Cassini’s Astonishing Super-Senses

Curiosity and our hunger for knowledge have always prompted humans to embark on heroic endeavours. Arguably one of the grandest expeditions in the last couple of decades has been the Cassini Mission. In 1997, a team of NASA’s scientists launched spacecraft, Cassini, towards Saturn, with the aim to unravel the mysteries behind this remarkable planet and its majestic rings. In 2004, after a 7-year journey, this well-equipped explorer finally reached its destination and began examining the system. Data that Cassini has been streaming back to Earth for the last 13 years has been collected by an outstanding range of different instruments that are testament to the ingenuity of humankind. Among the instruments, two  deserve special attention.

Like digital cameras on the Earth, the Imaging Science Subsystem (ISS) has provided us with clear and detailed pictures of Saturn’s system. Despite having been manufactured in the 1990s, the resolution of the ISS approaches 1 megapixel. Because of its high resolution, ISS has helped scientists study the atmosphere of Saturn and its satellites, as well as the characteristics of Saturn’s famous rings. What’s more, ISS maps the planet by integrating the pictures it takes, helping us to study topographic and composition features. Not only do these maps benefit scientific research, but they also enable viewers to gain the feeling that they are there.

The Cosmic Dust Analyser (CDA) is an instrument that can capture dust particles in space and determine their physical and chemical properties. After analyzing these data, scientists can trace back where these materials originated from and determine their relationships with Saturn, its rings and satellites. For example, the CDA enabled scientists to discover that some particles that originated from Enceladus, one of Saturn’s more famous satellites, is rich in silica, which implies that there is hydrothermal activity on Enceladus.

The data collected from particles can also give an insight on the satellite’s conditions and whether conditions are suitable to sustain life. One of the more significant discoveries the CDA has made had been to determine that some of the dust it has collected in this region actually originated from outside of Saturn’s system. Surprisingly, it was found that these particles contained elements we associate with life, such as carbon, calcium, sulphur and magnesium. This raises the exciting possibility that conditions to create life are more abundant in our solar system, and perhaps our galaxy and universe, than we had previously thought.

Similar to the way that our eyes and mouth enable us to interact with the terrestrial environment, the ISS and the CDA constitute Cassini’s main senses. Through them this spacecraft has been able to gather invaluable information about Saturn and, more generally, our solar system. As well as expanding our astrophysical knowledge, this mission has also acted as a test-field for new technologies. Since 1997, many of the Cassini’s instruments have been improved, their range of applicability extended and their accuracy increased. Future space missions will certainly rely on the technical and practical experience gained from this magnificent endeavour.

Niccolo Bitossi, Feiya Xu, Sisheng Shu, Chenyang Du – Centre for Academic English, Imperial College London

Banner image: Cassini spacecraft, JPL/NASA