About Stratosonde

Stratosonde is an open-source platform for ultra-lightweight, solar-powered atmospheric sensing at stratospheric altitudes. This documentation site tracks development progress, technical decisions, and test results as we build toward multi-day autonomous flights.

Development Approach

We’re taking a methodical, validation-first approach:

  1. Platform Validation (current phase) - Prove the technology through test flights
  2. Model Refinement - Validate thermal models, power budgets, and trajectory predictions
  3. Extended Operations - Push toward week-long missions
  4. Scientific Missions - Deploy validated platform for atmospheric research

Technology Stack

Hardware: STM32WLE5 MCU with integrated LoRa radio, solar energy harvesting (BQ25570), 2S LTO batteries + 1.5F supercapacitor, environmental sensors (SHT31, MS5607), ATGM336H GPS

Firmware: Real-time power management, H3Lite geospatial indexing for autonomous LoRaWAN region detection, adaptive transmission scheduling, flash-based data logging

Target Specs: <15g total weight, -65°C to +60°C validated operation, multi-day mission duration, 12-18km float altitude

For detailed specifications, see the Technical Specifications page.

Community Foundation

Stratosonde builds on decades of work by the amateur radio and picoballoon communities. We contribute back through open-source designs, detailed documentation, and active participation in these communities.

Key Resources:

Get Involved

Join the Discussion

Contribute

  • Review code and hardware designs
  • Test components and subsystems
  • Improve documentation
  • Share flight data and results
  • Build your own platform

Repositories

Project Background

The name Stratosonde honors Environment Canada’s 1986 atmospheric research program - a reminder that impactful science doesn’t require massive institutional resources. Today’s platform weighs grams instead of kilograms and operates on party balloons, making stratospheric research accessible to a wider community.

For complete project details and mission objectives, visit the Stratosonde landing page.

All hardware designs, firmware, and documentation are open source under permissive licenses (CERN-OHL-S v2, MIT, CC BY-SA 4.0).