Connect and communicate with a satellite via the LEDSAT Digipeater Challenge

Connect and communicate with a satellite via the LEDSAT Digipeater Challenge

Credits: ESA

The Fly Your Satellite! (FYS) programme, initiated by the European Space Agency (ESA), presents an exciting challenge for radio amateurs and space enthusiasts worldwide to establish communication via the LEDSAT CubeSat digipeater. This unique opportunity invites participants to connect with the ESA Education Office ESTEC Ground Station in the Netherlands through the satellite digipeater, with a chance to win a special prize – a custom QSL card issued by the ESA Education Office and the LEDSAT team. Running from June 26 to July 30, this challenge offers an exciting chance for radio enthusiasts to engage with space technology and demonstrate their communication skills.

LEDSAT: An Overview

Developed by students at Sapienza University in Rome, LEDSAT is an educational 1U CubeSat that participated in the second edition of the Fly Your Satellite! programme. Its primary objective is to demonstrate a LED-based payload for ground-based optical tracking. The successful launch of LEDSAT on Vega flight VV19 on August 17, 2021, marked a significant milestone for the project. Upon launch, a competition for radio and space enthusiasts from all around the world was launched, encouraging participants to record the first signs of life of the spacecraft.

The Digipeater Challenge in Detail

The LEDSAT digipeater is a special feature capable of storing and retransmitting digital messages sent via UHF, serving as a transponder for long-distance communication. Messages can be retransmitted immediately or with an optional delay of up to two days.

To participate in the competition, radio amateurs are invited to send a message using the UHF band addressed to the ESA Education Office ESTEC Ground Station, with the callsign PI9ESA. The digipeater will be activated during specific time windows (see below), and operators involved in the project will be available at the station, “listening” for incoming messages.

LEDSAT Digipeater Challenge 2
LEDSAT Digipeater Challenge 2

Once a message is received successfully, the sender’s callsign and contact details will be recorded on a customised QSL card, providing recognition for their achievement. LEDSAT follows a Sun-Synchronous orbit, resulting in two communication windows each day – around midday and midnight – where it is possible to establish contact. To predict passes precisely above the ESTEC ground station or your area of residence, refer to this link. Additionally, the latest Two-Line Elements for LEDSAT can be retrieved here.

Considering the monitoring and housekeeping requirements of LEDSAT, as well as the potential high demand from operators, the digipeater activation time slots will follow a pattern of one day ON and one day OFF, with the switch-on/off always occurring at 00:00 UTC. This schedule will commence on Monday, June 26th 00:00 UTC, and conclude on Sunday, July 30th at 24:00 UTC.

While the challenge is supported by our operators on a voluntary basis, efforts will be made to cover as many LEDSAT passes as possible, especially those occurring around local midday on weekdays. A detailed schedule of passes coverage will be published, please make sure to check this article regularly for updates.

Specific Time Slots for LEDSAT Digipeater Activation

Date Status Switch on Switch off
June 26 ON 00:00 UTC 24:00 UTC
June 27 OFF
June 28 ON 00:00 UTC 24:00 UTC
June 29 OFF
June 30 ON 00:00 UTC 24:00 UTC
July 1 OFF
July 2 ON 00:00 UTC 24:00 UTC
July 3 OFF
July 30 ON 00:00 UTC 24:00 UTC

Please note that this schedule may be subject to change, so stay updated on any revisions by referring back to this article or additional information provided by the FYS programme organisers on the ESA Education social media channels.

The LEDSAT team has prepared a software package for connecting to the digipeater, along with a user manual available for download on the LEDSAT website. Specific parameters are required to communicate with the LEDSAT digipeater (see table).

Parameters for LEDSAT Digipeater Communication

Parameter Value
LEDSAT TX frequency (uplink) 435.190 MHz
LEDSAT RX frequency (downlink) 435.310 MHz
Modulation GMSK
Protocol CSP + Golay + ASM (AX100 Mode 5)
Baud rate 1200

Important note: If you are not a licensed radio amateur, transmitting to the satellite is prohibited. Nevertheless, you can still participate in the challenge by listening to the messages transmitted by the ESTEC ground station. If you provide evidence of successful reception, including the date and time, you may also receive a customised QSL card.

So, mark your calendars, prepare your messages, and don’t miss your chance to connect and communicate with the LEDSAT spacecraft to receive your QSL card. Let’s unite and make this event a memorable celebration of our shared passion for space exploration and amateur radio communication.

For any questions regarding LEDSAT or the digigpeater challenge, please email

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