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), LTO batteries, environmental sensors (SHT31, MS5607), GNSS positioning

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, -50°C to +60°C operation, multi-day mission duration, 12-18km float altitude

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).