EnduroSat One Mission

The Space Challenges program and EnduroSat are collaborating for the first Bulgarian CubeSat mission named EnduroSat One.

The mission will 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.

Main goals of the mission are to provide practice-oriented satellite communication education for the first time in Bulgaria and to foster the Radio Amateur’s participation in space missions.

See the launch plan

Mission Overview

The mission will include launching of 1U CubeSat from International Space Station and operating it through a Mission Control Center in Sofia, Bulgaria. In this unprecedented cooperation, the entire mission was designed as outreach and educational program with the main goal to inspire young Bulgarians and to give them a real chance to participate in the space exploration through EnduroSat One.

Space Challenges Team and EnduroSat have invested time and efforts in planning, designing, engineering and assembling of the Bulgarian CubeSat. Once in orbit, the satellite will be used as an educational tool, providing access for young Bulgarians to practical satellite education. More information will be published just before the launch of the CubeSat.

The educational component of the mission is under development. EnduroSat One will enable thousands of people to communicate directly with the satellite for free and to learn the basics of satellite communication techniques. The mission is a major step forward in the development of the space sector in Bulgaria.


Mission Profile

The 1U CubeSat is a multipurpose platform engineered for space research and applications. The EPS+ (Electric Power System) and the solar panels will ensure power supply during the mission. Two UHF Transceivers Type II and UHF deployable antenna will provide reliable communication system for TT&C and payload data. Processing capabilities are ensured by low power consumption and high performance Onboard computer. A network of sensors and actuators will guarantee spacecraft control during the entire mission.

The satellite will be completely autonomous. It will perform entire sequence of test commands and verifications on both hardware and software-level once in orbit. The satellite will have two beacons:

  • CW (A1A) beacon which will transmit its own call sign and TLM data using Morse code
  • Telemetry beacon using AX.25 in datagram-mode

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 information and instructions required to connect with the satellite will be published few weeks before the launch. An online database for the users/participants to upload the data they receive directly from the satellite will be available at EnduroSat One website.

An educational competition is planned and the call sign with the most uploaded telemetry data will be announced through the satellite’ beacon. A log file with all successful communication packages will be published and updated live on the website.


How to connect with the satellite

Satellite name: EnduroSat One
Frequency: 437 050 000 Hz

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

A competition page with the rank of call signs with the most uploaded telemetry data will be published on this page. If you want to receive notifications via email about the mission

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Launch Plan

UPDATE: EnduroSat One will be embarked on the Cygnus cargo resupply spacecraft of the OA-9 mission to the International Space Station manifested to be launched on the 20th of May 2018 from the Mid-Atlantic Regional Spaceport in Virginia, USA.

Let’s countdown together:

2018/05/20 22:00:00

Educational Material

During the mission, Space Challenges Team will publish educational video materials online in both Bulgarian and English, teaching satellite communication principles and technology. The mission will also significantly increase the popularity of the Radio amateur community in the region.

This will be made possible through Spaceport online educational platform – the biggest online platform for space education in Europe https://spaceport.academy. The content developed during EnduroSat One mission will guarantee long-term outreach effect.

As first ever Bulgarian Radio Amateur CubeSat mission, it will undoubtedly create good practices in correct registration and launch preparation processes for future educational and Radio-Amateur CubeSat programs on local (Bulgarian) level.

This know-how will be shared online on the educational platform of Space Challenges, accessible to interested students and radio-amateurs.

What does the satellite include?

The 1U EnduroSat CubeSat is a multipurpose platform engineered for space research and application. The EPS+ and the solar panels will ensure power supply during the mission. Two UHF Transceiver type II and the UHF deployable antenna will provide an high-reliable communication system for TT&C and data. Processing capabilities are provided by the low power consumption and high performance Onboard computer. A network of sensors and actuators will enable spacecraft control.


EnduroSat One Subsystems


It provides a simple and safe environment for payload as well as operational ability of all subsystems during the mission. All the elements are made of Aluminum 7075, pearl finishing and hard anodization (30 μm).

UHF Deployable Antenna

The antenna is designed to cover the amateur satellite band 435-438 MHz. It has a circular polarization and uses a redundant burn wire mechanism with feedback for deploying the radiating rods.

Communication Module

The two UHF transceivers will work in the frequency range 430-440 MHz with GFSK modulation. The devices are encapsulated in an aluminum shell that takes care of heat dissipation and significantly reduces the EMI.

Power Module

The EPS+ has two integrated Li-Po battery packs encapsulated inside an aluminum box. Capacity of the battery packs is 20.8Wh. Three independent channels control and monitor the solar panels for each axis.

Solar Panels

They are equipped with 2 Solar cells with 29.5% efficiency. On the PCB, a network of sensors (Gyroscope, Sun sensor, temperature sensor) and magnetorquer provide attitude determination and control system.

Onboard Computer

The OBC is a low power consumption and high performance computing platform. It is based on ARM Cortex M4 with frequency rate up to 180MHz. It has double redundancy sensors: 3-Axis accelerometers and compass.

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