# HELP ! construction of payload

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I am designing an experiment to collect bacteria from the stratosphere and need some help / advise in constructing a payload capable of collecting some air samples from there.

With thanks,

Christiana.

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i wish i had some suggestions instead of questions but are you looking for xenotrophs?

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How do you collect bacteria anyway? a few aspects that are different are:

-Bacteria will be much less common up there

-You must avoid contamination at launch and when the sample comes back down!

I'd say your biggest issue is to get your probe up there uncontaminated. I propose a weather balloon - those can go up to 30 km I believe? Make a timer to open the whatever-you-use-to-collect-bacteria

Your second biggest issue is to find the probe back after it was up there for some time, again uncontaminated. How do you keep bacteria separated from the rest of the planet in the lab? You have ways to close off a system, right?

Also, the winds in the stratosphere can be hundreds of kilometers per hour, so the sample will travel quite a bit. Again, I suggest that you copy whatever the meteorologists do... they probably somehow retrieve their equipment too.

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if you just wanted to observe them, with todays technology it would be very simple to set up a small CCD with appropriate lensing, use a simple 433MHz RF module and send the telemetry back to your receiver station, All using off the shelf parts!

the whole thing neednt weigh more than a couple 100 grams either.

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Didn't NASA do something like this using aerogel to capture solar wind particles in space? If I recall, the premise was that a canister opened, solar particles struck the gel, and were trapped. Eventually the canister was resealed and returned to Earth. Where it smashed into the ground when it's parachute failed to open, but that's neither here nor there.

Some sort of moist filter (hepa filter soaked in some sort of media?) attached to a small fan to suck air through the filter should be able to trap bacteria and keep them alive until they get back to the ground.

You'd need to find some sort of way to seal up the filter after a predetermined collection time.

As for height, would a sizeable weather balloon attached to fishing line help? Have the canister attached to the fishing line, and the canister attached to the balloon via some sort of breakable connection. Once the balloon reaches a certain height, the device starts to collect. Once the max height is reached, the fishing line yanks the collection device off of the balloon. Then you follow the line to the collection filter.

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its worth pointing out also that you Will require FAA approval to do this also.

although you shouldnt really have any problems getting permission, buying the time window that youll need can be quite expensive!

oh yeah, and where it comes to Structural parts avoid the use of metal as much as you can, your more likely to get permission.

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I'm a bit skeptical about the fishing line idea, for a number of reasons.

A 30 km long fishing line is hard to find.

30 km of 0.23 mm thick fishing line (rated 8 lb) will have a weight of 1.43 kg (about)... which is not negligible.

The line does not have to be exactly vertical, so your sample will still land up to 30 kilometers away.

Trees, houses and whatever will make sure that you cannot follow the line, and might even break the line.

This simple method does not close the sample when it descends... something which is important for the test to succeed.

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what you have to consider with the line idea also is the Wind!

its going to catch A LOT of air and easily exceed the breaking strain.

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I am designing an experiment to collect bacteria from the stratosphere and need some help / advise in constructing a payload capable of collecting some air samples from there.

I am designing a spaceship to take a few friends with me to Mars, can someone help me out please?

Leave it to NASA, the pros and the corporations. Because of all the difficulties listed above, try something easy instead.

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I am designing a spaceship to take a few friends with me to Mars, can someone help me out please?

Leave it to NASA, the pros and the corporations. Because of all the difficulties listed above, try something easy instead.

not really practical or helpful that.

back on topic: i do agree you shouldn't go with the fishing line idea, a small radio beacon(perhaps you could make a set up for an onboard phone to text you GPS coordinates?) or something would be immensly better.

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I don't see anything practical about what she is trying to do. She will most likely just get into trouble or waste a lot of time and money. How about studying something more accessible? Nobody asked Christiana what her educational level is or what her credentials are. Let's get some context before encouraging her. That was her first post here, and we don't know anything about why she wants to do something so difficult.

Hey Christiana, how old are you? What experience do you have?

Edited by Airbrush
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clearly I didn't think very far

I like i_a's idea, since there are off the shelf devices that will send a text message with their location at certain intervals. A google search will pull up several.

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One more thing, what does her question have to do with Astronomy and Cosmology? Her post should have been moved to a relevant discussion area.

Edited by Airbrush
Consecutive posts merged.
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I don't see anything practical about what she is trying to do. She will most likely just get into trouble or waste a lot of time and money. How about studying something more accessible? Nobody asked Christiana what her educational level is or what her credentials are. Let's get some context before encouraging her. That was her first post here, and we don't know anything about why she wants to do something so difficult.

Hey Christiana, how old are you? What experience do you have?

It doesn't matter how old she is or what her level of expertise is. as long as she gets permission from the FAA then its all fine.

heck the post even sounds like its a hypothetical thing anyway. how about you try and encourage people rather than just going 'you can't do that! its too inaccessible!' i say bollocks to that.

I have dablled inmodel rocketry a fair bit (not 30km altitude scale right enough but i know some people who have built sounding rockets that'll reach there) and getting a payload to 30km isn't particularly difficult. so even the inaccessible part doesn't apply, you just need the money.

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Well Mr. Alien, I can go along with the hypothetical thing. You probably know a lot more about this stuff than I do. But I beat you with common sense. She posted that a week ago and never returned, and obviously doesn't take it seriously. She is probably in high school.

