Telltale tells tale of winds at Mars Phoenix landing site (EPSC09/14)
September 17, 2009


Wind speeds and directions were measured for the first time in the Mars polar region using the Phoenix lander’s Telltale instrument. Astronomers recorded Easterly winds of approximately 15-20 kilometres per hour during the martian mid-summer. When autumn approached, the winds increased and switched round to come predominantly from the West. While these winds appeared to be dominated by turbulence, the highest wind speeds recorded of up to nearly 60 kilometres per hour coincided with the passing of weather systems, when also the number of dust devils increased by an order of magnitude. The results are being today at the European Planetary Science Congress in Potsdam by Dr Haraldur Gunnlaugsson.

Phoenix landed in the North polar region of Mars on May 25, 2008 and operated successfully for 151 sols (1 sol is a Martian day, which is 37 minute longer than a day on Earth). The Telltale device consisted of a lightweight tube suspended on top of a meteorological mast, roughly two meters above the local surface. The onboard camera continuously imaged the deflection of the tube in the wind, taking more than 7500 images during the mission.

“Telltale has given us a wealth of information about the local Martian wind velocities and directions. At the Phoenix landing site, we were able to see meteorological changes caused by interactions between the dynamic north pole, where there are ever changing evaporation processes, and the Martian atmosphere” said Dr Gunnlaugsson.

Mars is typically a rather windy place and learning more about the planet’s climatic conditions will contribute to the understanding of the Martian water cycle and the identification of areas on the red planet that could sustain life. Local wind measurements by the Telltale instrument, amended with daily images of the whole northern hemisphere by the Mars Reconnaissance Orbiter spacecraft, have allowed astronomers to gain much deeper information on weather systems on Mars.

“We’ve seen some unexpected night-time temperature fluctuations and are starting to understand the possible ways dust is put into suspension in the Martian atmosphere. For example, we could see that some of the dust storms on Mars do not require the existence of high winds,” said Dr Gunnlaugsson.

Telltale was designed and constructed in Denmark at the Mars Simulation Laboratory at the Aarhus University as a part of the Canadian built meteorological package for Phoenix.

“The challenge was to develop an instrument sensitive enough to detect very light breezes and at the same time able to withstand the violent vibrations during the mission launch. The Telltale instrument, although quite simple, has operated very successfully in the thin atmosphere of Mars,” said Dr. Gunnlaugsson.


The Telltale consists of a gallows that is mounted on the top of the Meteorological Mast of the Lander. The active element of the instrument is an extremely lightweight Kapton tube hanging in Kevlar fibres. Images taken of the instrument will show the deflection of the Telltale due to the wind. A mirror is mounted below the active part to enable better direction information.
Credit: Mars Simulation Laboratory ( / University of Aarhus


Launched in August 2007, the Phoenix Mars Mission is designed to study the history of water and habitability potential in the Martian arctic’s ice-rich soil. Phoenix uses some of the most sophisticated and advanced technology ever sent to Mars. A robust robotic arm built by JPL digs through the soil to the water ice layer underneath, and delivers soil and ice samples to the mission’s experiments.The Phoenix Mission is led by Principal Investigator Peter H. Smith of the University of Arizona, supported by a science team of co-investigators, with project management at NASA’s Jet Propulsion Laboratory. The Telltale is a passive wind indicator for the 2008 NASA Phoenix lander developed and constructed at the Mars Simulation Laboratory at the Aarhus University . Haraldur Páll Gunnlaugsson is the project leader of the Telltale experiment.
For more information see: following the Telltale Project link. European Planetary Science Congress (EPSC) 2009
EPSC 2009 is organised by Europlanet, a Research Infrastructure funded under the European Commission’s Framework 7 Programme, in association with the European Geosciences Union. It is the major meeting in Europe for planetary scientists. The programme comprises 37 sessions and workshops covering a wide range of planetary topics.
EPSC 2009 is taking place at the Kongresshotel am Templiner See, Potsdam, Germany from Sunday 13 September to Friday 18 September 2009.
For further details, see the meeting website:

Europlanet Research Infrastructure (RI)
Europlanet RI is a major (€6 million) programme co-funded by the European Union under the Seventh Framework Programme of the European Commission.
Europlanet RI brings together the European planetary science community through a range of Networking Activities, aimed at fostering a culture of cooperation in the field of planetary sciences, Transnational Access Activities, providing European researchers with access to a range of laboratory and field site facilities tailored to the needs of planetary research, as well as on-line access to the available planetary science data, information and software tools, through the Integrated and Distributed Information Service.   These programmes are underpinned by Joint Research Activities, which are developing and improving the facilities, models, software tools and services offered by Europlanet.
Europlanet Project website:
Europlanet Outreach and Media website: