Made for Mars

摘要

A silicon chipthat can measure wind speed and direction on Mars will be a key component of a roving weather monitoring station due to be launched by NASA next year. The Roving Environmental Monitoring Station (REMS) will be carried by NASA's Mars Science Laboratory (MSL) rover on its scheduled mission to the Red Planet. The station will spend an entire Martian year (about two Earth years) measuring and providing daily reports on atmospheric pressure, humidity, ultraviolet radiation, wind speed and direction, and air and ground temperature. The new chip, designed by scientists at Universitat Politecnica de Catalunya (UPC) in Barcelona, is part of the REMS' anemometer, a device used for measuring wind speed. It is a silicon-based version of a technology to collect wind data used by the Mars Pathfinder in 1997. The previous technique, called hot wire anemometry, involved heating a platinum-iridium alloy wire then letting air cool it to vary its temperature. Calculations were then performed to relate heat convection to the wind speed. In the case of the new chip, the hot point is not a wire but a piece of silicon. Each silicon chip is 1.5mm thick, said Luis Castaner, co-ordinator of the Micro and Nano Technologies (MNT) Research Group at UPC. The silicon substrate is heated up to 25℃ above ambient temperature by sending a current to a platinum resistor deposited on top of it. The temperature changes are measured with a second platinum resistor.