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Graham writes …  The launch window for this mission to visit Jupiter’s moon Europa opens in October, but the engineers at NASA’s Jet Propulsion Laboratory are currently troubleshooting a serious issue with the Europa Clipper spacecraft. The objective of the mission is principally to determine whether Europa is a suitable place for life to develop, and as such it is generating a fair degree of excitement amongst astrobiologists. Looking at Europa – a distant and cold, ice-covered world – it doesn’t look at all like an environment where life could flourish. However, in this case, appearances are deceptive. There is strong evidence that beneath the ice crust there is a warm water ocean, the heat being generated most likely by volcanic vents on Europa’s ocean bed.  Jupiter as seen from the icy surface of its moon Europa. Credit: Ron Miller (artist) and Getty Images The problem with the spacecraft lies with the transistor elements, which are essentially the building blocks of the micro-processors onboard. The Jupiter system, where Europa Clipper will operate, exposes the spacecraft to intense radiation similar to the Earth’s Van Allen radiation belts, but 50 times more intense. In order to survive this environment, the spacecraft’s electronics need to be ‘radiation-hardened’ to achieve its planned 4-year mission lifetime. However, the hardness rating for these elements turned out to be incorrect, and the transistors were found to fail before they should in laboratory tests. This poses a real headache for the engineers. There are currently two main avenues of investigation; firstly, the obvious route of replacing the transistors, and secondly to assess how long the existing integrated spacecraft could survive the radiation environment and whether it could achieve its mission in a shorter time scale. The second option would at least allow them to launch the currently integrated spacecraft in October, but with the prospect of a shorter mission at Jupiter. The first option however is also possible, but it would risk missing the 3-week launch window in October. There are however later launch opportunities, but not until 2025 and 2026.  An impression of a Europa fly-by of the Europa Clipper spacecraft. Credit: NASA. So, everything is very much ‘up in the air’ at the moment, while the engineers mull over the options. I will most likely write a post on the various aspects of this fascinating mission in October – when hopefully we will know better what’s going on. I hope to ‘see’ you then, and in the meantime please see my main blog post for August below (… on water on Mars). Thereafter, I hand over to my co-author John for the September blog! God bless all.
Graham Swinerd Southampton, UK August 2024
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Graham writes ... “When I consider your heavens, the work of your fingers, the moon and the stars, which you have set in place, …”: Psalm 8.  Credit: Unknown source. As we have commented before on this blog page, Mars has not always been the arid desert that we see today. The confirmation of this view from data acquired by orbiting, imaging spacecraft is overwhelming, with clear evidence of water erosion and features such as river deltas and lakes. See for example, my blog post in February 2021 (just click on that date in the blog archive list on the right-hand side of this page), concerning the immanent adventures of NASA’s Perseverance rover as it set out to explore what was once a Martian lake bed. The second post in March 2021 looks more generally at the question of life elsewhere in the Universe. Coming back to Mars however, we can ask 'where has all the water gone?'. The planet is small – about half the size of the Earth – and the consequence of this is that Mars’ gravity field was not strong enough to retain the atmosphere that it had more than 3 billion years ago when it was a ‘water world’. As the atmosphere slowly leaked away into space, the conditions were set for the surface water to evaporate rapidly (in geological terms). Recently, a groundbreaking discovery has added a new layer of intrigue to Mars – the presence of liquid water deep beneath its surface. This finding, made possible through the detailed analysis of seismic data from NASA’s Insight lander, marks a significant milestone in our understanding of Mars and its potential to support life. The Insight lander, which touched down on Mars in 2018, was equipped with a seismometer that recorded vibrations from Mars quakes over four years. By carefully analysing these seismic waves, scientists were able to detect the presence of liquid water reservoirs located approximately 10 to 20 kilometres below the Martian crust – a process that is often used here on planet Earth to detect oil or water deposits underground. This discovery is particularly significant because it provides the first direct evidence of water on Mars, beyond that previously identified frozen in Mars’ ice caps. The amount of water discovered is staggering – enough to uniformly cover the planet’s surface to a depth of more than a kilometre. There is speculation that this underground water was there in Mars’ early history when surface water was plentiful, and that its underground location sustained it as the surface was transformed into an arid landscape.  An impression of the Insight lander on the Martian surface, with seismometer deployed. Credit: NASA. So, why does all this matter? Well, as the astrobiologists will tell you (or any other biologist comes to that …), water is a crucial element for life as we know it. The presence of liquid water on Mars opens up new possibilities for the planet’s habitability. While the surface of Mars is a cold, arid desert, these underground reservoirs could potentially harbour microbial life. Moreover, any such underground life would likely to be quarantined from Earth-based life, so providing an uncontaminated environment to try to understand how life began (both on Mars and the Earth). It is also clearly a great resource for future missions with the objectives of exploring and possibly colonizing Mars - access to water would be vital for sustaining human life and supporting agricultural activities on the planet.  The assembly, integration and test of the Insight lander in a clean-room environment. Credit: NASA, Lockheed Martin Space.  The stowed configuration of the lander, about to be sealed into the entry capsule. The capsule entered the Martian atmosphere at about 5.5 km/sec. This was reduced to effectively zero in about 6.5 minutes, to achieve a successful soft landing. Credit: NASA, Lockheed Martin Space. However, before we get carried away with all this, it is obvious that accessing these deep reservoirs poses significant challenges. The water is buried deep within the Martian crust, making it difficult to reach with current know-how. Future missions will need to take with them advanced drilling technology to tap into these resources. Additionally, the harsh conditions on Mars, including a global average temperature of -50 degrees Celsius, a harsh surface radiation environment (Mars has no protective magnetosphere) and surface dust that is potentially toxic to humans, present further challenges that need to be overcome!
If you would like to hear more on this, click here to hear the ‘5 Questions on’ podcast: ‘Huge reservoirs of water deep inside Mars’ (7 minutes), with the BBC’s science correspondent Victoria Gill talking with Michael Daventry. Graham Swinerd Southampton, UK August 2024 |
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