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fahnen/11.jpg SSETI Express Information
Launch Pad Return

XO-53 (SSETI Express) Is Launched

The SSETI Express mission is an educational mission that was launched 27 October 2005 at 06:52 UTC on board a Kosmos 3M rocket launched from the Plesetsk Cosmodrome in central Russia. It was designated XO-53 by AMSAT by request of the SSETI team, and was assigned the NORAD ID 28894.

Shortly after launch SSETI deployed three CUBESAT pico-satellites developed by universities. After launching the CUBESATs, XO-53's batteries stopped charging and the spacecraft went silent. The control team is hopeful that recovery will be possible.

When XO-53 is recovered it will also function as an amateur radio transponder for the remainder of the mission. SSETI will also downlink earth images and demonstrate technology for the European Student Earth Orbiter

Three cubesats will be deployed by SSETI Express :

  • XI-V from Japan, University of Tokyo
  • UWE-1 from Germany, University of Würzburg
  • Ncube-2 from Norway, Andoya Rocket Range

The Cubesats were deployed from a T-Pod launcher developed by UTIAS Space Flight Laboratory, Toronto

Amateur Satellite Information

SSETI Express automatically downlinks general telemetry at 9k6 on 70cm. It will also be possible for radio amateurs to request specific downloads. In addition it is planned that the satellite will downlink 38k4 telemetry transmitter on the 2.4GHz transmitter. SSETI will also be available for amateur voice operation as a Mode U/S transponder after initial tests on the satellite have been completed.

SSETI Express provides amateur radio payload functionality (states) using a combination of the S-Band unit, the UHF unit and the OBC software. There are five main functions of the amateur radio payload, each with two (or more) states, as explained below.

  1. Friendly Telecommands
  2. S-Band Carrier
  3. S-Band Configuration
  4. DTMF Telemetry
  5. Picture Downlink

More information on these states please see the SSETI Radio Amateur Playload States page. The Status Schedule on the Radio Amateur Connection page shows which functions are available at which times. This should be used as a regular reference for all participating radio amateurs.

Frequency Information

Uplink/Downlink: 437.250 MHz AX.25 9600 baud or voice
Downlink: 2401.835 MHz AX.25 38,400 baud or voice

SSETI contains a FM transciever at 437.250MHz that transmits and receives the AX25 packet telemetry and payload data at 9k6bps with 3W into a canted 1/4 wave whip mounted on the top plate. It also has an audio and RSSI feed to the S-Band transmitter.

SSETI also contains an S-Band FM transmitter at 2401.835MHz. This will transmit data at a data rate of 38k4bps and can be configured to work as a voice transponder. It produces approximately 2.5 watts of RF output which feeds a three way splitter to the three patch antennas.

Current Keplerian Elements

Current Keplerian elements are available from SpaceTrack and from the SSETI project team.

Software Downloads

The SSETI Team has provided a number of software downloads to decode telemetry, payload data and images from SSETI in AX.25, Carrier Pulse and DTMF decoders. The primary decoder, the SSETI Express Radio Amateur Communications Client (SERACC) is the preferred client for downlinking and commanding the spacecraft.

For additional information please see the SSETI Express Downloads Page

Operational Schedule

The SSETI Express operation status schedule can be found on the Radio Amateur Connection page.

More Information

For the latest information on SSETI Express including file downloads and launch information please visit the AMSAT-UK Website. Also visit the SSETI Mission Page at the SSETI website. SSETI Mission Control at Aalborg University in Denmark maintains a page for overall mission control called EXPRESS@AAU that will include live video of the lift off.

AMSAT UK has published "The SSETI Express Handbook"

A printed version will be available after launch.


AMSAT Acknowledges the members of the Student Space Exploration and Technology Initiative (SSETI),
Graham Shirville G3VZV, and David Bowman G0MRF for assistance in preparing this page.
Photo credit to SSETI and ESA.


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