Secrets under the surface – Pasimodo® simulates Mars mission
Scientists of DLR’s Institute of System Dynamics and Control have used Inpartik’s software Pasimodo® to computer-simulate the hammering process of HP3-Mole, as part of the preparation of NASA Mars mission InSight. The simulation used a novel ground model implemented in Pasimodo®. This made it possible to optimize the hammering mechanism so that now less than 2.5 Watt are necessary for the hammering process – which is an incredibly low power consumption considering the depth of the hole created by the hammering process.
We are running out of space on earth. The population is continually growing and living space and the necessary resources might become scarce sooner or later. Luckily, not far away from earth, measured in astronomers’ units, there is a planet which might one day serve as living space. We are talking about Mars.
At first glance the red planet appears to be completely unsuitable for human settlement. Due to its distance from the sun, which is much larger than the distance between Earth and sun, it has average temperatures of -55°C (-67°F), much colder than on earth. Even while wearing polar gear, staying outside on Mars is not advisable, because its composition makes Mars’ atmosphere unsuitable for humans and the strong UV radiation makes even ozone holes on Earth appear harmless in comparison. Moreover, with only about one third of Earth’s surfacei) Mars is a lot smaller in comparison and has therefore also lower gravity.
Despite all adversities, however, the conditions described are the most compatible ones that can be found on any astronomic object far and wide. Because space is one thing above others: it’s empty. As one can see when looking up at the night sky, there are lots of stars, possibly even with planets similar to Earth, but they are distances away that are almost unconquereable for humans. Even compared to its other neighboring planets in Earth’s solar system Mars has significantly better conditions.
However, before settlement or only manned exploration of Mars can be considered a lot of open questions need to be answered. Is there, e.g., liquid water on our red neighbor? In addition to answering such popular questions exploring Mars also serves to gain information which can help us to better understand the geology of our own planet. Since the 1960s, when the Mariner probes transmitted the first photos of the red planet to Earth, technology has improved greatly. By now exploration vehicles have been put down on Mars’ surface and two of these rovers, Opportunity1 and Curiosity2, are still providing regular pictures and data from their exporative excursions.
New discoveries often create new questions. Therefore the next Mars mission of NASA in cooperation with JPS/Caltech is about to start. In the near future, mission InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport)3,4 will leave Earth for Mars. For this mission, unlike for previous mobile exploration missions, the focus is on exploring the geological properties of Mars. The examination of the division into core, mantle and crust and the exact measurement of heat emitted from the surface are hoped to provide new insights into the formation of the planet.
The German Aerospace Center (DLR) is providing the Heat Flow and Physical Properties Package (HP3)5, one of the two main instruments of the InSight mission. It is a specially developed temperature probe (HP3-Mole) which can hammer itself five meters deep into Mars ground – a larger depth than ever achieved before on any astronomic object. It takes temperature readings in different depths. In order for the probe to get to this comparatively large depth a special construction is necessary. This construction makes it possible to hammer the measuring head, which is several centimeters thick, into the ground by using a limited amount of power which comes solely from solar engergy. Anyone who has ever compared the various hammer drills available for sale knows that, based on their construction, their efficiency can vary significantly. The scientists of DLR’s Institute of System Dynamics and Control have therefore optimized HP3-Mole with regard to its shape and dynamic adjustment, so that its driving process is as safe and energy efficient as possible.
Scientists of DLR’s Institute of System Dynamics and Control have used Inpartik’s software Pasimodo® to computer-simulate the hammering process of HP3-Mole. The simulation used a novel ground model implemented in Pasimodo®. This made it possible to optimize the hammering mechanism so that now less than 2.5 Watt are necessary for the hammering process – which is an incredibly low power consumption considering the depth of the hole created by the hammering process. At the same time the optimization also reduced the number of hits necessary.
Inpartik wishes the InSight mission and especially the HP3 package a good start and a successful mission!
To NASA’s project pages: http://insight.jpl.nasa.gov
To DLR’s project pages: http://www.dlr.de/rmc/sr/desktopdefault.aspx/tabid-8178/
i)The comparatively smaller surface area is balanced by the fact that only a very small part of those 30% of Earth’s surface that are not covered by water can be considered inhabitable. Mars, on the other hand, has, as one knows, no oceans and therefore doesn’t do too bad in a comparison of this aspect.
1) NASA/JPL: MER Rover Homepage (Opportunity); http://mars.nasa.gov/mer
2) NASA/JPL: MSL Rover Homepage (Curiosity); http://mars.nasa.gov/msl/
3) W.B. Barnerdt et al.: INSIGHT: A discovery mission to explore the interior of Mars, in 44th Lunar and Planetary Science Conference, Texas, USA, 2013
4) NASA/JPL: NASA InSight Homepage, http://insight.jpl.nasa.gov
5) T. Spohn et al.: Measuring the Martian Heat Flow using the Heat Flow and Physical Properties Package (HP3); in 45th Lunar and Planetary Science Conference, 2014
6) R. Lichtenheldt; B. Schäfer; O. Krömer: Hammering beneath the surface of Mars - modeling and simulation of the impact-driven locomotion of the HP 3 -Mole by coupling enhanced multi-body dynamics and discrete element method, In Prodeedings: Shaping the future by engineering : 58th IWK, Ilmenau Scientific Colloquium, Technische Universität Ilmenau, 8 - 12 September 2014