The French seismometer SEIS has received its protective cover. However, its full use has some problems.
The installation of a seismometer on the surface of Mars is a sacred work of patience. The proof: arrived on the red planet on November 26, 2018 after a long space journey, SEIS (short for Seismic Experiment for Interior Structure, or seismic experience for the inner structure) is indeed not fully implemented in its configuration definitive.
Certainly, several milestones have been achieved in the last two months: the machine was removed from the InSight lander and put on the ground in December and its operation was verified at the beginning of January.
The good news is that there is only one big maneuver to do before you start listening: putting a bubble above SEIS to protect it against all external distortions that could interfere with its measures or interfere with its proper functioning. And this is exactly the phase in which the technical teams have been busy for a number of days.
The protective dome of the seismometer #SEIS of the probe @NASAInSight landed on the surface of Mars. Congratulations to all teams that have been mobilized on earth! 👏👏 #SEISsurMars pic.twitter.com/CS9FzwJno4
– CNES (@CNES) February 4, 2019
This protective dome has been in place since 4 February. His role is crucial: he must preserve extreme SEIS temperature variations that take place on the red planet. It is composed of aluminum with a honeycomb structure and is the upper part of the wind and thermal bubble (WTS). It is SEIS 'first line of defense, which has its own protective device.
The RWEB (Remote Warm Enclosure Box) is indeed the second defensive ring of the seismometer. This hexagonal housing consists of several layers of a special polymer with remarkable insulating properties. This is not all: in order to further limit the thermal conductivity, the outer and inner surfaces of all layers have received additional treatment.
Meanwhile on Mars, heated by the 🌞, the expandable mantle of the wind and the thermal shield (WTS) of the probe @NASAInSight continue slowly, floor after floor, to relax. #SEISsurMarshttps://t.co/llutedUtsr pic.twitter.com/aIqNzLnbtP
– SEIS (@InSight_IPGP) February 4, 2019
A skirt to go down
Now it remains only in the "skirt" that is rolled up in the aluminum dome. Once it is deployed, it is in contact with the ground. But one should rather speak of medieval armor, because one of his three layers is actually a chain mail. It is his job to mainly burden this barrier, so that it remains stable, even in the case of storms in the Moroccan storm.
The second layer is a kind of shell armor that is essentially aimed at sealing the barrier against everything that comes from outside, especially pebbles and dust. If debris is accidentally thrown on SEIS due to a whirl, this layer will be present to intercept it. Finally, the third layer is an insulating coating similar to survival blankets.
Problems in the last part
It is a fact that this ultimate look in the installation of the protective dome is not absolutely satisfactory. If the installation of the shield went very well, a " real success According to Philippe Laudet, the project manager InSight / SEIS, it appeared that the release of the skirt had some problems. She did not go away properly and some roughness was noticed in the chain mail
Philippe Laudet told the National Center for Space Studies that this concern is most likely due to the fact that the skirt remained compressed for months and subjected to very low temperatures, which could cause stiffness. The sun needs to heat and loosen the materials, but the task is hampered by the low gravity, which does not help to lower the skirt.
It remains to be seen whether this skirt can be fully used. Even if this is not the case, SEIS still remains protected by its own housing but also by the aluminum cover.
Reading Numerama: InSight: How will the mission listen to the heart of Mars?