Near-Space Resources
(→Hydrogen and Helium) |
(→Hydrogen and Helium) |
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Drawbacks: cost | Drawbacks: cost | ||
| + | |||
| + | ; Camera placement | ||
| + | Some people have used two cameras: one pointed at horizon, for those "curvature of the earth" shots, one pointed down | ||
= Batteries = | = Batteries = | ||
; Lithium Photo (Lithium / Manganese Dioxide) | ; Lithium Photo (Lithium / Manganese Dioxide) | ||
Non-rechargeable, 3V. <br> | Non-rechargeable, 3V. <br> | ||
| + | Rated for continuous or photoflash output <br> | ||
Operating Temperature: -40C to 60C <br> | Operating Temperature: -40C to 60C <br> | ||
Energizer "123" $10 1500mAh 16.5g Specs: http://data.energizer.com/PDFs/123.pdf | Energizer "123" $10 1500mAh 16.5g Specs: http://data.energizer.com/PDFs/123.pdf | ||
| + | ; Cylindrical Lithium (Lithium / Iron Disulphide) | ||
| + | 1.5V, matches standard battery sizes <br> | ||
| + | Rated for continuous output <br> | ||
| + | Operating Temperature: -40C to 60C <br> | ||
| + | Highest energy density (more energy per unit mass) <br> | ||
| + | Energizer "L91 Ultimate Lithum" AA size; 14.5g 3200-4300mAh, http://data.energizer.com/PDFs/l91.pdf | ||
| + | ; Lithium / Thionyl Chloride (Li / SOCl2) | ||
| + | 3.6 V, highest operating temperature range (to -55 C) <br> | ||
| + | at -55C, energy reduced to 50% <br> | ||
| + | expensive, dangerous, hard to get | ||
; Lithium Polymer | ; Lithium Polymer | ||
| Line 80: | Line 94: | ||
it safely, to be our safety officer. | it safely, to be our safety officer. | ||
Dangers of hydrogen are discussed here: http://www.eoss.org/pubs/faqloon.htm | Dangers of hydrogen are discussed here: http://www.eoss.org/pubs/faqloon.htm | ||
| + | |||
| + | The difference in buoyancy isn't huge. | ||
| + | At IUPAC standard temperature and pressure, 1 cu m of Helium weighs -1097g (relative to the same volume of air), while 1 cu m of Hydrogen weighs -1186g. | ||
| + | So Hydrogen gives us an extra 89g of payload allowance per litre of gas. | ||
| + | Or, 1.08 cu m of Helium has the same lift as 1 cu m of Hydrogen. | ||
Helium costs: | Helium costs: | ||
| Line 90: | Line 109: | ||
** regulator is ~$75 (need to research flow rate) | ** regulator is ~$75 (need to research flow rate) | ||
| − | + | Our first mission might require 1-2 cu m of helium, depending on balloon and payload mass. | |
| − | Max legal limit (CAR regulations) is | + | Max legal limit (CAR regulations) is < 4 cu m, for a high altitude mission. |
=How To Guides to Near Space Missions= | =How To Guides to Near Space Missions= | ||
Latest revision as of 13:41, 18 March 2010
This page describes technologies that can be used for a near-space balloon launch.
Contents |
Camera/Imaging
- Canon Powershot
Using the CHDK project, you can run arbitrary software on the camera's CPU. Project Icarus used CHDK to disable the LCD display and loop, taking a picture every 5 seconds.
The cheapest new Powershot is $150, but these models haven't been ported yet. The cheapest supported Powershot (new) is $270 from Best Buy (which is too much). A more practical option is to find a cheap used Powershot.
Benefits: no microcontroller required, high quality images
Drawbacks: cost
- Cheap camcorder
dealextreme.com has cheap digital camcorders (no lcd display or other frills) for $50-$70.
http://www.dealextreme.com/details.dx/sku.31878
Cost: $55
Mass: 296 grams
Benefits: no microcontroller required, video
Drawbacks: image quality of stills
- "Real" camcorder
http://accessories.dell.com/sna/products/Camcorders/productdetail.aspx?c=ca&l=en&s=dhs&cs=cadhs1&sku=A2612051
US $120 Kodak ZX1 HD camcorder
Benefits: decent picture, video (get what you pay for)
- Cheap camera, disassembled
We take a cheap camera, like Gus's $25 camera, take it apart, and hook up some simple electronics to take a picture each 5 seconds.
