Destination Space

On the 5th of February Destination Space took place at Dynamic Earth in Edinburgh. Dozens of children came to our booth to try pedagogical experiments and learn more about science. Questions were also asked about our PhDs and our day-to-day life at work.

The kids had a lot of fun playing with the Theremin and were blown away by optical experiments! It was also the perfect occasion to introduce basic physical concepts such as waves and light propagation.

We joined ESR Yifang Wei from the TESLA project and the cross-collaboration was a huge success allowing the kids to hear about the different projects and the research that we carry out as part of the projects.

Explorathon and Midlothian Science Festival

As usual, at the beginning of every academic year many public events take place in Edinburgh. Among these events, there were public engagement activities that were addressing mostly to young children and how we could inspire the new generation in science. So, during the last week of September and the two first weeks of October, Heriot-Watt university and REVOLVE were involved in many of these activities.

Explorathon 2019 took place this year at the Botanic Gardens of Edinburgh, a wonderful centre for plant research conservation and education. Diverse researchers from various scientific backgrounds from the city of Edinburgh represented Universities and Research Institutions. Hands-on activities from topics like medicine, biology, physics and sociology were demonstrated to the young visitors. Dozens of young people flocked to the building located into the magnificent landscape of the Botanic Gardens. Heriot-Watt University and REVOLVE had their own booth named ‘Engineering for Beginners’, with two tables full of experiments for young people and not only.

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The visitors had the opportunity to get involved in experiments from the field of science and engineering while the smile on their face revealed their pleasure to the experiments and filled us with joy and satisfaction. Wireless power transfer, visual tricks and illusions, magnetic and electric fields with batteries and magnets as well as experiments with acoustic waves were some of the activities demonstrated to the kids and the attendants. Finally, there is no doubt for the great organization and the well succeeded objective of the venue that is nothing but inspiring the new generation in science.

In the context of Midlothian Science Festival, Heriot Watt University teamed up with Black Diamond radio station in an open day event called ‘Making Radio Waves’. The concept of this collaboration was to invite people interested in learning about radio waves to the beautiful premises of Black Diamond FM on the outskirts of Edinburgh. The hosting of the members of Black Diamond FM was outstanding and the attendees (people of different ages) had the opportunity to listen to a presentation about the basics of radio waves, visit the premises of the radio station and see how a radio show is set up and broadcasted, as well as put their hands on the experiments provided and demonstrated by the Heriot-Watt team.

Finally, again in the context of Midlothian Science Festival, Heriot-Watt and REVOLVE participated in a third outreach event which took place at the local library of Penicuik. Universities and other institutions related to science teamed up for demonstrating experiments related to science and nature with view to inspire the young attendees in this exciting world.

Penicuik Library 2

Penicuik Library Outreach

The local community responded massively to the Midlothian Science Festival’s call and dozens of children with their parents flooded the library. Heriot-Watt’s booth experienced α strong traffic from the enthusiastic young girls and boys who came to see our experiments and learn all this ‘magic’ that exists at this planet and universe.


REVOLVE Fellow attends Alpbach Summer School


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How can you know about Earth composition or Earth sub layers activities that provoke earthquakes and continental drift? You can always try to go down a volvano crater like in Journey to the Center of the Earth, however satellite observation would be a much practical solution ! Measuring magnetic and gravitational fields with satellites can give much more information on our Earth that Jules Verne would have dreamt of. Check the maps and data provided by ESA missions such as SWARM for magnetic field or GOCE for the gravitational field to convince yourself.

Earth magnetic and gravitational fields were the topic of Alpbach Summerschool organized by FFG (Austrian Research Promotion Agency) and ESA in which I took part this summer. 60 students from all over Europe attended this event in the middle of the beautiful Austrian Alps.

During the first few days we attended courses on magnetic and gravitational fields and on satellite mission design. Earth magnetic field comes from the movements of electrically charged particles, these movements may comes from the rise of less dense matters from the core of Earth (that may result in volcanoes or continents rifts). Measurements help to explain the geologic phenomena happening under our feet. Gravity field measurements help us to know about the composition of Earth (densier regions of Earth will have  higher gravitational field) and its geodesy (the Earth shape is not completely a sphere).
In groups of 15 people we worked on a mission proposal to leverage satellites constellations for magnetic and gravitational remote sensing. Our team was called RUBIKS (Reconstruction of Undercrust Behaviour with Interconnected Kube Satellites) and we managed to propose a mission of 8 satellites that would map both the gravitational and magnetic field with a low-cost design and unprecedented time resolution.
Alpbach Summerschool was a tremendous experience that I recommend to anyone interested in space and science. It was intense with a lot of work but with what I learnt and the mission we came up with in the end, it was completely worth it. We were supported by two tutors and lecturers who gave us a lot of precious feedback.

