High altitude balloon payload, from Sable-3 discussion Options

[djellison]

http://www.unmannedspaceflight.com/index.p...20&start=20

We began talkin about a UMSF balloon - and who know what might happen if enough people think about something hard enough, thoroughly enough and long enough.

How's about this as a starting point.
http://vpizza.org/~jmeehan/balloon/ with http://www.chem.hawaii.edu/uham/part101.html as an important regulatory start point (I'm going to look up the UK regs for this as well)

http://www.srcf.ucam.org/~cuspaceflight/nova1launch.html is also very impressive - all done in the UK

This http://www.makezine.com/blog/archive/2007/...video_podc.html is particularly impressive - I like the multiple-cameras slant.

Anyway - thought I'd get a thread going - this is an idea I like too much to let it gather dust in a corner - the one thing that I think would be nice to achieve is self-portraiture of some sort - think Beagle 2's WAM etc....perhaps in a corner of the FOV of one of/the imaging system. What sort of limit's should we set ourselves? 1kg 10x10x20cm? (sort of 2U Cubesat-on-a-diet budget)

Doug

[helvick]

I'm definitely on board for this but I'm in the middle of some chaos as I'm moving so my input may be patchy over the next couple of weeks. Putting up shelving, rewiring lights, fitting out kitchens etc is sort of top of my list at the moment.

I think it's a very good idea to put a stake in the ground for mass budget - 1kg sounds about right but obviously it would need to be confirmed against the carrying capacity of the balloon(s). I'm not 100% sure that there is a real need to set strict constraints on physical dimensions but I think going with the 2U cubesat framework is a good starting point and thermal insulation will almost certainly mean the payload will be a very compact box.

I'd love to see a shot of a UMSF logo against a deep black background with the curve of the upper atmosphere just below it - that's definitely got my vote for #1 mission success criterion.

[Paolo Amoroso]

[...] the one thing that I think would be nice to achieve is self-portraiture of some sort - think Beagle 2's WAM etc.... [...]

A mirror might be useful for this.


Paolo Amoroso

[djellison]

That's what WAM means - Wide Angle Mirror - you can see it above one of the two cameras here -
http://www.beagle2.com/download/number9-mid.jpg

and folded to one side here
http://www.beagle2.com/download/number7-mid.jpg


Doug

[Paolo Amoroso]

That's what WAM means - Wide Angle Mirror

Thanks. MTA: Mind The Acronym.


Paolo Amoroso

[djellison]

A starter for 10:

Powershot A570IS (IS would be a good thing on a rough ride to near-space)
89.5 x 64.3 x 42.8mm - 175g's.

It takes two AA's. NiMH's are typically 230g's a pair - and produce a total of 1.2v x 2500mAh - 3 whrs. - the same as the optional NB-3AH cells. In terms of Whrs/kg - LiPoly gives double the performance of a good pair of NiMH's - perhaps enough to accomodate TWO similar cameras. I would like to see something near 4 hours at 4 shots per minute - 1000 photographs. That would require somewhere around 9 whrs of power.





Doug

[dvandorn]

I'd love to see a shot of a UMSF logo against a deep black background with the curve of the upper atmosphere just below it - that's definitely got my vote for #1 mission success criterion.

That sounds like a good definition. Just remember, though, that in NASA-ese, you always capitalize Mission Success Criteria -- so that, if you don't meet those critera, everyone will know that You Have Failed...

-the other Doug

[helvick]

Things to bear in mind.

Not all digital cameras have a time lapse \ "intervalometer" mode. Whatever models are considered have to have that capability either built in or available cheaply (in terms of mass and money) as an add on.

A reasonably wide angle lens would be nice - most Compact Digicams have a wide end that's equivalent to ~ 35mm focal length on a classic 35mmm SLR providing approximately 55x37deg FOV but some have a more useful 28mm wide end giving a ~65x46deg FOV that covers about 50% more solid angle.

Storage capacity depends very much on how new the camera is - storage above 2GB may not be possible on older SD only devices for example. 1000 7Megapixel jpg shots stored in fine mode would be just about 2GB I reckon so that would be OK (just).

I think that a 2 camera approach is a very good idea. I'm torn between having them pointed in such a way that stitched panoramas are possible versus having them pointed so that we optimize the probability of getting a wider range of individual shots.
As far as power is concerned something like the Tekkeon MyPower MP3300 would give us 40whrs for 320grammes which is probably way more than we need for just the cameras but we still have to build in some sort of tracker\GPS unit and a transmitter which will both need juice too. Taht 40whrs is probably optimistic, no doubt there are losses in the voltage conversion circuitry and we'll probably have temperature related power issues so the margin with that might not actually be all that high.

Anybody got any information on a tracker\transmitter so we can find the thing once it comes crashing back to mother earth?

[nprev]

Well, here's something for that; not cheap, though (US$700). It calls a cell phone with position, and can be set for time-based or event based (jars, impact) reporting. 2.5 m accuracy isn't bad, but may be overstated for straight civilian GPS; would love to find a DGPS for more precision. Battery-powered, so no additional load on the vehicle bus.

I'll look around some more.

[Juramike]

This is an absolutely excellent idea.

I'll volunteer whatever feeble skills I've got. And I'll definitely kick in bucks when we start passing the hat.

[I've set my Davis Vantage Pro station (with WeatherLink datalogger) aside with a post-it note saying "Save for UMSF high-altitude balloon flight."]

-Mike


"Up, up, and awaaaayayyy...."

[ElkGroveDan]

Anybody got any information on a tracker\transmitter so we can find the thing once it comes crashing back to mother earth?

I tracked down the Sable-3 equipment. I'd say some of that would be a fine starting point due to it's proven abilities

The tracking device comes in a kit and is inexpensive:
http://www.byonics.com/microtrak/mt300.php

Here are some balloons
http://www.scientificsales.com/SearchResults.asp

[djellison]

I saw 'kit' and thought 'great- I've done loads of soldering..' but if it's $10 to get it built and tested...screw it

Doug

[helvick]

Well, here's something for that; not cheap, though (US$700). It calls a cell phone with position, and can be set for time-based or event based (jars, impact) reporting. 2.5 m accuracy isn't bad, but may be overstated for straight civilian GPS; would love to find a DGPS for more precision. Battery-powered, so no additional load on the vehicle bus.

