Zheda Pixing 1, 1A

The pico-satellite Zheda Pixing 1 is probably the "MEMS-Pico" satellite, which is being developed in China under a joint program between Zhejiang University and Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences. The original propose of this satellite is to provide a testbed in near-earth space for MEMS devices, such as accelerometer, micro-gyros and infrared sensors, being developed in China.

MEMS-Pico is designed as a tumbling satellite with neither attitude control nor propulsion. It consists of no moving parts, only solid-state electronics and the structure. The MEMS-Pico is a 26-face object, with 18 square faces and 8 triangle faces. 17 squares are covered by solar cells, with total size of 270 cm². The solar cells are expect to provide 2 W of electrical power in orbit.

Payload of the MEMS-Pico includes a MEMS infrared sensor and a CMOS camera. However, the most important part of the spacecraft is probably the communication transceiver. The transceiver works on S band, with uplink at 2100 MHz and downlink at 2300 MHz. The downlink rate is 4096 bits per second with QPSK modulation on the carrier. Since there is above 200 MHz difference between the frequency of downlink and uplink, 2 different sets of antenna are used for downlink and uplink, respectively. Each set of antennae composed of 2 antennae installed on two reverse triangle faces of the MEMS-Pico. So that each set of the antennae equivalents to an omni antenna. This design makes it possible to receive signal even the spacecraft in a random attitude or in tumbling.