Our efforts were rewarded by an award for the most innovative mission by a panel of experienced scientists and engineers. Special thanks for the CNES for the sponsorship, to Peter Faulkner, Michaela Gitsch, our tutors Olivier Carraz and Tyler Jones, and all the RUBIKS team.

That’s all for today, see you soon when I pop back to update my blog with more of my PhD experiences!


The 13thEuropean Conference on Antennas and Propagation took place from the 31th of March until the 5thof April in the beautiful city of Krakow and included a wide range of delegates from academia and industry from all over the world.

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The massive participation and the high quality of the antennas and propagation representatives denote the big success of the conference. Of course, REVOLVE project could not be absent from this big event. Many delegates from the REVOLVE consortium were present in EuCAP and among them myself.

Above all, I want to express my absolute delight and satisfaction for being a part of the most important meeting held by the best both academic and industrial representatives on antennas and propagation. From my side, I presented the paper with title ‘Design of a Compact Four-Way Dual Polarization Orthomode Power Divider for Multiport Radiating Elements’ in the 23rdConvened Session named ‘Antenna needs and solutions for future Space missions’. This work presents briefly the design and evaluation of a dual-polarized microwave excitation network, which comprises 4 outputs and its afterwards connection to feed a stacked Fabry-Perot cavity antenna. The successful presentation of this project as well as the massive attendance and interest of the conference’s delegates at this session were the two most memorable things for me.

Of course, during the conference I had the chance to meet people from industries as well as academia (universities, R&D sections at companies, research centers), with whom I had time to exchange views and ideas about several aspects related to the emerging microwave and antennas technologies. On the whole, this EuCAP has been an absolutely inspiring and motivating experience for me.

Caltech Space Challenge

Andrea, REVOLVE PhD Fellow participated in Caltech Space Challenge week.

The workshop brought 32 undergraduate and graduate students from all over the world to gather at Caltech and their task was to design a pre-phase A mission to Enceladus in 5 days. The participants came from different scientific backgrounds, representing engineering, science, business, graphical design, and many others. They were divided in two different groups and they were able to benefit from working under the mentorship of experienced engineers and managers from NASA’s Jet Propulsion Laboratory (JPL), Caltech (Keck Institute for Space Studies and Galcit) and private industry (Lockheed Martin, The Aerospace Corporation and Northrop Grumman).

Andrea worked in his team as the System Engineer (telecom, thermal and power subsystem dimensioning), and collaborated on the scientific instrumentation study as well as for the mission analysis concept and architecture. The opportunity to work with the other 15 people in his team, each from a different background gave him the opportunity to learn other scientific fields, and provided him with an opportunity to refine the rough work done in 5 days in order to have a more rigorous proposal and the opportunity of a conference paper (to be detailed soon). It is uncommon to have 16 people selected among several applicants working together on a mission concept!

The Workshop gave the team the opportunity to visit the Jet Propulsion Laboratory under the guide of A-team and X-team experts for half a day. The rest of the day was dedicated to classes under the mentorship of JPL engineers. During the week they enjoyed several lectures (soon to be online) on space exploration, science objectives and instrumentation. We had an afternoon of mentorship from the former JPL director Charles Elachi. He was also available to answer any technical and non-technical questions about their proposal.

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Edinburgh Christmas Market
Edinburgh Christmas Market

Once per year, the REVOLVE fellows meet for a training week. In December 2018, the event took place in Heriot-Watt University, Edinburgh. During this week our REVOLVE Fellows had the chance to meet experts from the telecommunication industry (Eutelsat, Thales, LSS, Sofant) and academia (Heriot-Watt, IETR, ESA). The topic discusses was mainly about antenna systems for satellite or user terminals. The Fellows enjoyed a presentation from an expert who gave them advice to patent their designs. Moreover it was the occasion to have a review of our activities and plan for the future (publications, conference, demonstrators…). Some of them are considering (or have already!) submitted patents which shows that the project is progressing well.

