One year ago, Andrea Accomazzo and his team made space history. He tells DW why the Rosetta spacecraft, in spite of being in the wrong location when it dropped Philae, was a spectacular achievement.
DW: You once mentioned that every spacecraft has its own behavior. What kind of "character" does the Rosetta spacecraft have?
Andrea Accomazzo: Well, Rosetta is a beast on the one hand. I mean the mission itself, not really the spacecraft. The spacecraft is complex, but it behaves. My boss once said: "This spacecraft is a rock!" - meaning that it's very solid. And I have to say I fully agree with him, particularly after this year we've spent at the comet. We've done all kinds of maneuvers, operations, very challenging things. And Rosetta always did it very, very well.
Have you developed a personal relationship with Rosetta over that time?
I started working on Rosetta in the beginning of 1997. So it's now been more than 18 years. I have spent the vast majority of my professional career linked to this project. And naturally, with my wife, we always joke: It's like our baby, it's part of my family. Definitely, I could not live without Rosetta.
What's special about the Rosetta mission?
If you exclude the science - I am not a scientist, I don't dare to judge on the value of the science done by Rosetta - the biggest thing is the navigation we've done in flying around such a complex body. The comet is very small, so there are extremely small gravitational, accelerating forces - one billion times less than what we experience here on the Earth, and one thousand times less than what the astronauts see in the Space Station.
The complexity there is that there are other forces acting on the spacecraft. There's gas coming out of the comet. And that pushes the spacecraft away. [Creating] a system that can characterize the comet's environment, in the sense of measuring these accelerations, creating an engineering model that would tell you those numbers to fly Rosetta around the comet - this is a technical masterpiece. And we did this within six weeks!
Despite all these obstacles, you hit the target on the comet...
Well, the landing was of course the most appealing part, for me as well. But this is the easy part. It just came at the end of the process. What was done before was the difficult part. And the fact that we touched down with 100 meter's error (330 feet), this is a remarkable achievement, of course.
When we released Philae, the Rosetta spaceship was in the wrong position by 32 meters. And the velocity was wrong by 1.7 millimeters per second. And all this controlled at 500 millions kilometers away from the Earth! So this is quite an achievement.
Philae and Rosetta are as popular as movie stars....
I was expecting a lot of media success for Rosetta. What I did not expect is that it would last so long. I expected a lot of attention on the day when we landed ... Now it's one year on, and there's still a lot of attention being paid to this. So I'm glad for the European Space Agency. I'm glad for the European taxpayers. And I'm also glad for mankind. Because I think it still gives us the hope that we can do proper things in the future, maybe steer this planet in the right direction.
What's your next target in our solar system?
We are preparing a new mission to Mars, to Mercury, to the Sun, to the Jupiter system with its moons. I find it extremely interesting from a scientific point of view. Scientists are thrilled by these opportunities. From an operational point of view, I'm looking forward to ESA's mission to fly to the Jupiter moon system. But personally I wish - I've been a pilot - to see a mission that takes care of planetary defense: We go to an asteroid, we hook to an asteroid, we deflect the trajectory of an asteroid. Then, I think, we would be doing the right thing.
Can robotic spacecrafts explore other solar systems?
Quite difficult to say yes or no, if you look at what mankind has achieved. Let's think of 2000 years ago. Would people have believed that we would fly? That we would fly to moon and come back...? I believe it's very likely that one day we'll be able to fly to another solar system. But it will definitely not be in our lifetime. It will definitely not be in the next century. It will take much, much longer. I don't know how much longer will be - centuries, millennia or even more. We need completely new technologies.