Index number 50 /Tribune

Designing for the void: the ongoing challenge of space mechanisms

Lionel Gaillard, Head of European Space Agency’s Mechanisms Section (ESA)

Lionel Gaillard, Head of European Space Agency’s Mechanisms Section (ESA)

Lionel Gaillard, Head of European Space Agency’s Mechanisms Section (ESA)

Space mechanisms – two deceptively simple words; what does it mean to place them together?

Separately, the word ‘space’ is a source of inspiration for many of us. For centuries we have been looking up to the sky with awe, attempting to find some answers to essential questions of our origins and existence: Where have we come from? Where are we going to? Who are we?

‘Mechanisms’, on the other hand, can seem a much more mundane term, related to what are often considered basic devices, surrounding us in our everyday existence, from DVD players to computer hard disks to data servers and so on. Most of the time such terrestrial mechanisms have been developed to make our lives easier, and are constantly improving in terms of performance and flexibility, seemingly with no limit to what can be achieved.

But put the two words together and things become much more complicated. Designing mechanisms for space is a hugely demanding matter. It might be thought at first that space would be a benign realm to operate in, but this is forgetting the violent launch phase of a mission, during which any spacecraft gets mechanically ‘tortured’. Then, once within the space environment, which seems so calm and enchanting from Earth, the satellite and its mechanisms are then subjected to many other kinds of stress, such as wide extremes of temperature, radiation exposure and perpetual hard vacuum – all without any easy possibility of repair.

The contrast between the enticing appearance of space from here and the reality is huge – it is true to say there is in fact scarcely any place more hostile. It is certainly not a welcoming locale for the technologies we have optimised over long centuries on the ground, targeting mainly everyday uses. This is also what makes space mechanisms so interesting to develop. Just as in art, where it is often the constraints that are imposed upon artists or they impose upon themselves that leads to the highest level of creativity and artistic steps forward. Developing mechanisms for space can therefore also be understand as an art, within which many limitations are faced due to physics alone, such as the inability to use the same materials, equivalent lubricants or the standard combinations of the two that would be utilised on the ground. In addition –as in art– the masterpieces being achieved may not be easily understood by the neophyte, and some basic knowledge is needed in order to fully appreciate their complexity and capabilities. All the details count, and have their own weight when it comes to making space mechanisms more complete and reliable.

Technologies for space exploration have only been in existence for a little longer than half a century. There is still a long road ahead, full of unknowns needing to be understood and tackled in order to permit humankind to continue our quest for knowledge, and the acquisition of new services from space to help in our day-to-day life: internet and multimedia broadcasting; satellite navigation; weather forecasting; climate change monitoring and so on. Examples of the kind of challenging mechanisms being developed for such purposes include scanning mechanisms for Earth observation missions, antenna and thruster deployment and pointing devices for telecommunication missions.

For the even more challenging missions to come, novel mechanisms will certainly also be needed, and in most cases their role will be mission enabling. New breakthroughs in this domain will be essential, for which the space artists who are within us will blossom further.


Lionel Gaillard during ESMATS 2015 an event coordinated by SENER along with ESA.

Copyright SENER 2018