The spacecraft has to be extremely clean. The entire spacecraft—that includes the rover, the heat shield, the descent stage, and back shell—must contain less than 500,000 bacterial endospores, or spores. Just to give you an idea, a teaspoon of seawater has ten times more bacteria.
This NASA Scientist Helps Prevent Mars from Contamination
Published: February 23, 2021
Moogega Cooper: The most amazing part of my job is that I get to touch parts of the hardware that will go to Mars.
When the Perseverance rover lands and conducts its science, the big thing that I hope it accomplishes is to determine if life ever existed on Mars. It is our job to make sure that when we send the spacecraft out that it doesn’t contaminate the native environment that we’re trying to explore. So when we explore moons and planets and other bodies in the solar system, we want to make sure that we don’t send microbes from Earth that may contaminate that environment and affect our ability to find biosignatures on the surface and allow us to bring the sample back so that we can definitively find ancient microbial life on Mars.
The spacecraft has to be extremely clean. The limit for the entire spacecraft—that includes
the rover, the heat shield, the descent stage, the back shell has to be less than 500,000 what we call bacterial endospores, or spores. Just to give you an idea, a teaspoon of seawater has ten times more bacteria than that entire spacecraft has. Spores can stay in a dormant state for millions of years until another habitable or a favorable environment comes along. So that’s why we target those types of microbes specifically because they could possibly survive a journey to Mars—the vacuum of space, the huge temperature fluctuations, the UV radiation.
Humans are the dirtiest thing in that clean room. We have all kinds of microorganisms in our body and on our skin. And so we have to make sure that from head to toe, and including our eyes, that it’s protected from the spacecraft, especially our most critical parts. So that’s why we have gloves on our hands in the clean room. We have full bunny suits, which is a head-to-toe covering of a very clean material that allows us to stay separate. It’s a barrier between humans and the spacecraft.
We also have the spacecraft going through bakeouts. They go in high temperature chambers—350C—and we kill a lot of the microorganisms. Our most critical parts that touch the Martian soil are extraordinarily clean.
The most difficult part of my job is worrying whether or not I was paranoid enough. Did I miss something? How about if this fails? How about if that fails?
It’s hard enough to build spacecraft. But on top of that, as we were approaching launch, the COVID-19 pandemic was surging in parallel. As I step outside, it looks closer and closer to what I see in the laboratory. Everyone’s wearing face masks, they’re social distancing, and making sure that they don’t spread contaminants from person to person. So it’s my job, but in the real world.
But what was most worrying was that off the clock, you might catch COVID and there is now a vector to wipe out an entire team. That could completely derail the mission and throw us off of our scheduled goal. And that was a major concern as we were marching to launch that a person would get sick and we couldn’t launch at all. That’s what we did not want to happen, and fortunately it didn’t.
It’s truly heartbreaking during this particular mission that many people, due to the COVID-19 pandemic, couldn’t actually fly out to Florida and witness the launch in person. There were tons of team members that had to cancel their flights because they didn’t want to put themselves or their family at risk.
I was fortunate enough to be one of the final two people to sample the rover, the aeroshell and the fairing before it was closed up. So it was nice to kind of say that last goodbye to the spacecraft.
Launch was extra special for me, not only because I put my heart and soul into this mission, but also I was able to participate in the launch commentary...
That eyeball, what looks like an eye is actually a laser. It shoots at the rocks.
Anchor: A laser!?
Cooper: A laser! Lasers! And then depending on the signature that comes back, the spectrometer reads it and tells you what the geology is.
Open a window or door to the rest of the world that is watching to allow them to understand what science instruments are on the Perseverance Rover. And what is the journey going to look like from here to Mars? And that experience, on top of experiencing the launch, was just unforgettable.
I hope to just spread the joy like, “Love science, love it, like, please.”
Producer/Editor: Ari Daniel
Producer/Director: Terri Randall
Production Assistance: Jedd Ehrmann
Camera: Kevin Stevenson
Sound: Timothy Kitz
Production Coordinator: Steven Reich
NASA, NASA 360, NASA/JPL-Caltech, NASA/Michelle Stone, NASA’s Goddard Space Flight Center, Storyblocks
© WGBH Educational Foundation 2021