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Sarah Gillis (AeroEngr’17) is a lead space operations engineer and astronaut trainer at SpaceX with literal out-of-this-world experience.

The University of Colorado Boulder alumna recently returned from a five-day orbital mission aboard which took astronauts further from Earth than any have traveled since the end of the Apollo program in 1972.

On Nov. 11, she spoke to students and community members in a special event at Fiske Planetarium.

A Boulder native, Gillis shared what life was like in space for the four-member crew and details of the science and engineering that brought them to orbit and safely home.

What it is like experiencing launch for the first time.

Intellectually, I had studied all the physical changes you go through going to space, but actually going through them is fascinating. For this one moment, you’re defying gravity as the rocket lifts off the pad and you start accelerating and accelerating. You get pushed into your seat. The Gs get to about 4.5. When you get to second engine cutoff and you’re just floating, you no longer have pressure pushing you into the seat — you have fluid in your face. You suddenly feel like when you’re a kid and you’re laying upside down off the bed.

There’s an adjustment period once you are in orbit.

Every crew member goes through this time on board where you’re adapting. The first two days are pretty hard in space. You’re figuring it out. You’re going through all the physiological changes. You have this brain fog; you have elevated fluid. You can have space motion sickness.

You’re probably not feeling your best, in all honesty. How you set up a timeline for crew members in space should account for that. You could not possibly have talked our crew into doing any less on our mission, but hindsight is definitely helpful, and it’s just a reality that it takes a bit of time for crew members to adapt.

Keep an eye on space while following your passions.

I always knew how unlikely it was to ever become an astronaut. The statistics are not in your favor right now at our point in human history. I do think that’s going to change in the very near future if SpaceX is successful in bringing Starship online. You go from having four people in a spacecraft to 100 people in a spacecraft. As you change those numbers, cost of access to space will go down, so the opportunities that will exist will look much different in next 10-15 years.

For me, knowing how unlikely it was, it was super important to find things I was genuinely interested in. That way, no matter what happening in life, I couldn’t be disappointed because I was doing things that were interesting and engaging and things I wanted to be pursuing. Follow your curiosity, and it will take you to extraordinary places.

The incredible complexity of designing a space suit from scratch.

It was about a 2.5-year development program where one day we would show up and we’d have the left shoulder rebuilt in a certain way. The next Monday we’d show up and they’d have a whole new elbow for us to try. Then we’d go and get in the simulator and understand what worked and what didn’t and really fed that into the design process of these suits. It was a pretty extraordinary development effort.

There were times that we were learning stuff that went against industry knowledge. One of the things we discovered pretty late was the risk of electrostatic discharge in the suits. That led to an entire deep dive into understanding material testing.

One of the last tests we did still on Earth was once the suit had gone through all sorts of iterations, we actually took them to a vacuum chamber at Johnson Space Center and we wore them in the vacuum chamber and ran through the entire depress and repress sequence. It was just an extraordinary test of competence into the suit, understanding what the pressure changes and temperature changes would feel like.

Moving in space without gravity to weigh you down creates challenges.

What’s so cool about moving in a pressurized suit is it’s really almost physical problem solving. You can only rotate your shoulder so many degrees, or you can only extend your arm so far in the suit. What that means is you have to make sure that a person of a certain stature can perform everything they need to in that pressurized environment. It was a really cool development process with SpaceX to figure out what new mobility aids we needed in the spacecraft. What additional handholds and footholds would be required to make sure we could accomplish all the tasks we needed to.

On flight day two we got pressurized in the suits and did a dry run (of the spacewalk). It was really fun to actually see how things worked, and what were the things we hadn’t accounted for. As soon as I went to the controls and interfaced with them, based on where my center of mass was, my feet would suddenly start rotating up, and so I had to find a whole new strategy for how to secure myself when I was at the displays and how to transition out from the displays.

Train for the worst day so you can experience the best day.

In training we had really prepared for every possible scenario we could come up with for the EVA (extravehicular activity). Really as much as we could use the imagination to prepare bad day scenarios, we had trained for them, and it was so smooth. You train for the worst day so you can actually experience the best day. The spacewalk went exactly as we had hoped.

There is so much we do not know about life in space.

We partnered with 31 institutions on 36 research experiments, a lot of which came from CU, which I was really excited about. Some of my former professors actually contributed experiments to the mission.

Overall, the research was really focused on experiments that needed human involvement, things that could benefit future life as we try and look toward Mars. There’s a lot of health issues that astronauts encounter over long duration, and this includes space motion sickness, and spaceflight associated neuro-ocular syndrome.

Many astronauts do have degraded vision over time, and we don’t actually understand the mechanism at this point. It’s often associated with the fluid shift that happens where you suddenly have more fluid in your brain, but if we’re going to actually mitigate that and fix it in the future, we need to get to the heart of the cause, so we did a whole slew of experiments looking at different eye pressure and vision change data.

Re-entry is awesome.

It’s so, so cool to reenter Earth’s atmosphere. We start seeing a glow around the spacecraft at around 100 km. Then as you start to get lower you start to see these neon colors, pinks and oranges, and you actually see some of the sparks flying past the window. As you get lower in the atmosphere you start encountering turbulence with the different layers of the atmosphere. The thrusters are firing all around and it really feels like Dragon is clawing its way back into the atmosphere.

The mission does not end at splashdown.

We were picked up by the recovery vessel, and about 30 minutes later we climbed out of the spacecraft. We were checked out by the doctors before being flown by helicopter back to Kennedy Space Center, where we met our families. From there the mission wasn’t over, we had about a week of science and research and data collection post flight. We traveled to Houston pretty immediately for some high-density bone scans.

Trusting others with your life — teamwork is critical.

Human spaceflight is the ultimate team sport. It’s not only you have to have an extreme working relationship with the people on that mission — you are absolutely trusting them with your life to keep you safe. That extends to the people on the ground team as well, you have this entire team supporting you, and even more people behind the scenes beyond that.

As a trainer, I knew the technical side of Dragon and what you need to do to live and work in space, and what I found most interesting was in one of our early sims, the four of us go in the spacecraft, and we did terribly. We completely messed up the scenario. We were all going in different directions, chasing rabbit holes and ultimately just failed the simulation in so many ways. You have to learn how to work as a team.

It doesn’t matter what you bring to the team, you have to learn when to lead, when to follow, how you bring what you can contribute through a different lens because ultimately the success of the crew is what’s most important versus your own knowledge.

Seeing Earth from space changes you.

Seeing the Earth from that perspective cannot not change someone. All of our time here on Earth is so precious, your life is only so many hours overall. I have this immense appreciation for maximizing what we are here to do in this world. I think you certainly take calculated risks when you put yourself on a rocket and launch to space, or reenter the atmosphere. Those are all things that you have to believe that the risk is worth it for the benefit. It’s shifted my perspective a little bit on how cherished our time is with our family and our friends and what we’re here to do on this Earth. I’m still reflecting on it. I think it will continue to change me.