Anthony Marston is one of the brilliant minds behind ESA Science

Excellence and perseverance - astrophysicist Anthony Marston is one of the brilliant minds behind ESA Science

Anthony, you’re a scientist on the Herschel project and your team is based in the European Science Astronomy Centre (ESAC) in Spain. You’re convinced that good science arises from the combination of two qualities: excellence and perseverance. What recommendation do you give to young people who are interested in following your path and want to work as a scientist for ESA?

I’d say, take up or continue studying Mathematics, Physics or Astrophysics. Enjoy what you’re doing and keep on doing well. Go for the challenging projects, not just the ones with quick results – that way you will learn more and be more flexible. Furthermore, don’t be afraid to try out new ideas of your own and not just what your supervisor suggests.

Keep persevering with your career choice until it is clear you cannot go any further. I started along a career path and just kept going. No one has told me to stop yet! Remember, you can be spending decades of your life doing a job – if you enjoy what you’re doing you will do a better job and will want to continue doing it for a long time.

You joined ESA in 2003. Did you ever imagine that one day you’d be one of the responsible scientists on such an ambitious space mission as Herschel?

Maybe this sounds strange, but my passion for the stars and the origin of our Universe has always existed. This has helped me a lot to know which road to follow as a profession. I remember that I was thirteen when I got my first telescope, I loved it. And until today I have simply continued along a path towards trying to be a professional astronomer. After my studies of Physics and Astronomy at the University of Manchester, I continued with a postdoc there. I then moved to the U.S. and became an Associate Professor and later on the Chair of the Physics and Astronomy Department at Drake University in Des Moines, Iowa. This was very enriching, and I ended up staying in Iowa for twelve years.

As early as 1988 already I had started to collaborate in various smaller space projects with a small number of scientists. Those projects usually concentrated on star formation processes in galaxies and in evolved massive stars, such as Wolf-Rayet stars. I found it a wonderful experience to be at major telescopes making discoveries, seeing the data and understanding what it meant. I was very lucky that my research work allowed me to use some of the largest ground-based telescopes in Chile and Australia. With time I developed a strong wish to move on and to get as much involved in the development of new space missions as possible.

In 2000 I joined the Spitzer Science Center, IPAC, at Caltech. I stayed for the following three years as the Observer Support Team lead in this NASA project. In September 2003 I started with ESA as an instrument and calibration scientist for Herschel. That was six years prior to the Herschel launch in May 2009.

Herschel is a one billion Euro project. It’s one of the most ambitious space missions ever realised and its results shed an entirely new light onto the origin and development of our Universe. What makes a project like Herschel so complex?

It’s all about high technologies, you’re literally moving along the cutting-edge. These technologies have only recently been produced for use with science instruments. There’s most often only one of a kind and it’s built from scratch. You also have to deal with the lack of space available on the spacecraft. This often requires needing to have a design with many mirrors to “fold” the light. The fact that the instruments must be able to withstand the rigours of space and remain very stable in temperature and response is also crucial. Remember, there is a hot side, towards the Sun, and a cold side pointing away from the Sun, which makes this last requirement very difficult.

Until the launch of Herschel in 2009 you had to travel quite a lot across Europe. What efforts are necessary to keep all the strings of this ambitious project together?

When I started on the Herschel project I spent much time at ESTEC and in Groningen in the Netherlands, especially during the testing and early operations phases of the telescope and its instruments. Since I was also involved in the early physical tests of the instruments, such as monitoring and measuring the response of the HIFI instrument during electromagnetic tests, I also travelled fairly often to places such as Astrium in Ottobrunn, Germany.

Nowadays my main work is done on a daily basis by email and videoconferencess. There are also more formal regular weekly and monthly meetings in different groups. On average I spend half/one day in meetings per week. In addition, every three months I participate in HIFI co-location and consortium meetings. This is because I report to the HIFI consortium of astrophysicists and work with the instrument building site personnel on the improvement of science data products. I also still spend three to five days every few months at SRON-Groningen in the Netherlands.

Every six months I chair in-person meetings of a calibration steering group, which is dedicated to following up on progress concerning the calibration of the instruments and on how to further progress with the project. With the Herschel Calibration Steering Group I meet up regularly with other colleagues from ESA, NASA and various universities for a day at different ESA and university sites (often ESAC). Last but not least we have one or two science research meetings per year which usually last between three to five days, where I present results of my own research.

What do you find most interesting about your work as an ESA scientist?

It is very satisfying to be at the forefront of making things happen, making them work. Especially when there have been problems. I find great satisfaction in making things work so that many astronomers can benefit from the data which the missions are able to obtain. My work helps to ensure that the science instruments work as expected and that they provide understandable telemetry.

I am also involved in making sure that the instruments on board are healthy, and we continuously check for any possible degradation or changes in response to light. We check the calibrations and ensure that the data processing provides the correct products which can then be passed on to scientists for their research. I simply find it great to be able to answer scientific questions, to provide workshops to scientists and to assist them in understanding and using the data from Herschel. At the same time it’s a permanent challenge to be looking at ways to improve the way in which data is obtained. We do this mostly by improving the performance of the satellite overall and thereby improving the quality of the scientific data.

What difficulties have you had to overcome in the Herschel project?

One of the hardest parts is to provide test conditions which are sufficiently like in-flight conditions. When we tested Herschel there were many things that were not quite as they would be on the spacecraft, making the HIFI instrument’s behaviour difficult to judge properly. We needed to understand the packets of data from the instrument to diagnose how it was performing and behaving. And we needed to learn quickly, since we only had very limited time with the instrument in true space conditions, where all the parts of the instrument could be used. We also had to learn how to cope with the fact that different pieces of the instrument were available at different times.

For the HIFI instrument in particular, we needed to find a mechanism for creating observations and changing instrument setups all in a controlled way, without having damaging commands be sent to the instrument. And then, after the launch, the learning continued. On the 81st day in-flight we suddenly had a major instrument anomaly and the HIFI prime electronics burnt out. We have been running on the backup electronics of HIFI ever since.

Later on, we also needed to learn how to react adequately to single event upsets, caused by cosmic rays hitting on-board electronics, while guarding the health of the instruments. Last but not least we are continuously trying to remove impurities in the signal received from HIFI.

What are the key things you have learnt on the job?

No doubt there have been four major things: how to understand the HIFI instrument and the pointing system of the spacecraft; to learn how requirements can help or hinder the science possible with Herschel; how to effectively combine the work of many individuals to get results as efficiently as possible in a mission which only has a limited operational time period; and finally, how to stay calm and focused under extreme pressures – don’t panic!

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