Launched · 1 Oct 2026
↓ 436.888 MHz
ES
THE UNNE-1B CHALLENGE

Mission
Space Cowboy II

A lost spacecraft. An unknown signal. An encrypted message arriving from orbit, week after week.

Start the story Knowledge pills
LOG 001STATUS: SPACECRAFT MISSING

A spacecraft, Space Cowboy II, disappeared 10 years ago. Nobody knows where it is.

In 2024 a Spanish university launches a small satellite into space and starts receiving an unknown signal. Because of where it comes from, people begin to think it might come from that spacecraft, long given up for lost.

The signal is analysed and turns out to be a string of numbers: an encrypted distress message that will lead us to the start of an adventure in search of, and to rescue, the Space Cowboy II.

01

How the challenge works

UNNE-1B carries an Arduino board with the game by the ARIES group at Nebrija University. Once released, the satellite will broadcast a new fragment of the message every week in its own data packet: packet type 10. To progress you have to follow the whole path of a signal from space.

  1. 1ListenTune to 436.888 MHz during a pass with an SDR receiver.
  2. 2DemodulateTurn the 200 bps FSK tones into ones and zeros.
  3. 3DecodeUndo the scrambler, check the CRC and find the type 10 packet.
  4. 4ExtractRead the week number and the 8 bytes of game data.
  5. 5ShareUpload your reception to the shared registry.
  6. 6DecryptPut the fragments together and break the cipher of the distress message.
02

Anatomy of packet type 10

Each game transmission lasts 1.4 seconds and holds 280 bits. Most of them help your receiver synchronise and check that everything arrived correctly; the message is in the last fields. Hover over (or tap) each block.

Training
Sync
T/A
Clock
Wk
St.
Game data · 8 bytes
CRC
Tap a block to see what it contains.

Source: UNNE-1B transmissions overview, AMSAT-EA. The whole packet except the training, sync word, type, address and CRC travels «scrambled».

03

Knowledge pills

Every week we publish a pill with what you need for the next step. Mastering these concepts is essential to get started.

One community, one message

No single station receives every pass. Each shared reception is one more piece of the puzzle: upload it to the shared registry and see what other radio amateurs have captured.

Go to the data registry →