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The career of an astrodynamicist

Image of Dr Nicola Baresi

Tell us a bit about yourself and what you do

I am an astrodynamicist, which means I study the motion of man-made objects in space. The original roots of the field go way back to the celestial mechanics of Galileo and Newton, but the modern field has emerged since the launch of Sputnik in 1957. I look at how spacecraft behave in space, with a focus on how the different forces in action – mainly gravity, but also spacecraft engines – can be used to navigate satellites in the most effective way.

Astrodynamicists like me plan orbits for missions and control them. It’s not enough to just put a satellite into space. You need to ensure the satellite is in the right orbit to achieve its mission objectives, which often implies communicating with it and ultimately steering its course. After all, if you can’t make your spacecraft point the right way, you can’t take the pictures you need, direct the thrusters to move it the way you want, or ensure its antennae can send data back to Earth. People in my role play an essential part in any successful mission, including contributing to their initial design and supporting their operation in Space.

What inspired you to work as an astrodynamicist?

When I was growing up, the Space Shuttle was still operational and NASA had just arrived in orbit around Saturn with their Cassini mission. I’m Italian, and our national space agency, the Agenzia Spaziale Italiana or ASI, played a key role in the mission by supporting a module called Huygens that ultimately made it to the surface of Titan, the largest moon of Saturn.

That inspired me to take a module on orbital mechanics during my undergraduate degree studies in Physics. We looked at the two-body problem – how two masses move in space under their mutual gravitational attraction. I was awed by the maths involved and by how a very complicated subject like the motion of objects in space can be explained via relatively simple and elegant equations.

Since then, I have been more and more fascinated by how we can use calculus and computer programming to calculate fuel-efficient trajectories for space exploration. When you’re in space, the most powerful resource is gravity. I love working with computational models of the solar system to figure out how the gravitational influence of a planet or a large moon can help steer the course of a spacecraft trajectory without having to fire its engine and consume precious propellant. It’s like playing a video game that rewards you from exploring the environment – the solar system – while utilising minimum resources – fuel.

What are you working on at the moment?

Lots of different projects! I’m involved with MMX, the Martian Moons eXploration, the next flagship mission from the Japanese space agency, JAXA. The aim is to land on the largest of the two moons of Mars, Phobos, and retrieve samples to find out where it came from. There are theories that Phobos was formed beyond Jupiter, and finding out the truth about whether it was pushed inwards towards Mars could support the hypothesis that water on Earth was delivered by the constant bombardment of asteroids and comets during the early stages of our solar system. Before MMX attempts to land, it will need to orbit Phobos for a year, during which time the moon’s surface will be mapped and a landing site selected. From an astrodynamics perspective, it’s a huge challenge to remain in orbit around Phobos, firstly because of the gravitational pull from Mars, but also because Phobos isn’t spherical which really complicates the calculations for finding a scientifically valuable and operationally safe trajectory. My role on the project involves estimating the orbit of MMX so that we can geolocate all the pictures and data it will collect. We can’t pick a site and land on it if we don’t know the gravity field of Phobos very well or if we don’t have a better understanding of what the moon is truly made of.

I’m also working on a Moon-Enabled Sun Occultation Mission, MESOM, which aims to recreate total solar eclipse conditions in space once a month. This would enable scientists to investigate the Sun’s atmosphere and better understand space weather events like solar flares and coronal mass ejections, which impact electronics in space and on Earth. I am working out where the satellite needs to be so that the Moon regularly blocks out the Sun and causes the totality we see only rarely on the Earth’s surface.

The Volatile Mineralogy Mapping Order is another project I am involved with that aims to examine water ice distribution and composition in the permanently shadowed regions of the lunar south pole. I’m helping to design lunar orbits for the suitcase-sized satellite which will conduct the surveillance. However, orbiting the Moon can be difficult because of its lumpy gravitational field. Anything attempting to fly in a circular orbit will crash in a few months owing to gravitational perturbations that can quickly accumulate over time.

Other projects look at cheaper routes to explore the vicinity of the Moon and support the establishment of a brand new space station that will allow astronauts to return to the surface of the Moon for the first time since the end of the Apollo programme in 1972. Another project I am working on will see space flight dynamics meeting aerodynamics for enabling very low-altitude reconnaissance missions (around 200 km above the surface of the Earth). I love that I get to work on so many different mission scenarios and play with diverse and exotic dynamic environments.

How do you test if your designs work?

The ultimate test is to see if the spacecraft behaves like you have predicted once it is deployed in space! This is not straightforward and the big breakthroughs in astrodynamics have taken place when things have gone wrong in various ways. For example, it was astrodynamicists who came up with “free-return” lunar trajectories that ultimately made it possible for the crew of the Apollo 13 mission to return safely to Earth despite the loss of the main spacecraft engines.

What’s the best thing about your job?

I get to work on exciting spacecraft missions and support exploration of our solar system, helping to push the boundaries of human knowledge and underpin scientific discoveries. I ought to be creative in my daily tasks, and I get to share knowledge and brainstorm ideas with teams of like-minded people at the Surrey Space Centre who share my curiosity and enthusiasm for space exploration. I enjoy working with students at the University of Surrey to pursue new research ideas and explore how emerging technologies in different fields, like computer vision and machine learning, can be applied to enhance the efficiency of spacecraft missions. I’ve also got to travel a lot and live in different countries – as well as my native Italy, I’ve lived in the USA, Canada, Japan and the UK, making life-long friendships and experiencing different cultures and ways of living.

What qualifications did you need to get to where you are now?

The formal qualifications I obtained were an undergraduate and postgraduate degree in Physics, which gave me the fundamental tools I needed to understand the basics of orbital mechanics and how spacecraft can be manoeuvred and re-oriented in space. Then I did a PhD in astrodynamics, which further equipped me with the key engineering skills I need in order to interface with spacecraft manufacturers and operators to design and support spacecraft missions. Space work is necessarily multidisciplinary – lots of different areas of expertise are needed – which is why it is never too late to wear your spacesuit and join the space race.

What advice would you give to someone wanting a career in space, and especially in your field?

My career has benefitted from having a multi-faceted background and skills. In astrodynamics, you need to be good at maths, but the ability to code and write computer programmes is extremely useful as well. For other space-related disciplines like space propulsion, being able to handle nuts, bolts and screws, and having a general understanding of thermodynamics and the laws of plasma physics can be a more valuable resource. If sending packets of data via encrypted messages is your thing, then having a basic understanding of electromagnetism and how waves propagate in space would be a good place to start. Nowadays it is possible to receive signals from satellites via relatively simple and inexpensive equipment that can be installed in your local school with the help and support of your teachers.

My advice is to stay curious and don’t be afraid to take different approaches to problems. Enthusiasm and passion can take you a long way, especially when facing technical challenges or concepts that may seem difficult to grasp at first, like calculus and advanced maths.

To stimulate your curiosity, I’d recommend reading online about different missions and getting your head around why we are exploring space and why particular spacecraft trajectories are chosen for the projects that most inspire you. Joining local events during the World Space Week (October 4-10 of each year) or attending space universities’ open days can give you a taste of what a career in space engineering could look like. Soon enough, you will discover that there are still a lot of questions that need to be answered about the origin and evolution of our solar system. These are the questions that will underpin the next generation of spacecraft missions you might be able to contribute to in the near future.

Orbital path of the Martian Moons exploration (MMX) mission

Orbital path of the Martian Moon's exploration (MMX) mission, credit: JAXA

Dr Nicola Baresi

Lecturer in Orbital Mechanics at Surrey Space Centre, the University of Surrey