Paris Sud students experience weightlessness

In October 2018, three students from Université Paris-Sud were chosen to take part in the 55th microgravity flight campaign organised by the National Centre for Space Studies (CNES).

On Earth, the only way of testing conditions close to weightlessness over a period of several tens of seconds is to board a plane and ask the pilot to pitch the aircraft at 50 degrees, before switching off the throttle: the plane continues its trajectory then follows a parabolic curve. No longer subject only to the force of gravity, it is in free fall. All the people and objects inside fall at the same speed, a weightlessness similar to that which occurs in the International Space Station.

The company, Novespace, a subsidiary of CNES, has an A310 “zero-G” (zero gravity) plane with specifically well-trained pilots. It offers scientists a series of free falls during which it is possible to perform experiments in weightlessness. Each year, CNES selects 3 student projects for their scientific quality and offers them the opportunity to participate in one of the “parabolic” flights. The “Phenomenology of the Stability of a Magnetic Fluid Sample in Weightlessness” (PSELA) project of Université Paris-Sud’s students is one of the winners!

An experimental device for ferrofluids

The team behind this project is made up of three Master’s graduates in fundamental physics from Orsay: Thibault Vieu, Clément Walter and Luc Barast. In 2016, they were part of the university’s first team to take part in the French Physicists’ Tournament, a competition that requires students to apply a research approach to a series of physics problems. One of the problems focused on the behaviour of a drop of ferrofluid (magnetic fluid) when exposed to a magnetic field produced by a magnet. Ferrofluids exhibit various morphological instabilities when exposed to a magnetic field and are the subject of current research in many laboratories.

Intrigued by the subject, the three students continued to work on this topic in their free time. Through both a theoretical and experimental approach, they conducted a comprehensive scientific study on the subject. Furthermore, their results have been judged to be of the level of researchers, confirmed by experts in the field, who recommended publication in the prestigious Journal of Fluid Mechanics, which they were placed on the front cover of.

A flight on board Air Zero G

In November 2017, they decided to continue their study of ferrofluids at the same time as their M2 Master’s courses. They made a case to apply for CNES’s zero G flight: their project aimed to study the effect of weightlessness on the shape of magnetic drops. Assisted by the technical team from the physics Master’s and the Laboratory of Solid-State Physics (Université Paris-Sud/CNRS), Thibault, Clément and Luc professionalised their experimental device, developed a physics experiment worthy of a research laboratory and demonstrated its compliance with the very strict safety standards drawn up by the Novespace engineers.

The field test took place on 4 October. After having spent two weeks at Mérignac (Bordeaux’s airport) to finalise the experiment’s set-up, the students boarded the A310 and conducted their experiments for 30 parabolas of weightlessness from 20 to 22 seconds each. Despite some unforeseen events, the experiments proceeded perfectly and the results are promising! It only remains for the data obtained to be analysed at the same time as the beginning of their careers: Luc Barast is beginning a thesis in chemical and physical oceanography at Université de Bretagne Occidentale, Clément Walter is working on artificial intelligence applied to cosmology research in and Thibault Vieu is starting a thesis in theoretical astrophysics at Université Paris-Diderot. Entirely unrelated to ferrofluids… but when a question goes around your mind… and the weightlessness will remain an exceptional and unforgettable experience!