Maxwell House
REVOLVERS at the James Clerk Maxwell Foundation

The REVOLVE Fellows also visited the birth place of James Maxwell, the genius behind the equations that rule Electromagnetics. It was interesting to see that he had great achievements not only in electromagnetism but also in mechanics, astrophysics, thermodynamics and poetry! The James Clerk Maxwell Foundation welcomes visitors and you can visit his elegnat Georgian house which displays a growing cllection of heritage material associated with James Clerk Maxwell and his associates. To find our more visit the James Clerk Maxwell Foundation website.

Figure 4 - The ESA Academy's Concurrent Engineering Workshop - May 2018 participants(credit ESA)

One week at ESA

Blog post by Florian Vidal, REVOLVE Fellow

It has been a while since my last post! Don’t worry I didn’t suffocate under research papers and on the contrary, my work is progressing fine. Today I’m going to focus on an event I participated in which was a workshop organized by ESA. ESA stands for European Space Agency and its role is to provide, for exclusively peaceful purposes, cooperation among European states in space research and technology and their space applications. It also promoting space with outreach (follow their mascot Paxi!) Furthermore, ESA is involved in state-of-the art project such as Galileo, the European GPS.

The topic of the workshop I attended was about concurrent engineering, the art of combining several engineering fields to find an optimal design. I am going to present to you the process we went through to design a spacecraft to go to the moon.

Figure 1 - Redu position in Europe

Figure 1 – Redu position in Europe

The workshop took place in ESA’s European space Security and Education Centre (ESEC) in Redu, a remote Belgian village 2 hours from Brussels. This place was chosen years ago by ESA to minimize interference for satellite operations while remaining in the center of Europe. When I arrived to the hotel I was really surprised by the diversity of nationalities amongst the participants. We were 20 university students, Spanish, German, Polish, Dutch, Italian, Romanian, Portuguese, English and French. Moreover 2 system engineers from ESA were there to support us during this week.

Figure 2 - ESA-ESEC site in Redu, Belgium

Figure 2 – ESA-ESEC site in Redu, Belgium

We were welcomed by ESA staff at ESA Academy’s Training and Learning Centre. There, we were presented ESA and ESA Education Programme, and our mission for the following days: designing a low-cost spacecraft to bring a rover to the moon using ESA Educational Concurrent Engineering Facility (CDF). The name of the mission was LIAR (Lunar Impactor And Rover). The mission consisted in a spacecraft that would impact the moon instead of landing softly. That way we would use less fuel hence a lighter spacecraft. This spacecraft would bring a rover to the moon for an observation mission (taking pictures).


Figure 3 - ESA's Educational Concurrent Engineering Facility (CDF) (credit ESA)

Figure 3 – ESA’s Educational Concurrent Engineering Facility (CDF) (Credit:ESA)

The team was composed of several sub-teams divided by subsystems: thermal; communications/data handling; structures; trajectory; configuration;  propulsion; and, power. I was working on communication and data handling subsystems with another student. Concretely our work consisted in finding a/some ground station(s), designing the communication module to enable control, telemetry, and the downlink of the pictures the rover would take on the moon.

Figure 4 - The ESA Academy's Concurrent Engineering Workshop - May 2018 participants(credit ESA)

Figure 4 – The ESA Academy’s Concurrent Engineering Workshop – May 2018 participants (credit: ESA)

We also had the opportunity to visit ESEC facilities. For example, we went into the Proba Operations Control Room. Proba satellites are 3 Belgian observation satellites: Proba-1 is observing Earth; Proba-2 the sun; and, Proba-V vegetation. Their information is precious and can be used for agricultural, weather or scientific purposes.

Figure 5 - Photo of the sun taken by Proba-2 (credit: ESA)

Figure 5 – Photo of the sun taken by Proba-2 (credit: ESA)

During the last 2 days of the Workshop we worked hard to find an optimal solution. It was really challenging in the way all the subsystems interact with other subsystems. For example, as I was working on communications, trade-offs between the number of pictures we can send and the power required on the spacecraft were to be made. It was hard negotiations! The tools provided by ESA and the fact that we were all in the same room were essential to iterate quickly to cross out non-feasible solutions.

In the end I was really surprised by the result of our work. I honestly thought that we could not achieve anything in 4 days for such complex mission but finally the solution we reached seemed not too far-reached! Many thanks to ESA Education Office team for this exciting week!










