Searching for E.T.

Julian Fagge introduces our latest Engineering Explained on the Europa Clipper mission

‘Is there life beyond Earth?’  It’s an age-old question, but one we’ve yet been able to answer definitively. In 2030, maybe, that will change.

That’s when NASA’s recent mission – the Europa Clipper, which launched in 2024 – will begin its detailed study of the fourth largest of Jupiter’s 95 moons.

Europa has excited the scientific community because, like Earth, it is an ocean world, with a vast, energised body of saltwater locked under its icy surface that could harbour extraterrestrial microbes.

What’s more, it experiences continuous ‘impact gardening’ – with meteor showers churning the top 30cm of its surface. This not only enriches Europa’s internal ocean ‘cocktail’ with fresh ingredients but means that the biosignatures (scientific evidence of life) of any displaced ‘sea aliens’ might be present in the newer craters or mounds above them.

Europa Clipper is tasked with investigating this tantalising possibility - using nine highly innovative systems to conduct non-contact studies of Europa’s water and ice, geology, chemistry and energy patterns - as well as identifying a landing site for a potential future astrobiology mission.

Its findings could rewrite our understanding of the cosmos - but only if it first completes its tour and then manages to send its research data home. Vital to both is the performance – and stamina - of the on-board Telemetry, Tracking and Command (TT&C) unit, which will maintain the probe’s link with Earth.

At its heart is a radio frequency (RF) panel comprising two transmission systems. The first, operating through the relatively low-frequency (8GHz) X-band, is active throughout the mission and will support two-way communications between Clipper and the established deep-space network of satellites. This enables the spacecraft to send continuous short reports on its condition and location, and Earth-based controllers to make repairs or adjust course if required.

However, the research phase will require a lot more power to enable transmission of what’s hoped will be a vast body of data and detailed images of Europa. So, the second system operates in the much higher frequency (30GHz) Ka-band which can carry a lot more information - and much faster.  It will be dormant for the six-year outbound journey and will only ‘wake up’ for the subsequent four-year research programme. With the very real possibility that this sensitive comms equipment will fail to ‘wake up’- or indeed last for the whole of the research phase, it’s been designed in duplicate to provide a back-up.

Given what’s riding on them, the survival of both systems is mission critical. That can’t be taken for granted on what’s one of the most gruelling space journeys planned to date. First there are the brutal vibrations of the launch and rocket-release, then the galactic mechanical shock of the unfurling of the probe’s solar ‘wings’ - the longest NASA has ever used (14m each) and necessary for powering the longest mission attempted so far from the sun’s energy.

There will be thermal swings from +250C to -230C, possible asteroid strikes and, with minimal fuel aboard, the stress of the gravity assists from Mars and Earth that will ‘slingshot’ the Clipper into the Jovian system will be significant.

And that’s just getting there. The research travel plan involves orbiting Jupiter while using multiple gravity assists from Europa and fellow moons Ganymede and Callisto to conduct 49 close fly-bys along successive segments of Europa.

Throughout, any course corrections will be executed via gas bursts which, over the marathon ten-year tour, could corrode the sensitive RF components.  And, although the route complexity has been designed to minimise exposure to Jovian system’s sizzling radiation and powerful magnetic forcefields, and the RF panel is well-shielded, the exceptionally aggressive environment will eventually take its toll.

To optimise the panel’s chance of survival, its designers at Johns Hopkins Applied Physics Laboratory incorporated Smiths Interconnect’s isolators into both RF systems – to protect the super-sensitive equipment from any power surges or signal interference.

Additionally, our innovative coupler will enable a seamless switch between the two Ka-band systems should one fail.

All of which means that our tiny components could be the ultimate difference between mission success or failure.

It’s an astronomical responsibility, but Smiths is no stranger to deep-space missions having supported the likes of ExoMars, the Parker Solar Probe and the DART asteroid redirection project. All this experience was channelled into ensuring that the Europa-bound components stay the course.

We used our patented low/no outgassing materials in innovative designs to avoid corrosion or degradation, and our shielding expertise will give the components immunity against Jupiter’s exceptionally high electromagnetic and radiation levels.

We also undertook rigorous space-condition testing at our Dundee facility to prove the components’ ability to perform through the vibration and mechanical shock of launch and solar sail deployment, the worst-case combination of power surges and temperature extremes as well as a full range of potential fault scenarios.

Throughout, we adhered to strict measures to reduce the chance of carrying human germs into space – such as wearing full-body protective clothing, conducting trials in sealed rooms and sterilising parts in special ultrasonic tanks that vibrate them to ensure the cleanser reaches every nook and cranny.

John Hopkins then undertook the specialist radiation and magnetic testing before providing NASA with the assembled control unit.

This small-but-mighty system has now helped Europa Clipper launch successfully - and every month is taking it a little closer to (perhaps) finally answering that defining question: ‘Is there anybody out there?’