Goodbye, Cassini

In April, Cassini began its Grand Finale, a set of daring dives between Saturn’s rings and the planet itself. Come September 15, it will plunge into Saturn’s atmosphere, where it will keep transmitting data until its antenna can no longer keep locked onto Earth, over a billion kilometres away.

Cassini has done so much science: it showed us Titan in more detail than ever before, revealing a world strangely familiar and yet strangely alien. It taught us so much more about the structure of Saturn’s rings. Even as it goes to break up in the atmosphere, it will keep making measurements of Saturn’s gravity and magnetic fields and further exploring the rings. Cassini launched just under twenty years ago – there has been a steady stream of scientific discoveries and, since April, media flutters about how this is very definitely the very end for Cassini.

I think its impact on science outreach and on my generation hasn’t been talked about quite as much. That’s a shame, because I think it’s been incredibly important.

Saturn is one of the most beautiful planets in the Solar System, with its extensive ring system. It also has 53 confirmed moons, with another 9 provisional moons and hundreds of tiny moonlets, which make up the rings. (Cassini was launched in October 1997, when I was one year old. At the time, we thought it had eighteen moons, and that seemed a lot.) When I was growing up, it was my absolute favourite planet because of its rings, but I didn’t know much else about it. Before Cassini, our most recent observations had come from Voyager flybys in November 1980 and August 1981. I’m sure these must have been a revelation – my uncle proudly showed me his copies of National Geographic magazine with the Voyager photos of Saturn and its moons – but no dedicated probes had been sent to study the planet. When I was a child, we knew even less about Titan than we did about Saturn; it was a hazy, foggy ball about the size of Mercury and some people thought it might potentially be habitable.

I was in single digits at the time and extremely excited about the prospect of somewhere else in the Solar System being able to support life, so I was elated when I found out that Cassini-Huygens was not just going to Saturn, my favourite planet ever, but that Huygens was going to land on Titan and send back pictures! It was my first real exposure to any kind of space mission and one of my most vivid memories is my parents letting me stay up late to watch a documentary about Cassini.

I still remember the first data being sent back from Huygens. At the time, it barely registered that Huygens transmitted data for 90 minutes after touchdown – I was just so excited to see the first images.

Everything I thought I knew about Titan had changed. This was a freezing moon, with a completely different atmosphere and climate. Maybe it couldn’t support humans, but I still felt so privileged to be alive while we learned so many new things about Saturn’s largest natural satellite.

As it turns out, nine-year-olds are not usually particularly well-informed about space missions, and I was very surprised when the Cassini mission kept going after Huygens had touched down. I admit that I didn’t always keep up with the mission, especially as I got older and school took priority over being awed by space – but having scientific discoveries unfold in front of my eyes definitely kept me interested in physics and almost certainly influenced my decision to study it at a high level.

Today, outreach is so very different from when I was growing up; I really like what NASA and ESA have done with their social media, even if it’s sometimes confusing. You can keep up with space missions in real time in a way that I wasn’t aware of when I was a child. While I’m worried that the media presence (social and otherwise) of actual scientific organisations is being drowned out by crackpots who think that NASA has a child sex slave colony on Mars (yes, really) or that Nibiru is going to kill us all, I feel like space agencies have become much more transparent. Citizen science is now much bigger. Scientists run blogs where they discuss their findings. We have newer, specialist sites like Nautilus and Quanta which cater to people who don’t necessarily have a scientific background, but who are ill-served by science communication which assumes that they know nothing. Even open science notebooks, initiatives where scientists publish all their data online, are taking off.

There is now so much more out there than there used to be. I don’t think that’s always a good thing; I think it can be confusing and overwhelming, and I think that right now the forces of science and reason are being overpowered by the forces of fearmongering and lies. At the same time, I feel humbled by just how much information is accessible now. I hope it helps the next generation to fall in love with space the same way I did.

So what do Cassini and its Grand Finale have to do with all this? Cassini-Huygens was arguably a defining mission for people of my generation; the missions reached Saturn and Titan just as we were hitting our preteen years and better able to appreciate their goals. We grew up with Cassini. I grew up with Cassini, and I suppose that’s why I feel so emotional about it plunging into Saturn. Cassini was the first space mission I really paid attention to. Cassini was the space mission I stayed up for. Cassini was the space mission I followed on and off through my childhood and adolescence. Cassini means a lot to me because I associate it with growing up and with being inspired to do science.

Thanks to Cassini and Huygens, we now know so much more about Saturn, its rings and its moons. We’ve learned so much in such a short space of time, and we’ll keep learning even after Cassini breaks up in Saturn’s atmosphere. But Cassini also managed to get people who had never opened a physics textbook emotionally invested. Complete strangers cared – and still care – about a hunk of metal transmitting data from around a ball of gas. Maybe Curiosity has a funnier social media presence. Maybe the Voyager spacecraft have gone further. Cassini is not unique in getting people to engage with the mission or in getting people to have feelings about it – but it was a lot of people’s first serious space mission and the one that laid the groundwork for appreciation of future work. As such, it will always have a special place in my heart.

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