8 comments

  • happyopossum 13 hours ago
    Fun writeup! I was surprised by the part about styrofoam boxes though:

      Despite their popularity, they have a few disadvantages:
    
      They come in predefined sizes which mandate a certain weight allowance
      They cannot be flexible for your specific payload, making it hard to be efficient with payload layout
      They are expensive compared to more custom solutions
    
    
    This shocks me, as styrofoam is one of the easiest materials in the world to cut, shape, fasten, and customize to your heart's content. I'm all for 3d printing stuff, but in the theater world we build a ton of very detailed (and shockingly durable) stuff out of foam all the time....

    Buying a styrofoam box and just accepting that it's gotta be that shape and size feels like a huge waste.

    • rtkwe 13 hours ago
      Seems like the simple solution is a Styrofoam sheet, a $10 hot knife and some glue solves the customization problem almost trivially.
    • radeeyate 11 hours ago
      I think another point I hadn't included was the flexibility I had with prototyping different boxes. The hardware was changing all the time, and being able to just 3d print another revision was very convenient.

      If I did something like that with styrofoam, it probably would have gotten pretty expensive. The precision you get from printing was also a plus, as there needed to be slots for cameras, antennas, and circuit board mounting holes.

      • happyopossum 8 hours ago
        There’s something to be said for using the tools your comfortable with. I’m a woodworker by passion, and a technologist by trade so I dabble in everything from cnc to 3d printing to hand tools.

        If I happened to be super comfortable with fusion360 and 3D printers and not my overstuffed workshop full of other tools, I’d probably make the same choice.

      • wlesieutre 10 hours ago
        You can get a 4' x 8' sheet of 1" EPS insulation from Home Depot for under $20 (thicker available if you need it, costs more) along with compatible construction adhesives.

        You do have to be careful with glue selection because a lot of solvents will dissolve it, but there's plenty that will work.

      • TylerE 11 hours ago
        What's expensive? You can buy a medium sized cooler for $5 at Walmart. That's a fair bit of foam.
    • nkrisc 12 hours ago
      In my intro Industrial Design class long ago we fashioned styrofoam and many other kinds of foam into every shape imaginable with a hot wire, some utility knives, and contact adhesive. A wood rasp worked well for organic and rounded forms (wear a mask), though that’s probably not needed in this application.
  • jmpman 3 hours ago
    I'd assume hydrogen is a significantly cheaper fill gas than helium. Other than the danger during filling, any other concerns?
    • radeeyate 3 hours ago
      That was really our main concern. Being our first launch, we didn't want to risk it and wanted to wait until we were more comfortable with the process until taking that step.
  • macintux 13 hours ago
    Impressive level of detail, impressive work for anyone, much less high school students.
  • colingauvin 11 hours ago
    I live in Montana and routinely hunt the Musselshell river valley/Meagher county area. It's maybe my favorite place in the world. So few folks have been there, but spend some time there and you might just find yourself feeling depressed when you leave and not knowing why.

    Glad to see other folks go through the area. The wind in Judith Gap is insane, so I'm surprised that you never found it. I'll keep an eye out when I'm out there in Sept/Oct.

  • Felger 10 hours ago
    "which would have otherwise been expensive for the budget of two high school students"

    High school students !? You are more capable than most of adults from my country, even "of the trade" if I might say.

  • verelo 13 hours ago
    Wait, so at 28k/km the temp goes up to 15C?

    This is all very cool but this temperature reading caught my eye as unexpected.

    • radeeyate 13 hours ago
      I found that surprising too! This probably isn't a completely accurate number, as the sensor is black and likely experienced some heating from the sun. Something also worth noting is that different layers of the atmosphere experience different temperatures www.noaa.gov/jetstream/atmosphere/layers-of-atmosphere
      • verelo 13 hours ago
        Amazing. I love that i didn't know this. When i was studying weather as part of my pilots license i noted the basic mental math that i'd lose ~2 degrees celsius per 1000ft, but never did i take a second to ask, what happens when i go up 28,000 km.
        • newtwentysix 12 hours ago
          the article says 28.42 km. where are you seeing 28000 km ?
          • verelo 12 hours ago
            yeah i have no idea why my brain decided to type that (twice...), its clearly 28km
  • karim79 10 hours ago
    Must have been a UAP.
  • ErroneousBosh 13 hours ago
    The images seem a bit scrambled, presumably due to missing data blocks. At that low a resolution, have you considered maybe Robot36 SSTV?
    • radeeyate 13 hours ago
      Images are all in order, but some have missing packets.

      The problem with SSTV is the power required. From some looking it seems that transmitting would need at least 5 watts. This wouldn't be feasible running on the balloon, as it was powered by Energizer Ultimate Lithium batteries.

      • ErroneousBosh 12 hours ago
        Oh, yeah FM transmitters can require a fair bit of power.

        What is it using then, LoRA type stuff?

        • radeeyate 11 hours ago
          Yep, the radio link runs LoRa on the 33 cm band (915 MHz)
          • iberator 8 hours ago
            you should read about ham radio mate... there are some amazing protocols and modulations to save power.

            And of course: 7mhz 0.5W transmitter could be heard worldwide... no jokes.

            • radeeyate 7 hours ago
              I have my license, and I noted about this in the post. I experimented with the U4B for tracking and found it not to be reliable enough. For the future, I'm planning on using the 70 cm ham band for LoRa.