Project - sending a Jeb figurine into stratosphere

[TheFlyingPigs]

Thanks Vanamonde, the info was being scattered everywhere

[NERVAfan]

OK, so what has been obtained and what still needs to be obtained? And who will be launching it, and from where?

If the launch is US, I believe there is a weight limit below which you don't need FAA permission.

[dbmorpher]

I'll just leave this here:

http://www.jacobsrocketry.com/aer/caramel_candy_propellant.htm

[astropapi1]

I'll just leave this here:

http://www.jacobsrocketry.com/aer/caramel_candy_propellant.htm

Ah, good ol' rocket candy. Horrible isp but very easy and cheap to make, I've been told.

I just wish I could get my hands on bulk quantities of potassium nitrate without being put on a watch-list of some sort.

Unfortunately, there's no such thing as "Stump Remover" where I live. We don't even have a word for "stump".

[dbmorpher]

Ah, good ol' rocket candy. Horrible isp but very easy and cheap to make, I've been told.

I just wish I could get my hands on bulk quantities of potassium nitrate without being put on a watch-list of some sort.

Unfortunately, there's no such thing as "Stump Remover" where I live. We don't even have a word for "stump".

I tried to get it one time but the store only had this really heavy molecule.

[lajoswinkler]

I'll just leave this here:

http://www.jacobsrocketry.com/aer/caramel_candy_propellant.htm

Rockets are totally irrelevant for this project, as was being explained in detail in earlier posts.

[linkxsc]

SO like really, If anyone can get the balloon, and a weight limit that balloon can lift. And I can get a sensors/gps setup picked out and set up. Honestly I probably have most of the sensors already, just no GPS chip thats not already built into anything or a GPRS board to send the coords to a phone or something. And as long as the thing doesn't smash on the ground and we pick the thing up when the projects done, its not like it'll cost me anything in the long run cause I can reclaim those sensors after the project (or leave them, and shoot for a higher altitude with a subsequent project)

The biggest monetary loss on this project is definitely the guy who gets the balloon, and the gas for the balloon. Honestly though if someone could link me to good sites about getting the balloon, I doubt that those are super expensive either.

Hell sounds like a great geocaching adventure anyways when the thing comes down, depending on where it lands.

[NERVAfan]

We could do a Kickstarter to fund the balloon/gas, I think they're a couple thousand at most. I would definitely contribute.

[Frida Space]

have you considered http://sentintospace.com ? They sell full launch kits with instruments and stuff. That said, I'm no expert, I just found it interesting.

[TheFlyingPigs]

The Kerbals salute you

*salute 🎉

[linkxsc]

Fredaspace. That websites pretty great. Thanks.

With some guesstimation on their prices (dunno whay shipping to the us would be if i were launching the thing) but for 400-500£ can get the balloon and gps and everything for the launch but jeb and the camera.

When i get off the job im on for the next couple weeks i can order the gps and all myself (cause assuming they dont break, i can reuse them) and then do up a kickstarter for a few balloons and gas (since those are the expended parts)

[YourEverydayWaffle]

Ah, good ol' rocket candy. Horrible isp but very easy and cheap to make, I've been told.

I just wish I could get my hands on bulk quantities of potassium nitrate without being put on a watch-list of some sort.

Unfortunately, there's no such thing as "Stump Remover" where I live. We don't even have a word for "stump".

I bought a 2-pound bag of it off of amazon. Still doing me good today! I I don't cook it though; I've been experimenting with powdered fuel mixes, and I have found that <50 grams of fuel in pvc can propel a rocket about 200 feet sideways (bad center of mass balancing) in only a second or so. Pretty powerful when done right, and very cheap.

[Skyler4856]

So what exactly shall we study whilst in flight?

[YourEverydayWaffle]

All except the Geiger counter could be assembled for less than 30 USD, and the counter itself would be in that price range. Nothing fancy, just CPM and microsieverts or micrograys per hour.

I don't think they'd mind. In fact, if the next Soyuz would use it as their 0 G indicator instead of Dimler the cat and Red from Angry Birds, it would be great.

The cheapest I've seen for Geiger counters is about $150. That particular one can detect gamma particles and beta particles, but I don't suspect there'll be too much beta up there. There also might be issues with the GM tube, if it were to crack do to rapid temp changes. The 100% copper probably won't though. The glass tubes are probably more susceptible to that if there is a really quick temp change.

[lajoswinkler]

So what exactly shall we study whilst in flight?

As said in the earlier posts, it would be cool to measure pressure, temperature, relative humidity, ionizing radiation.

The cheapest I've seen for Geiger counters is about $150. That particular one can detect gamma particles and beta particles, but I don't suspect there'll be too much beta up there. There also might be issues with the GM tube, if it were to crack do to rapid temp changes. The 100% copper probably won't though. The glass tubes are probably more susceptible to that if there is a really quick temp change.

Yes, actual counters you hold in your hand and wander around are expensive. DIY counters are very cheap.

There are no rapid temperature changes during balloon ascent even if the tube is outside the insulating capsule, which is not the case.

[YourEverydayWaffle]

As said in the earlier posts, it would be cool to measure pressure, temperature, relative humidity, ionizing radiation.

Yes, actual counters you hold in your hand and wander around are expensive. DIY counters are very cheap.

There are no rapid temperature changes during balloon ascent even if the tube is outside the insulating capsule, which is not the case.

Keep in mind that data-logging will be a very important feature. I'm not sure which DIY ones have this, other than just the "clicker", I've never looked into them.

