
satellite module or satellite system up there, right.
There is satellite communications network sort of arose. In the 90s, as a satellite phone company, and have sort of been a little still do a lot of that for the US military and but have also been reborn in a way for really short bursts of data from usually high value assets in far flung places. So like containerships have used these a lot, because you can track you know, it's worth a lot. You want to know where in the world it is.
Yeah, I've actually played with their, their module before. And sent a couple it was one of those things, like I said, bytes of space, and whoo, I got it back. And then I'm like, I'm like, this is expensive to run. And I show the project.
Yeah, I mean, yeah, it costs a lot to go to space. But
I did save those bytes on my desktop.
There you go. They went to space, your space bytes, space bytes.
Mo, just actually just the bits on my hard drive. But it's the principal
Iridium is actually they're replacing their entire satellite.
We could that that would be the code word space bytes. Space
bytes. That's right. Excellent. So if, if you email us space byte, with your address, we'll send you a macro fab koozie.
Sorry, guys, read through a little bit.
We always forget to have a code word and then we're and then Parker's always just like Oh, that.
Will you accept any spelling of space bytes? That's my question.
Ah, no, it's got to be spelt the the computer way. The space by C space. This space by the way. Yeah.
So if you if you were listening, and you just typed it in, make sure you got it right.
Well, cool. Okay. So how about well, Parker was gonna ask this earlier, but and then he got all sidetracked on electronics. But unexpected issues that you ran into with the project?
Oh, boy.
This is where we always get into the juicy juicy. Oh,
yeah, this is the projects because this this is the part where everyone can relate to you.
Think we should talk about us start with the Pacific
one the Pacific. Yeah. So we've sent to one balloon of all the balloons we've launched, we've only ever lost one balloon in the Pacific Ocean, despite the fact of rain California, because the winds usually go to the east, like point to the east. And in the Pacific, was on one of the very early valve tests, we were blue was just a valve. We launched it at night. We're driving to a hotel, the launch sites kind of far away. And so when watch at night, it's a real pain to get back home. So we check into the hotel. And we've seen that the balloon event has worked once. And so it's starting to level off. And then it's supposed to go again, it's supposed to vent a couple of times, then it cut down. And only the first one worked. And the we never got the balloon back. So our best guess is that it froze like that the system just froze shut. The valve shut out. Because the way it was built when it froze shut, that also, we think broke the cut down mechanism, which is basically like a spring it was going to try and push the balloon away from the payload. And there's like a piece of string holding a piece of fish in line to be cut by a piece of nine chrome wire. And we think that the nichrome wire definitely cut if we have power data, which is the micro wire got run. But we think that it froze stuck. So even when it got caught the spring wasn't enough to push it apart. So we are going to the east, we're going to the east end, but we start we started flying higher than we normally do. So we we crossed into like well into the ozone layer about 20 Something kilometers. And it turns out that the winds of their start blowing to the west. So we'd been going east, and then arct back west, like almost making a beeline for San Francisco, which was terrifying. Fortunately, went south then almost crossed over Stanford, which was again, kind of a mixed bag.
Yeah, what if it landed like right on top of your building? That was awesome. That would
be incredible.
I think actually, NASA has a prize for that if I remember right. There's something like the moon in the path that you launched it something like like a multi million dollar prize if you can land a balloon in a like well bounded box. You can say where you're going to land it
What if you just move the well bounded box?
Anyway, so Well, mountain? I think you have to call Google and ask God angle and ask.
Can you imagine the support line and you ask that the level one be like, I have no idea what you're talking about.
Hello, is this Google? Is this Google? Okay, so your balloon, your balloon, Beeline.
We did a couple of loops just over the peninsula, like, fortunately, not over anything frightening, but like, really high up. And then we found at sunrise, we were over the Pacific Ocean, and it looked like we were gonna start coming back towards land and basically land at home, like pretty close to Stanford. And then the sun came up and we started going up, and we had no way of stopping the valve broke. And so we just popped the Pacific Ocean, the thing fell into the water. And I would say it was never heard from again, except actually, we did hear from it again, once like six hours later, we got like one ping. And it was in the wrong direction for the ocean currents. So we have no idea how it got there, huh.
Fishermen picked it up how far?
A 10s of miles I want to say
shark aidid Yeah.
That's that's not the only vowel that's landed the ocean. We've also had one landed the in the Atlantic. That was he previous world record that was launched in June, that one was also had some issues with the valve.
Yeah, that was so I swear the valves works. Sometimes it's a feel probably 60% of the time it works 100% of the time is empirically accurate. results.
So what the job changed on the design of the valve, then, to prevent that from happening.
