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Ice on Mars!

It’s been a long time since I wrote about anything research-related. Well, that’s because research is hard! The science is happening slowly but surely. In the meantime, something vaguely related to my research popped up on the NASA website: ice on Mars!

Many people have heard about water on Mars. Recently, liquid water has been in the news because of the “Recurring Slope Linea,” or streaks of wet sand observed by spacecraft orbiting the planet. These suggest that there is liquid water (laced with some kind of antifreeze, like salts) flowing on modern Mars. But we also know that Mars has had much more water on its surface: enough, in fact, to carve massive “valley networks” early in Mars’ history. The valley networks, an example of which is shown below, are still an area of debate in the scientific community. How did they form? Did Mars once have rainfall? Did groundwater seep to the surface, coalescing into channels protected by a thick layer of ice?

Mars Valley network

A valley network on Mars, showing that liquid water once flowed in abundance on (or near) the surface. This image is about 200 kilometers across.

Whether or not liquid water flows on Mars today, we do know that the planet has plenty of ice – both water ice and “dry ice,” or frozen CO2. Yes, it gets so cold on Mars that CO2 snow falls! Mars has two polar ice caps, both of which can be seen from Earth with the aid of a telescope. In the summer, Mars’ polar caps are predominantly water ice. In winter, CO2 snowfall blankets the surface.

One of my fellow graduate students mapped an area around the south polar cap, called the Dorsa Argentea formation, and found many signs not just of ancient glaciers, but of their melting. This is important, because glaciers on Mars today are “cold-based.” That is, even the very bottom of the glacier is well below freezing, and the ice is frozen to the rock below. On Earth, most glaciers are “wet-based” and their base is at the melting point of ice (0 degrees Celsius). The major exception to this is Antarctica, where planetary scientists often go to explore a Mars-like environment.

Though there are competing hypotheses for why glacial melting could have occurred on Mars, the presence of liquid – a lot of it, based on the observed glacial landforms –  suggests a long-lived environment in which nascent Martian life could have survived. The type of life that might have survived under these conditions is an interesting subject in itself; check out “tardigrades” (a.k.a. water bears)!

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Could this little guy, known as a tardigrade, live on Mars?

Climate therefore becomes an overarching theme of ice on Mars. How did the ice form? Did it melt? Where did it go? What does this mean for the climate on Mars, and whether the planet could have supported life?

We use ice to answer similar questions on Earth. Ice cores, drilled from glaciers and ice sheets around the world, contain records of the climate in which each layer of ice formed. Cores are expensive and difficult to obtain, however, and represent only one point in a massive ice sheet. To track these climate-induced layers throughout the ice sheet, researchers sometimes use ice-penetrating radar. An airplane flies over the ice sheet in a straight line, sending out radar pulses and collecting the returns as it goes. The waves bounce off of layers in the ice, with some layers reflecting more strongly than others. These strong reflections, which can be tied to individual layers in an ice core, can be traced for many miles within the ice!

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The NASA IceBridge aircraft, ready to collect radar data over Earth’s ice sheets. (photo: NASA)

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Diagram of radar mapping of the Greenland Ice Sheet, showing how layers identified in an ice core can be traced for many miles using radar. (image: WordlessTech.com)

In this way, the combination of ice cores and radar data allow us to explore the records of Earth’s climate locked away in glaciers and ice sheets.

Recently, planetary scientists have traced similar layers in Mars’ polar caps using radar from the Mars Reconnaissance Orbiter (MRO) spacecraft. Unfortunately, we don’t have ice cores (yet!) to calibrate these radar reflections with, but the data can be used to draw conclusions about major features of the ice caps. For instance, the north polar cap appears to be divided into two sections. The upper layers in the ice, above what seems to be a major erosional surface, seem to have accumulated rapidly and regularly compared to the ice below.

The period of erosion at the base of the upper layers reflects a time when the climate at Mars’ north pole was warmer than it is today. Planetary scientists believe this could have occurred when Mars’ polar tilt, called “obliquity,” increased.

Mars obliquity

Obliquity, or axial tilt, of a planet. Mars’ obliquity is thought to vary from 0-60 degrees!

