Sending a potato to near-space | Hacker News Reader

Sending a potato to near-space

ianww.com

38 pointstyppo17 comments

Great read & cool project. Somewhat disappointed I did a ctrl-F and couldn't find the term 'Spudnik'.

I am a contributor to the project and for my reward, I named my potato "Spudnik".

He didn't mention it, but if you look carefully in the third image: http://i.imgur.com/r1EvMIwl.jpg

totally missed this image. They did get it in there!

Having built potato cannons in my high school days, I half-hoped that this article would be about launching a potato to near-space via a launch. Pretty cool, regardless!

Would a potato even survive the sort of acceleration required? Would you just end up delivering mashed potatoes to near-space?

If the potato came apart early enough then the drag would increase exponentially and you'd just have potato mist a few meters above ground level.

I was thinking something similar, however if you want the potato to reach 100,000' though a ballistic launch it would have to come out of the spud gun pretty quickly.

Lets see, converting 100,000' to SI units that is about 30,500 meters. 1/2at^2 for distance, solving for time that is about 78 seconds (sqrt(30500 * 2 * 10)) and using at as velocity that is 780 m/second at launch (assuming no air resistance etc, this is just for fun) 780 m/second converting back to imperial is 2,560 ft/second or 1,745 mph. Basically supersonic (expected) about mach 2 at sea level. Probably be mashed potato as soon as it left the tube :-)

I love the idea -- whisperer, meal and all. Did you punish the disobedient GoPro?

Gerald Bull would be proud.

Could costs be reduced by using hydrogen?

Yep, definitely. We chose helium because it's easier to come by (party stores) and generally safer.

Actually hydrogen is pretty easy to come by if you get some Sodium Hydroxide (known as caustic soda or Lye) and aluminum you can mix some NaOH in water, drop in the alumninum and out will boil out hydrogen. Capture it in your balloon membrane and voila, done.

In general its not a problem if it isn't mixed with oxygen, if you live in the desert (as I did as a youngster) you can fill up a garbage bag this way and launch it into the sky) we tried to get one to explode but it just burns as the oxygen from the air comes into contact, and then waits for more oxygen to show up. Now if you mix it two parts H to one part oxygen? Then you can make a very loud pop :-)

...And stupid me, I tried to electrolyse _very_ salty water using household AC when I was in primary school. I manage to fill tiny bottles with potentially dangerous gaseous mix and leave foul smelling faintly green gas in the room (chlorine surely). Thankfully the worst that happened was a blown fuse. I was of course planning to make a hydrogen powered rocket missed the part about cryo... something :)

Yeah, that is a challenge (the cryo part). I was, of course, a huge fan of the space program and in reading about things like liquid oxygen decided to try to make some. Lots of books about it talk about using compression and expansion of the gases to cool down atmosphere to the point where you can pull out the liquid oxygen. What I didn't appreciate at the time was CO2 freezes solid and nitrogen liquifies before oxygen does. So my setup of four air compressors, each being fed by the previous compressor and having their tanks cooled by an ice bucket failed in an interesting way. The third in the series seized up when the tank's CO2 froze into ice and blocked the output port, and then the tank "rapidly self disassembled" from the compressor as it warmed up and I was trying to debug the problem :-) The tank and compressor separated, the tank moved about 20 feet away while doing its impression of a balloon flying about the room as it deflated.

It killed me when the old Intel Santa Clara 4 facility was demolished to become data center space that they scrapped the Liquid N02 generator that was part of that building. I drove by one day and it was laying in the parking lot in pieces. I would have loved to figure out some way to save it, all that liquid nitrogen on tap for what ever evil mad science experiment I wanted. Sigh.

Any idea of the max and min temps seen inside the box during the flight? How'd the potato fare?

Unfortunately, no real measurements. I would love to do it again with a thermometer and other interesting payloads.

The potato looked generally fine when we recovered it, but not incredibly appetizing, as its insides had been exposed to air for a while. The styrofoam box is a pretty good insulator and when we opened the capsule there was a lot of condensation and the enclosure was hot and damp.

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