Numerical Simulation of Aerobots Dynamics and Control for Planetary Exploration of Titan

Giacomo      Colombatti; Alessio      Aboudan; Nicola      La Gloria; Stefano      Debei

Abstract

A future mission to return to Titan after Cassini/Huygens has now a really high priority for planetary exploration. Recent Cassini discoveries have revolutionized our understanding of the Titan system and its potential for harboring the ingredients necessary for life. These discoveries reveal that Titan is one of the most exciting places in the solar system; data show a complex environment, both for the atmosphere and for the surface. The data obtained, enriched by continuing observations from the Cassini spacecraft, show hydrocarbon lakes, river channels and drainage basins, sand dunes, cryovolcanos and sierras. All these features demonstrate that dynamic processes are present on Titan and have raised the scientific interest in a follow-up mission to Titan. A robotic lighter-than-air vehicle has been suggested as a possible platform for an extensive exploration of the moon. NASA centers and universities around the US, as well as the European Space Agency, are studying the possibility of sending, as part of the next mission to this giant moon of Saturn, a hot-air balloon or similar for further and more in-depth exploration. Several patents cover different aspects of airship subsystems, such as design, propulsion and energy production; here we discuss some critical aspects taking into account the outcomes of our work. Recent studies on airships have demonstrated the high capability of airships to be considered as scientific platforms for extended explorations, both in space and time, on planets with atmosphere. Here we analyze the dynamics of the airship in response to the encountered Titans environment. Possible trajectories for an extended survey of the moon are investigated; these allow us to have a precise quantitative analysis of the energy necessary for a journey on the moon. Analysis on stability is performed in order to check the possible scientific slot windows available for investigations. A 1.2 km x 1.4 km region is selected as baseline: time necessary for performing a complete survey is investigated. Investigations are conducted both in a quiet situation with no wind and in wind conditions. Trajectories are followed with airship at 1.5, 3, 5 and 7 m/s velocities; surface science ( < 100 m) scenarios are proposed. Considered winds are in the range 0.0 - 1 m/s parallel and orthogonal to the ground track.

Keywords: Airship, Aerobot's Dynamics, Planetary Exploration, titan, cryovolcanic, manoeuvering capability, Z Inertial Altitude, Numerical Simulation, Hill analysis, tail rudders, exploration, simulator, dynamics