I'll look around some more.

The MicroTrak looks like an ideal solution and as Dan says it has the significant advantage of being proven for the purpose and the whole thing is cheap (~$100) and weighs less than a couple of ounces. Receivers for a tracking team (or teams) seem to be dirt cheap - this site has the RF part for less than 20 euros and it looks as if linking this into a PC\laptop is also cheap and straightforward if we wanted to do that.

If we were happy to use a cellular phone type device for tracking then I can build a solution using any Windows Mobile\Pocket PC Phone Edition device with an internal GPS ( I have one of these that's got a broken power connection that I'm happy to donate to the cause if I can fix it ) that is certainly good for <5m accuracy which is more than good enough. It will probably need additional power to keep its GPS and cellular radios running for the sort of time we're talking about. I don't think it would be able to give anything like live telemetry at any serious altitude (a couple of thousand m) but it's no problem to get it to log to an SD card and send what it can over GPRS when its available so it might not be a bad approach. Total mass without the battery is about 190g. It's even got a very lousy cell phone camera that we could use to get some additional pictures as a backup.

[djellison]

The smartphone is a genius idea - it would make an excellent secondary system that's virtually stand alone. GPRS'ing lat/long - ESPECIALLY once it's landed again would be GENIUS because a VHF transmitter from ground level is unlikely to get very far. We can call it the Independant Backup System. IBS

Just because I like getting my hands dirty - I'm going to look at foam insulation at lunch time and make a gondola. Not to fly - just to make something cool.

Doug

[AndyG]

Here's a more-or-less self-explanatory table of altitudes with some notes. The only odd column here is the one called deg - this is the dip from the local horizontal at the listed altitude to the Earth's horizon. Higher the dip, the better the curve!

There's a few potential Mission Success Criteria here that would be good to see: personally, I think that the old tropopause feels almost too achievable with off-the-shelf weather balloons. I'd be, well, tempted to aim just a little higher...not too much, but still...


km deg tempC Pa kg/m3 notes
53 7.4 +27.3 60 0.7
52 7.3 +24.3 67 0.8 51.82km - highest unmanned balloon flight
51 7.2 +21.3 76 0.9
50 7.2 +18.3 85 1.0 800km to horizon
49 7.1 +15.3 96 1.2
48 7.0 +12.3 108 1.3
47 6.9 +09.3 121 1.5
46 6.9 +06.3 137 1.7 Shuttle SRB burnout
45 6.8 +03.3 155 2.0 SpaceShipOne engine cutoff
44 6.7 +00.3 175 2.2 750km horizon
43 6.6 -02.6 198 2.6
42 6.6 -05.6 225 2.9
41 6.5 -08.6 256 3.4
40 6.4 -11.6 291 3.9 40.00 km - QinetiQ (failed) manned record attempt
39 6.3 -14.6 332 4.5
38 6.2 -17.6 379 5.2
37 6.2 -20.6 434 6.0
36 6.1 -23.6 497 6.9
35 6.0 -26.6 570 8.1 34.67km - Highest manned balloon flight
34 5.9 -29.6 654 9.4 1% reduction in gravity
33 5.8 -32.5 753 10.9
32 5.7 -35.5 869 12.7 Mars surface pressure
31 5.6 -38.5 1003 14.9 Above 99% of the atmosphere
30 5.6 -41.5 1161 17.5
29 5.5 -44.5 1346 20.5
28 5.4 -47.5 1564 24.2
27 5.3 -50.5 1821 28.5
26 5.2 -53.5 2124 33.7
25 5.1 -56.5 2523 40.6
24 5.0 -56.5 2952 47.5
23 4.9 -56.5 3453 55.6 FAI definition for the lower edge of near space
22 4.8 -56.5 4040 65.0
21 4.7 -56.5 4727 76.1 Above 95% of the atmosphere
20 4.5 -56.5 5531 89.0 500km to horizon
19 4.4 -56.5 6471 104.1
18 4.3 -56.5 7571 121.8
17 4.2 -56.5 8857 142.5
16 4.1 -56.5 10363 166.7 Above 90% of the atmosphere
15 3.9 -56.5 12125 195.1 SpaceShipOne release altitude
14 3.8 -56.5 14185 228.2
13 3.7 -56.5 16597 267.0
12 3.5 -56.5 19418 312.4
11 3.4 -56.4 22707 365.2 Approximate height of Tropopause
10 3.2 -49.9 26516 414.0 Commercial Airliners
09 3.0 -43.4 30827 467.7
08 2.9 -36.9 35688 526.6
07 2.7 -30.4 41152 591.0
06 2.5 -23.9 47274 661.2
05 2.3 -17.4 54114 737.7 250km to horizon
04 2.0 -10.9 61734 820.7
03 1.8 -04.4 70201 910.7
02 1.4 +02.1 79584 1008.1
01 1.0 +08.6 89958 1113.3 ~900m - Montgolfier Brothers, 1783
00 0.0 +15.0 101401 1226.6

[jamescanvin]

Great info AndyG.

Looking at some of the other folk who have done stuff like this, 30 - 35km seems to be reasonable.

Surely we've got to be aiming for the 32km 'Mars surface pressure' mark.

J

[djellison]

At that level it's a little bit about luck - but I'd say the 30km, 100kft, 10% air pressure, mars air pressure type level is a sensible ultimate goal. Maybe not first time around - but eventually.

Doug

[ustrax]

Hey Doug...what do you think of this first approach to a possible name anf badge for the project?...

On following opportunities we could follow this policy and use our beloved ones names...I'm sure each launch would have a distinct personality...

[jamescanvin]

I think that a 2 camera approach is a very good idea. I'm torn between having them pointed in such a way that stitched panoramas are possible versus having them pointed so that we optimize the probability of getting a wider range of individual shots.

Hopefully even with just one camera some nice panoramas will be possible.

Some quick tests:

Nova - images taken 15 seconds apart - altitude change 300ft - altitude 100,000ft


Even at low altitudes and with large time intervals this can still be done.
SABLE-3 - images taken 1 minute apart - altitude change 800ft - altitude (above ground) 10,000ft


If we had two cameras I'd vote for one pointing horizontally and one pointed down at 45 degrees and turned 90 degrees 'portrait', which should give maximum coverage.

