How did the Solar System form? Are we alone in the Universe? What scientific methods can we use to prove the existence of extraterrestrial lifeforms? These questions fascinate scientists and non-scientists alike. Planetary research seeks to find answers. Numerous missions and projects to explore the Solar System and neighbouring planets have revealed a varied image of the Universe, bringing scientists gradually closer to resolving these issues. Tilman Spohn, Head of the To the Institute's website at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) until the end of October, and Professor Heike Rauer, who has been Head of the research Institute since 1 November 2017, are convinced that it will not be long until we discover clear indications for the existence of other life forms. In this interview, they discuss their fascination with planetary research, the power of images, current and past missions – as well as candy.
This interview was conducted by Julia Heil
How did you end up in the field of planetary research?
Spohn: It was a long and winding road for me. In my youth I was interested in art and theatre. But my father insisted that I learn a proper profession, so I enrolled in an architecture course, but that did not work out. Then I remembered a book I had recently read entitled 'Die moderne Physik' – modern physics – which prompted me to sign up for a course in physics at the University of Mainz. I stayed with it until the end. I became involved in planetary research during my post-doc in the United States. At a conference, I saw images of Saturn and its moons taken by the Voyager orbiter – and I lost my heart to them.
Rauer: At school, I actually wanted to study art, but was unable to get a place at the time. So I remembered my original fascination as a child: the Apollo mission and Skylab. That is why I decided to study physics. Even if I had been offered a place for an art degree the following year, I would not have gone back.
Art and planetary research: how do they fit together?
Rauer: Images are an important medium to convey what we do. We are able to provide genuine, real images of planets or asteroids. They capture the hearts and minds of people, beyond their scientific benefits. I believe it is this factor that makes space travel so fascinating. We travel to distant worlds and come back with pictures. Doing so certainly includes an artistic component. For instance, I once organised a small art show with students at the Institute, in which they were asked to consider their research work from the perspective of an artist.
We also see the significance of images in the area of extrasolar planets. They are so far away that we cannot physically go there. So we are hugely dependent on artists to depict our measurement values. Visual stimulation is part of being human, and images are the most memorable medium. But just to be clear, research results are not gained primarily through images. In most cases, a large number of institutes work together on measurement data from numerous instruments in order to obtain their scientific results.
The Rosetta mission travelled for 10 years before reaching its destination. What does it feel like to finally receive the first data from these missions and acquire new insights into hidden worlds?
Spohn: Of course, it is always fascinating to see real images or measurement data for the first time. I remember like it was yesterday how surprised I was when I glimpsed the first images of Pluto. The rugged morphology of Comet 67P/Churyumov-Gerasimenko that we explored on the Rosetta mission shocked me at first. Like my colleagues, I asked how we would ever manage to safely land the Philae lander on that surface.
We like to think that we know what properties distant locations will possess. Many people believed that other stellar systems would be similar to ours. But every time we venture out into uncharted territory, it turns out to be completely different to what we would have been able to imagine. Take the asteroid Vesta - an asteroid full of surprises, for instance. I would never have thought that it would have such a distinct structure with troughs running around the equator. These kinds of details fascinate us our entire lives. This is not only true for us, but also for the young people working here at the Institute.
Rauer: These are very exciting times. From the Voyager mission that reached the boundary of the Solar System to the research of exoplanets: these areas have cast planetary research in an entirely new light. Everything we have done has led to surprises. Today, the various areas are converging more and more. Whether or not a planet belongs to the Solar System is increasingly unimportant to its research. We can now gaze much further into the Universe than we could 50 years ago. We are currently preparing the PLATO mission, which is specifically designed to search for extrasolar planets that may harbour life. This is another step toward answering the question of whether we are alone in the Universe. I am personally convinced that life exists on other planets. We only need to find and recognise it. So I am already looking forward to a future mission that will detect biosignatures on exoplanets, even if it means that I might no longer be able to play an active role in this.
Spohn: Planetary research always extends over generations. Some colleagues who helped to launch the Rosetta mission are unfortunately no longer with us. Nevertheless they gladly accepted that, by the time the mission came to fruition, they might be unable to actively follow its course. In a way, we are doing the same thing. For instance, BepiColombo, a mission that is very dear to me, will soon be launched by other people.
Looking to the future from today’s perspective, what are you looking forward to?
Rauer: The next 10 years will be extremely interesting. We will fly to Mercury with BepiColombo and search for traces of life on Mars with the ExoMars mission. The CHEOPS mission will accurately characterise exoplanets, and PLATO will do the same for other planets that might indeed resemble Earth …
Spohn: …the InSight mission will set up a geophysical observatory on Mars, and our heat flow probe HP3 will burrow into the surface of the Red Planet. The ExoMars rover Pasteur will search for traces of life on the planet using data from Mars Express. In addition, the JUICE mission will be on its way to Jupiter to explore the planet's moons. These are just a few of the missions we are currently working on; others are in planning. So a great deal of exciting things lie ahead. The geophysicist Maurice Ewing once said that geophysics is like a candy store where you can help yourself to as much as you like without paying. If that is true, planetary research is an entire candy department store.
Rauer: One thing is certain: all these missions, projects and ventures will bring plenty of surprises.