With ice caps melting and sea levels rising, there has never been a greater need to understand the role oceans play in life on Earth. Whilst seeking answers deep underwater, space agencies are also on a mission to learn vital lessons from the solar system - Mars and Venus, for example, both had oceans until their protective magnetic fields degraded, triggering runaway greenhouse effects, temperature rises and evaporation.
Sound familiar?
To advance our knowledge the European Space Agency (ESA) has launched ‘JUICE’, the £1.4 billion Jupiter Icy Moons Explorer, to uncover the secrets of the giant gas planet and three of its largest moons which are believed to be ocean-bearing: Ganymede, Europa and Callisto. Because of the potential significance of JUICE’s findings, its first post-launch message raised cheers around the world - none louder than at our facility in Dundee, Scotland, where some of JUICE’s critical communications components were designed and manufactured. Smiths Interconnect is no stranger to the thrills and technical demands of space programmes, having provided products to many deep-space missions including ExoMars, the Parker Solar Probe, the reusable Orion space capsule and the DART asteroid redirection project.
But JUICE demanded a new level of performance and resilience.
Firstly: it has a complex, 6,000kg payload.
In addition to the ‘usual’ Explorer equipment and fuel, JUICE needs 85sqm of solar panels to harvest available sunlight that is some 25-times weaker than on Earth. It also has a 2.5m antenna to send data 500 million miles homeward, and a powerful suite of scientific instruments ranging from sub-millimeter to ultraviolet to facilitate such studies as the composition of the moons’ ocean layers, the geophysical traits of their surfaces, and how Ganymede's intrinsic magnetic field interacts with the Jovian magnetosphere.
Secondly: the eight-year outbound journey is anything but straightforward – or straight.
After suffering the brutal vibrations of the launch and rocket-release, and the mechanical shock of the unfurling of the vast solar array, JUICE will battle thermal swings from 250C near Venus to -230C at Jupiter, sizzling radiation, strong magnetic fields and the ever-present hazard of bullet-like micro-meteorites. With minimal fuel aboard, JUICE will seek gravity-assist from flybys of the Earth-Moon system, Venus and then Earth (twice) to slingshot to Jupiter. Although a well-proven means of reaching the outer solar system, it is risky as the gas bursts used to execute course corrections could, over time, corrode sensitive communications components.
Thirdly: that’s just the beginning.
After arriving, JUICE will commence a four-year research mission involving a tour of Jupiter and a record 35 icy moon flybys culminating with an orbit of Ganymede – all in little-known atmospheres, and whilst transmitting petabytes of data to Earth.
Critical control unit
Essential to JUICE’s ‘wellbeing’ are subsystems that continually monitor its temperature, position and status. They are supported by the Telemetry, Tracking and Command (TT&C) unit. This operates throughout the mission to maintain the vital link between JUICE and Earth’s deep-space communication network, relying on an on-board, high-power X-Band transmitter. To mitigate the risk of this mission-critical transmitter failing, the TT&C designers wanted to incorporate a ferrite isolator to act like a one-way valve, smoothing the standing waves from the RF power source and antenna and absorbing any unwanted RF power reflecting from the antenna.
ESA’s payload contractors selected Smiths Interconnect’s WR112 waveguide isolator for this critical role. They were reassured by its qualified performance and flight heritage - and impressed by our superior quality controls, expertise and customer support, the foundation of which is our world-class Test and Qualification Lab in Dundee and a project design and manufacturing team with a combined 250 years of deep-space experience.
Alan McNeill, Product Line Manager, Ferrite and Waveguide, Smiths Interconnect, said, ‘Our knowledge and commitment enables us to add value to every stage, including risk mitigation interventions and a sounding board for new ideas.’
Our waveguides passive components are optimised to operate over broad assigned frequency bands. Product screening and qualification are conducted inhouse using our comprehensive suite of test facilities including thermal shock and cycling, sine/random vibration, mechanical shock and, where appropriate, CW and peak power under TVAC, critical power and seeded multipaction. Summary and qualification data reports are available to prospective customers.
Pressure point
Because the isolator is classed as a potential ’single point failure’, the team went beyond the extra mile to prove its reliability.
This started with material selection. Only certain, space-approved, low/no outgassing materials could be used and in combinations designed to avoid negative interactions such as corrosion or degradation. Plus they had to be lightweight yet mechanically highly robust.
Once manufactured, the isolator was rigorously tested including:
- For vibration and mechanical shock simulating the stresses of launch and solar sail deployment
- To demonstrate performance under the worst-case combination of RF overpower (220W) and temperature extremes
- To demonstrate the ability to survive fault-scenarios and perform as specified afterward
- all whilst operating in a Thermal Vacuum Chamber (TVAC).
Throughout, they adhered to the highest production standards - including interplanetary cleansing measures designed to prevent Earthly biologics being accidentally transported into space- and fastidiously recorded their steps in documentation that will be available for review for up to 20 years.
In all, it was a galactic effort. No surprise, then, at the site’s pride in knowing JUICE’s first transmission was successfully made and received. Nor that the team has saved JUICE’s July 2031 date of arrival at Jupiter, after which Smiths Interconnect’s isolator will be helping to relay data that is highly relevant to Earth’s immediate future.
You, too, can track the journey of JUICE (and Smiths Interconnect’s isolator) live at ESA - Where is JUICE now?