It may take a while to sort through the images but with a couple of cameras like this firing quite frequently some pretty spectacular stuff should be possible.

James

[nprev]

Nice logo, ustrax!

Just a general engineering note based on AndyG's terrific table: need to determine an optimum rate of climb (ideally, maximized) in order to minimize thermal effects on the electronics, unless the payload will be environmentally controlled. Major trade-off in all areas is, of course, that more payload weight equals less achievable altitude...

[djellison]

Payload wouldn't be thermally 'controlled' per.se - but something like a foam (there's 3cm thick foil covered foam available at my DIY store) cube which would thermally insulate it from the cold - and then the electronics inside would hopefully keep it fairly warm simply by using up the Whr's.

I knew someone would start thinking of logo's and names before we got too far

Doug

[jamescanvin]

One more stitching test using the SABLE-3 images. These images are fully 6 minutes and 6,400ft apart and still stitch nicely. With two cameras taking pictures 15 seconds apart and we could have 50 images within this time frame, nice.



James

EDIT: just came across this page of records for this sort of thing - http://showcase.netins.net/web/wallio/ARHABrecords.htm

[ustrax]

You know how this guys are Doug...

Seing those images I can't avoid to think about something I already made reference here, I would L-O-V-E to see some video footage with sound...what are the major constraints for something of that nature?...

[djellison]

Storage, Volume, Mass, Power, Money If you can find a small digital camera that can take movies of approx 2 hours onto SD card etc, and last that long on the battery, that's small enough (10 x 10 x 3 cm sort of size) and light enough (<300g) - then maybe. While movies are cool - I think I'd rather have mega-pixel stills than a lower res movie ( although both would be cool.)


Real time video transmission is possible but typically not further than 5km with the transmisison power allowed by the radio spectrum laws.

[nprev]

Payload wouldn't be thermally 'controlled' per.se - but something like a foam (there's 3cm thick foil covered foam available at my DIY store) cube which would thermally insulate it from the cold...

Doug

Yeah, that'd help. Main concern here is electrical connectors. Probably a good idea to seal them with ScotchGard or RTV, which in addition to adding another insulation layer to minimize thermal contraction/expansion would also prevent moisture intrusion/condensation.

[scalbers]

Hi - this link has a nice high altitude photo from the Edge Of Space Sciences balloon group:

http://www.eoss.org/ansrecap/ar_030/recap13.htm

[Juramike]

One possibility might be to put all the batteries in a custom battery harness which is itself inside a small thermos. That should keep them from getting too cold during the trip up. The downside will be making sure that all the connections are nice and tight.

Yet another possibility would be to put a small "box" of solar panels around any package. At least one of the panels would be pointed towards the sun and delivering power. But then you gotta deal with transformers, etc.

-Mike

[JRehling]

[...]

[djellison]

Actually - the altitude will be limited by the envelope which seem to always burst at 80-110kft

Doug

[nprev]

Good point, Doug. However, ascent velocity is still contrained by payload weight, so it's still a significant consideration. For recovery purposes, seems like you want to get up & down as rapidly as possible in order to limit your touchdown CEP.

[dvandorn]

Have y'all thought about where you'd want to fly this thing? Most of the U.S. has severe restrictions on flying any non-commercial, non-military vehicle above about 2,000 feet, and there are a lot of places where the restriction is lower than that, or where you can't fly anything. Most of this is due to airlanes, landing patterns, etc., but some has to do with laws against unlicensed surveillance.

I can't imagine Europe is a lot more open about this kind of thing -- if anything, Europe has more crowded skies than does the U.S.

And to add another inconvenient point -- even if you could launch from, say, the U.K., won't the camera pod come down several hundred miles from the launch point? There are a lot of things several hundred miles away from Britain that aren't very welcoming places for recovery of a pod -- the North Sea and the Alps are a couple that come to mind.

Just asking the obvious question I haven't seen raised yet...

-the other Doug

[Astrophil]

Here's an idea for a future mission: re-enact the Huygens probe.

You'd need three cameras (or two if one had a big enough FOV), arranged so as to cover the angles covered by Huygens' cameras. Once you'd recovered the payload, you'd release a subset of the pictures, downgraded to Huygens quantity and quality. The challenge then is to stitch them together as people did with Huygens, making mosaics of the landscape and identifying the landing spot in it if possible.

It'd be an interesting game - and it'd help one imagine what the Huygens imagery really means.

[djellison]

Actually - the FAA ( and I'm looking up the UK version, the CAA ) are fairly liberal with these things up to a certain mass. Many of these balloons have ( and indeed one is going up today ) been launched from the UK - in a typical 2hr up 30 min down flight - you'll cover something like 30-100 miles. Launching from the western UK ( Wales ) would put you back down in central UK.

I think the flight reg analogy is that if you're not going to launch something heavier than a duck, then what's the problem as no law's going to ground all the ducks and swans at 12000 ft \

I got bored - I went out to Maplin ( local electronics store ) and thought that I might need some soldering practice, as whatever we make I'm sure some soldering - even if just for power leads - will be required. They've got LOADS of cheap little kits - so I found the only one that seemed to make any sense for a payload...a small super bright white LED strobe kit. I figure I can rewire the LED's to be external to the WEB on cables running out the box, and perhaps on strut I thought we could mount a WAM for self portraits and in the case that we're still looking for the payload at night...it might help find it. Three little transistors, two capacitors, half a dozen resistors, a variable resistor and a brace of switches - cute little setup really (and suprisingly bright)

Sorry - crap pics - using my cell phone's camera.

And I've found a supplier for a suitably sized parachute for a 2kg payload ( 36 inch diam ) - it's on its way.



Doug

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[djellison]

Just a bit of fun using Google Sketchup. Never used it until about an hour ago, it's amazing!

The GMC is somethign I already have. It's a £20 digital camera that takes 1280 x 1024 images at pre-determined intervals. It runs from a single AAA. The Convex Mirror would be the sort you can get to stick on your car side mirror to see blind spots. Having the GMC as a stand alone component is a good move for redundency. I want to see if I can make the GMCSA from what was 'cat cam' - some foam, a mirror ,and then put it in the freezer to see how long it can last.

I got some foam insulation yesterday - and it's too thick really - 50mm thick which is a bit crazy. The thermal properties are amazing, just leaning up againt it you feel hot after 5 seconds because it's not letting heat get away, it's bizarre.

