focus | earth and space
ASU KEDtalk: Journey to a metal world
Congratulations to Lindy Elkins-Tanton, director of ASU's School of Earth and Space Exploration, for winning a NASA Discovery mission to the asteroid Psyche! Hear Elkins-Tanton talk about the mission and how she launched a career in space exploration in our ASU KEDtalk.
Lindy Elkins-Tanton, director of the School of Earth and Space Exploration at Arizona State University: Hello, everyone. I’m Lindy Elkins-Tanton, and I am the director of the School of Earth and Space Exploration at Arizona State University.
My son, Turner, and I were standing on a causeway next to an estuary in coastal Florida, as the sun was rising. We were peering through binoculars at the launch pad at Cape Canaveral, where they were about to launch the MAVEN mission to Mars. Even from where we were a number of miles away, the launch was absolutely breathtaking. The hair stood up on the back of my neck. Rocket engines ignited with the roar of a thousand racecars. Then Turner and I turned to each other and said almost at the same time, I really hope the next launch we come to is ours!
Because I’d come to this amazing moment in my life where I was proposing a mission to NASA. Had I imagined that I would do this when I was a student? No, I had never imagined that.
Unlike most of the scientists working on the MAVEN launch, I had not gone straight through in science. After my master’s, I worked in business for eight years, I worked as a management consultant and I did financial forecasting for U.S. News and World Report and I wrote business plans for young high-tech ventures looking for investment. And then I taught math at a liberal arts college for two years before I went back for my PhD. I started my PhD at age 31 as a single parent. I had been investigating some different fields of human endeavor, trying to figure out which one had the most meaning for me. And in the end academia has given me both the opportunity to ask the biggest questions and also the schedule flexibility to stay deeply connected to my family.
And so now I’m a planetary scientist, trying to understand how rocky planets like Earth get their structure, how they’re built, and also what makes them habitable. And the best way to understand Earth is in the context of the other rocky planets in our solar system: Mercury, Venus and Mars. And that requires space missions.
So why do we explore space? First of all, because, exploration is a human imperative. It’s built into us. Everything from Magellan to Captain Janeway. And exploration aligns humankind looking outward, instead of allowing us to be distracted with the irritations that lie between us both as people and as nations. And for me personally, I’m really interested in the asteroids and the small bodies that lie among the familiar planets of our solar system because they’re the leftovers of planetary formation early in the solar system. By studying them, we actually travel back in time to study the processes that built the planets. And then we can take that information with us when we investigate planets around other starts, exoplanets.
But not every institution can do this kind of big science, can try to answer this kind of big science question. It requires a dedication to interdisciplinary work and it requires patience with the long timelines that big questions require. And it also requires a positive, collaborative, teamwork kind of culture. And a lot of institutions don’t have that but we have that here at ASU.
Making progress in science requires new observations. Every time we send a mission into space we get surprises. The solar system surprises us and gives us things we don’t anticipate every time we send a mission out there. Think of the New Horizons mission to Pluto and the amazingly detailed images we have of Pluto’s surface for the first time ever. A lot of us feared that Pluto would be, well, a yawn, a dirty ice ball. But these images showed us that there are smooth areas on the surface, mountains and features that indicate Pluto was a warm active body much longer than we anticipated.
And so in the summer of 2012 I found myself at the Jet Propulsion Laboratory, planning a space mission. Some people there had read a paper I had written and wanted to design a space mission to test it. Who could resist? We were in a room called Left Field. The room is lined with whiteboards and shelves of Legos and construction sets and pipe cleaners and Post-Its and markers. It’s a playground for creativity. In fact, when we walked in, we found some Post-Its notes that were left by the previous mission planning session. It’s a very effective room.
I was there with about ten of my favorite science friends, planning a space mission to help us understand how rocky planets get their structure. Rocky planets like Earth, Venus, Mars, and Mercury have an iron nickel metal cores and rocky exteriors. How and when did they get this structure?
Planets are born as gas and dust orbiting the infant Sun, and in just 1/100th of the age of our solar system, they build up into the familiar planets we see. These differentiated bodies, with ice nickel metal in the middle and rock on the outside.
We decided that the best place to go to investigate this progress is the asteroid called Psyche. Psyche is a small world that seems to be made entirely of iron-nickel metal. Imagine that. Humankind has visited rocky planets and moons, and icy planets and moons, and planets and moons made of gas, but we have never seen a metal planet. We do not know what this would look like. Psyche is out between Mars and Jupiter. Psyche has never been visited or had a picture taken that was more than a point of light, so its appearance remains a mystery. This mission would be true exploration, true discovery!
What might Psyche look like? Does it have sulfur lava flows on its surface? Is it covered with towering fault scarps created when the solidifying metal shrank and the exterior of the body broke into faults? Is its surface a glittering combination of iron metal and green crystals, as some iron meteorites are? And what does an impact crater in metal look like? Could its edges or its metal splashes have frozen in the cold of space before they fell back onto the surface?
We think Psyche is the metal core of a small planet that was destroyed in the high-energy, high-speed first 1/100th of the age of our solar system. By visiting Psyche we can literally visit a planetary core, the only way that humankind ever can. There is no other body like it in the solar system, and we will never get to our own planets’ cores. The Earth’s core is at 2,800 kilometers depth, and the deepest humans have ever managed to drill is just 12 km. The pressure at the core is over 3 million times surface air pressure. And the temperature is about 5,000C, which is ~10,000F. We are never going to go there.
Psyche lets us visit inner space by visiting outer space!
About 40 of us teamed up and with Jet Propulsion Laboratory and Space Systems Loral, we wrote the proposal to fly this mission to Psyche. And the Psyche mission has just been chosen as a finalist in this round of selections! We hope to fly to Psyche and orbit it for a year, learning about planetary interiors and how rocky planets are formed.
Science must make progress in increments, but we hope to make them the largest increments we can, on our way to understanding that biggest of all science questions, are we alone in the universe? So please cross your fingers and toes that Psyche will be selected for flight, when the decision is made in the fall of 2016! We hope to be standing on that causeway in Florida, watching our spacecraft get launched to Psyche.
Just like science, people make progress in increments, as well. It’s hard to know which skills you have picked up along the way that, in the end, make it possible to fulfill a vision. And every vision starts with a moment of inspiration. Sometimes it’s an image that is just a point of light in space. Sometimes it is as simple as a pile of Legos or Post-Its notes. Like the ones we found in the Left Field Room when we went in to plan our own mission.
Thank you very much.