To actually see if it is possible to super-pressure mylar/foil balloons - this requires more balloons (of the same size) and a lighter payload. Launching would need a quicker ascent rate and an earlier launch time to make use of the solar heating.

• Lighter payload
  • Smaller battery - 1000mAh
  • Better power saving in the code
  • Smaller GPS antenna
  • Lighter wire UHF antenna
  • Use seeeduino rather than arduino pro
• More balloons - order 4 91cm balloons and see how many we need to use
• Preamble before tx'ing when in modes that have gaps
• battery voltage monitoring
• solar panel to charge battery during the day

• Seeeduino film
• GPSbee
• Mini GPS antenna
• Radiometrix NTX2
• Wire 1/4 wave + radials
• 1000mAh LiPo battery - ordered
• Some insulation

• Aiming for 75g total mass.

• 36“ (91cm) Balloons ebay - £6.65

• rebuild 1/4 wave with lighter radials
• code to reset GPS settings if fails
• finish insulation
• Tests
  • Run battery test - 12hrs
  • Test if solar panel can charge battery (sat)
  • calculate best time for launch - launch before 10am
  • Test narcsleep
  • check radio EN