Anyway - if anyone wants the GSU file - let me know

I'm still aiming for something like 10 x 10 x 15-20 internal space - and then if the foam is a few cm thick, you can always carve into it a little.

Weather permitting, I'll be going to Cambridge next Sunday to see a launch by James - http://www.pegasushabproject.org.uk/ -

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[ElkGroveDan]

Just a bit of fun using Google Sketchup. Never used it until about an hour ago, it's amazing!

Never heard of it before. Thanks for the idea. Any idea what all "pro" does.

[djellison]

I think it just lets you interface with other formats more easily (import and export 3DS etc ), and do pretty plans. As it is - GSU (£free) is making me hate 3ds max (£thousands) for lacking the annotation tool.

[ngunn]

I really hope you guys pull this off. Unfortunately I've got nothing technical to contribute, just a greedy suggestion:

Fly two of the things in tandem, set to separate at some altitude. You could get beautiful stereo cloud imagery. I can imagine something like this being done on Titan one day to study the morphology of storms there. Earth's atmosphere seems the perfect place to try it out.

[remcook]

Cool project! How much would a weather balloon set one back these days?

I think for the stereo idea you'd want the two cameras on the same platform (a bit like the SIM mission) since the balloons will drift apart quite quickly and randomly I would think,.

[remcook]

By the way, did this link get mentioned?

http://www.ukhas.org.uk/

Seems like this might be useful in this case.

[ugordan]

I think for the stereo idea you'd want the two cameras on the same platform (a bit like the SIM mission) since the balloons will drift apart quite quickly and randomly I would think,.

Yet the baseline you can feasibly pull off in such a way would be useless for producing stereo of clouds tens of kilometers below. I think stereo is a no-go here.

[Juramike]

The twin balloon idea is pretty good. Launching two simultaneously from slightly different locations will give some really cool information:

If they stay together, you could pull off a stereo image. (Launcing them a few kilometers apart should give a stereo good baseline at altitude.)

If they drift apart, your tracking data gives great information on weather patterns.

With two balloons, you'll also get an idea of the consistency of ascent rate under nearly identitical conditions. And all the telemetry data will be doubled, so you get double information on performance that you can use to cross-check.

Two attempst also increase the chances of mission success, should one fail (or land on someone's roof).

Plus you'll have the fun of two recovery teams chasing around the countryside....

If they're cheap, send two! (which is pretty much my sentiment regarding all missions)

-Mike

[ugordan]

If they stay together, you could pull off a stereo image. (Launcing them a few kilometers apart should give a stereo good baseline at altitude.)

Even if they stay together, there's no guarantee they'd be pointed in the same direction at any given time. You'd probably only get a couple of lucky shots, I'm not sure if it's worth launching 2 balloons just for that.

[djellison]

Plus -two of everything to buy (and in this case, there are not any savings) - double the ground-station equipment to acquire - double the number of people.

Lovely idea - but think of this more of Ranger rather than Mariner ( consecutive, not simultaneous )

Doug

[nprev]

Lovely idea - but think of this more of Ranger rather than Mariner ( consecutive, not simultaneous )

Just as well, given that there was only one successful launch of a Mariner pair (6 & 7)...

[dvandorn]

Well... considering the fact that Voyagers 1 and 2 were originally to be Mariners (though I have no idea if they would have been Mariners 11 and 12 or not), we *almost* got a second successful pair-launch out of the program!

-the other Doug

[dvandorn]

...think of this more of Ranger rather than Mariner...

Hmmm... maybe not the best choice in concepts, there, karma-wise, Doug...

-the other Doug

[ugordan]

Well... considering the fact that Voyagers 1 and 2 were originally to be Mariners (though I have no idea if they would have been Mariners 11 and 12 or not), we *almost* got a second successful pair-launch out of the program!

I'm wondering... had they been indeed called Mariners, would they have both launched successfully or would Vgr 1's Titan booster for example decide to underperform some more?

[AndyG]

Is there an issue with expanded polystyrene at very low pressures? Or is the plastic part of the matrix mechanically strong enough to withstand the expansion of the embedded gas?

Andy, also looking at envelope materials for high altitude balloons - not the rubberised standard Met ones.

[djellison]

Is there an issue with expanded polystyrene at very low pressures?

Tens of thousands of met balloons have gone to 100k+ without any trouble of that nature - as well as probably dozens of amateur projects. They all use polystyrene or similar materials.
oug

[djellison]

Status update :

Proposal :
<2kg payload - on the order of 20 x 20 x 30 cm external + extras.
VHF APRS GPS for realtime tracking
Multiple internal cameras for mosaicing Horizon-to-Nadir view
External camera on independant power supply using WAM or Fisheye lens for self portraiture
Standalone system for tracking via SMS / GPRS

On order:
36 inch chute ( suitable for up to 2kg )
Microtrack 300, GPS and VHF antenna.
10 x (cheap lot off Ebay) 31x21x24cm external, 26x16x17cm internal polystyrene boxes
Wide angle mirrors ( circular and rectangular )
Literature study so I can pass the Fundamental radio licence course to allow broadcast by the Microtrack.

On offer:
Independance Backup System from Helvick in form of Smartphone with camera and GPS

Investigating:
Balloon
Gas (both kind of important)
Power supply
Groundstation
Gondola cameras - powershots with intervalometer, or other cameras with a shutter-release via a timing circuit. Will multiple cameras carry keep their intervalometers in sync if set off together - or will a timing circuit be needed - and if so, is it worth tying that into the GMC (even though I said I wanted that to be independent)


Future options for later flights:
Data logging of GPS Lat/Long/Alt, Pres, Temp, Accel ( nice science to tie in to Huygens with accel data) other params.

[volcanopele]

I would seriously look at the design of Huygens as the best analog for this project. It sounds like the camera system is designed to be akin to the Huygens camera system, with three cameras imaging from nadir to horizon. For mosaicking purposes, look at the design of Huygens and how it spun so that full 360 degree mosaics would be possible. of course, make sure it is designed to spin in the correct direction.

[djellison]

I was having similar thoughts, how controlled can we have the rotation (up the hill or down) - because looking at other similar projects, the imagery seems very very chaotic.

