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Availability: Archived at NSSDC, accessible from elsewhere


This description was generated automatically using input from the Planetary Data System.

Data Set Overview =================

The Telltale wind indicator is a mechanical anemometer designed to operate on the Martian surface as part of the meteorological package on the NASA Phoenix lander. It consists of a lightweight cylinder suspended by Kevlar fibers and is deflected under the action of wind. Imaging of the Telltale deflection allows the wind speed and direction to be quantified and image blur caused by its oscillations provides information about wind turbulence.

The Telltale data set consists of a single comma-delimited ASCII table, TELLTALE.CSV, and its PDS label TELLTALE.LBL.

The table contains the following columns:

Sol Phoenix Sol LTST Local True Time given in image header

LMST Local Mean Solar Time calculated from LTST

v (m/s) Wind speed in meters/second

dv+ (m/s) Error in wind speed (positive)

dv- (m/s) Error in wind speed (negative)

Dir (deg) Wind direction in degrees given in meteorological convention (0 = from N, 90 = from E, 180 = from S, 270 = from W)

dDir (deg) Error in direction (given in degrees)

Exposure time Exposure time by SSI in milliseconds

File name SSI image filename used for the analysis

Processing ==========

This data set has been generated by analysis of SSI images of the Telltale. The images have been analyzed to determine the position of the Kapton tube in the Telltale reference frame. The shift from rest position is calculated, and the wind velocity and errors determined from the methods described in [HOLSTEIN-RATHLOU2008, GUNNLAUGSSON2008]. The directions are finally converted to areographic directions using the orientation of the lander. The result is an ASCII table of time, wind velocity and direction, errors in wind velocity and directory, and names of SSI images used to derive the values.

These data are available on-line from the Planetary Data System (PDS) at:

Alternate Names



  • Planetary Science: Atmospheres

Additional Information


Questions and comments about this data collection can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Dr. Haraldur GunnlaugssonGeneral ContactAarhus Universitet
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