Less than three years ago, you could read an article about Ondřej Šlajs on the FME website. At that time, he was a bachelor's student who was interested in space technology and applied for an internship at OHB Czechspace. And today? He is a graduate and started working at ESA ESTEC in the Netherlands in the fall.

When we spoke last time, you weren't even sure which master's program you would pursue. Now that you are a graduate of Precise Mechanics and Optics, we are speaking via video call because you are in the main development center of the European Space Agency.

That's right. Since October, I've been working at ESTEC, ESA's R&D headquarters in Noordwijk, the Netherlands, roughly halfway between Amsterdam and The Hague. I make performance models for Earht observation satellites here. That means I simulate what an optical system see: from what it captures to what it images. So it's optics, which I research here, but also with programming.

How can a recent graduate get a job at ESA?

My position is called ESA Graduate Trainee. I have a two-year contract and I am a regular employee; however, the position is intended for graduates who have completed their studies with maximum of 1 year of industrial experience.

Getting this position is not easy—it helps to have internships or projects under your belt. My work at OHB Czechspace and my internship at OHB in Germany, where I contributed to the PLATO mission, an ESA mission, undoubtedly benefited me. The topic of the position also plays a role.

At the same time, it is worth noting that ESA has a so-called "georeturn policy", meaning each member state of the agency contributes a certain amount to the budget. This ratio is then reflected in the country's degree of involvement in projects or the number of employees. The Czech Republic still lacks sufficient representation, which is an advantage when recruiting.

Do you have a mentor as a trainee?

I have a supervisor who, in turn, has his own line manager. The role of the supervisor is similar to that of a thesis supervisor: I share my work and progress with him, and I can consult with him. You apply to the ESA Graduate Trainee program for a specific position with a particular topic, which you then work on. And every trainee—because there are more of us here—has their own supervisor, so they are not alone.

You had been eyeing a career in space since your bachelor's degree. I assume that this also influenced your decision to pursue further studies?

I tried to connect the two. Several options were available at the Faculty of Mechanical Engineering, including aerospace engineering, mechanics, and physics. In the end, physics, or rather optics, won out for me. At the time, I was working at OHB Czechspace, whose German parent company manufactures optical systems for space applications. I saw a great future in this because few people in Czechia are involved in this field. While my bachelor's thesis focused on dental implants, my master's thesis centered on the development of a test collimator for the QUVIK satellite telescope.

Paradoxically, my master's degree was less demanding than my bachelor's degree. I had the pleasure of working with absolutely fantastic people at the Institute of Physics, and I thoroughly enjoyed my studies. Thanks to this, I was able to continue working with OHB Czechspace throughout my master's degree. I remained there until I received an offer to work for ESA.

Working at ESA is a dream come true for you. What is the reality?

There are great people here! Fascinating, true experts in their field. With my focus on space optics, it's even better because it's not a significantly developed field in Czechia, and I didn't have much to draw on. Here, I can constantly draw inspiration—sometimes I feel like it's too much and I have to pace myself.

I sit in an office with six other young researchers. The entire ESTEC is truly multicultural, with representatives from various countries, including Germany, France, Italy, Spain, and Ireland. ESA has 23 member states, and there are people from every country here, which is excellent.

Last but not least, it's essential to note that it serves as a hub, a central location where various events, including conferences, international schools, and workshops, are held. And we have the opportunity to attend these events.

Is ESTEC more of a world for itself, or are you able to live an everyday life alongside your work?

I am a regular ESA employee. We don't have any "dorms," so I had to find accommodation myself. Which is very difficult here; I searched for two months. Fortunately, ESA has a Housing Officer who helps people find housing. He recommended landlords who wanted to rent a house through ESA, and luckily, it worked out. I am here with my girlfriend; we have a dog, so we live in a suburban house. Just don't look at how much you pay for rent, because that view hurts quite a bit.

Do you meet other people from the Czech Republic at ESTEC?

There are about fourteen of us here. Sometimes we go out for lunch, take a walk, attend a concert, or grab a beer together. There is a pub, a swimming pool, and a tennis court right on the ESTEC premises, so we take advantage of that.

You said that this is a one- to two-year position. What happens after that? Can you stay at ESA?

The Graduate Trainee program does not expect people to stay here. It is more about training the next generation of space engineers who will then go on to work for companies. So we'll see where I end up next. Of course, it's not just my decision. I'm here with my partner, so we'll work it out in a way that makes us both happy.

You mentioned that you work on performance models. Will you be involved in any specific upcoming missions?

I test the model on ECO – Earth Climate Observatory. That space mission will measure the Earth's energy imbalance, the difference between the total solar irradiance and the Earth's total outgoing radiation, both reflected and emitted. Because of a increase in anthropogenic greenhouse gases, that imbalance is positive (> 0), which causes the Earth to warm up over time. If we can quantify that energy imbalance well, we can predict global warming accurately in the long term. So it's great that I get to work on a specific mission where I can test my models.

What do you enjoy most about optics?

Probably the complexity of the problem. When you design optics for the visible spectrum, you do it differently from those for the UV spectrum, the far infrared spectrum, and so on. And now, when I'm working on performance models, I take all of that into account in a program that will predict the behavior of optics for different parameters. It's something you can really get into.