Håvard Grip works at the Jet Propulsion Laboratory in Pasadena, California, which functions as a control center for NASA probes. Grip is the lead pilot of the Mars Ingenuity helicopter, which has successfully completed half a dozen flights to Mars. He graduated from the Norwegian University of Science and Technology in Trondheim, where he teaches today, as well as Washington State University. He used to work at the Norwegian research institute SINTEF in Trondheim, where he was part of a collaborative project with the German vehicle manufacturer Daimler.
THE MIRROR: The International Civil Aviation Organization has recently added a new airport code to its lists: JZRO. What does the code mean to you?
Flu: The code means the first extraterrestrial airfield, in the Jezero crater of Mars. It means something special to me, not only because we flew from there, but because I spent several weeks day and night choosing that particular location. One of my roles right after the Perseverance rover landed on Mars was to direct the work to find that airfield. I spent a lot of time studying individual rocks and pebbles and measuring them to find the perfect place. So yeah, this place really has a special place in my heart.
THE MIRROR: What made the place so perfect?
Flu: We wanted to find a place that was relatively close to the Perseverance landing site. We always hoped we wouldn’t have to go great distances, so we immediately started looking around this area. The fact that we could find something nearby was a great benefit in itself. But the place also had some very nice properties, almost surprisingly good. Although it was very flat and did not have many obstacles that could be dangerous for the helicopter, it still had a good texture for the navigation cameras. This is something that ingenuity needs so that it can determine how and where it flies.
THE MIRROR: On April 19, for the first time, an artificial motorcycle flew over another celestial body. And you are the main pilot. How did that feel?
Flu: It was just a huge relief. I’ve spent seven or eight years with this project. And you always have those concerns: what if you’re wrong about this or that thing? What happens when the wind dominates the helicopter as it takes off, what happens if it tries to land too soon when it’s still in the air? There is a list of hundreds of small concerns like this. And in a moment, all of a sudden, all of these disappear, because it just works. The helicopter did its job perfectly. This was perhaps the strongest emotion: all these worries suddenly came out the window.
THE MIRROR: And what is it like to fly to Mars?
Flu: It’s a very neat feeling to pull the ropes from this distance, hundreds of millions of miles away. This is simply magical. And speaking in a more practical way, there are all sorts of special things to keep in mind. Upload commands to the helicopter, then try to go to bed while this thing is flying, and then wake up again later and retrieve the data.
THE MIRROR: Sending direction orders to Mars takes about eight minutes in one direction. This means that the helicopter basically has to fly on its own. So is being the “lead pilot” rather an honorary title?
Flu: My main job since the project started has been to lead the development of these algorithms that the helicopter runs while flying. Piloting the helicopter is the culmination of this work, as the helicopter needs someone to command and use these algorithms. The helicopter does not decide when to fly, if the weather is good enough or where to fly. It does not decide the speed and height it flies, it does not take into account whether the terrain flown over is suitable. Therefore, all this planning is done from Earth.
“… then an anomaly occurred”
THE MIRROR: To what extent can you influence the behavior of the helicopter now that it is on Mars?
Flu: We have many ways to influence the helicopter. There are hundreds or thousands of parameters that can be modified. For most of these, we have already spent a considerable amount of time on Earth before launch in order to find the right balance. So we try to change only the necessary things from one flight to another: we are looking at the waypoints that control where the helicopter flies. Think about the speed and the aggressive way you maneuver between these waypoints. We define where you take pictures along the way, and so on. We also need to estimate the energy consumption that will be required. And after landing, we need to check if all the systems are healthy and ready for the next flight.
THE MIRROR: Post-first flights have become increasingly complicated. The craft has reached higher altitudes, traveled at higher speeds, and covered longer distances with each takeoff. What was the hardest flight of those flights so far?
Influenza: S Flight six was quite difficult. We chose an altitude and speed on the ground and a complicated route. And then an anomaly occurred.
THE MIRROR: The helicopter did not behave as expected.
Flu: Exactly. For a while, he was leaning intensely during the flight. The reason was a temporary anomaly. And that’s a problem for a fast vehicle like Ingenuity. The helicopter has to adjust its maneuvers at a very fast pace, because it is naturally unstable, small and has a fast dynamics. If the weather becomes inaccurate, this is a problem.
THE MIRROR: The problem was caused by a problem with one of the images that made the camera responsible for navigation.
Flu: The navigation camera helps you understand where the helicopter is. But an image of this camera was dropped. That shouldn’t have been a problem in itself. But all the subsequent images also had incorrect timestamps. We could easily tolerate an image missing. But when we get a stream of images that have incorrect timestamps, the algorithm is constantly confused when it tries to compare what it sees with what it should see.
“There is an end date, maybe in August. But we will try to make as many flights as possible until then.”
THE MIRROR: You managed to land safely even after that flight. And ingenuity has achieved what it was built for, to show that it is possible to fly even in the thin atmosphere of Mars. So how many more flights will you be allowed to do now?
Flu: We don’t know yet. We initially planned up to five flights. We have already surpassed this mark. There is an end date, maybe in August. But we will try to make as many flights as possible until then.
THE MIRROR: What have we learned for future Ingenuity flight missions so far?
Flu: We wanted to prove to us and to everyone that you can actually fly and operate a helicopter on Mars. Now, you can see with your own eyes that the helicopter is flying and doing a good job. This opens doors to future missions. We can be confident that our approach works, and that means we can design more capable helicopters in the future, because we can have more confidence in our models and our processes.
THE MIRROR: What can helicopters be used for in future missions to Mars?
Flu: There are a few things that stand out. One is that helicopters can act as ideal reconnaissance platforms. They can explore terrain for future rovers or even future astronauts once you have humans on Mars. But we are also thinking about the possibility of building larger and more capable helicopters that can carry scientific instruments to places that cannot be accessed by land vehicles, such as steep cliff slopes. There are even ideas for using helicopters to explore caves on Mars.
THE MIRROR: So far, the ingenuity still seems to be in good shape. Your ultimate goal is to push the helicopter so hard to the limits that it crashes?
Flu: We definitely wouldn’t intentionally destroy it. But there may come a time when we stretch it to the point that we then don’t have a safe landing. Ingenuity has done its job to prove what we have come to do. So no matter what happens when we exceed your limits, I am very happy with how the mission has ended.