We've been we've been continuously iterating, the valve seal used to us used to use like this latex, we use these like latex seal with a, like a Teflon fitting on the bottom. Do away from that because of the problems with degradation with latex. And so this brief period where we used these Teflon coated thrust bearings, but they were designed and manufactured with a hole in them. And I had to like flip that with epoxy, it was just it was really bad design. And so right now, our current design is a Teflon fitting in an acrylic circle, which has to be extremely clean and extremely smooth. And then a spring underneath, which allows for some stabilization. So the word still out on if this one, how this one works, because we're going to be flying it on Saturday. And it's never been flipped before. But it has been accepted extensively tested on the ground through the very scientific method of putting our mouths on the blue neck and blowing into it.
Like you're like, because I've done like testing of electronics for like cold weather and stuff. It's basically stick it in your freezer, and then stick it in the oven for a bit and stick it back in the freezer, put it back in the oven, like temperature swings that way. So I'd be interested in if I guess the valve works at extreme temperature swings.
Yeah, so actually, we have to do something kind of like that with our motors. Because the the motors that we use when when you when they arrive we get them off Amazon, the grease inside of them is definitely not rated for cold temperatures. And if you'd sent up a motor with just the regular grease in it, it would freeze and that would not be good. So what we have to do is like decrease the motor completely. Substitute in a different type of cold grease. And then we have a box of styrofoam box of dry ice that we steal from the physics department. We know the chemistry department
to get that one right yeah, sure.
Who's gonna show up with pitchforks tomorrow morning.
They're fine with us. We stopped by scoop up our dry ice and scheduled to leave. But yeah, we stick the stick the motors once they've been greased inside the dry ice for like five minutes and and try running them to make sure that they're actually going to operate the temperatures up in the atmosphere because actually, that's another challenge that we had to overcome was just how cold it is up there. It's like negative 60 degrees Celsius it's and that's that's way too cold for for batteries to operate. So what we have to do is actually yeah, we have some heaters but like just having heaters alone would be enough to keep it warm. So we have to have some extreme insulation. So we actually have these aero gel blanket so we use their gel composite blankets and have you heard of air air gel before.
It's like one of the like least dense solids. Yes.
It's also like a ridiculous insulator.
Uh huh. It's it's, I think the best manmade insulator to date. The, the blankets that we use are these fiberglass composite blankets with like chunks of air gel inside of them. Which are,
can you get those on Amazon as well?
I was about to ask. I've got a kegerator at home and I could use an arrow gel. How do I get a hold?
No, we should totally make koozies out of Arrow jelly.
Oh my gosh, I wouldn't recommend it's
fragile, right? Well, it's
not that it's fragile. It's fragile. When you have it in like the solid state in the blankets aren't too fragile. But they are extremely messy, like the air gel like especially when you cut it like some of the air gel comes out in like dust and it gets on your hands and your clothes and like it's very difficult to get. It's like cutting it is always an ordeal we actually have these like Tyvek suits that we use to cut it because if it gets on your clothes, it's just a pain to get off. So I don't recommend just like handling error gels usually
koozie research here to actually handle it
to answer your earlier question or you get it by Arrow GL calm, trusted supplier.
Really? Okay. Go figure shows shows that I've done a lot of research into this
I cool. So I guess we're gonna slowly wrap up this podcast, right? Yeah, x. We're closing in on the 45 minute mark, to the launch this weekend. Where can listeners that are listening right now find more about this launch? Because it's gonna be live, right?
Yes. So we're most likely, I mean, barring topic, technical difficulties, we're going to be trying to, to, like Facebook Live the lunch. And so that'll be at, like 10am. Pacific Pacific Standard Time.
Stay like them. But it's got the timezone. Right. Is it?
Yeah, yeah. Okay. That'll be that'll be this Saturday 10am Pacific Time. And additionally, if you'd like to track the balloon, we actually have this very cool website that receives all of our, our communications, satellite communications, parses them displays the data in like a map so you can see where the balloon is, at the time. And that is have MC to have MC dot Stanford ssi.org. Sanford ssi.org. Yeah. So, I'll repeat that at hab MC dot Stanford ssi.org. And that's H A B. MC. So standing for high altitude balloon Mission Control.
We'll definitely put that in the punch.
Yeah, yeah. So also on Facebook, you guys are Stanford SSI. Right. And on Twitter, it's at Stanford SSI.
I should I should say, on the have MC side at the end. So there we have like a default view to the public. That's basically it's really just position and altitude right now. But we have a couple of codes we'll set up every now and again for like to give you he can see like
everything. Yeah, so Yeah, normally sight and then the insiders. Oh.
It's slash code slash macro fab at the end.
Oh,
thank you guys.
Yeah, that's awesome. Thanks, guys.
So um, is there anything else? Y'all have to add or Steven?
I think I'm good.
Yeah, good over there. Yeah. Yeah. All right. Y'all want to sign us out? It's that bold part at the bottom of the of the sheet.
Sure. Okay. So that was the macro fab engineering podcast, where we are your guests,
Sasha Maldonado and Paige Brown.
And we're your hosts, Parker, Dolman
and Steven Craig. Let everyone take it easy.