Doug

[nprev]

Weight distribution would also be very important for platform stability; you might have to use some soft lead weights to at least get a three-point balance, bottom heavy (thinking of 1/2 oz fishing sinkers...)

Spin's a little harder. I guess some fins to offer wind resistance might help, but wouldn't do much good at peak altitude...

[djellison]

The problem isn't a million miles from MER terminal decent. It's not chute-backshell-lander but it's envelope-chute-gondola.

I'm reminded of this : http://www.jpl.nasa.gov/news/features.cfm?feature=1449

[jamescanvin]

I don't think controlling the rotation is going to be possible, certainly not to the level required to guarantee that we get 100% coverage.

iirc Huygens was designed to spin just to make sure all the images didn't point in the same direction, not to have a controlled sweep to pan the camera. Looking at images from other balloons it doesn't look like forcing the balloon/parachute to rotate will be a necessary, it looks like quite a wild ride.

Lets just concentrate on taking as many shots as possible, it looks to me that we won't have to be too lucky to get good 360 coverage and we have plenty of talent here to fill in any small gaps in the data.

James

[djellison]

Discovered the FM transmitter may be a no-no in the UK

OO - no - 144.800 is good for APRS in the UK Sweet.

Grrrrrrrr

[ngunn]

Doug - I wanted to reply to your paragraph about options for future flights but when I click on 'reply' to your post that part seems to be missed off the quote. Anyhow, you know what I'm going to say - "What, no stereo? " I think this is a significant, attainable, genuinely scientific objective given that weather phenomena are complex four-dimensional things. It could have practical applications not just on Titan but for Venus and the giant planets too. I can see why the first flight should be as simple as possible though.

On the cost issue - would there be some way for us 'spectators' to chip in a little, perhaps anonymously?

[djellison]

For stereo to work - you either have to have a very long baseline within one payload ( which is a near impossibility given the limitations of size and mass ) - or two simultaneous balloons pointing in the same place, at the same time, at the same altitude ( a near impossibility given the limitations of chaos).

Clouds are usually fuzzy, roughly defined, dynamic objects - I can't imagine that getting stereo imagery of them would be particularly valuable anyway. They're not like a rock. If someone can explain to me how it could be done and why it should be done, then why not....but I struggle to see a means or a purpose at the moment.

You are right however - the first launch ( and indeed I would have thought the first few launches ) are intentionally simple and as far as possible, with redundant systems. i.e VHF GPS, and GPRS/SMS GPS, GMC and onboard cameras etc etc.

And I've got to get a Radio license

Doug

[ngunn]

OK this is getting off topic and I won't keep on about it here, beyond this one post. Understanding the detailed dynamics of atmospheres is surely a major target for planetary exploration. Clouds may be fuzzier than rocks but they can sometimes take quite crisp forms, on scales of just a few metres in some cases. They act as visible tracers of air movements and markers of humidity levels as well as possible compositional gradients of gaseous and suspended liquids and solids. In short they are most worthy imaging targets. I envisage possibly a cluster of mini-balloons descending through a planetary atmosphere each taking pictures in perhaps three different directions. Even with random separate orientations and spins there could be enough dual 'hits' to generate a 3D movie of the atmospheric goings-on. I think this would be an exciting thing to do and could be done with simple 'Ellison' balloons. Getting even one lucky stereo hit with just two of the things in Earth's atmosphere would demonstrate the potential and would perhaps be a technical first.

all this aside I wish you every success with the exciting stuff you are planning.

[AndyG]

Thirty Thousand Metres Via A Plastic Bag

The above is a Flash tool for helping develop high altitude balloons. Briefly: the Met balloons are made of some rubbery compound which stretches under reduced pressure until the point at which they burst. With a given quantity of lifting gas in them, the approximate altitude for the burst can be calculated beforehand. Much more Romantic, and Golden-Age-Of-Ballooningy, are the light plastic/Mylar balloons that are part-filled with lifting gas, and gain sphericality at altitude. These are truly bouyant - with the right parameters, they'll find a level of no-lift, no-sink - which makes them ideal for higher altitudes and longer durations. Naturally UMSF engineers could employ a timer to cut loose the Earth-Return Package from such a balloon and achieve higher altitudes than otherwise.

On to the tool...

There's four yellow sliders, one for altitude, three for the balloon. Set the desired balloon parameters first. Radius is the desired balloon radius, Density is envelope density (970kg/m3 seems to be ok for most commercial polyethylenes) and Thickness governs the quality of the envelope, measured in gauges, as shown below:

Gauge Sort-of-Thing
70 Light Duty Rubbish bags - (those bags which literally are rubbish when they burst after putting hardly anything in)
150 Heavy Duty Rubbish bags
200 Refuse Sacks
800 Heavy Construction Film

Setting the three balloon sliders produces a number of results for the balloon. Most important are the volume and envelope mass.

Now move the altitude slider - as the height increases, the figures for Hydrogen and Helium's excess lift drops. Once the excess lift, for a chosen gas, falls below the payload mass, that's the maximum altitude achievable. At this point, the Hydrogen and Helium required figures make sense - these are the mass and volume of the chosen lifting gas required at sea level.

Example: Radius - 5m, Density - 970kg/m3, Thickness - 70 gauge. Max Helium altitude with 2kg payload = 30500m, 31100m with Hydrogen (so not worth the bother for the added risk?)

Max altitude for same balloon with a 100kg Doug payload (generously including thermal gear and some oxygen) ~14000m.

Enjoy!

Andy

[djellison]

The envelope itself is arguably the easy part. Buy it - fill it - launch it. They're a commercially available part that doesn't need that much thinking about.

The stats are here : http://www.kaymont.com/pages/sounding-balloons.cfm : you over fill compared to those stats slightly - and get a better lifting capacity - but you reduce your ceiling as a result.

Oh - and the chances of flying me on something like that to 14km.....slim....unlike me

Doug

[jamescanvin]

OK a few simulations of camera coverage.

Two cameras, one landscape pointed horizontally, one portrait, pointed 45 degrees down both normal 35mm field of view. Take one image with each and here is the coverage on a 360x180 degree equirectangular projection.



Rotate and swing to the payload, 30 degrees looks about right from a lot of images I've seen from other attempts.
Take 25 images per camera (one every 15 seconds for ~6 minutes say) and you'd be unlucky not to get a 360 and most terrain should be covered twice.



