The winds of Mars
To continue exploring the surface of Mars we must first understand its atmosphere
he film The Martian saw astronaut Mark Watney marooned on Mars after a dust-storm threatened to topple his crew’s ascent craft. Although the film (and the book it’s based on by Andy Weir) is pretty true to the science and technology that will be needed for a human mission to Mars, this opening scene played with dramatic licence. Even though Martian winds can peak at over 100kph, the atmosphere is so thin you would barely notice this buffeting a space suit.
That’s not to say that a more complete understanding of Martian winds is not needed. Scott Guzewich of NASA’s Goddard Space Flight Center has led the publication of a White Paper
– a scientifically supported persuasive report – stressing the key importance of global Martian wind observations within the next decade.
A detailed description of the winds around Mars is a major missing piece of the jigsaw puzzle of our understanding of the planet’s climate and the shaping of its features. Wind transports dust, water vapour, and trace gases like methane around the planet, and redistributes the Sun’s warmth from the equator towards the poles. Over the past three billion years, winds have also been one of the most important processes for moulding the Martian landscape: depositing dust and burying older surfaces, moving
“Getting a clearer picture of the atmospheric behaviour on Mars is important for sending human missions to the planet’s surface”
TGetting a clearer picture of the atmospheric behaviour on Mars is also important for safely sending human missions to the planet’s surface. The entry, descent and landing sequence is affected by atmospheric variables – in particular the winds while descending under parachute – as is the launch from the surface back again. Equipment can be damaged by wind-blown dust; the Apollo missions to the Moon showed just how destructive fine, abrasive dust particles can be to the joints of a spacesuit. Solar panels providing power to the habitat are especially sensitive to the build-up of wind-blown sediment. A robust understanding of the winds blowing – not only at ground level but also at varying altitudes in the atmosphere – and how this atmospheric circulation changes with the seasons, is crucial for reducing the uncertainty and the risks involved in crewed missions. To plug these gaps in our knowledge, Guzewich and his colleagues argue that a comprehensive mapping of Martian winds must become a priority over the decade from 2023–32. They say that the necessary measurements are Martian wind direction and speed, from the surface up to at least 80km altitude, covering at least one Mars year and across the entire planet with a resolution of less than 300km. Suitable instruments are already in development to be ready to fly on Mars orbiter probes in the next decade. These include techniques like Lidar (that functions like radar but with a laser beam), which can measure wind speeds by looking at the suspended dust in the lower 50km of the atmosphere. This works day or night, and even within dust storms, which we are most in the dark about at the moment.
was reading… Measuring Mars Atmospheric Winds from Orbit: A White Paper submitted to the Planetary Science and Astrobiology Decadal Survey 2023-2032 Read it online at https://arxiv.org/abs/2007.05412