Do not lose your satellite! The reliability of CubeSat radio link and electronics design: system analysis, problems, and proposed decisions.

A lot of CubeSats were launched but never contact their authors. And the causes of failure stay hypothetical (really, unknown). This is more than lost money – it is lost lessons, repeated errors and discouraged teams.

We analyze the most probable causes of failures of CubeSat electronics and radio link subsystems and propose the main causes and decisions to prevent the unknown loss of satellites.

• The CubeSats are usually pure tested (because of strictly limited time and budget), especially for the control system and radio link at uncommon conditions. These tests are absolutely required – and they can be done well before the whole satellite are ready (the similar way as “extreme testing of components” in software development).
• We recommend the separated telemetry radio link optimized for reliability: unidirectional antenna, UHF or VHF range, low speed with strong error correction, redundant/spare power supply, open downlink specification (for international community help in receiving), onboard storage for telemetry history (from the moment of rocket start). The possible technical decisions, link budget, data protection schema will be presented.
• The advances in the development of reliable computer systems and IOT provide the possibility for redundant control system even for 1U CubeSat. Several ideas unconventional for small satellites will be proposed: WiFi as local databus, O-ring or high-frequency AC power subsystem, and possible redundant schema for Earth observation CubeSat as a sample.
• The international cooperation for CubeSat reliability is required - most CubeSats are non-commercial, so the exchange of knowledge and lessons learned are easy.