At periods of “high obliquity,” when Mars’ north pole was tilted us much as 60 degrees from vertical, the poles become much warmer. This causes ice to move away from the poles and shift to lower latitudes – i.e., a period of erosion of the polar ice! When the obliquity lowers, moving the poles back toward vertical, ice shifts back to the poles. This idea is consistent with the ice layering seen by MRO. Thus, scientists are exploring Mars’ climate history with a spacecraft!

MRO ice layers

Layering in Mars’ polar ice as observed by the Mars Reconnaissance Orbiter (MRO).

Now we just need some ice cores to figure out what all of the layering in Mars’ polar ice means in terms of dust content, chemistry, and snow texture. For the record: I have volunteered for that field work.

EarthKAM!

I recently visited Christine Mendonca’s class at Vartan Gregorian Elementary School to talk about my favorite subject: SPACE! After learning about the history of human space flight, the students learned about Sally Ride EarthKAM – a digital camera, mounted in the window of the International Space Station, which allows students to photograph the Earth from space by submitting photo requests that are transmitted to the Station. The students at Vartan brainstormed areas of the Earth they were curious to see from space. Today, I visited the students again to showcase their results!

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2016 App Submitted

Last-minute tips on your application to #BeAnAstronaut

The moment is finally here. After months of obsessing over our applications to “#BeAnAstronaut,” we will finally be released from worry by the closing of the announcement! Rumor has it that over 8,000 people have already applied to be a member of the NASA Astronaut Class of 2017. If NASA selects 8 Astronaut Candidates (like last time) then we need to show off what makes us 1 in 1,000+. How does someone make the cut between “Highly Qualified” and “Better luck next time”? Since we still have a day or so to fiddle with our resumes, here are a few tips for folks like me who just can’t stop wondering if their application could use a last, little bit of polish.

DISCLAIMER: I am neither an expert nor a member of the Astronaut Selection Board; this is my first time applying, and at least one astronaut applied fifteen times before being selected. Over the years, however, my friends at NASA and I have had many conversations with folks related to astronaut selection. This is a compilation of the advice garnered in these many conversations – which I am passing along to help my fellow astronaut hopefuls reach for the stars! (Yes, I’m cheesy, too.)

The Number One Question any reviewer asks: Would I want to go to space with this person? Astronauts spend days in small capsules with their crewmates. The Space Station, though it has the volume of a 3-bedroom home, is still a relatively small, confined space isolated from the rest of humanity. Evaluating whether an applicant would fare well in these circumstances – whether they’d get along with their crew, be productive, stay calm under stress, etc. – is understandably a key consideration in the selection of astronauts.

Answering that question via the current application system requires you to be a bit of a resume Jedi. If you’re reading this you probably already know that the application itself is technically quite simple, which is a big change from the astronaut applications of old. There’s no personal statement, no cover letter, no “why I want to be an astronaut” section. It is, simply, your resume in the standard USA Jobs format. In this case, though, you’re applying for a highly unique job (understatement of the century) and it’s important to keep yourself from being confined to the “resume box.” Astronauts need a broad skillset, and some of the important skills – like how good you are at fixing things – may be hard to communicate via a traditional resume. As astronaut Cady Coleman told me, “If you think it’s important [to answering the questions below], find a place to highlight it,” even if you have to be creative with your resume’s content.

In addition to the “big question” above, here are some specific questions a potential reviewer might ask as they look over your application:

  1. Does this person have “operational” experience? Do they have experience working in isolation?
  2. How well does their work experience relate to being an astronaut?
  3. Can this person adapt to new situations and environments? Space is a new environment for most people. (Understatement of the century #2.)
  4. Is this person handy? Can they fix things and follow directions? As a former ISS flight controller, I know from experience that astronauts spend a lot of time fixing things – including the space toilet. They also have to follow procedures to correctly run research experiments, so following directions well is key!
  5. Can this person learn new languages?
  6. Is this person a team player? As Duane Ross said in his interview with Popular Science, “Everything we do at JSC and the other centers is a team effort, whether a big team or as small as a flight crew.”
  7. Do they have the ability to push themselves physically and mentally?
  8. Would this person be a good representative of NASA?

You’re off to a good start if your application addresses these questions. I hope that sharing this compiled advice helps you put your best foot forward and, perhaps, end up on a spaceship someday. Good luck!

Now, off to proofread my application one more time…

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In addition to personal communications, this post also draws from two sources:

[1] Hadhazy, A. “Popular Science Q&A: How NASA Selected the 2013 Class of Astronauts” Popular Science. 31 Jan. 2013

[2] Anderson, C. C. (2015). The Ordinary Spaceman: From Boyhood Dreams to Astronaut. U of Nebraska Press.