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Well Mr. Alien, I can go along with the hypothetical thing. You probably know a lot more about this stuff than I do. But I beat you with common sense. She posted that a week ago and never returned, and obviously doesn't take it seriously. She is probably in high school.

So what if she hasn't returned yet? forums can be slow methods of communication if they aren't that busy. there are some forums i post on where i'll post something and return a fortnight later to get replies. its not that uncommon.

you said yourself that we know nothing about her and yet there you are making all sorts of inferences and judgements. chill out, bugger off and let the thread progress on its own. we'll often have our own discussion about the subject long after the OP has disappeared into the depths of the internet.

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OK, sorry to be so critical. In the hypothetical sense, she would need to send a balloon up into the stratosphere with a device that will open a trap at a certain height, and stay open long enough for the sample, then close tightly. Then it should release enough helium after the sample trap shuts so it will come down gently. You may need to retreive it from the middle of an ocean, or in very remote wilderness, or in the middle of a foreign country, all depending upon many variables. It should have a GPS tracking device so you can travel half-way around the world to retrieve it. And don't forget to have a sign on it (in every conceivable language) for a substantial reward for its' safe recovery.

A better way is hire a plane that can take the device, attached to the outside of the plane, that high. That will solve the problems encountered with a balloon. Wiki gave stratosphere heights starting at 10 km (6 miles or over 32,000 feet) and up to 50 km (31 miles or ~164,000 feet).

Edited by Airbrush
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OK, sorry to be so critical. In the hypothetical sense, she would need to send a balloon up into the stratosphere with a device that will open a trap at a certain height, and stay open long enough for the sample, then close tightly. Then it should release enough helium after the sample trap shuts so it will come down gently. You may need to retreive it from the middle of an ocean, or in very remote wilderness, or in the middle of a foreign country, all depending upon many variables. It should have a GPS tracking device so you can travel half-way around the world to retrieve it. And don't forget to have a sign on it (in every conceivable language) for a substantial reward for its' safe recovery.

A better way is hire a plane that can take the device, attached to the outside of the plane, that high. That will solve the problems encountered with a balloon. Wiki gave stratosphere heights starting at 10 km (6 miles or over 32,000 feet) and up to 50 km (31 miles or ~164,000 feet).

That post is a lot better than all the others you wrote in this thread... finally some constructive comments.

Hypothetical questions still need answers, and I wouldn't be surprised if this forum is actually visited by actual NASA employees, so this might just be the right place to ask these questions... and anyway, if we would not think about hypothetical issues, we'd probably still live in caves.

And anyway, I wouldn't leave this to NASA: they'd make a 100 million, 10 year project out of it... but it would have a cool acronym Which is why we will now try to find a cheap solution (cheaper than an airplane that has to be modified... I doubt that you want to simply open the door at >10 km altitude). If Christiana doesn't read the answers, then it's still fun to post, and secondly, somebody might just google this thread and use the results.

On topic:

Would it be possible to have a pressure-triggered system for opening and closing? I imagine a piston with a gas inside at pressure lower than 1 bar. When the balloon goes up, the air pressure outside the piston reduces, and the gas inside the piston is allowed to expand, moving the piston.

This should open the sample container in the stratosphere, and also close it again when it descends.

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• 3 weeks later...

These guys already did the job!

I found the article through slashdot.

Three new species of bacteria, which are not found on earth and highly resistant to ultra violet radiation, have been discovered in the upper stratosphere by some Indian scientists.

[...]

According to ISRO, the balloon experiment was conducted using 26.7 million cubic feet balloon carrying a 459 kg scientific payload soaked in 38 kg of liquid neon which was flown from the national balloon facility in Hyderabad, operated by the Tata Institute of Fundamental Research (TIFR).

The payload consisted of a cryosampler containing 16 evacuated and sterilised stainless steel probes. Throughout the flight, the probes remained immersed in the liquid neon to create a "cryopump effect". These cylinders after collecting air samples from different heights ranging from 20 to 41 km were parachuted down and safely retrieved, it said. (Source)

Seems like they made quite an elaborate sample mechanism. The sample thingy was 459 kg!

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• 2 weeks later...

Hehe.. whoever it was who said 'maybe''she's still in highschool is just ludicrous. In high-school , they certainly would not ask to construct or come up with ideas how to send a payload of bacteriae sampling to the stratosphere. This is more likely an assignment in year 2, maybe 1 (depending if the criterias were more conceptual) of an aerospace engineering undergraduate course.

Anyway, In all agreement with the pro-positive attitude. The question was perfectly viable for these kind of things, and to put it in astronomy cosmology.. ok maybenot perfect, but viable enough.. I 've seen more comments and subjects totally idiotic than I have seen misplaced topics.

Anyway, the last poster found another reference (perhaps so did the OP?). Shame no feedback frmo OP, then again was first post.. happens.

PS. What I wanted to reply to just the post before last, to captian:

About the pressure.. yes , I was also thinking using pressuredifferentials as a working mechanism (not just for piston operation.. as would be good for opening, but what about resealing?). Anyway, I was thinking pressure differentials would be useful as a way of starting the experiment. It is true many weather conditions would play in so it wouldn't be easy to get it accurate in height necessarily! However, with optimal conditions , it should be able ot place on within the stratospheric belt.

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