[linkxsc]

As said in the earlier posts, it would be cool to measure pressure, temperature, relative humidity, ionizing radiation.

.

Then gimme a couple weeks to get off this job, and ill get a datalogger ready. At home i literally have a pressure altimeter (also gives straight pressure readings) temp sensors, and humidity sensors (and an arduino microsd shield to store readings on) i have a gps chip (not unlocked, but not much i can do about it. Itd actually be interesting to learn the cutoff altitude of the thing, cause none of my drones that use the same chip are allowed to exceed 1000ft) and a gprs board (the cellphone part, send a txt every 1-5 secs with all the info)

All i need to buy for the datalogging is the geiger counter, which when im 2 days from going home, ill order that.

[NERVAfan]

At home i literally have a pressure altimeter (also gives straight pressure readings) temp sensors, and humidity sensors (and an arduino microsd shield to store readings on)

Awesome!

i have a gps chip (not unlocked, but not much i can do about it. Itd actually be interesting to learn the cutoff altitude of the thing, cause none of my drones that use the same chip are allowed to exceed 1000ft)

Is it altitude limited or altitude and speed limited?

[sal_vager]

Great thread lajoswinkler, congrats, you've been stickied

[linkxsc]

Is it altitude limited or altitude and speed limited?

Probably both. I know the 1 in my phone cuts out at 250mph when on flights (im such a rebel not shutting off all electronic devices.)

Dunno though, ive been told by the faa that if they ever catch my drone above 2000ft, theyll slap me with a 25000 fine, and when its airborn, every 30 seconds, when it sends position update to my phone (does the phone at .5 sec increments) I also have to have it send them an update.

Paranoia man, but I dont really blame them. It flies at 80mph and can technically be operated anywhere as long as its got good cell signal, and it streams video, so meh. Great for airsoft though.

[magnemoe]

Probably both. I know the 1 in my phone cuts out at 250mph when on flights (im such a rebel not shutting off all electronic devices.)

Dunno though, ive been told by the faa that if they ever catch my drone above 2000ft, theyll slap me with a 25000 fine, and when its airborn, every 30 seconds, when it sends position update to my phone (does the phone at .5 sec increments) I also have to have it send them an update.

Paranoia man, but I dont really blame them. It flies at 80mph and can technically be operated anywhere as long as its got good cell signal, and it streams video, so meh. Great for airsoft though.

Attitude cuttoff is far harder to do than speed, 250 mph is faster than cars and small planes goes. Attitude is a bit harder to simply put an lock on as your gps don't know your attitude above ground, you can be at 4000 meter in the mountain lots of places so guess its higher.

[lajoswinkler]

Great thread lajoswinkler, congrats, you've been stickied

Thanks. I hope it will help with the project which is not exactly going anywhere yet.

[linkxsc]

Attitude cuttoff is far harder to do than speed, 250 mph is faster than cars and small planes goes. Attitude is a bit harder to simply put an lock on as your gps don't know your attitude above ground, you can be at 4000 meter in the mountain lots of places so guess its higher.

I remember reading somewhere that the cutoff for most GPSes is in the 15000-18000m range. And when I say cutoff, I mean the GPS chip is still getting full data, its just not giving it to you to use.

[Bunsen]

I wish I had seen this thread back when it started, because I've learned some pretty direct lessons about this:

1. The electronics can be assembled very cheaply by anyone with Arduino-level knowledge. Raspberry Pi works too, and Linux can make managing data flow a hell of a lot easier. Simple sensors like those being discussed here probably won't generate enough data to be an issue, though.

2. Getting the balloon is trivial and not terribly expensive. Getting helium may be tough due to supply shortages, but once you've found somebody that will sell you a tank of non-oxygenated helium you're pretty much set.

3. Real-time tracking in flight is important. If anybody involved in the flight has an amateur radio license, there are off-the-shelf APRS trackers that work quite well. Not all GPS receivers cooperate at high altitude, but there are plenty that do. Ublox units seem happy with high altitude after being commanded to enter "flight mode."

4. If you don't mind putting in some design and assembly work, you can make a functional payload amazingly small and light. There's a community of balloonists in the UK that goes utterly crazy at this, and they make their designs pretty public.

5. Make sure Jeb is well affixed to the payload, to avoid what happened to ours at 1:37:14 in the video:

The actual, plastic Jeb was a bit of an afterthought on our mission, the University at Buffalo Nanosat/SEDS Joint Experimental Balloon (which was launched to measure radio noise levels for a proposed 2.4 GHz link for our cubesat). He was a totally unauthorized model cranked out from our 3D printer in clear and green PLA, then decorated with white-out and Sharpie. The visor on his helmet was from a $1 pair of sunglasses, and was intended to serve as a mirror for watching the envelope during flight. It ended up misaligned enough that you could only see the edge of the envelope once in a while.

Shortly after the balloon burst, it becomes evident that Jeb and his carefully engineered mounting structure (i.e. some foam, tape, hot glue, and a scrap of 1/8" all-thread that we slapped together in about 2 minutes) were aerodynamically unstable, and the resulting vibration fatigued the mount to the point of failure after about 25 seconds. Starting around 26km altitude, Jeb then conducted an unplanned, independent descent toward an unknown (and likely subterranean) resting place in rural New York. While this may be a completely appropriate fate for a Kerbal, we want to make sure it does not happen again. It was pure luck that we didn't end up reading about somebody getting impaled by a plastic space alien on a metal rod.

[lajoswinkler]

That's exactly what I was thinking about. Well done!

Too bad it detached, but for the most part, it looks incredible!