Calling all radio amateurs

Radio amateurs worldwide are being asked to help collect data from the student-built SSETI Express satellite, due to be placed in orbit on 27 September. To encourage them, ESA’s Education department has organised two competitions and is supplying free downloadable software.

“We will be happy to receive all the help we can, particularly during the early operations phase,” says SSETI Express Project Manager, Neil Melville. “If a radio amateur receives a signal from SSETI Express before we do then the main ground station in Aalborg, Denmark will be delighted to hear from them.”

Radio amateurs wherever they live are being asked to help with the downlink of housekeeping and payload data. In return, various functionalities of the SSETI Express UHF and S-Band communications systems will be made freely available to the radio amateur community, along with the mission data downlink, once the main mission objectives of SSETI Express are complete.

SSETI Express will downlink telemetry in AX25 format at 9600 baud on 437.250MHz and at 38400 baud on 2401.835MHz. It will also be available for radio amateurs to use as a single channel FM transponder. The software needed to downlink data and to submit telemetry to the SSETI Express Mission Control can be downloaded free from the Radio Amateur Connection pages on the SSETI Express Mission site. Submissions will be automatically recorded and published on the site.

Radio amateur competitions

Once radio amateurs have the software needed it will be up to them to demonstrate that the amateur radio ground station ‘network’ is a valuable resource for satellite projects. To provide extra motivation, ESA has organised two competitions.

The winner of the first will be whoever submits the largest number of valid telemetry payload packets to SSETI Express Mission Control by 00:00 of 1 January 2006.

The prize is an invitation to the three-day STEC06 (Student Technology Education Conference) conference and exhibition, to be held in Germany in spring 2006, as well as a private visit and tour of ESA’s Spacecraft Operations Centre (ESOC) near Darmstadt.

A unique “I heard it first” SSETI Express T-shirt is the prize for the second competition. This will be sent to the first person to receive, decode and submit a transmission from the spacecraft to SSETI Express Mission Control. All information on equipment needed, software available and where to send data can be found on the Radio Amateur Connection pages of the student SSETI Express Mission site.

SSETI Express sub-systems for radio amateurs

Of the 12 sub-systems on SSETI Express, two involve radio amateurs. The ultra high frequency unit (UHF) has been designed and built by a radio amateur in Hohhenbrunn, Germany. It contains a radio and terminal node controller, and is the spacecraft’s primary communications system. It will provide uplink of telecommands from the ground station, audio uplink from amateur radio users and downlink of mission data at 9600 bps, all via a top-mounted rigid monopole antenna.

Radio amateurs from AMSAT-UK, although no longer students, are also involved in the project as they developed the S-Band, microwave radio communications transmitter. This provides both high-speed mission data downlink at 38400 baud and in combination with the UHF system, a single-channel audio transponder.

Graham Shirville (call sign G3VZV) is coordinating the team of radio amateurs from AMSAT-UK, the club for users of amateur radio satellites. “I’m involved in frequency coordination of spacecraft using the amateur satellite service. In early 2004 a group of us from AMSAT, UK were asked if we wanted to help with the project. The answer was ’yes’ and we protoyped the S-Band TX within eight weeks.”

“It has been a real challenge and not always easy,” he says “particularly when some of the hardware we built did not perform 100% – we felt we were letting everyone else down. But we have learnt an amazing amount of skills and knowledge which we hope to invest in future space projects.”

Shirville will be present at the launch, a nail-biting moment for all the team. “I will be elated if we hear the radio signals but sad and worried if we don’t ”. He hastily adds that he is not expecting failure. “The SSETI Express students are bright, enthusiastic and determined to succeed; they have also put an incredible amount of time and effort into this project. Now it is up to the radio amateur community to do our bit to help them.

Over to you fellow amateurs and 73 from G3VZV.”