Sima is moved by the forces of Space.
Subject: Space/Runway radars
Job: Space Mission Scientist
Works for: Qinetiq
Interests: Single Aircraft Flying, Bollywood dancing, Reading
Age: 28 yrs
A levels: Physics, Chemistry, Maths, Further Maths
Degree course: Natural Sciences (Physical) BA, MSc,
Downing College, University of Cambridge
Degree course: Space Science, MSc, University College London
Sima wanted to be an astronaut as a kid and now looks at the forces that effect the movement of spacecrafts as they orbit the Earth. Sima even flies planes in her spare time.
My job is…
Sunlight causes spacecraft to move as they orbit round the earth. My job is to model those movements so we can determine spacecraft position accurately.
I share a flat in Pimlico with my brother. Its slap bang in the middle of London and is a great place to live. I can walk everywhere St James Park, the Tate Gallery and Big Ben are just round the corner and I love the energy of central London.
Story so far
When I was a child, I was amazed by the moon and stars and dreamed about travelling to space. At school I found I really liked the fact that there were laws governing the universe, and using them you could explain and predict things. I had a particularly inspiring biology teacher who always pointed out the beauty and elegance to be found in the natural world. Coming form a family of medics, for a long time I assumed thats what I would do. At about the age of 16 I realised that I found pure science and maths the most interesting and rewarding subjects and decided to pursue these at university. I chose a course in Natural Sciences at Cambridge which offered a very broad science background, and I had the chance to examine dinosaur fossils in geology, make bouncy balls in chemistry and study quantum mechanics in physics amongst many other things.
After finishing an intensive four year degree, I decided it was time for a change and a break. I wasnt certain of my next career move and was very keen to travel and experience other parts of the world. So I set off with a backpack and spent several months in Australia and South Africa working as a temp and learning to dive and sky dive along the way. Though these months were fantastic, towards the end, I felt a pull back towards science and in particular to my childhood fascination with space. I returned to England and took up a Masters in Space Science at the University College London. This led onto my PhD in spacecraft orbit determination and my forthcoming job as a Space Mission Scientist in the Space Department of the company QinetiQ. Though I have never really had a master plan, my choices at each moment in time have been based on what I enjoyed and have ultimately led me to work in a job which find very exciting, important and fun.
Day in the life
Its 8:40 and Im cycling to work. Ive just passed Westminster Abbey and am riding through St James Park. By nine Im sat at my desk and firing up my computer. I chat to Ant, another PhD student about the film he saw last night. After making a cup of tea, I settle down and check my emails, one in particular catches my eye – results from a model that we sent off to the States. I quickly glance over it and send an email to my supervisor arranging a meeting to discuss it this afternoon. I then settle down to puzzle over how spacecraft solar panels emit heat and how this affects the orbit. Its mainly computer work, though I spend a bit of time discussing an idea with Ant on the whiteboard; Prof Cross sees us and joins in too.
This takes up most of the morning, and by 12:30 Im ready for lunch. The weathers not great if it was Id take a sandwich out into the quadrangle so we decide to go to one of UCLs cafeterias. On other days, if were feeling rich enough, we go to a nearby restaurant – my favourite is a thai place where the prawn noodles are fantastic.
After lunch, I do some more calculations and set a program running. This will run for an hour, which gives me time to go to the gym. I get back in time for the meeting with my supervisor which lasts until about six.
Some nights I stay in and around UCL to attend a salsa class or a life drawing session, or catch up with some friends in a pub before going home for dinner. Tonight I think Ill settle on the sofa with a glass of wine and watch an episode of 24.
A spacecraft in orbit has many forces acting on it, causing it to rotate around the Earth in a particular way. By far the largest force is due to Earths gravity though gravity of the Sun, Moon and planets may also be also important. There are another set of forces that affect the motion of a spacecraft, caused not by gravity but by the suns radiation. Solar radiation is made of light particles called photons. These photons act as very tiny ping pong balls which strike the satellite, exerting a force on it and causing it to move. This is an exceedingly small force, roughly the weight of a grain of sand on Earth. An even smaller force is caused when a spacecraft which is warmed by the sun, starts to emit heat. When the spacecraft fires out this radiation, there is a recoil force like the force you feel on your arm when firing a gun. This is called thermal re-radiation and is the subject of my study. Understanding these forces helps us predict where a spacecraft will be.
So why do we care about these small forces? Its because positioning systems such as the Global Positioning System (GPS) use receivers on the ground which communicate with satellites orbiting the Earth. These systems must know the spacecraft position to work out the position of receivers on the ground. The better we know the spacecraft position, the better we know where the receiver is on the ground.
These positioning systems have wide ranging uses including navigation, for example, for hikers trying to find there way in remote areas and for the landing and flying of aeroplanes. As this technology gets better, scientists can use this to study earthquakes by looking at the relative motion over time of two receivers on either side of an earthquake fault. Scientists also use satellite measurements to monitor the melting of the icecaps, which are a result of global warming.
Some of these applications will help to understand our planet better and allow us to better protect our environment. This research is of international significance, and we work with the Jet Propulsion Laboratory, a NASA centre in California and regular visits are required for this work.
Im learning to fly and have recently spent most weekends having lessons, trying to build up both solo hours and hours with an instructor. I also enjoy salsa dancing (and danced in the Notting Hill Carnival in 2002) and scuba diving. I enjoy outdoor activities and recently climbed the 3,000-metre Half Dome in Yosemite National Forest in the USA. I enjoy watching films and reading and going out with friends for drinks and nights out dancing.
My childhood dream was always to be an astronaut. Failing that, I would love to work as a scientist for NASA.
The best thing is…
The best thing is that I find my work really exciting and worthwhile. Working on space projects involves much international cooperation and allows me to travel to many countries and present my research.
I dont really have many regrets. I aspire to the belief that anything is possible and as long as you try, then you havent failed.