Coverage tends to improve (less likely to get that jagged line of missing data) if you don't have the cameras going off simultaneously (which should also be easier to implement )

[djellison]

Now that's cunning - and even though the data would suggest otherwise - I'm still tempted to use a simultaneous release just because we then know we've got n 2 or 3 frame panoramas. What do your sims say for two cameras in portrait, two in landscape, three in portrait, three in landscape with say, 10% FOV overlap?

I've had another idea for a self monitoring camera which could be cool....got to wait till I have the gondola boxes and a few cheap digi cams

Doug

[jamescanvin]

Your wish is my command...

In each of these I've used the same orientations of the gondola when each picture is taken to make them somewhat comparable. In each case there are 15 images from each camera. Also included is the coverage after one shot from each camera and two percentages indicating the total coverage and the coverage in the lower hemisphere (as the upper one should be mostly black sky ). Of course this is very biased as a lot of pixels near nadir represent very little solid angle in this projection but hopefully it tells us something. The cameras are arranged so they have about the same amount of overlap between the images (5 degrees or so).

1) Similar to before two cameras, upper in landscape, lower in portrait and pointed down at 40 degrees. 61% 86%



2) Both cameras in portrait one pointed down at 45 degrees. 65% 91%



3) Both cameras in landscape one pointed down at 35 degrees. 54% 71%



Sims using three cameras to follow.

[JRehling]

[...]

[jamescanvin]

4) Three cameras all in landscape with elevations +15, -20 and -55 degrees. 76% 99%



5) Three cameras all in portrait, two side by side (35 degrees) with one underneath (-45 degrees) 72% 96%



So in conclusion, if we can stretch to three cameras I'd go for option 4 (even with just 10 images per camera I still get 94% coverage of the ground hemisphere in this simulation). This one also has the added benefit of being a bit Huygens like.

James

[ngunn]

Why not just have two photographers head to mountaintops, link up by cellphone and synchronized watches, and shoot photos of the same cloud formations at the same time? You could even do this without the mountains, but I think someplace like the Cascades of Oregon or Washington state would be ideal locations.

Venus Titan and Neptune, on the other hand would be less than ideal. Nobody was suggesting that you need balloons to study terrestrial cloudforms. Indeed a movie or sufficient still shots from any fast aircraft or satellite would achieve excellent results without the need for mountaineers. My idea was to use Earth's conveniently accessible and largely transparent atmosphere and Doug's simple-as-possible balloons to try out a technique that might prove practical and cost-effective in more awkward locations elsewhere in the solar system.

[djellison]

Well - I've just ordered three very VERY cheap 3 megapixel cameras. Cheap enough that I don't care if they get...

1. Broken by me stripping them out to work with a timer circuit
2. Frozen to death
3. Broken on landing via drowning, crushing etc
4. Lost for all eternity - last seen at 95,000ft over Norfolk.

And also - if they're any good at all - I''ll get another half dozen just so we've got 'stock' as it were. Once I know roughly how large their images are, I'll get SD cards to suit the requirements of >3 hrs at 20 second intervals.

For the price of my 400D (which isn't going within 10 miles of a polystyrene fish storage box hung under a giant condom full of helium some idiot from Leicester's going to let go) - I could by 24 of these 3 megapixel jobs. Once I have them (this weekend - I'm away giving a talk tomorrow) - I'll 'calibrate' them to find their actual FOV and work on some sort of internal framework (balsa and/or foam) to mount them at appropriate angles to one another in landscape (if the vertical FOV is >45 degrees) or portrait (if the vertical FOV is <45 degrees)

Before that - I want to figure out how to power all three from one big-ass central power supply, how long that will last, and if I can wire them up into one relay - or if I'll have to power three relays with the one timer circuit relay...to trigger them. Once I've got my mirrors - I'll be figuring out if CatCam can do the GMC campaign on its own - or if I want to tie that in with the same circuit (I think I do)

Meanwhile - got to convince the photographer that she wants to let catcam get trashed....could be difficult.

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[helvick]

Stunning work with those coverage sims James.

The coverage question and whether we should try for three cameras leads me back to some research that we need to close out on. We know that some of the mid range Digicams (Some of the Canon PowerShots (S3is, S5is , 570) and some Casios have an internal time-lapse\intervalometer mode that is hugely useful. What we really need is to find a camera that meets the following:

Must have features:
Lightweight: <200g ? If we want to fly three cameras then we really should be looking for <133g
Time-Lapse mode \ Intervalometer _or_ a lightweight trigger circuit
Capability to be powered by external DC source
Fully automatic exposure control (this is a given in a digicam)

Desirable Features
Low cost: The cameras are very likely to be consumables in this exercise so it would be smarter to select a cheap one.
Wide Angle.
High resolution
Good optics

Any other suggestions?

Doug - My Fujitsu Siemens Loox-T is not responding to intensive CPR so I've given it to someone better qualiied to try and recover it. In the meantime I'm trying to scam a replacement out of my various contacts. If all else fails I'll buy sufficient kit for the cause. I reckon I need about a week to get the code to send GPRS and SMS GPS coordinates working, fortunately I don't need a working GPS enabled device to develop and test that so we should have a high level of confidence in that system fairly soon even if I haven't nailed down the hardware.

[djellison]

Well - I think with these cheap cameras I've got coming - I'll tick the low-cost, wide angle boxes and bolt on a simple timer circuit. I need to establish what, if anything, is happening when the shutter is pressed ( is their current or voltage involved that might feed back from one camera to another etc - and does that even matter if they're all identical anyway )

With multiple cameras, the independent timer circuit is going to be a better bet than relying on the intervalometers of whatever type of camera we have - as I imagine they would drift out of sync with one another Power is still a 'hmm - what to do' issue - because the FM APRS Tx needs a power source as well - although it will happily run of a standalone 9V for a week or more. Amazingly - there are some C and D recharable cells that run to 5000Ahrs and 11000 Ahrs respectively. A pair of those for each camera would give us all the juice we would need (5000Ahrs is twice the capacity of an excellent AA)

I was worried about the cold on the GMC - but going for the most simple possible solution - http://www.bargainboards.co.uk/P/MyCoal-Fo...mers(1252).aspx - would make the problem go away entirely.

