Research is fascinating!

We get around 20 seconds of weightlessness per parabola. Our experiment has to work in that short time. That is why we spend months planning and try to automate as much of the experiment as possible. We design the components, assemble the experiment and test it thoroughly before the actual flights begin.

I was incredibly excited before my first flight. I was glad I was there as an observer and wasn’t responsible for the experiment. That meant I could focus on getting through the parabolas first.

Two colleagues with experience of these flights were also on board, which was reassuring.

At first, it feels very much like falling. During the transition into weightlessness, you get butterflies in your stomach, a bit like being on a roller coaster or experiencing turbulence.

During my first few parabolas, I wanted to hold on to something. It was only after a few rounds, once I knew what to expect, that I could start to enjoy it and really take in the fact that I was experiencing weightlessness – and how special that was.

The phases before and after weightlessness are more strenuous because of the strong acceleration. Weightlessness itself is a bit like swimming – but without the water. The movements you make instinctively don’t work in quite the same way.

I actually had to be careful not to drift away whenever I touched something. For example, when I type on my laptop, I push myself away from it at the same time. This makes coordination much harder, and moving around feels very different from everyday life under normal gravity.

We are investigating how lunar dust behaves under lunar gravity. If people return to the Moon and establish a base there in the future, the dust will need to be transported and processed. Many research groups are already investigating how it could be turned into building blocks. We are looking at the step before that: how can lunar dust be transported reliably in the first place?

Lunar dust is very different from sand on Earth. Its grains are extremely fine and sharp-edged. They easily stick to surfaces, which means that funnels and pipes can become blocked more quickly. The Moon’s weaker gravity also changes how the material flows.

We have used two facilities for this: the drop tower at the Centre of Applied Space Technology and Microgravity (ZARM) in Bremen, and parabolic flights in Bordeaux. What makes our project unusual is that we use both. The drop tower allows us to simulate reduced gravity, including lunar gravity. This lasts for just over two seconds. During a parabolic flight, by contrast, we get around 20 seconds of weightlessness.

At the GraviTower, each measurement takes about five seconds, around two of which are spent under reduced gravity. On a good day, we can carry out up to 100 measurements.

We have found that the material blocks more quickly under reduced gravity. We have developed a model that describes the risk of blockages based on factors including funnel geometry, particle size and what is known as the Bond number.

Put simply, the Bond number describes the balance between cohesion and gravity: how strongly the particles stick together compared with how strongly gravity pulls them downwards. When gravity becomes weaker, cohesion becomes more significant.

Our model helps us work out how large a funnel needs to be to allow the material to flow through as reliably as possible. The Bond number can be measured and also calculated for other gravitational conditions.

No. I studied physics, followed by a master’s degree in astroparticle physics and cosmology. For my master’s thesis, I worked on the IceCube experiment [JB12], a particle detector located deep in the Antarctic ice. Francis Halzen, one of the key figures behind IceCube, is now receiving the Nobel Prize in Physics for his contributions to neutrino research. That makes this part of my research background particularly special, too. [JB13]

IceCube detects faint flashes of light produced when fast-moving elementary particles interact with matter. These particles can originate and be accelerated in places such as the environments around black holes, as well as in the Sun.

I then came to the University of Duisburg-Essen to do my PhD.

During my master’s thesis, I was part of a large project and worked on just one small component of it. Now I follow an experiment from the initial idea through its design and construction to the analysis of the data. Seeing an experiment I helped develop actually work is the best feeling I’ve had during my PhD.

Yes, pretty much at every conference. At first, I often think that everyone else knows much more than I do. But once we start talking, I quickly realise that we all share the same enthusiasm for our particular subject.

I think that will be technically possible at some point. Of course, I can’t say when that might happen.

It’s the fact that an idea can ultimately lead to new insights. And you get to experience that whole journey yourself – from the initial idea through the experiment to the results. That’s what research means to me.

Oliver Gaida, Faculty of Physics, Tel. +49203 379 2958, oliver.gries@uni-due.de

Research paper: https://arxiv.org/abs/2506.18771