 

Women eXploring Space: Eryn Beisner, Spacewalk Controller

Have you ever wondered what it’s like to walk in space? Eryn Beisner knows better than most Earth-bound astronaut hopefuls what it’s like to put on the big white suit and climb out of the airlock. She teaches astronauts how to walk in space – and maybe, someday, she’ll get to take a zero-gravity jaunt, too!

…mankind’s role in the cosmos is here to stay and there’s no going back, only forward.” – Eryn Beisner

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Eryn Beisner, EVA Flight Controller (photo credit: NASA)

What is your role in space exploration?

I work on the ExtraVehicular Activity (EVA) Flight Control Team at the Johnson Space Center. Simply put, we train astronauts how to spacewalk and watch over them during an EVA from the Mission Control Center. We are the experts on the space station airlock, spacesuits, and the tools and systems that support EVA.

Fun Fact: The first EVA was performed by Russian cosmonaut Alexei Leonov in 1965. Since then, more than 200 people have walked in space!

How did you get to where you are? Did you always know this is what you wanted to do, or has it been a winding path?

It’s been a little of both. I’ve known since I was 8 years old that I wanted to work for NASA. Like most children at one point or another, I wanted to be an astronaut when I grew up. I still do and am actively pursuing that goal. Since you can’t get hired right out of school as a professional astronaut, I had to find something else to do in the meantime but I didn’t know what that could be. I was fortunate enough to be hired at JSC [Johnson Space Center] only a few months after I graduated college. [It] Being my first job in the industry and honestly, not knowing any better, I was going to take whatever I could get and work from there. That was in 2008 and I held two different positions in various engineering groups before I found my way to the EVA Flight Control Team. They were all good jobs and great for life experience, but I can honestly say I LOVE my current job. It’s quite literally the next best thing to being an astronaut.  Because we train astronauts, we frequently get to do the same training they do in order to make us better instructors and flight controllers. This means I’ve gotten to wear the spacesuit myself and take it for a run at the Neutral Buoyancy Lab (NBL), where we can simulate the microgravity effects of space. That was the highlight of my career thus far!

Fun Fact: The Neutral Buoyancy Lab is a 6 million-gallon pool near Johnson Space Center, holding an entire mockup of the International Space Station. Astronauts (and their instructors) are able to make themselves “neutrally buoyant” – that is, they neither sink nor float in the water – to simulate the zero gravity of space.

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Eryn suited up in a training version of the suit astronauts wear when conducting spacewalks.

Was there a certain person or event that inspired you to pursue a job at NASA?

Absolutely: my parents. We lived in Florida, not far from Cape Canaveral, when I was young child and they made a point to take my sister and I to the shuttle launches. Living that close to Kennedy Space Center we also made trips to the space exhibits. My parents instilled in me the excitement [of] space exploration and the thirst for curiosity for knowledge. They always supported me when I told them I wanted to be an astronaut and never once suggested I wasn’t good enough or that it was not something girls did. When it came time to look at colleges and chose a field of study, they suggested I pick engineering since NASA is well known for hiring engineers. When I found myself struggling in school, they were there to remind me of my dreams and encourage me to keep pushing. I owe a lot of where I am today to them and their unfaltering faith in me.

What has been the most rewarding aspect of your job(s) at NASA? What was most surprising?

The most rewarding aspects of my job is actually talking to people outside of NASA. I love visiting classrooms or chatting with strangers. I always get lots of questions because most people are very curious and excited about NASA. I get a giddy thrill engaging them in conversation and making them feel comfortable enough to ask me their most embarrassing question (usually “how do astronauts use the bathroom in space?”). My favorite moment is when a student asks me a question phrased in such a way that they think they already know the answer is a negative one. When I can tell them “Absolutely you can do it too!” or “What you’ve heard is not true!” and see that look of disbelief (and, daresay hope?), in their eyes. That’s the most rewarding feeling in the world. I truly hope I’ve made a difference in at least one person and helped them on their journey just as I’ve been helped along mine.

You’ve been in a spacesuit, underwater at the NBL. What was it like? Were you nervous? Scared? Excited? What did you do while underwater?

