Sanjay Vijendran, ESA engineer, talks about the project that collects solar energy from Space and transmits it to Earth

DiFabio Meneghella

Ott 25, 2022

We met Sanjay Vijendran, engineer, team leader of the Mars Exploration Strategy and coordinator of the Future Mars Studies (MarsX Team) of ESA (European Space Agency). Vijendran is also the head of ESA’s proposal called SOLARIS. The latter has the task of studying and testing the feasibility of the Space-Based Solar Power (SBSP) project, or the innovative idea of producing electricity in Space, through solar panels installed on a team of giant satellites and, subsequently, converting microwave energy and send it to Earth, in the direction of the terrestrial receiving stations.

What is the mission or program that has given you the most emotions in your career, and that has taught you something important in life?

Before I joined ESA, I was privileged to work as a member of the Science Team on the NASA Phoenix Mars mission between 2006 and 2008, where I was responsible for developing and testing a set of microscopes that was launched to Mars in August 2007 and landed on Mars in May 2008. On board the lander were also some small pieces of hardware that I had built with my own hands and delivered to NASA while working as a Research Fellow in Imperial College in London. It was an amazing feeling of accomplishment to know that something I had made was now sitting on the surface of the Red Planet! I also had the opportunity to operate these microscopes for five months while they were on the surface of Mars which was a thrilling experience working with a large team of dedicated scientists and engineers from NASA and around the world at our science operations centre in Tucson, Arizona, undertaking experiments on Mars that no one had done before and taking the highest resolution images of the dust and dirt on Mars that had ever been done. It is this experience that provided me with the skills and background that allowed be to successfully obtain a position at ESA in 2010 to contribute to designing new missions and preparing new technologies for ESA’s future Mars programme, an area that I’m still working in today.

What the Phoenix Mars mission experience thought me is that with motivation. hard-work and a shared goal, we as people, working together, can accomplish amazing things that contribute to the world and that we can all be proud of. And that space exploration is a great challenge that is extremely rewarding to those involved directly in it, but also to those who are following from further away, like friends and family and the general public.

What is the biggest challenge to overcome (or what are the most important problems to solve), to realize the dream of the SOLARIS program?

SOLARIS is ESA’s latest proposed initiative to more deeply assess the feasibility of Space-based Solar Power (SBSP) as a source of clean energy for Earth to contribute to decarbonizing our societies and mitigating global warming. The biggest challenges we have are to rapidly perform technical studies and technology development activities to show whether we can achieve very demanding performances for solar power generation, conversion of electricity to microwaves, accurate and efficient wireless power transmission from space to Earth and finally, the ability to assemble, robotically, very large structures in orbit. All of these areas need to be advanced substantially during the next three years of the SOLARIS initiative, if SBSP is to be confirmed by 2025 to be both technically and economically viable to be implemented at full-scale by 2035-2040. In addition to that, we need to understand better safety issues surrounding the use of low-intensity microwaves for beaming power to receivers on the ground as well as regulatory issues that may need to be overcome to allow SBSP to be used internationally. Any decision to go-ahead, or not, with a full development programme for SBSP would be expected to be taken only once the SOLARIS activities are completed in 2025 and a clearer picture of the feasibility of SBSP for contributing to Net Zero is obtained.

How many satellites would it take to collect solar energy and convert it into microwaves? And what should be the dimensions of these satellites?

The most common approach that has been studied recently is based on using a number of individual, very large satellites placed in Geostationary Orbit, about 36000km above the equator, that can provide about 1-2 GW of continuous power into the grid, in a similar way as a nuclear power station. Even though sunlight is much more intense in space that on the ground, it is still limited to about 1.4kW per square meter only. Therefore, to collect many GWs of power on a satellite, very large collecting areas are still needed; something in the order of a few km2. Such GW-scale solar power stations in orbit would each be many thousands of tonnes in mass and perhaps 2 km in size. In order to provide a significant (~10%) fraction of Europe’s electricity needs in 2050, something like 25-50 of such satellites would need to be deployed by that time. Alternative approaches have also been suggested, where a larger number of smaller satellites operating in lower orbits could be used to provide a similar service of 24/7 clean energy from space. However, even in this case, such satellites would still be extremely large compared to anything in orbit today.

ESA’s SOLARIS program.
Credit: European Space Agency (ESA)

How much electricity do you think can be produced with this method?

If a first GW-scale satellite was achieved by 2035-2040 in Europe, perhaps 10% of Europe’s electricity needs could be satisfied by 2050 through SBSP, if the system could be scaled up rapidly. In the longer term, there is potential for this to be further increased through building many more satellites. It is not clear yet where the limit might be for how much of the world’s energy could come from SBSP; certainly there is plenty of energy available in space and enough room to put even thousands of satellites into geostationary orbit around the Earth.

To have a pollution-free world by 2050, are nuclear fusion, the energy produced by solar panels and the SOLARIS program enough?

Nuclear fusion and SBSP could in principle provide all the world’s power needs in the far future, but this is very unlikely to be achieved by 2050. There is much work to be done still to answer this question with any certainty.

Regarding the “Mars Sample Return” mission, which will bring the first Martian samples to Earth. What will be the role of the European Space Agency in this mission? And why is it so important to bring the Martian samples to Earth, which the Perseverance rover is collecting?

ESA is an enabling partner to NASA in the Mars Sample Return ‘Campaign’ to return samples to Earth from Mars for the first time in the early 2030’s. ESA’s main role in the mission is to contribute the Earth Return Orbiter, which is the spacecraft that will collect the samples from Mars orbit (after it has been launched into orbit by a NASA rocket called the Mars Ascent System), and return them safely to the Earth. ESA will also contribute the Sample Transfer Arm, which is a 2m-long robotic arm that will be part of the NASA Sample Retrieval Lander mission, and will transfer the sample tubes from the Perseverance rover into the Mars Ascent System.

Mars Sample Return mission animation.
Credits: Animation credit: NASA/JPL-Caltech, ESA, NASA/GSFC and NASA/GRC. Technical assistance: James Tralie, NASA Goddard. Music credit: Axel Coon and Ralf Goebel of Universal Production Music

READ ALSO –> Fran Bagenal, NASA astrophysicist, talks about her missions in the Solar System

The many past missions to Mars have tremendously improved our understanding about the planet’s history and evolution as well as its potential for harbouring signs of past or present life. However, due to the challenge and cost of sending robotic spacecraft to operate around and on the surface of Mars, we are still quite limited by the type and quality of the scientific instrumentation that we can send to Mars to perform further studies of the conditions on the planet. Bringing samples back to Earth would allow us to study the samples in unprecented detail with the best available instrumentation that we can produce here on Earth now but also into the future when new analysis techniques may be invented and used. This has the potential to increase substantially our knowledge of how Mars formed, how it evolved and to what extent it was conducive to the emergence and evolution of life. The knowledge gained from analysing Martian samples on Earth would also help us better prepare to eventually send humans to Mars in the future in a safe way.

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