Guide to 21. CanSat (Satellite Prototype Mission): Designing a miniaturized telemetry satellite deployed from a high altitude to transmit real-time environmental data during descent.

CanSat Mission: Designing a Miniaturized Satellite for High-Altitude Telemetry

A step-by-step guide to building, programming, and launching your own high-altitude telemetry satellite—just the size of a soft drink can.

A typical CanSat deployed from a high-altitude balloon during test flight. Credit: ESA Education.

What Is a CanSat?

A CanSat is a miniature satellite in the shape and size of a standard soda can—66 mm diameter and 115 mm height—designed to replicate the essential functions of a real satellite: data collection, telemetry transmission, and recovery. Its purpose is to teach students and engineers how satellites behave in near-space environments while enabling hands-on experimentation with atmospheric sensors, GPS, and telemetry systems.

Why Build a CanSat?

CanSats sit at the perfect intersection of accessibility and authenticity. Unlike cube sats that cost thousands to launch, a CanSat can be built for under $200 and launched on a high-altitude balloon for under $100. This makes it ideal for classrooms, makerspaces, and hobbyist teams aiming to:

• ✓ Test sensor calibrations in low-pressure, low-temperature conditions
• ✓ Develop end-to-end telemetry chains (onboard → radio → ground)
• ✓ Validate mechanical and thermal shielding for aerospace conditions

Step-by-Step CanSat Design Process

Think of building a CanSat like assembling a tiny, resilient space mission. Below, we break it down into five iterative phases—each with checklists, hardware suggestions, and practical tips.

1. Define the Mission

What will your CanSat measure? Common payloads include temperature, humidity, pressure, light, altitude, orientation, or even radiation. Limit yourself to 1–3 core sensors—simplicity ensures reliable flight data.

2. Choose the Avionics

Popular choices: Arduino Nano 33 IoT, ESP32 (with ESP-NOW or LoRa), or Raspberry Pi Pico. All are compact, low-power, and support multiple I²C/SPI sensors.

3. Design the Structure

A plastic or lightweight aluminum cylinder fits inside a standard 330 ml can. Include a foam or 3D-printed payload frame to secure components and absorb shock on landing.

4. Add Telemetry

Use 433 MHz or 868 MHz RF modules (e.g., SX127x LoRa) or 2.4 GHz nRF24L01 for short-range downlinks. Pair with a ground station using SDR or a dedicated receiver.

Hardware Selection: A Practical Comparison

Your choice of microcontroller depends on power consumption, onboard memory, and I/O needs. Below is a side-by-side to help you decide.

Component	Best For	Power Use (Active)	Telemetry Options
Arduino Nano 33 IoT	Low-latency data logging, WiFi-ready for debugging	~18 mA	WiFi, BLE
ESP32	Long-range LoRa, low-power sleep modes	~30 mA (2.4 GHz), ~5 mA (LoRa)	LoRa, BLE, WiFi
Raspberry Pi Pico	Real-time sensor reads, CircuitPython flexibility	~22 mA	UART + USB + custom RF
Adafruit ItsyBitsy nRF52840	Bluetooth-rich telemetry and over-the-air updates	~12 mA (BLE)	BLE 5.0, SPI/I²C

💡 Pro Tip: Power Management Is Critical

At high altitudes, temperatures drop to –60°C. Batteries lose up to 40% capacity in such conditions. Use lithium-thionyl chloride (Li-SOCl₂) cells if you need months of shelf life and reliable performance in cold—alternatively, pair a LiPo with a heating pad (just 100–200 mW) inside the CanSat.

Flight-Ready Code Sample

Below is a minimal, flight-test–ready sketch for an ESP32-based CanSat. It logs temperature, barometric pressure, and altitude every 5 seconds, then transmits via LoRa to a ground station.

canSat_esp32 telemetry.ino

#include <Wire.h>
#include <Adafruit_BMP280.h>
#include <LoRa.h>
#include <EEPROM.h>

Adafruit_BMP280 bmp;
const int eepromAddr = 0;

// Mission parameters
const float altThreshold = 28000; // meters: trigger parachutes
const unsigned long txInterval = 5000; // ms
unsigned long lastTx = 0;

void setup() {
  Serial.begin(115200);
  Serial.println("[CanSat] Initializing...");