Dreaming of a career in Space…

CBenteynOne of the most difficult things when we are in high school is to know what we want to do. For my part, I have always been impressed by passionate people who knew exactly what they wanted to be in the future : Biologist, Actor, Doctor, Policeman…

In primary school I wanted to be President, in College a Biologist and in high school, I didn’t know what I wanted to be…..perhaps an Archaeologist or an Engineer. During my first year of Engineering my Human Resources colleague asked me, “What is your professional project?”  The only answer I could give her was, “My dream is to have an interesting job, in an interesting company and to be involved in a project which will allow me to dream!”

During my Scholarship I met a number of passionate and interesting people and enjoyed a variety of useful experiences (internships, travels) which, step by step, have helped me to find my way and determine what I wanted to do.

I used the context of the REVOLVE project and the initiative of Mrs. Richard, my Teacher in Physics and Chemistry at the Lycée Condorcet, Paris when speaking with her final year students where I presented my scholarship, my experience and my research. It was really interesting for the students as they could relate to the different experiences of the various panel members.

I hope that my talk inspired the students and that they were touched by the concept of Space Engineering!

Post by Claire Benteyn, PhD Fellow


Feed Antennas

Being already in 2018 there is no doubt that satellite communications are an integral part of our life. Although not visible from earth, their importance can be met in a wide range of services. Just imagine the two most common facts: Using a positioning system to track yourself in an isolated place and using your smartphone to communicate with other people or have access to multimedia. Obviously, the satellites can provide these kind of services in an excellent way, whereas there is a great variety of further applications where their use is vital as well, such as weather prediction and space exploration to name a few.

Satellites are in principle big and complex structures, where many components are assembled together so that the satellite can be launched from the earth to the space. One of the most significant part of a satellite is the antennas. If we could compare a satellite with a human, the antennas are “the eyes and the ears”. You can easily understand that without the antennas, a satellite cannot communicate with nobody and after all has not a reason to exist!

Here at REVOLVE we are doing research around antennas for satellites as you may already know. Every one of us studies different aspects and technologies. In a very fundamental analysis, the antennas implemented and used on satellites can be categorized into two principal domains: the so called Focal Array Fed Reflectors and the Direct Radiating Antenna Arrays. In the first category belong the typical parabolic structures fed by the so called feed-antennas (usually horn antennas) which are more or less widely known, whereas in the second single antennas are formed in an array and they radiate themselves.

My subject of research concerns the feed antennas. These antennas are almost always the typical horn antennas, which are used many years now because of their great performance. Although they are described as feed antennas this might be a bit confusing or misleading as the same antennas could be used as direct radiating arrays without the presence of a reflector. In any case, my 3 year journey at REVOLVE will go through the different existing technologies around the feed antennas and we will try to find out how we could make them function better and in a more compact shape as the current solutions have a bulky profile.

At last, somebody might wonder…so what is it so important about it? There may be many things important that neither myself could even recognize, but as I mentioned earlier the satellites are big and complex structures so imagine how important would be if we could provide something smaller and lighter. Furthermore, think about that this “something” are the antennas which constitute a very basic and important part of a satellite and after all we are moving ahead to the 5G era and the next years a great increase in the multimedia usage and communication services is about to take place, so we need to confine with these rules.

Advanced Synthesis of Reflect-Arrays

It is very likely to be that if you think about a space antenna, the image that appears in your mind is a parabola that sends electromagnetic waves toward the Earth or the deep space. An antenna, as it appears, is a metallic structure that captures and/or transmits radio electromagnetic waves. Antennas come in all shapes and sizes from little ones that can be found on your roof to watch TV to really big ones that capture signals from satellites millions of miles away (figure 1). The antennas that space satellites uses are a special bowl shaped antenna that focuses signals at a single point called a parabolic antenna. The bowl shape is what allows the antennas to both capture and transmit electromagnetic waves.

via GIPHY Figure 1 New Horizon mission spacecraft, a courtesy of

But what if this concept of capturing and/or transmitting electromagnetic waves would be performed in a slightly different way? Keeping in mind that a parabolic or shaped antennas exploits the geometric features of the reflecting surface to create a narrow and symmetric antenna beam, we can imagine to exploit another concept to perform this signal directivity.

The concept of a Reflect-Array is based on the fact that we want create this narrow and symmetric beam by using flat reflector, or we can say, flat antennas. This is the key point of the Reflect-Array technology. So, does not matter which kind of signal or for which application, a spacecraft would be equipped by a flat antenna.   The simple geometric shape of this kind of antenna would allow to reduce the cost of manifacturing, would allow a more flexible allocation on the spacecraft, since it can be conceived foldable, it can be lighter (reduction of mass in Space satellite is very important) and, last but not the least, it can offer a very performing and smart technology for space application.