Once I have chute, box, cameras, FM APRS Tx, GPS - I can think about the mass budget and figure out how many Whr's we can get into it. If it's looking desperate then in order..things would get culled like this

3rd camera
2nd camera
GMC
IBS
Replace 1st camera with GMC fitted internally.

The bare minimum is one camera, and the FM APRS Tx & GPS. Then it's that + the IBS etc etc.

If your Loox is properly dead - and ignoring the beggars can't be choosers factor - it'd be brilliant if you could scrounge a similar model so that the dead one can become a mass model.

[ElkGroveDan]

If Helvick can't come up with another unit, I have a fully functioning Palm Treo 700 that I'd be willing to part with for this project.

[JRehling]

[...]

[djellison]

Someone else can drown their cameras intentionally - I'm only aiming to do it unintentionally There's a real engineering challenge in 'depth' for the payload protection - far more so than altititude - but the 'transport' would be so much easier ( a line, and some rope) interesting concept though.

[AndyG]

I was worried about the cold on the GMC - but going for the most simple possible solution - http://www.bargainboards.co.uk/P/MyCoal-Fo...mers(1252).aspx - would make the problem go away entirely.

Top marks for the heating option - though I would be somewhat wary of enclosing one of these in a thermally insulated sealed box. Could get toasty! Any idea of their wattage?

And I'm sold on the idea of flying a thermometer - Maplins do a 100k Bead Thermistor (for 90p!) that works down to -55C. But if a thermometer is to go - then a manometer's a must, too, in order to check altitude.

Andy

Edit: Rs Components offer a suitable manometer - but it's £40! Surely they can be found for less than that?

[djellison]

A 90p thermistor's great...BUT....you need something to read it, log it, and then spit it back out to you on the ground - it becomes a big problem.

There are commercially available stand alone thermometers that log - but they're not cheap. More sense for a first flight might be a simple standalone max/min system like this http://www.maplin.co.uk/Module.aspx?Module...er&doy=3m10 Something like that will also let me test the GMC sub-ass in the freezer with the lead hanging out.

We wont have a full trace- but we will have a record of the 'worst' conditions both internally and externally. For understanding the 'system' - that's a usefull point.

I want to pack this thing full of as many simple, stand alone, independent systems to get as much as we can, as easily as we can, as cheap as we can - to learn how it all works - so we can say "Yes - we know how to fly a balloon to >80,000 ft and get it back safely"

THEN....we can start thinking about some onboard intelligence that can measure and log...

Lat
Long
Alt
Pressure
Multiple temperatures ( internal battery - internal camera - external - external GMC )
Voltages
Acceleration in 3 axis
Orientation in 3 axis

PLUS - scientific study such as UV etc etc.

But that's a whole realm of 'how the hell....' beyond my knowledge - and I want to figure out how to fly a balloon and get it back before figuring out how to make it a genuine platform for investigation.

[AndyG]

Monitoring various sensors sounds exactly like a mission for a Basic Stamp or similar...light, affordable and programmable. I wouldn't rule it out of the equation even for a first test.

Andy

[JRehling]

[...]

[tedstryk]

Well... considering the fact that Voyagers 1 and 2 were originally to be Mariners (though I have no idea if they would have been Mariners 11 and 12 or not), we *almost* got a second successful pair-launch out of the program!

-the other Doug

Well, really we did. The mission was approved and in many official documents was referred to as Mariner Jupiter-Saturn. It simply underwent a name change.

[centsworth_II]

It might even be worth it to have an "instrument cam" that ONLY looks at a panel loaded with cheap little instruments.

I find this an interesting possibility. I'm surprise to not see any response to it.
One of the instruments could be a compass.

[volcanopele]

Someone suggested donating a Treo. There might be some Palm software that could run the exposures for the camera system or store information from a weather station. Would require a serial connection, IIRC.

[helvick]

Re Treo's and other potential offerings. They are great end user devices but trust me on this cos I do this for a living - you will encounter pain beyond belief if you try to develop any network oriented software worth attempting on any hand held platform that isn't based on Windows Mobile. I am a major, major fan of free (as in beer and as in speech) software and open source \ collaborative \ what not software but when it comes to hand held systems the only open platform worth working on today is Microsoft's. It seems mad to say it but their development environment is the most open and developer friendly system that you will find today. I know I can develop a GPS aware application (using either a built in GPS or one connected via Serial\IR\Bluetooth) that periodically (every 15-30 seconds) posts updated position data via a GPRS\UMTS\EVDO data connection, or via SMS, to a remote server of some sort using totally freely available tools for development and testing (via emulators for the platform and for the GPS). I've tried to do the same with Palm, Symbian (Nokia) and Linux (Motorola) and have been cut off at the knees every time.

Just my 2c.

[volcanopele]

It is sad because I refuse to use a Windows Mobile device, to the point that I am still nursing my 4 year old Sony NX80v.

[ElkGroveDan]

Re Treo's and other potential offerings. They are great end user devices but trust me on this cos I do this for a living - you will encounter pain beyond belief if you try to develop any network oriented software worth attempting on any hand held platform that isn't based on Windows Mobile.

It is a Windows based Treo. Sorry I didn't make that clear. http://www.palm.com/us/products/smartphones/treo700w/

FWIW I used it for two or three months but hated some of its features and went with a Blackberry instead. I can probably sell it for $200-$250 on eBay, but I'm still willing to donate it if it will work. I'll even include the 2G SD card.

[djellison]

Will it work in the UK do you think? Quad/Tri band is the requirement I think. I can buy a pay-as-you-go sim card over here and drop it in.

[ElkGroveDan]

Will it work in the UK do you think?

You got me on that one. Maybe Helvick has some idea. I had assumed it was all global now, subject to service arrangements.

[djellison]

Got my three very very cheap cameras and the polystyrene enclosures ( perhaps a bit big - but even if I chop a chunk out of them and glue it back up it'll be a better job than a DIY effort ). Bloody postal strikes mean lots of other cool bits won't be arriving for a while.

Doug

[djellison]

Well - my idea of a front-door peep hole lens to get fish-eye for the GMC isn't going to work. On both the old catcam, and the new 3 MP cameras - they're FOV is too large to crop into the round FOV from the lens. So it's a WAM technique that'll have to work.

