Interview with Tim de Zeeuw, Director General of ESO

Paweł Ziemnicki from The Heavens of Copernicus Planetarium talks with Tim de Zeeuw, Director General of ESO

Since 2012 Poland belongs to European Space Agency (ESA), and from August 2015 – to the European Southern Observatory. In the same time, general directors of those two organisations Tim de Zeeuw from ESO and Johann-Dietrich Wörner from ESA signed cooperation agreement.

Paweł Ziemnicki: ESO is rather an astronomical organisation whereas ESA is rather considered to be an astronautic organisation. What was the reason that these two organisations decided to sign an agreement and start to cooperate?

Tim de Zeeuw: It is a very good question. ESA's mission is much broader, they build launchers, they build rockets, but they also have a mandatory science program, which is about twelve per cent of their budget. We have worked with them in the past already in many areas. We wrote joined studies to see what could happen in the exoplanet field where we need missions in space to do certain things but to do the full science you also need observations from the ground and it is good to combine this. At ESO we also take care of some of the outreach for the ESA part of the Hubble Space Telescope. It is something that ESO is good in and it is sort of outsource by ESA to us. And we have then decided than with the new Director General coming of ESA, Johann-Dietrich Wörner, it would be good to sign a frame agreement which makes it easier in the future to intensify the collaboration. I invited him to Chile to sign it there because in this way we could bring him to the VLT so that he could see what it is that we do in space science and studying the universe which is complementary to what ESA can do. It was quite a good visit.

Is it possible that joining forces you may lower the costs of some of the activities performed by each of both organisations?

That is not how I see this collaboration. I see it more as further increasing the scientific value of the two programs because we will coordinate them a little closer. To be more specific: ESA will launch in 5-8 years time a mission called PLATO which will find many exoplanets. But to get the full science out of that mission we need to study many of these objects with the spectrographs we have in Chile. We want to be sure that the program is coordinated well so that ESA doesn't fly the mission when there is no follow-up observations from the ground or we don't have the instruments etc. So it is more a better use of the funding than lowering costs.

What technology issues are most probable to be exchanged in the near future?

The complexity of instruments on big ground-based telescopes is getting quite close to the complexity of building a space instrument. Of course space instruments are smaller because you need to be able to launch them and everything has to checked many times because you cannot go and repair them after you have launched them. But ground-bases observatories are often in very remote places, instruments are big and complex and you do not want to go to fix them all the time. They have to work almost as well as if they were in space.

There are certainly areas of collaboration in detectors. They have to be very sensitive to catch the very faint light coming from the universe. In many cases we use the same detectors on the ground that fly in space missions.

Photo: Director General of ESO (on the right) and Director General of ESO are signing cooperation agreement.

What are the closest scientific common purposes?

One is the study of exoplanets. Another one is a basic one which we are already doing. ESA's spacecraft GAIA is measuring the positions and movements of the stars very accurately. But to reach the ultimate precision ESA needs to know exactly were the satellite is in space (it is as far as 5 times further from Earth than the Moon, going around the L2 point) and needs to know the speed of the satellite with precision to 2.5 milimeters per second. For that they need every night observations from the ground against the starfield, where is GAIA – so we do that for ESA. With information of the exact positions of the satellite they are able to reconstruct where all the stars are.

GAIA will discover many interesting stars. Then astronomers will want to study them more carefully than it is possible with the GAIA mission. To fully understand the physics of these stars they will use ESO instruments and telescopes. So again, the aim of collaboration is optimizing the science program.

Is it possible that in 20, 30 years ESO would like to have its own orbital telescope, send it with support from ESA?

Originally ESO was established to build a big telescope in the southern hemisphere. Now its mission is to build world-class observing facilities – it doesn't say „in the south” and it doesn't say „on the ground”. Having said this I don't think that it is very likely that we would ourself start building satellites. The division of work between ESO and ESA is quite normal and ESA is doing well. But it does not always has to be like this that ground based observatories follow research done by spacecraft. It might be also like this that we spot something interesting from the ground and than we need the space mission to study it better – so we can go to ESA. It's the same science no matter if it is from the ground or from space. We just want to be sure that we do not duplicate efforts. But who knows, we would be happy to launch a satellite.

Astronauts have to know the sky quite well for navigation. Is ESO going to provide astronomy courses for ESA astronauts in Chile?

I think they mainly study the sky at the universities. But we have had several visits of astronauts and they liked our hardware. I would be happy to do something but we've got nothing planned at the moment. ESA trains its astronauts quite well on its own.

What are the most important benefits for countries like Poland, that participate in both organisations?

The goals for membership in ESA and ESO are somehow different for most countries. This goes back to the fact that most of ESA's program goes to launchers, rockets and Earth observations. Observations of the universe is part of the mandatory science program so they have to do it but very important is the role of ESA for the industry. There is also national pride to have space progam or be involved in such program.

As for ESO we are an organisation that enables scientific discoveries so it is mainly for astronomers. But building our facilities requires the same level of industry engagement like it is with ESA. For the governments, like for example in Poland, the goal is double: to support astronomers in doing science but also to gain opportunities for industry.

Did ESA Director General enjoy the visit at Paranal and did he like the VLT?

He loved it. His background is more of engineering but he liked very much what he saw because there is a lot of engineering on Paranal. He also liked very much the kind of scientific questions that we are trying to answer and he realizes that to do it you need both ground and space instruments. Some things you cannot do from the ground. I was extrememly worried before his visit because we had an unusual day. The sky over Paranal was clouded in the evening. But in the middle of the night it cleared up. He woke up and he enjoyed looking at completely dark sky with the beautiful Milky Way. He liked it. I think he will come back.

Iterview by Paweł Ziemnicki from the Heavens of Copernicus Planetarium
Publishing date: 27th December 2015