Figure 2: C-band Reflect-Array demonstrator, a courtesy of Thales Alenia Space France

Another milestone concept of Reflect-Array is that it is constituted by a flat panel that is printed with several metallic patches. Electromagnetic waves can be reflected in different way if they imping of different surfaces, in this case on different patches. The way the signal is reflected by every single patch will determine an ensemble of small signals that interact, they sum up or erase each other. The result is a directive narrow signal as would be produced by a traditional shaped antenna.

Figure 3: Deployment scheme of a faceted Reflect-Array, courtesy of Thales Alenia Space France.

Mechanically Reconfigurable Antennas

In October 2017 I began my PhD and every time I answer the question, “What do you do?”, the next question would be, “What is your subject?”

The first time I answered whilst quoting the e-mail describing the job, “My PhD is part of the REVOLVE project which is a European initiative dealing with the study of the Smart Reflector Surfaces with processing capability based on actuated flexible thin organic large area surfaces.”

The second question, ‘What is your subject?’ took me by surprise and led me to create my PhD title: ‘Mechanically Reconfigurable Antennas.’ At this moment I was very proud of myself as I had finally found a way to explain what I will do using a title that people can understand. I looked at the eyes of my interlocutor and I understood that what I had described was not very clear. Describing or explaining something is much more difficult than trying to find a title, even more when you already have read a lot of papers about the subject area and when you try to interest people. It is my purpose on the blog to try and do this so do not hesitate to comment or to ask questions – I am still learning!

The first step to clarify a subject is to know more about the general context.

What is the context of the ESR5 ?

The REVOLVE project is a European initiative aimed at developing new solutions for future satellite systems. It will aim to investigate new technologies that will make the satellites easier to build and cheaper thus gaining time and reducing costs which is very important for industries. Moreover, the growth of the technical improvement is very fast and it is important to adapt in order to be competitive in the market.

The second is to understand a subject, and it is important to know the meaning of each word used :’ Smart Reflector Surfaces with processing capability based on actuated flexible thin organic large area surfaces’.

What is a Smart Reflector Surfaces for antenna?

In this PhD, the ‘Smart Reflector Surfaces’ will be a reflectarray. What is a reflectarray ? It combines some features of reflectors and of array antennas. A reflector antenna is a device that reflects electromagnetic waves while the array antennas is composed of groups of radiating elements which are distributed and oriented in a specific configuration. I have described two interesting experiments around Smart Reflector Surfaces for Antenna below:-

Experiment 1:

Take one curved mirror and a flashlight. Turn off every light. Illuminate the curved mirror with the flashlight, you will see on the wall in front of the mirror a circular lighted zone : it is the same process for the reflector antenna. The light rays are replaced by the electromagnetic waves which are directed on a precise zone on the Earth (see below)…



Experiment 2:

Take four plane mirrors and a flashlight. Turn off every light. Gather all the mirrors together but give them different orientation. Illuminate all the mirrors simultaneously with the same flashlight, you will see on the wall in front of the mirrors a lighted zone : it is the same process for the array antenna. Same as before, the light rays are replaced by the electromagnetic waves which are directed on a precise zone on the Earth. Nevertheless, it is important to note that the impact of the given incidence of the miror is equivalent of the array radiating elements geometry.

In conclusion, the reflectarray combines the simplicity of the reflector antenna with the performances of the array type. In fact, the reflectarray is a planar reflecting surface with a lot of radiating elements.

What is the meaning of processing capabilities?

As it is presented before, the technologies and the market change continuously and it is important to have an overview of all the possible applications a system could manage. For an antenna it could be : radio applications, space tracking or communications.

Furthermore, the main goal of this subject is to be able to reconfigure the antenna. We could say that for one mission, for exemple a satellite place at 500km of altitude which as to cover France, the antenna has one fixed shape and the satellite will be design and product during approximately 10 to 15 years. In conclusion what we ask now will be in-orbit in 2028-2033, it is too long as regard of the needs growth.

The figure below presents one cell phone of the year 2003:




 What is TOLAE (Thin Organic Large Area Surface)?

It is an emerging technology and is the goal is to have a large area electronics that are thin, light weight, flexible and/or stretchable, suitable for large market sectors.