Benefits: low mass (strip stuff we don't need), can separate lens/ccd from electronics for heat management
Drawbacks: extra electronics work, crappy resolution (300K pixels? -- you get what you pay for)
- Cell phone
If we are going to include a cell phone anyway, maybe we can use its camera. I think this only works if we can load our own software into the cell phone. Eg, like an Android based cell phone.
Drawbacks: cost
- Camera placement
Some people have used two cameras: one pointed at horizon, for those "curvature of the earth" shots, one pointed down
Batteries
- Lithium Photo (Lithium / Manganese Dioxide)
Non-rechargeable, 3V.
Rated for continuous or photoflash output
Operating Temperature: -40C to 60C
Energizer "123" $10 1500mAh 16.5g Specs: http://data.energizer.com/PDFs/123.pdf
- Cylindrical Lithium (Lithium / Iron Disulphide)
1.5V, matches standard battery sizes
Rated for continuous output
Operating Temperature: -40C to 60C
Highest energy density (more energy per unit mass)
Energizer "L91 Ultimate Lithum" AA size; 14.5g 3200-4300mAh, http://data.energizer.com/PDFs/l91.pdf
- Lithium / Thionyl Chloride (Li / SOCl2)
3.6 V, highest operating temperature range (to -55 C)
at -55C, energy reduced to 50%
expensive, dangerous, hard to get
- Lithium Polymer
Weather Balloons
http://www.novalynx.com/400-balloons.html
http://www.yunhuanelectronics.com/Meteorological_balloons_manufactured.htm
http://www.scientificsales.com/category-s/25.htm?gclid=CLTRov69vqACFQUMDQod2Gv1TQ
http://www.kaymont.com/pages/sounding-balloons.cfm
Project Icarus used a 300g Kaymont balloon. For this balloon, Kaymont recommends:
- 0.97 cu m of helium
- 250 g payload weight
producing the following behaviour:
- 117 cm diameter at release
- 810 g nozzle lift (before accounting for payload)
- 320 m/min rate of ascent
- 77 min to max altitude
- 24.7 km bursting altitude
Adding more payload decreases net lift, slowing the ascent. Adding more helium increases ascent speed (or allows bigger payload), and decreases bursting altitude.
Balloon math, explains some terminology:
http://balloon.pbworks.com/BalloonMath
Hydrogen and Helium
Hydrogen is cheaper and more buoyant, but it is also quite dangerous. If we use hydrogen, we need somebody with the training and skills to handle it safely, to be our safety officer. Dangers of hydrogen are discussed here: http://www.eoss.org/pubs/faqloon.htm
The difference in buoyancy isn't huge. At IUPAC standard temperature and pressure, 1 cu m of Helium weighs -1097g (relative to the same volume of air), while 1 cu m of Hydrogen weighs -1186g. So Hydrogen gives us an extra 89g of payload allowance per litre of gas. Or, 1.08 cu m of Helium has the same lift as 1 cu m of Hydrogen.
Helium costs:
- need tank, regulator, gas (also hose, balloon nozzle adapter for filling)
- TSC stores: empty tank purchase: $200, refill: $52
- TriCounty Welding:
- size 16: 2.4 cu m, $62 + $50 refundable deposit. We get to keep the tank for a week. Tank is 49 lb.
- size 50 smart top: 8.9 cu m, $140 + $50 deposit, includes 1 week tank rental. Tank is 134 lb.
- longer rentals are available -- need to become a registered customer
- regulator is ~$75 (need to research flow rate)
Our first mission might require 1-2 cu m of helium, depending on balloon and payload mass. Max legal limit (CAR regulations) is < 4 cu m, for a high altitude mission.
How To Guides to Near Space Missions
http://www.eoss.org/pubs/faqloon.htm
http://balloon.pbworks.com/
http://moo.pl/~tygrys/balloon/