  // Initialize sensor
  if (!bmp.begin(0x76)) {
    Serial.println("BMP280 not found. Check I²C.");
    while (1);
  }

  // Initialize LoRa (433 MHz band)
  LoRa.setPins(14, 12, 13); // SS, RST, DIO1
  if (!LoRa.begin(433E6)) {
    Serial.println("LoRa init failed!");
    while (1);
  }
  Serial.println("LoRa initialized.");

  // Initialize EEPROM (for flight counter)
  EEPROM.begin(4);
}

void loop() {
  float temperature = bmp.readTemperature();
  float pressure    = bmp.readPressure();
  float altitude    = bmp.readAltitude(1013.25); // sea level pressure

  // Log to serial
  Serial.printf("T: %.2f°C | P: %.2f hPa | A: %.1f m\n", temperature, pressure, altitude);

  // Transmit data packet
  String telemetry = String((int)temperature) + "," +
                     String((int)(pressure / 100)) + "," +
                     String((int)altitude);

  LoRa.beginPacket();
  LoRa.print("CAN:");
  LoRa.print(telemetry);
  LoRa.print(";");
  LoRa.endPacket();

  // Update flight count
  int flightNum = EEPROM.read(eepromAddr);
  EEPROM.write(eepromAddr, (flightNum + 1) % 255);
  EEPROM.commit();

  // Sleep between readings
  delay(txInterval);
}

This sketch uses the Adafruit BMP280 library and a LoRa module (e.g., SX1278). Replace 433E6 with 868E6 if operating in EU or AS regions—and always check local RF licensing rules.

Ground Station & Data Interpretation

Once your CanSat transmits, you’ll need a receiver to decode and visualize data. You have three practical options:

📡

SDR-based Receiver (RTL-SDR)

Free and highly flexible. Use SDR# or CubicSDR to capture raw IQ data, then decode packets in Python or GNU Radio.

🖥️

Dedicated HF/VHF/UHF Radios

The Yaesu VR-5000 or Icom IC-R30 work well with demodulators like AX.25 for packet radio (AX25LoRa works for ESP32).

📦

Open-Source Telemetry Tools

Try Radiosonde, Predict, or GPS-Track to map the flight path and log sensor values over time.

Recovery & Data Integrity

You’ve launched and tracked your CanSat—but how do you ensure it returns safely with data intact?

• ✓
  Include a GPS logger. Store raw NMEA sentences in on-board flash or microSD. Even if telemetry fails, you’ll recover location post-impact.
• ✓
  Use a redundant radio chain. A backup frequency (e.g., 2.4 GHz nRF24L01 + 433 MHz LoRa) gives you two shots at data capture.
• ✓
  Simulate descent in a vacuum chamber. Low pressure affects sensor bias—especially barometric altitude. Calibrate before flight.

Real-World CanSat Performance

In 2023, a student team from TU Delft flew a CanSat to 31.2 km altitude using a weather balloon. Their ESP32 + LoRa payload returned 97% of telemetry data, even at –58°C, and landed within 320 meters of the predicted GPS coordinates—thanks to low-noise power traces and a lightweight carbon-fiber shell.

Safety, Ethics, and Legal Compliance

Flying any payload near the edge of space requires planning and legal awareness. Below are three essential requirements:

Radio Licensing

In the US, LoRa at 433 MHz is unlicensed under Part 15—but in the EU and UK, 433 MHz requires an amateur radio license or short-range device approval. Check ARRL, Ofcom, or ETSI guidelines.

Airspace Authorization

Balloons exceeding 1,000 ft AGL typically require FAA (US), CAA (UK), or EASA (EU) approval. Submit a NOTAM and include a radar reflector + strobe light for night flights.

Data Privacy

Avoid transmitting raw GPS coordinates publicly during flight—this can alert wildlife or sensitive ecosystems to your payload. Store locations in encrypted local storage and publish only post-recovery.

Your CanSat Is Ready for Flight

What began as a simple student project now powers citizen science, climate monitoring, and even emergency beacon prototypes. Every line of code, every sensor calibration, and every launch—no matter how small—contributes to a much larger exploration of Earth and space.

Ready to launch your own mission? Share your CanSat story with the community—#CanSat on Twitter, GitHub, and Reddit’s r/SpaceEngineers.

© 2024 Space Engineering Lab • Designed for educators, engineers, and explorers.