Why do we need TOLAE?

To reconfigure an antenna we could do it electromagnetically or mechanically. In my PhD we will try to do it with the second possibility in order to increase the fiability of the final system. If we take the hypothesis presented before : one shape of the antenna for one mission. So if we change the shape we change the mission and so the targeted zone on Earth, but it is quite more complicate.

To simplify the reflectarray is made of two layers separated by vacuum. On the upper layer you have the radiating elements which are illuminated by a feed (the flashlight). The electromagnetic waves will pass through this layer and be re-radiated by the second layer (the ground plane) in one direction.

Using the principle of the second experience presented before, if we modify the shape of the second layer, we will change the specification of the missions. To do it we could use some actuators which will push on this second layer at different zones and that is why we need a flexible surface.

In conclusion, the main purpose of my PhD is to find a mechanical way to change in-orbit the mission’s specifications which has to be lightweight, cheap and simple.










Reconfigurable Beamformers

What are beamformers good for? And why do they need to be reconfigurable when used on a satellite?

Once in orbit, the key task of every satellite is based on the transmission and reception of electromagnetic waves. These waves carry all the information that is necessary to provide for example a certain channel on your TV or to explore the Earth’s surface. Due to the spherical shape of our planet it is obvious that at a particular time, only certain parts of the Earth can be in contact with a satellite while other parts are out of reach. But that’s all right because many services are only needed in a certain area. In fact, it is often essential that a satellite reaches only users that are located within a specific region, for example to provide a TV channel that is only available in your country. But which part of the satellite takes care that information arrives only at relevant points on Earth?

Correct – it’s the beamformer! The beamformer is only one part of the satellite’s antenna system but as you’ll see, it packs quite a punch. We should have a look first on what would happen if a satellite was launched without beamformer. As shown on the left below (not to scale), the antenna of a satellite emits electromagnetic waves which spread as distance increases.


Since a satellite is very far away in space, only a smaller (and in this case random) portion of the transmitted waves will impinge somewhere on the Earth’s surface, while a major part will be lost. To avoid this, the satellite is equipped with a beamformer (below depicted as a crescent).


As shown in the figure, this allows us to direct or form the emission of waves so that as many as possible of them reach the Earth’s surface. But this is rather the very basic task of every satellite antenna. The beamformer itself makes sure that the transmitted information strikes the region on Earth where it is actually needed, that is within a certain footprint, such as a single country or a whole continent. In many cases it is also useful to have a beamformer that allows the satellite to communicate with two or more separate regions at the same time.


So far, so good – but there is an important point that we must not forget: everything goes round. More precisely, the Earth rotates around its axis and the satellite orbits around the Earth. This is no big deal for geosynchronous satellites which appear to be at a fixed point in the sky if you could spot them from ground. But to follow the Earth’s rotation, they need to be placed at a very large distance. This is not always unproblematic because the further a satellite is away from us, the longer it takes to transmit and receive information. A satellite at lower altitude, by contrast, is able to communicate much quicker with us but he does not remain at a fixed position relative to Earth. Here it gets tricky if we want to make sure that we don’t loose connection once the satellite has passed us. In fact, a stable connection is only possible if more than one satellite is used so that every time a satellite leaves our field of view, a following one on the same orbit takes over. It seems like things are getting costly at this point. Is the beamformer of any help here?

The answer is…yes, if it is reconfigurable! To make it more clear, “reconfigurable” means that the way the beamformer shapes and directs the emission of waves can be adjusted. This flexibility opens up a lot of possibilities and allows us to do fancy things with a beamformer. In the previously mentioned case with multiple satellites we can use the beamformer for example to track a target zone on Earth. In this way, a satellite can stay in connection with a certain point for a longer time during each orbital period. This has the great advantage that we get by with a lower number of satellites in space. But take a look at this video – it should give a bit more of insight into what is actually going here.

The reconfigurable beamformer helps us here every time the satellite orbits our planet, that means it works in a recurring manner and for the long term. But there are also sporadic scenarios where this flexibility is of great help. Imagine for example the Olympic games are just around the corner. In this case, reams of information need to be transmitted from and received within a relatively small area on Earth, but all that only for a couple of weeks. Satellites that are equipped with such beamformer can then be used to focus all capacity, for a certain amount of time, on the region where the event takes place. That’s all very well, but what is it that I am actually working on?

