Creating and launching your own satellite 🙂

The Space Challenges program and EnduroSat have successfully developed the first Bulgarian CubeSat mission, called “EnduroSat One”.


The main purpose of the mission is to provide practically-oriented education on the topic of satellite communications for the first time in Bulgaria. The cadets of Space Challenges 2018 will communicate with the satellite and download data from it.

The mission aims to popularize the Radio Amateur activities in Bulgaria and it will include cooperation with Bulgarian Federation of Radio Amateurs (BFRA), including workshops and additional educational activities.

See the launch plan

The Mission

We are launching a CubeSat (a satellite with dimensions 10x10x10 cm) from the International Space Station (ISS).

What our satellite lacks in size, it has in soul 🙂

The satellite will be controlled through the Mission Control Center, EnduroSat. We, the EnduroSat team, have developed this satellite to prove that effort brings success (sometimes 🙂 ).

The spacecraft has been completely build in Bulgaria. This first educational mission aims to inspire young Bulgarians and give them the chance to participate in a real space program!

The Space Challenges and EnduroSat teams have invested considerable resources, time and effort in preparing the Bulgarian CubeSat. In order to support the Radio Amateur community, the satellite emits in frequencies which are readily available for receiving by anyone with basic communication skills and radio equipment.

We hope that the mission will help more young Bulgarians learn the basics of satellite communications through practical exercises empowered by the orbiting satellite.


How smart is our satellite?

Quite smart it seems…

  • The satellite has a fully autonomous system for navigation and control in orbit. The spacecraft will be conducting a series of tests commands and manage all of its systems in orbit.
  • The satellite will emit two beacons: CW (A1A) beacon which will transmit its own call sign “EnduroSat One” and TLM data using Morse code
  • Telemetry beacon using AX.25 in datagram-mode

Mission Profile

Radio amateurs from around the Globe will be able to listen to the satellite beacon and to receive telemetry data from the satellite on a regular basis. They will be able to connect to the satellite, receive detailed telemetry information and receive a confirmation from the satellite for every established connection which will serve as QSL card. All the neccessary information and instructions on how to connect to the satellite will be made available on this webpage. You can directly upload all the satellite data you have downloaded to this page. The callsign of the user with the most data uploaded will be broadcast by the satellite during the mission duration. A log file with all successful communication packages will be published and updated live on the website.


Track the satellite

Satellite name: EnduroSat One
Frequency: 437 050 000 Hz
Output Power: 27dBm

Telemetry beacon transmission details:
Modulation: 2GFSK(GMSK), Frequency deviation 2400 Hz, Speed 9600 bit/sec
Preamble: 5 x 0x55, 0x55, 0x55, 0x55, 0x55
Sync word: 0x7E
Packet format: AX.25 UI-bitstuffed, NRZI-encoded, G3RUH-scrambled, CRC16-CCIT
Source call sign: LZ0AMS
Destination call sign: CQ
Payload format: YYMMDDHHMMSS ph000 th000 ps000 BV0000 BI0000 3I0000 5I0000 PO0000 UV0000 BC0000, where YYMMDDHHMMSS – real-time stamp of the telemetry data ph000 th000 ps000 – euclidean 3-angle coordinates of the satellite [deg]
BV0000 – Battery voltage [mV]
BI0000 – Battery current consumption [mA]
3I0000 – 3V-bus current consumption [mA]
5I0000 – 5V-bus current consumption [mA]
PO0000 – Power-on events number
UV0000 – Under-voltage events number
BC0000 – Battery charge cycles number
Beacon reception validated with SDRConsoleV3 + direwolf1.4

Audio transmission details:
Call sign LZ0AMS in Morse code (tone F5 – FA 5th octave 698Hz, dot delay 60 ms)
Ode to joy in MIDI format
Audio reception validated with SDRConsoleV3 or TYT TH-UVF1 radio

We could have organized a lottery for the participants…

But we have a far better offer for you – anyone who has received information packets from the satellite is able to publish them online. We have a ranking list based on the amount of telemetry data uploaded by the most active radio amateurs.

Join the mission… here

Upload data

Call sign*:

Upload file*: (allowed file formats are: wav, jpg, jpeg, png, gif, txt up to 5 MB)


Rank Call sign Submits