Delfi-C3 satellite integration for planned autumn launch

Wouter Jan Ubbels, PE4WJ, Delfi-C3's project manager of electronic systems and communications at the Delft University of Technology in the Netherlands reports that their satellite is being integrated and tested in preparation for launch in September or October, 2007.

The Delfi team has posted photos of the satellite integration work at: http://www.delfic3.nl/photoblog/.

Delfi-C3 is a 3-unit CubeSat carrying redundant radio transceivers, connected to the antenna system by a hybrid combiner. Both transceivers consist of a UHF front end, a command receiver, linear IF, telemetry generator and the final stages capable of 400mW RF power.

Delfi-C3 contains no batteries because it's primary mission is to perform a solar cell and sun sensor experiment so the spacecraft will only be active when in sunlight.

The first three months of the mission will perform the science mission, in which the spacecraft will be transmitting 1200 bit/s AX.25 telemetry on the primary or backup VHF downlink. (See http://www.delfic3.nl for frequency information.) Telemetry will be transmitted once per second.

A Java application will be available for download from the website to display telemetry in real time, and upload it to Delfi's central server in Delft. A soundcard application in Java is planned to be available to decode the BPSK signal. The MixW software package will also be compatible with the telemetry signal.

After three months, the linear transponder will be activated, with a 40kHz bandwidth. In transponder mode, a CW beacon will be active instead of BPSK telemetry. It will transmit a message saying "hi hi de delfi-c3 delfi-c3". Since Delfi-C3 will transmit with only 400mW of downlink power, earth stations will need to prepare a good receive system.

TLE's will be anounced on the website http://www.delfic3.nl once they are available. Preliminary parameters of the orbit are:
+ altitude: 630km circular
+ inclination: 97.91 degrees
+ sun-synchronous

Wouter Jan Ubbels, PE4WJ