It was amazing, difficult, exhausting, painful, and exhilarating all rolled up together and I can’t wait to do it again! What an eye opening experience. I have newfound appreciation for what our astronauts go through in EVAs. The suit, even when fitted correctly, is very tight and can make you feel a little claustrophobic. You have to learn to move with it and not fight it when it fights you. The neutral buoyancy sensation in the water is fantastic and very much how I imagined it would be to be weightless. I was excited for the opportunity (my inner child was beside herself!) and nervous I would make terrible mistakes in front of the family and friends who came to watch me. We did a basic training run; the same introduction course we teach new astronauts. That involved skills like learning how to get one from point to another using your hands and safety tethers and how to successfully operate the commonly used tools to accomplish basic tasks.  Between the pressurized suit and the dynamics of moving in a weightless environment, everything you thought you knew kind of gets thrown out the window. It’s quite literally like learning how to walk again!

Eryn Astronaut 2

Eryn floating in the NBL, learning about the tasks astronauts do while walking in space. (Photo credit: NASA)

What kind of training got you ready for your “EVA” in the NBL?

My crew mate and I were given training on what we would be doing in the water, how to use the tools, safety protocols, and communication procedures. Also you need to be somewhat physically fit to operate the suit (hence why you’ll never see a fat astronaut!). So we hit the gym together regularly and worked on our aerobic endurance and strength. Because the suit is pressurized you have to fight against that pressure just to move. It’s like a constant arm wrestling contest any time you want to use your hands. So we did a lot of strength training in the months leading up to it and even then we were pretty tired by the end of our run. I noticed my hands were becoming clumsy when using the tools that required dexterity.

What is your advice for young people interested in someday having a job like yours?

There are going to be many times when people, yourself included, make you feel like you’re not good enough to do something this amazing. As if you have to be born a rocket scientist and anything less will lead to certain disaster. They won’t take you seriously when you tell them your goals and they’ll say discouraging thing like “That’s going to be so difficult. Why would you want to do that when you can do this instead?” To me those kinds of words always held a terrible underlying message: I think you’re going to fail. If you’re not careful you’ll find yourself believing it too. I’m certainly guilty of this. Quite frankly they are stupid, and they are wrong. I was reading an article about how people succeed and found this quote that I love and try to live by every time I start doubting myself. What a difference it’s made:

“You have to do the hard things in life. The things that no one else is doing. The things that scare you. The things that make you wonder how much longer you can hold on. Those are the things that define you. Those are the things that make the difference between living a life of mediocrity or outrageous success.”

The Apollo 11 moon landings defined space exploration for an entire generation of NASA employees. What mission or event do you think defines our generation of space explorers?

Ooh good question! I don’t know if it was or will be any one event. I grew up in the golden years of the shuttle program, which certainly impacted me. Then we have our International Space Station which is still going strong and making headlines almost every month. I think the Mars Curiosity Rover was another noteworthy event in which the whole world stopped for a moment and marveled at its significance. Personally I’d love to see a serious plan to get back to the Moon and establish a permanent lunar base.  I think that would solidify in the public’s mind that mankind’s role in the cosmos is here to stay and there’s no going back, only forward.

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The Great Instron Migration

The last few months have seen an almost unbelievable brightening in the light at the end of my PhD tunnel. Why? WE MOVED A MACHINE.

Yep. And you thought I was going to explain some insanely cool data I’d collected.

The triumph this month was relocating our Instron apparatus (which I highlighted in a recent post) to our new and improved Ice Lab. It’s something I’ve relentlessly coordinated (= was an interminable squeaky wheel to the people with the means and power to actually make this happen) over the last few years, and at times it seemed like the Instron would remain in purgatory across the street. First, we needed a place to put it. Then a lab space opened up, but we had to wait almost a year for the outgoing professor to take all of his equipment off to his new job (to be fair to him, though, he did let me use his lab equipment while it was still around).  The room needed a paint job, deep cleaning, and a new power outlet to accept the machine. Finally, at the beginning of my fourth year at Brown, the Instron began its journey.

In other words, instant activation of Mother Hen Mode occurred as the means of accomplishing my PhD research rose into the air, balancing on a 4×4 on a forklift.

First motion of the Instron!

First motion of the Instron!

