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“Follow the water”
The Europa Clipper spacecraft inside the assembled testing chamber - photo courtesy of NASA
Dr Aline Amorim Graf of the Materials Physics group holds a prototype panel made for NASA’s Europa Clipper mission
Ahead of the launch of its Europa Clipper mission later this year, NASA’s Jet Propulsion Laboratory (JPL) is sharing a livestream from its Clean Room in Pasadena, California, where Clipper will be built and tested. Researchers from the University of Sussex Materials Physics group have a special reason to watch; technology developed in conjunction with Advanced Material Development Ltd at the University of Sussex enabled the design and construction of a bespoke testing chamber for the space craft’s high-gain antenna.
The Europa Clipper mission will fly close to Jupiter’s moon Europa and perform detailed measurements, using multiple tools – including radar. There is strong evidence of an ocean of liquid water beneath Europa’s icy crust and the high-gain antenna is capable of penetrating below the moon’s surface to detect reflections from the liquid under the ice; signals are then relayed to Earth from the space craft for interpretation, allowing scientists to estimate the depth of the liquid and thickness of the covering ice.
However, the antenna must first be tested on the ground, in a clean room which mimics the environment in space. Such a facility would typically include an anechoic chamber, designed to stop reflections or echoes of either sound or electromagnetic waves that might affect or distort the antenna’s readings. In response to this challenge the team collaborated in developing and supplying radar-absorbing material to create a moveable testing chamber, insulating the antenna from background and surrounding interference such that the antenna’s ability to collect and relay data could be isolated, evaluated and perfected.
The technology that the team shared with JPL is based upon its work developing inks and coatings from graphene, particularly for shielding against electromagnetic interference (EMI). Nanomaterials were integrated into foam panels which were then soaked in ink and encased in plastic to make them safe to use in a clean room environment.
Dr Matthew Large, PDRF with Materials Physics, explains: “We built prototype panels from scratch in our labs here at Sussex, experimenting with different materials to ensure that when assembled, the chamber would absorb energy from the Clipper’s antenna consistently across the entire surface. The panels needed to be rigid enough to support their own weight, but light and flexible enough to be easily configured and, if necessary, cut to shape.”
The panels also had to be sturdy enough to survive the journey to JPL at the California Institute of Technology in Pasadena. Over a thousand panels were built, with members of the research group travelling to the AMRC in Sheffield to manufacture the panels in a facility selected for its ability to handle such a large order.
Dr Aline Amorim Graf, PDRF with Materials Physics and joint project lead, says: “Each panel had to be examined and tested to ensure a uniform saturation of ink and that the final performance met the project targets. We took all the raw materials with us to Sheffield and built the panels there, one by one. It took us a solid week, producing 200 panels per day.”
The panels were packed in Sheffield, couriered to USA and assembled in the JPL Clean Room, aligned to a supporting plastic framework – so testing of the antenna could begin. The final assembled walls were almost 8 metres tall and 7 metres wide, making the chamber similar in size to an average UK semi-detached house.
The Europa Clipper mission will be launched on 10 October 2024 and will take almost two years to travel the 628.3 million km to its destination, where it will spend four years conducting observations, with the expectation that the first data will be collected from 2030.
Professor Alan Dalton, Materials Physics PI says: “We believe that this represents a unique application for our inks, which are something of a specialism for our group. The panels we built are lightweight, portable, easily assembled and effective. They are also relatively cheap to produce, with each panel costing just a few hundred pounds. We developed the technology here at Sussex working with our main partner and funder, Advanced Material Development and came up with this solution to JPL’s specification. It’s very exciting to see how it’s now being used to support projects that are, literally, out of this world.”
Further links: Watch the livestream from the NASA JPL Clean Room ‘Building Europa Clipper’
Read about the NASA Europa Clipper mission.