vendredi 4 mai 2018

An EPFZ seismometer will fly to Mars

EPFZ - ETH Zurich logo.

May 04, 2018

The launch of the American robot InSight to Mars is scheduled this Saturday at 13:05 from the Vandenberg base in California. Seismologists from ETH Zurich play a key role.

InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) is the first mission dedicated to the study of the basement of Mars. It will last two years - a Martian year - and aims to advance understanding of the formation processes of all rock planets, including the Earth, as well as their evolution.

Last check. Image Credit: NASA

The NASA spacecraft will include a seismic measuring instrument developed under the guidance of the French Center for Space Studies (CNES). Various European teams participated in its elaboration.

The Swiss Federal Institute of Technology Zurich (ETH Zurich) has contributed to the ultra-sensitive electronics of the device, in collaboration with SYDERAL SA in Chules (BE). The latter has provided a housing that controls the operation of the seismometer and measure the minute movements of the Martian soil.

If the launch of the robot by an Atlas V-401 rocket takes place on Saturday as planned - the firing window is open two hours a day until Tuesday - it will arrive on the red planet on November 26th.

Geophysical Station

InSight aims to study the internal structure of Mars, through the deployment on its surface of a geophysical station embedded in a fixed lander. Once on the Martian soil, a robotic arm will deploy Seismic Experiment for Interior Structures (SEIS), a stethoscope of about 30 kilograms and a diameter of 60 centimeters.

A few weeks later, this "very wide band" seismic sensor of unparalleled precision should already deliver usable data, and EPFZ seismologists will be the first to consult them. The device will measure the tectonic activity of Mars, which will allow to deduce information on its structure, among others the size of the core and the thickness of the mantle.

Image above: This artist's concept shows the InSight lander, its sensors, cameras and instruments. Image Credits: NASA/JPL-Caltech.

The goal is to determine if the heart of the red planet is solid or liquid and why its surface is not composed of moving tectonic plates like on Earth.

The impacts of meteorites will also be analyzed, via the generated seismic waves. The seismometer will be covered with a shield that will isolate it from the storms of Martian wind and temperature variations.

Martian magnitude scale

As explained by Domenico Giardini, professor of seismology and geodynamics at ETH Zurich, the waves picked up by the seismometer will make it possible to draw conclusions about the density of the rock and the temperature inside Mars. Of the 728 Earth days that will last the mission, the specialist expects about fifty events.

By cross-checking the location, strength and distance elements, the researchers expect to obtain "a very good data structure", says the former director of the Swiss Seismological Service.

NASA InSight: ETH Zurich fuehlt Mars den Puls (in German)

One of the questions is how terrestrial models will apply. Professor Giardini's team has created for Mars a new scale of magnitude inspired by that of Richter. Earthquakes are indeed of low intensity.

Thermal history

The ground-based device also includes the Heat Flow and Physical Properties Package (HP3) sensor, capable of capturing heat flow to a depth of five meters. It must evaluate the cooling rate of the planet in order to reconstruct its "thermal history".

Another instrument, RISE (Rotation and Interior Structure Experiment), quantifies the variations of the axis of rotation of the red planet.

The researchers hope to understand "why this planet that was habitable a priori 4 billion years ago has ceased to be little by little", as the formula Philippe Lognonné, scientific leader of SEIS at CNES.

The mission had to be postponed for two years because of problems on the seismometer. Its cost is of the order of one billion dollars. And nothing is yet won, missions on Mars being deemed difficult, with a success rate of only 40%. The United States is the only one to date to have successfully placed and operated a lander.

Related links:

EPFZ - ETH Zurich:

Live televised coverage of the launch will be available at:

InSight Mars Lander:

Images (mentioned), Video, Text, Credits: ATS/NASA/EPFZ-ETH Zurich/ Aerospace/Roland Berga.

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