What surprised – and scared – me was that the forklift/4×4 combo was lifting the machine by its crosshead (the big, tan bar at the top). Nobody had discussed the fact that the clamps holding that crosshead onto the machine, which were now supporting the entire weight of the machine, were meant to resist only the force of the machine itself pushing on a test specimen. Would they now hold up the entire 1,200 lbs of very expensive apparatus? I didn’t know, nobody had checked in advance, and the legs of the Instron were gently swaying with every turn of the forklift. It was too late now! I closed my eyes, then turned away to find something to distract me while the forklift driver expertly navigated a maze of equipment between our machine and the exit.

I let out a huge sigh of relief when those legs once again met the ground outside. Thank you, Instron, for designing good clamps!

From there, a few “simple” steps got the Instron across the street and into our nice, new lab.

Step 1: Tip the machine on its side.

Timmmmberrrrr!

Step 2: Drive it onto a truck.

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Step 3: Drive it from the truck onto the loading dock at GeoChem.

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The conversation here went like this:

Rigger: “Are you sure those loading dock plates can support the weight of the forklift?”

Bill (guy in the photo): “Yeah, they’re 100 lbs of steel apiece.”

Forklift starts driving…

Bill: “Stop! Stop! The plates are bending!”

Fortunately, we were able to move the Instron onto a dolly and roll it into the loading bay without the forklift!

Step 4: Fit the Instron into…

a) the elevator

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b) a tiny doorway into the lab.

20150921_100535     20150921_100651Fortunately, we tested this procedure in advance with an incredibly high-fidelity INSTRON SIMULATOR.

Instron Simulator

The extreme high-fidelity Instron simulator. Yes, I got to spend a day doing crafts! These are skills I learned while working at NASA.

At long last, the Instron is in the Ice Lab.

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Now I can get started with the last phase of my research! You’ll be the first to know when that incredibly cool data comes out.

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THEO: Designing a Spacecraft to Explore An Icy World

This is a post nearly a year in the making!

Last summer I had the incredible opportunity to participate in NASA’s Planetary Science Summer School, which teams early-career scientists (a.k.a. current and recent grad students) with the Jet Propulsion Laboratory’s Team X to design a planetary exploration mission. In other words: we picked a place in the solar system and designed a spacecraft to go there! Two days ago, our mission concept study was published in the journal Advances in Space Research.

How do you design a mission to explore another world? For our group, it started with the help of Team X. What is Team X? Well… basically, it’s what happens when you lock 20 scientists and 20 engineers together in a room and tell them they can only leave when they have a viable plan for a space mission. Also known as: spacecraft design heaven!

Designing a space mission is a bit of a “chicken-or-egg” problem. The science motivates the mission, often guided by the Planetary Science Decadal Survey (which is basically the scientific community’s prioritized wish list for all things space). Reality sets in, however, once engineering gets involved – “sorry, team, but there’s just no way to fly a spacecraft with 700 instruments, powered by solar panels the 3 times size of the Empire State Building, into orbit around Saturn… for less than 10 dollars.” The two groups must compromise to achieve the most science possible within the bounds of engineering reality. The engineers design to meet the scientific objectives, which adapt to engineering capabilities, which evolve to meet the science objectives… and so on.

There are two options for completing this process: 1) continually go back and forth between the scientists and the engineers – the “serial” version, where each round of science or engineering discussion follows a report from the other team – or 2) put the scientists and engineers in a room together and let them make tradeoffs in real-time – the “parallel” process, in which both teams work together, simultaneously.

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Team X scientists and engineers hashing out design trades to design a planetary exploration mission.

Team X has made an art of the latter. Given the requirements for the mission and armed with years of NASA and JPL expertise in building spacecraft, this group of people hashes out the design of a mission with both science and engineering combined. Together, this group of people has designed over 1,000 planetary exploration missions (if only they’d all gotten funded!) for various customers, including NASA. They are the experts of “concurrent design and engineering.”

The JPL Planetary Science Summer School is a miniature version of the full Team X mission design process. To capitalize on a single week at JPL with the Team X experts, my teammates and I spent 10 weeks preparing via multi-hour teleconferences and a truly prodigious number of Google docs.

Step 1 in this process: decide where you want to go! We settled on Enceladus, moon of Saturn. This little moon, once thought to be geologically dead, has turned out to be full of surprises. Images returned from the Voyager spacecraft as they passed by Saturn in the 1980’s showed that Enceladus had a very bright, young surface… meaning that something (a geologic process!) was “freshening up” that surface! The Cassini spacecraft (which is still operating at Saturn today) next flew by Enceladus and observed plumes of water vapor and ice crystals spewing from the tiny moon’s south polar region. Aha! A possible source of the young surface.

