A Graduate Traineeship at ESA: Working on the James Webb Space Telescope

Not all PhD students join us directly after finishing their Master degree studies. Anurag Deshpande, a first year PhD student, spent a year working at the European Space Agency (ESA), as a Young Graduate Trainee (YGT). With the application process for the next round of YGTs now open, he discusses his time working on the James Webb Space Telescope, how he found the experience, and how it continues to influence him in his PhD research.

As I reached the end of my masters course, I felt like I needed a bit of a break from academia. It had long been my intention to carry on and do a PhD in Astrophysics, with an aim to pursue a career in the field, but after four years of intense learning, I felt like I needed a bit of a change.

I discovered ESA’s YGT program which allows recent graduates across disciplines the opportunity to work at one of ESA’s bases across Europe. Given that I wanted to stay in science long term, I applied a position working on the James Webb Telescope’s (JWST) NIRSpec instrument. Since JWST is poised to be one of the next major astrophysical observatories, it seemed like a great opportunity. This position was based at ESTEC, in the Netherlands, ESA’s largest centre. The application process was relatively straightforward; after the initial application, I had a video interview followed finally by an in-person interview at ESTEC. A couple of months after I applied, they told me I’d gotten the position. I was ecstatic.


An aerial view of ESTEC in the Netherlands.  Credit – ESA

My project there involved working on the Near InfraRed Spectrograph (NIRSpec) one of two European instruments onboard JWST. There are two particularly useful things NIRSpec can do. One of these is that It can take individual spectra for various objects in its field of view using an array of ~250,000 micro-shutters. Independently, it can also look at one object specifically, break it up into 30 slices, and get an individual spectrum for each slice. These two modes are mutually exclusive, meaning when using the latter, all of the micro-shutters used for the former must be closed. However, light can still ‘leak’ through the gaps between the closed shutters, resulting in a unique source of background light known as ‘MSA Leakage’. It was my responsibility to first carry out a comprehensive analysis of this signal, and then see if it could be modelled computationally.

From a practical point of view, much of my work involved using Python, in order to carry out a statistical analysis of this signal, and then attempt to construct a model. I became familiar with the workings of the instrument, and had the opportunity to play around with some of the bespoke NIRSpec software, in order to build my model. My Astrophysics knowledge also came into play, as I had to consider how this leakage would change depending on what its source was. For example, on the ground most of our data came from NIRSpec’s internal calibration lamps. However, up in space, most of the light would likely come from the Zodiacal light. During this process, I worked with data from the calibration unit which, serendipitously, was designed at MSSL. I had the opportunity to liaise and work with people from all around the world, from institutions such as NASA and the Space Telescope Science Institute (STScI).


An example of some NIRSpec test data.  Credit – ESA

Working as part of the JWST team gave me an insight into how modern-day space missions are run, and all the work that goes into them. It showed me the multi-disciplinary nature of the work, and gave me an appreciation for where all the data that we use in Astrophysics and Cosmology really comes from. In much the same vein, working at ESTEC showed me all the different sides of how a space agency runs, from the engineering to the space law considerations. The YGTs themselves tend to be a close-knit and sociable bunch, meaning you get to know people from across all departments, and gain a holistic idea of what it takes to get to space. And of course, it’s also nice to occasionally realise that there’s an astronaut having lunch a couple of tables over from you.

In fact, working at ESTEC even influenced my choice of PhD, as I opted for one closely tied to ESA’s upcoming Euclid mission. The traineeship also better prepared me for a PhD, making me more confident in doing science. ESTEC in general is, in many ways, similar to MSSL. That is, a friendly, multi-disciplinary place where you have the opportunity to get involved in a large breadth of activities. I loved my time at ESA as I do my time here, and look forward to potentially returning one day. I wholeheartedly recommend the YGT program to anybody who is graduating soon or has recently graduated. It only opens more doors.

The YGT application process for 2019/20 can be found here. You can read more about Anurag’s YGT work here, and here.


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