Japanese Satellites with Amateur Radio Payloads Launched


After a delay of a few days, the ChubuSat-2 and ChubuSat-3 satellites launched from Japan on February 17. Initially set for February 12, the launch was delayed due to unfavorable weather conditions. After separating from the H-IIA launch vehicle, beacons on both satellites began transmitting. A CW signal from ChubuSat-2 has been received in Brazil.

ChubuSat-2 and ChubSat-3 are message store-and-forward Amateur Radio payloads. Horyu-4 will transmit a telemetry in the 70 centimeter band. ChubuSat-2 and 3 are piggy-back payloads on the ASTRO-H X-ray astronomical satellite. Both satellites were built by Nagoya University graduate students.

After separation, each satellite will transmit a UHF CW beacon message, including battery voltage and other data. Those copying the beacon message are invited to forward the data via e-mail. After on-orbit checkout — possibly 1 month after launch — the message exchange service will be activated. Users can send messages via the VHF uplink, which are written to onboard memory. By sending an inquiry message, “anyone can read your message with UHF downlink,” the ChubuSat website says.

The ChubuSat-2 uplink is 145.815 MHz FSK 1200 bps; the downlink is 437.100 MHz GMSK 9600 bps and CW. The ChubuSat-3 uplink is 145.840 MHz FSK 1200 bps; the downlink is 437.425 MHz GMSK 9600 bps and CW. Details on the uplink/downlink format have been posted on the ChubuSat website.

On the same launch was the Horyu-4 satellite, with a primary mission to measure discharge current waveforms and capture images of the discharges occurring on solar cells. Horyu-4 has downlinks on 437.375 MHz and 2400.300 MHz 1200 bps AFSK, 9600 bps GMSK, S_BPSK, CW.