A sensitive ambient light sensing module with wide dynamic range has been designed for planetary wireless sensor networks. Its performance has been evaluated under different illumination conditions. Variations in ambient light intensities from <1 to 1.2×10 5 lx could be detected from dawn to dusk, including cloud obstructions during monsoon. Moon light variations during the waning phase and total lunar eclipse have been monitored to demonstrate detection of finer variations. The module is capable of registering the fine variations in ambient light expected on different planetary surfaces. This module along with other sensors integrated into a Wireless Sensor Network (WSN) would be a suitable prospective tool for many future planetary exploration tasks.