As part of a successful partnership between the Graphene Flagship and the European Space Agency, studies investigating graphene for two different space-related uses have demonstrated exceptionally useful outcomes. Depending upon these outcomes, the Flagship are constantly striving to create graphene devices for applications in space.
Graphene as we know has a lot of opportunities. One of them, recognised early on, is space applications, and this is the first time that graphene has been tested in space-like applications, worldwide.
Professor Andrea Ferrari, University of Cambridge, Science and Technology Officer of the Graphene Flagship.
Graphene’s exceptional thermal characteristics are propitious for enhancing the performance of loop heat pipes, thermal management systems applied in satellite and aerospace applications. Owing to its strong interaction with light and being light weight, graphene can also be used in space propulsion. The Graphene Flagship investigated both the applications in experiments conducted recently in November and December 2017.
The most essential element of the loop heat pipe is the metallic wick in which heat is conveyed from a hot object into a fluid that cools the system. Two differing types of graphene were investigated in a partnership between the Microgravity Research Centre, Université libre de Bruxelles, Belgium; the Cambridge Graphene Centre, University of Cambridge, United Kingdom; the Institute for Organic Synthesis and Photoreactivity and the Institute for Microelectronics and Microsystems, both at the National Research Council of Italy (CNR), Italy; and industry partner Leonardo Spa, Italy, a global leader in aerospace, operating in space systems and high-tech instrument manufacturing and in the management of launch and in-orbit services and satellite services.
We are aiming at an increased lifetime and an improved autonomy of the satellites and space probes. By adding graphene, we will have a more reliable loop heat pipe, capable to operate autonomously in space
Dr Marco Molina, Chief Technical Officer of Leonardo’s space line of business.
Following exceptional outcomes in the lab investigations, the wicks for the loop heat pipes were investigated in two ESA parabolic flight campaigns in November and December. “We have good tests done on earth in the lab, and now of course because the applications will be in satellites, we needed to see how the wicks perform in low gravity conditions and also in hypergravity conditions, to simulate a satellite launch,” stated Professor Ferrari.
It was amazing, the feeling is incredible and its extremely interesting to do experiments in these kinds of conditions but also to enjoy the free-floating zone. The whole experience was really great.
Vanja Miskovic, a student at Université libre de Bruxelles who conducted the experiment in microgravity during a parabolic flight carried out by Novespace.
The outcomes of the parabolic flight validate the enhancements to the wick, and the Flagship will constantly strive to enhance the graphene-based heat pipes into a commercial product.
I think this is a very nice example of how the Flagship is working. Bringing together three academic partners and one big industry with a clearly defined goal for an application at the moment, we have tested the principle and the core of the device. The next step will be to optimise the whole device, and have a full heat pipe that can go in a satellite.
Vincenzo Palermo (CNR), Vice-Director of the Graphene Flagship.
Investigating the space-propulsion capability of graphene, a group of PhD students from Delft Technical University (TU Delft), Netherlands, took part in ESA’s Drop Your Thesis! campaign, which provides students with the opportunity to conduct an experiment in microgravity at the ZARM Drop Tower in Bremen, Germany. In order to develop extreme microgravity conditions, nearly one-millionth of the gravitational force of Earth, a capsule including the experimental setup is hurled up and down the 146-m tower, resulting in 9.3 seconds of weightlessness. The TU Delft Space Institute, Netherlands, also supported the GrapheneX project.
The group named GrapheneX designed and constructed an experiment to investigate the use of graphene in solar sails, by using free-floating graphene membranes offered by Flagship partner Graphenea. The concept was to investigate the way the graphene membranes would act under lasers’ radiation pressure. The experiment was totally run five times from November 13 to 17, 2017.
“Our experiment is like a complex ‘clockwork’ where every component has to go off seamlessly at the right time,” stated Rocco Gaudenzi, one of the members of the GrapheneX group. “It does not often happen that you have to build up such a clockwork from scratch, and you cannot test it in real conditions but during the launch itself.”
The group strived hard to render the experiment a success. “Despite the initial technical difficulties, we managed to quickly figure out what was going on, fix the issues and get back on track. We are very happy with the results of the experiment as we observed laser-induced motion of a graphene light sail, and most importantly we had a great experience!” stated Davide Stefani, one of the GrapheneX members.
Santiago J. Cartamil-Bueno, leader of the GrapheneX team, stated that the experience and also the outcomes were very significant to the group. “The most important lesson is that always something will happen, and you need to be ready to adapt or to change,” he stated. “I think at the end of the day, it’s about the experience; you just need to create new challenges and learn from them, and be ready to grab more experience and go to the next level.”
Although the GrapheneX experiment has now been completed, the group is contemplating further investigations as part of an innovative and progressive research project, to continue the study of the impact of radiation pressure on graphene light sails.
The outcomes of the two projects clearly indicate the versatile nature of graphene and are the initial step toward enlarging the boundaries of graphene studies.