Well, obviously we are able to control a beamformer remotely from ground every time we want to reconfigure it. But resources are limited on a satellite and we can’t afford moving the whole bulky antenna system whenever we wish to sweep the satellite’s footprint on Earth. Instead, it would be much better if only a tiny part within the beamformer was adjustable – and this is what I am looking for. In fact, it might be even possible to do that without any mechanical movement at all, but more on that very soon.

Linked to a Satellite!

Imagine you are lost in one of the most remote place in Antartica or in the Amazonian jungle, it seems like all hope is gone and your life is about to reach an end… Except if you are properly linked to a satellite!


Figure 1 – Telephone linked to the satellite constellation Iridium manufactured by Thales Alenia Space

Then you can call anywhere on the earth and connect to anyone in a snap. The problem is to figure out how the satellite will know when and where to help you and that’s the moment my project comes into place. Louis described the ears of the satellite with mind-boggling antennas, I consider my work has more to do with the brain of the satellite: it must know in which region on earth it must focus its ears. To use specific words, my work is on satellite payload. But why adding a load on a satellite ? This payload is the brain of the satellite, it points the antenna and gives proper amount of power in the correct direction so you can for example communicate or surf the Internet. The payload shares these services with all the people who pays to use the satellite. This may seem easy but sometimes enabling a lot of people to use the satellite at the same time is a problem to pull one’s hair out. Just remember that time you wanted to send a text or make a call at New Year’s Eve. If the network is crowded you must find some way out, it is the same with satellite network so the focus of satellite’s resources must be on the busiest regions. On the contrary, steering the antenna towards Sahara desert would be quite pointless…

Moreover in the case you want to serve a busy area, interference between users becomes a serious problem you must take into account. If you want to have an idea of what interference is, imagine a meeting where everybody is speaking at the same time, the voice of each other would jam the conversation and it would result in a joyful cacophony. Exactly the same phenomena happens in some cases when either the satellite speaks to users on the ground or users on the ground to the satellite. Mitigating these effects is also part of my work.

To wrap it up, my work is to make satellites’ architectures smarter, more flexible to any situation that may occurs whether you are in Antartica at the brink of death or if you just want to wish a happy new year to your loved ones. The video presenting Thales Alenia Space constellation Iridium with worldwide coverage is below:



Deployable structures for antennas

So yes, what am I doing exactly? “Deployable structures for antennas” – what is it? And why does it have to be “deployable”?

When a telecommunication satellite is launched, it’s main goal is to talk with the Earth, to listen on one side, and to repeat the message on the other side. It works a bit like a phone in a way: it allows two people, two computers or two machines to discuss. But a satellite can be very, very far from the Earth, so how can he listen, or talk, to you? He needs really big ears, and a really big megaphone. Ok, the comparison stops there, because it’s not sound but radio waves that are used, and it doesn’t really have ears nor a mouth. But it does have big, sometimes very big antennas.

How big? you see the smallsatellite antenna dish on the roof antennas on the side or the roof of some building, pointing at the sky? Those are actually used to “listen” to TV satellites that broadcats all kind of channels. And they are probably about 50cm in diameter. Well, it is pretty common for satellite antennas to measure 2 or 3 m in diameter! And some are even much bigger: the largest antenna flying measures close to 20m in diameter – that’s a 6 floors building!

80sqvsgfkmEvftZuFcRJwQqiegCe-ORHEnWsmWyy8lcSo now that we have those big antennas (and I have only mentioned telecommunication, but they can also be used for earth or space observation, radars, etc…), how do we launch them? See, the problem is that you cannot put this 20m antenna in a rocket, it would not fit. The last stage of the rocket, where the satellite is, has a diameter of 4m for the biggest rockets. Because of that, even for a “small” 4m diameter antenna, there is only one solution: you have to fold it, and once up there, open it up. There is something really similar that is used really often here, on earth. It can be very small, fit in your bag, but when it rains it get big enough to keep you dry: that’s right, I’m building a giant umbrella, for a satellite.

Does it look like an umbrella? Hmm, not really, but the idea is there. How do you do it then? Well, that’s the whole point of my thesis! I wouldn’t spoil it all and tell you now, right? But as a trailer I can show you what Large Space Structures GmbH, a partner of the REVOLVE project, has been doing recently.

Banner image and video : courtesy of LSS GmbH.
Ariane 5: ESA-CNES-ARIANESPACE-Photo Optique Video CSG