Enceladus Plumes

Plumes of water vapor and ice crystals erupting from Enceladus’s south polar region.

Subsequent Cassini flybys have improved our knowledge of the plumes and their sources. We now believe that they are escaping from a global ocean beneath Enceladus’s icy crust! Could this ocean support life? It’s been warm enough to remain liquid for a very long time – one of Saturn’s rings is thought to be made up of ice crystals vented from Enceladus – and Cassini data suggests that hydrothermal reactions, such as those occurring at seafloor vents on Earth, are occurring in the moon’s ocean. Cassini has also detected traces of ammonia and organics. So far, though, the data is not conclusive as to whether Enceladus’s ocean could support life as we know it.

THEO Team w Curiosity

The THEO team in front of an engineering test version of Curiosity.

Fortunately, Enceladus is continually offering samples of its ocean. The plumes, erupting from the south polar region at predictable points in Enceladus’s orbit, are continuously flinging samples of this ocean out into space. Cassini has flown through the plumes a few times, returning a wealth of data on the plume structure and chemistry. As I mentioned above, though, the results of Cassini‘s analyses are not conclusive. The time is right for a spacecraft dedicated to exploring the plumes and determining whether Enceladus could support life!

Armed with a destination, we settled down to answering open science questions.

Step 2: deciding what questions to ask, and figuring out how to answer them. We divvied ourselves into teams based on scientific questions – how are the plumes and subsurface ocean connected? Is the abiotic environment suitable for life? How stable is the ocean environment? Is there evidence of biological processes? – and researched the instrumentation a spacecraft would need to answer those questions.

Step 3: Fit the instruments into a spacecraft!

At this point in the process we all traveled to JPL to meet our Team X mentors (and each other). With their help and expertise, we started piling items onto the balance between scientific goals and engineering reality.

This is what it looked like initially:

Sci Eng Balance_initial

We arrived at JPL with a list of scientific objectives that would have made Santa Claus think twice! In the Team X setting, though, the scientists and engineers are side-by-side, and one quickly realizes that the scientific goals must be balanced by engineering capabilities. This begins the painful process of “descoping” your team’s mission design.

 

 Step 4: descoping. The process was a bit like “Survivor: space!” Each instrument was listed on a whiteboard, along with its strengths and weaknesses. Which science questions can it address? How much space does it take up? Will it drain our limited power? Is it exorbitantly expensive?

As the questions were answered and the pros and cons were weighed, the list of science instruments slowly whittled down. Some beloved instruments fell by the wayside and were left behind, but nobody cried – at least, not in front of everyone else!

Sci Eng Balance_descoped

Slowly but surely, the science objectives synced up with engineering capabilities. On real missions, sometimes this is accommodated by technological developments that expand the envelope of engineering reality. For us, it meant descoping until we were within the realm of possibility.

The final result of these efforts is a spacecraft concept called THEO: Testing the Habitability of Enceladus’s Ocean. (Disclaimer: this design was completed as an educational exercise and is NOT an actual mission proposal, nor is it in any way a “real” mission being funded by NASA.) The spacecraft, which would travel to Saturn via gravitational “slingshots” around Venus and Earth, would eventually settle into orbit around Enceladus to begin mapping the plumes and sampling their chemistry.

We settled on a suite of four instruments (plus a freebie) to do this.

A sub-millimeter instrument. The Rosetta mission (remember the cute little Philae, who landed on a comet?) carried one of these and used it to map the temperature and composition of the surface of comet 67P. THEO would use the instrument similarly, mapping the temperature of the vents from which the plumes emanate, mapping the chemistry of the plumes themselves, and combining with the cameras to map the density of particles in the plumes.

THEO conversation

A THEO design trade discussion in action.

A mass spectrometer.  “Mass specs” gobble up particles as they fly through space and flings them through an instrument which measures the mass of the particles. This can then be converted to chemical species. Mass specs have been used on previous missions, most notably on Cassini, but the one on Cassini cannot detect some of important markers of habitability. Thus, THEO would fly an improved mass spec – the one being designed for NASA’s Europa Mission – with the ability to detect key signs of habitability within the plumes.

