One foggy morning in early May 2018, a twenty-storey-tall bottle of explosives lit up the sky over Vandenberg Air Force Base, California. On it rode the hopes and dreams of some of the world’s most gifted scientists and technicians – and those of one rather less distinguished PhD student on the other side of the world.
It was the beginning of an incredible adventure whose latest chapter was written on November 26 this year – six and a half months and half a billion kilometres later – when a 350-kilo robot named InSight landed on the surface of Mars.
InSight joins a venerable armada of robotic pioneers studying the Red Planet today. Over fifty years, we’ve photographed it, prodded it, tracked over its dusty dunes – hell, we’ve even sniffed it. No other mission has ever done what InSight plans to do: to take our neighbour’s temperature, and listen to its heartbeat. It’s a straight-up physical, and the diagnosis has been long-awaited. We want to know if Mars still stirs: if the planet, so to speak, is alive.
I’m (allegedly) a planetary geophysicist and let me tell you, the InSight mission is my marmalade jam. All day everyday I throw numbers at computers to probe the sorts of questions this plucky robot might resolve tomorrow: why some planets are young and animated, while others grind to a horrible halt. Hovering over all our inquiries, nourishing enough in themselves, is the ultimate question – where did we come from, and are we alone in the universe.
But let’s set aside the big-picture stuff and get into the nuts and bolts.
Build Me a Spacecraft, Step One: Being Smarter Than Me
After that big firecracker, the Atlas V, burnt out on the morning of May 5, it deployed stage two, the Centaur rocket, packed with enough oomph to get out of Earth orbit and into a new, highly elongated sun-centric orbit that just so happens to intercept Planet Mars this time of year. Having done its bit, the Centaur fizzled out and went adrift like Elon Musk’s car, leaving only the payload, naked to space.
The InSight lander is a mobile geophysics laboratory. Packed up for the surprisingly short journey to Mars, it weighed almost 700kg, including a heat-resistant shell for deflecting space rocks and blazing through the Martian atmosphere, and an 80-kilo ‘drive section’ to keep everything headed in the right direction. On arrival, InSight shed most of that baggage to reach a lean fighting weight of 358 kilograms, about the mass of a small camel: just enough to pack in half a kilowatt of solar panels, a big ol’ antenna, a bunch of selfie sticks, and three science experiments that could forever change the way we look at Mars.
Build Me a Spacecraft, Step Two: Analogies Not Included
InSight’s science tools are all aimed at figuring out the makeup and consistency of Mars’ insides. They are all common tools we’ve used to answer the same questions about Earth, except these ones had to survive being strapped to a skyscraper-sized stick of dynamite and dropped on rocks from the greatest possible height. So they’re a little bit pricier.
First, there’s the SEIS. It’s a ‘seismometer’, aka a wobbly needle that measures earthquakes – or ‘marsquakes’, as NASA dorkily calls them. Because vibrations travel through different materials in different ways, listening to these little rumblings – taking the ‘pulse’ of the planet – is a good way to figure out roughly how Mars is put together. (It also does a pretty good job as a microphone, gifting us this unforgettable recording of Martian wind). Seismometery on Earth has proven our world has a solid, rocky outer layer around a molten iron core with a big solid metal ball right in the middle. SEIS will provide a similar peek into Mars.
Next off the rank is HP3 – the heat probe. This cute little instrument is “like a mole with a sensitive tail” according to the cheerful folks at NASA. What they mean is it’s a drill with a thermometer in it. By taking the temperature at different depths – and applying some first-year calculus – we can figure out how fast Mars is cooling into space. Bonus: if we introduce a little heat of our own, we can also figure out how conductive the rocks are, which is the sort of thing that interests people like me.
Finally, there’s RISE. This set of super-sensitive antennae are designed to pick up radio broadcasts all the way from Earth and bounce them back the way they came. By measuring the Doppler shift on these signals, we can measure how much Mars wobbles as it spins. Because wobbling has a lot to do with balance, RISE could tell us both where the heavy bits of Mars are as well as which parts, if any, are molten. It’s like measuring what a figure-skater had for dinner last night by watching how well they twirl. RISE does that for a whole planet, a billion kilometres away, to an accuracy of ten centimetres.
I told you these people were smart.
Build Me a Spacecraft, Step Three: Or, What’s a Robot For?
Now you know what InSight does, you’re probably wondering what it’s for. The short answer: we want to know when Mars stopped moving, and why.
Earth is animated. That’s why we like it. Just as the atmosphere and oceans continually roll over to shed the sun’s heat, the rocky parts of our world do the same, transporting Earth’s internal heat out of the inside and into the great outside – also known as ‘the rest of the universe’. This slow movement of rock keeps the surface of our planet fresh and dynamic, providing – amongst many other things – a delightfully breathable atmosphere for everybody and low-paying jobs for people like me.
Exactly unlike the surface of a human, the surface of a planet boasts its youth by being wrinkly and free of pockmarks. So anyone with a backyard telescope can affirm that Mars is no spring chicken. Its surface is ancient: its riverbeds and mountains and coastlines and lava flows merely fading relics of a long-lost, bluer age. What happened to trigger this catastrophic change? Why is there only one Earth in our neighbourhood? More provocative still: what if there’s only one Earth in the cosmos?
The InSight mission won’t answer those questions outright. But it will take a bigger bite out of them than we’ve had in a long time. It will do this for less than one tenth of what Americans spent on handbags last year.
Epic Robots of Carbon and Steel
We have grown used to wonders – so Ronald Reagan said, morosely, in the aftermath of the Challenger disaster. That tragic event proved to be a turning point, precipitating the slow decline of human space travel. Today NASA lacks even the capacity to provision the human crew of the International Space Station – itself once mooted as a gas station for interplanetary adventure, now a relic of a more optimistic age.
Forbidden from hurling our mortality against the ultimate frontier, our yearning for horizons took a new form. Veins became wires; muscles, motors; eyes, cameras; mouths, transceivers. Spirit; Opportunity; Curiosity; Insight: these are the heroes of the modern space age. Through them we vicariously live out dreams so innocent they almost feel camp in our cynical times.
If you have a little spare time – and I’m certain that you do – head over to NASA’s website and look at the new world through InSight’s eyes. They belong to you.