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