A camera. You have to take the pretty pictures, right? Cameras are also incredibly useful for mapping geologic features, such as the plume sources, in great detail. By combining two images of the same feature taken at different angles, planetary scientists can create “digital topographic models” of the surface, which allow the height of a feature to be measured. THEO would map Enceladus’s intriguing South Polar Region more comprehensively than any mission yet flown. The cameras would also be used to image the plumes themselves, giving us an idea of the ratio of ice and vapor in them.

Two magnetometers. Magnetometers are sensitive to magnetic fields, and could be used to explore the depth and extent of Enceladus’s subsurface ocean. They are also useful in understanding the movement of ions in the plumes themselves!

Radio science. This is often referred to as the “freebie” instrument because all you need is a radio antenna – and you have to have one of those to communicate with your spacecraft! Radio science uses the doppler shift of a spacecraft’s communications with Earth to measure any change in its orbit. Just like the pitch of an approaching fire truck rises and falls as it drives past you, the rate of data coming back from a spacecraft is “nudged” by tiny shifts in its orbit caused by changes in gravity over Enceladus. These miniscule changes in frequency could be measured on Earth, allowing us to map Enceladus’s gravity field.

All of this would fit snugly into a little spacecraft capable of making the voyage to Saturn.

THEO configuration

The THEO spacecraft concept.

Last but not least: a cool thing about the engineering of the spacecraft itself! As I mentioned earlier, sometimes engineering breakthroughs facilitate even more science. The solar arrays on THEO would be roll-out arrays, which curl into tiny shrouds during launch. This allows a relatively large solar array – like, say, the one you’d need to gather enough light at Saturn! – into a rocket for launch. THEO would therefore use solar power at an unprecedented distance from the Sun.

So: science AND engineering came together in a very short timeframe to produce a viable mission to the outer solar system! If you want to read ALL about it (all 30 pages of it!) check out the article here. And if you’re a graduate student or early career scientist/engineer, I strongly recommend that you apply for the Planetary Science Summer School. It’s an incredible learning experience!

How Studying Geology Makes Me a Better Engineer

When I tell people that I decided to “leave engineering and become a geologist,” most of them respond with, “Wow, that’s different!”, or “That’s quite the change.” And initially, I thought the same thing. How much can building spacecraft and studying rocks overlap???

The years since beginning grad school have been eye-opening, to say the least.

As an engineering student I learned about materials; how to understand their limits and avoid them, so that I could design part of a machine, building, or spacecraft, secure in the knowledge that the item – whatever it was – wouldn’t fall apart. “How much load can you put on this steel beam before it bends? Divide that number by 2.5 and you’ve got your design limit.” Engineering is about avoiding breaking or bending, because when beams bend or a bolt breaks, your machine becomes useless at best and dangerous at worst.

Well, too bad for all the engineers: the Earth is CONSTANTLY BREAKING AND BENDING. Faults like the San Andreas are brittle fractures of the Earth. The Earth’s mantle is solid rock that is, at the same time, in constant, incredibly slow motion. So the study of geology is about understanding the limits of a different material – rock – and what happens after you go beyond them.

To that end, “we” (geologists and engineers) have spent unbelievable amounts of time coming up with carefully crafted machines – which need to avoid breaking – to squish the heck out of rocks – which we want to break or flow – and see what happens.

In my research, the rock in question is made up of a mineral called ice. Yes, ice is a rock!

To figure out what happens when ice is pushed beyond its limits, I had to apply my engineering background to designing an experimental apparatus that could a) keep my ice from melting, while b) measuring the extremely slow (you might even say “glacial!”) change of shape of the ice during my experiments. Geology provides the “design requirements,” which I then employ to make engineering decisions while designing the machine. The process has challenged my engineering skills and pushed me to develop better understanding of aspects of engineering – such as measurement system design – which I had little experience in.

The result? A machine originally designed for engineering tests, now outfitted with a cooling chamber that goes down to -100 degrees C and a sensor system capable of measuring position changes as small as 0.000000001 meters.

It looks like this:

Cryostat Detail

So despite most peoples’ first impressions, geology and engineering have a lot in common. In the process of using my geologic knowledge to define expectations for a machine, then using my engineering background to design, fabricate, and integrate the apparatus, I’ve merged two seemingly disparate fields and become better at both… meaning that my new job title is really “engineer and geologist,” rather than “engineer-turned-geologist.”