The normal cameras come apart fairly easily and I was able to hard-solder them to a housing and run them off 2 C cells instead of the two AA's that fit internally. I was also able to strip the flash and it's capacitor off the circuitboard with no ill effect - and I've been able to remove and re-attache the ribbon that drives the LCD with no problems as well. The shutter is actually on a tiny PCB of its own and that will be fine in terms of wiring something up. The trigger circuit that I thought would do the trick may not be up to it - it actually takes a 12v supply which seems excessive.

Current plan for imaging.

• Find a new triggering mechanism
• Wire up cat-cam as it is for C-Cell operation (it will happily do image after image at whatever interval I ask for as long as I want all on it's own...I'm not bothered about getting GMC and the other cameras in sync) and do some life-testing of a 4000 mAh C-cell with it - pointing at trees and clouds (appropriate target)
• Shout at the postal service because I don't have my wide angle mirrors, parachute, radio or half my order of electronic bits and pieces.
• Carve up these new polystyrene gondola's to make them an appropriate size, glue with a hot glue gun and then find some alu tape and possibly further insulation.
• Calibrate GMC and normal cameras. (let's call them FOC - Flight Observation Cameras - FOC A, B, C...from top to bottom) Find their FOV's and figure out a means to mount them. The way the l see it - A can mount in a side wall, C in the floor - but B is more difficult without cutting a lot of polystyrene or putting the camera almost outside.

Gizmo has a thing for Elysium and Chryse... she reached up like a Mearcat and pulled the pin I put in at the V1 landing site

Doug

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[Greg Hullender]

. . . but when it comes to hand held systems the only open platform worth working on today is Microsoft's.

Grin. I'm glad we built something you liked. I'm in MS Research now, but ten years ago I was on the original Windows CE team, from which Windows Mobile is descended, and I have the "Ship-It" award to prove it.

If it would help, I could donate some MS software towards this effort. Or do you already have everything you need?

--Greg

[lyford]

I have nothing to offer this project except encouragement!

I must admit I lurk in this thread in to bask in the glow of the great DIY spirit.

Oh, and for the occasional inside peeks at UMSF's "secret shedquarters" and Gizmo.

[djellison]

These crap 3 megapixel cameras will happily record a 15 fps 320 x 240 movie for 2 hrs none stop (just tried it - <200 meg video - 2 hrs 2 mins long). No sound...but I'm tempted to go with two cameras for photos, and one with a WAM for video. It works great.

Doug

[paxdan]

I have been following this thread pretty closely. I though the following links from makezine.com might be interesing:

Video podcast part 1 and part 2 about lanching a balloon with 4 canon sd cameras set up to take a panoramic picture every 7 seconds.

The second is a successful following the make guidelines using a video camera.

seeing the gondolas used is very interesting.

My 2cents, make sure you stick your name, email address and telephone number on the outside of the box and on the individual components inside.

[djellison]

Their wiki doesn't have many details on the timing circuit - that's exactly what I need. PICAXE might do the job - looks like the sort of controller that a moron like me can code, but will do what we need.

I have a LOT of that foam around - it's awesome.

[JRehling]

[...]

[djellison]

It's probably wishing too much

We're talking about a digital camera bought for less than £10.

Doug

[DEChengst]

This sounds pretty exciting In my mind this can be something with a lot of potential. First starting out with simple designs just to learn how to build, launch, take data and finally make a safe landing. The next step would be to fly real scientific instruments. The final step would be to fly on a commercial suborbital rocket. With companies like Masten Space aiming for $250 per kilogram to 100 kilometers altitude, I really think this is something we could pull off.

Before we start to do any real design work we first have to think about how to run a project like this. What software tools do we use to design the hardware ? How do we make sure parts designed by different teams are compatible with each other ? How do we communicate and share designs ? Perhaps the first step would be to look at how open source software projects are run. To put it as we say in .nl: "a good start is half the work".

The second thing that came to mind is that to achieve mission success, we need to keep things simple and cost effective. One way to achieve this would be to use off the shelf components, and thinking of creative ways to use them. One crazy idea that popped up in my head was to use MIDI for timing and synchronization.

Last night my mind kept racing and I couldn't stop myself from thinking about technical issues as well I mainly thought of ways how to decide when to open the chute:

• Open the chute as soon as the payload is released from the balloon
• Open the chute after x seconds
• Open the chute at x meters per second
• Open the chute at x meters altitude
• Open the chute at x g-load.
• Open the chute at x meters altitude and y meters per second

I guess the first option would be the easiest to trigger, but also has the highest risk of the chute not opening properly. With the last option you can calculate the dynamic pressure in real time and open the chute based on that. I think this would have the highest chance of the chute opening properly, but also has the highest risk of the triggering going wrong.

Can't wait until first ATLO

[djellison]

I mainly thought of ways how to decide when to open the chute:

Balloon
|
|
|
|
|
|
|
|
|
Chute
|
|
|
|
Gondola


Balloon bursts - chute opens automatically - couldn't be simpler. It's worked for hundreds of amateur HAB's.

Doug

[nprev]

Really! What kind of sensor is used to detect the balloon burst? Only things I can think of are some sort of tether tension cell (like a maritime winch) or an indirect acceleration measurement from an onboard nav system. Would be interested to know the actual method, because both of these techniques seem pretty awkward.

[ElkGroveDan]

Really! What kind of sensor is used to detect the balloon burst?

A sudden acceleration of -9.8 m/s/s is the triggering signal. When that force is applied on a (now) untethered gondola there will be (relative to the gondola) an upward movement of air that will inflate the parachute.

I tried to take out a patent on it in mine and Doug's names (using Doug's diagram) but apparently its been done before.

[JRehling]

[...]

[djellison]

The 144.8 Mhz FM APRS kit arrived. I need to get a 10mw radio module for it ( pin compatable swop out coming soon ) - but it WORKS.

This is the module just sat on my desk, the gps rec on the window - and my Icom IC-R5 listening in with an audio cable into my PC using 'Packet Engine Pro' and AGW Tracker. Couldn't BELIEVE It worked first time! Screenshot of the first lat-long coming out of it attached.

Just turned it on again - slightly updated Lat Long this time - and plugged the GPS Coords into Google Earth. It's REALLY working. That point is the corner of this garden - <10 metres.

Doug

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