DPS 2001 meeting, November 2001
Session 19. Mars Atmosphere Posters
Displayed, 9:00am Tuesday - 3:00pm Saturday, Highlighted, Wednesday, November 28, 2001, 10:30am-12:30pm, French Market Exhibit Hall

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[19.22] A new Wind Sensor for the Beagle 2 Mars Lander

C.F. Wilson, S.B. Calcutt, T.V. Jones (Oxford University, UK)

A hot-film anemometer has been developed for the Beagle 2 Mars lander. The sensor will return wind speed (up to 30 m/s) and horizontal component of wind direction.

Three hot platinum films are equally spaced around the circumference of a vertical cylinder. A small bead thermistor (0.2 mm diameter) located nearby is used to measure ambient air temperature. A known current is dissipated in each film, heating the film above the ambient gas temperature. The temperature of the film is obtained by measuring its resistance. An effective heat transfer coefficient is then calculated for each film. These coefficients can in turn be used to calculate the overall wind vector at the sensor.

The situation of the air temperature and wind sensors at the end of Beagle 2's motorised arm allows several new possibilities for wind and temperature measurement on Mars that were unavailable in previous missions. The sensors can be positioned at any height between ~ 20 cm and ~ 120 cm above the lander body, or can be moved laterally at a given height to study the effects of lander interference. Alternatively, the wind sensor may be positioned with its axis horizontal, thus allowing measurements of vertical wind speed.

The wind sensor was calibrated in a new wind tunnel facility, in which Martian surface wind conditions are simulated. Wind speeds of 0 - 60 m/s can be created in a CO2 atmosphere at pressures of 5 - 10 mbar and temperatures of 200 - 300 K.

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