When the Cassini-Huygens mission departed from Cape Canaveral in the United States in 1997, no one could have imagined how revolutionary its interplanetary journey would be. It took seven years for the mission to reach its destination: Cassini entered Saturn's orbit and the Huygens probe landed on Titan, the gas planet's largest moon. From then until the orbiter's disintegration in 2017, a large amount of data was collected. Many of them are under analysis and, it is expected, there will be years and years of studies.
It is in this context that the professor at the Institute of Geosciences (IG) from Unicamp, Alvaro Penteado Crósta, will disembark at the beginning of November for a six-month internship at the Jet Propulsion Laboratory (JPL). The laboratory, located in Pasadena, California, is NASA's main research center and where planetary geology studies are concentrated. Crósta, who is also dedicated to studying the formation of craters through meteoritic impacts, will study such processes on the moon Titan through analysis of data collected on the Cassini-Huygens mission. The satellite is the second largest moon in the Solar System and is almost the same size as Mars. The invitation came after a conversation with Brazilian Rosaly Lopes, senior researcher at JPL and one of the most important scientists in the world in the area of planetary sciences.
Titan has a different composition: it is the only moon in the Solar System that has a significant atmosphere and its surface is made up of icy hydrocarbons, with immense seas of methane – conditions called pre-biotic, as they are similar to those on Earth in primordial times. It is assumed that hundreds of km below the hydrocarbon ice cap there is liquid water. If these environments (hydrocarbons and water) interact in the presence of thermal energy, there would be theoretical conditions for the generation of rudimentary forms of life (microorganisms). Saturn's moon has a cratering process that can help us understand what's underneath this icy layer. “I will use the experience accumulated in the process of studying craters on Earth, combined with mathematical modeling tools, to simulate such formations on Titan and understand a little better how these surface layers are composed”, informed the professor.
In 1995, during an internship in the USA, Crósta had already carried out research focused on imaging spectrometry at the same NASA center. The professor, who will have a Research Grant Abroad from the São Paulo Research Foundation (Fapesp), hopes to contribute to research and bring topics of planetary geology to possibly develop a new optional subject at the IG. “These themes are very recent and will be progressively important in the future, and should become part of the training of contemporary geologist”, he stated.
Life on Titan and years of study
The Cassini-Huygens mission reached the limit of its useful life and was terminated in 2017. Huygens collected data for a few hours after landing on Titan in 2005 and had its communication interrupted with Cassini, which sent the data to Earth. The orbiter disintegrated in a dive towards Saturn after running out of fuel. According to the IG professor, “the ship could collide with one of the planet's satellites, which would not be desirable given that some of them, including Titan, have the potential for the development of microorganisms. The fear of the group of NASA scientists was precisely that the orbiter would contaminate the surface of one of these satellites.” In this way, they directed Cassini to Saturn, which would have a lower risk of contamination as it is a gas giant planet. On this final trip, scientists obtained extremely important information about all layers of the planet's atmosphere, including the rings, which will have to be analyzed in decades of study. The first articles based on this information began to be published this month in a special issue of the magazine Science.
