The Mars 2020 launch window opens on Thursday, July 30, 2020. First Mode team members have contributed to Mars expeditions dating back to Pathfinder in the 1990’s and up to the impending launch of Perseverance. As we lead up to the launch, our team reflects on the work that goes into building rovers that can traverse the surface of Mars. Check out other posts by Peter Illsley and Spencer Anunsen for more insights!
Becoming Friends with a Mars Rover
By Mallory Lefland, Senior Systems Engineer
My first job out of college was as a member of the Engineering Operations team for the newly landed Curiosity rover. One of my mentors left me with this message on his last day of working on Curiosity. He turned to me and said, “I’ve worked on this rover for 10 years, it feels like a child to me – please keep it safe.”
I couldn’t understand the sentiment of those words then. However, eight years later, I appreciate them more than ever and would like to share what it feels like to build a spacecraft.
Less than two years after my start at NASA Jet Propulsion Laboratory (JPL), I began working on Mars 2020 – what is now known as the Perseverance rover. Because of the build-to-print nature of the project, the majority of the hardware and software was inherited from the Curiosity program. Most of the spacecraft behaviors, especially in the landing system, were fully formed and being reused from Curiosity, so it gave the Mars 2020 team time to optimize areas that could use improvement. In contrast to my mentor’s feeling of having raised Curiosity as a child, I was beginning this work on a project that was far past that early stage of development.
As a member of the Entry, Descent, and Landing (EDL) team, my job was to understand the landing system we had inherited– and then try to find and implement creative ways to make the system safer and more operable without drastically changing the hardware or software.
I was forced to develop skills that allowed me to take a critical look at all of possible spacecraft behaviors and creatively put actions together to achieve new goals. It can be exhilarating when you finally figure out a way to solve a problem and equally soul-crushing when you reach the conclusion that there is no elegant solution – and you’ll have to live with the current design and operate within its constraints. For a few years, I stared at spreadsheets, PowerPoint slides, software code, mechanical drawings, and electrical specs; and that’s how the spacecraft felt to me – paper-like and two-dimensional.
It wasn’t until the design process morphed into testing that the spacecraft became real, full-fledged, and three-dimensional. We spent thousands of hours running simulations across multiple test environments to analyze and validate the behavior of the landing, which is a period of just 45 minutes in the spacecraft’s many-year mission.
To test these very special 45 minutes, it takes about five hours in the testbed to set up the spacecraft and simulations, and another hour after landing to collect data and power down. My test shifts were 8 hours of time one-on-one with the spacecraft, staring at a computer screen with a view to the inner working of its brain.
Testing in this way can almost feel like a dance or a conversation – you and the spacecraft take turns leading each other in new directions, with the end goal always being a successful touchdown on the Martian surface. There are shifts where you feel like you’ve spent the day with an old friend, or a teacher, or a doubles partner – and you get a rush of elation when you finally land safely. However, there are shifts when absolutely nothing has gone to plan, and it feels like you spent a day in a grueling battle with an adversary.
A rough estimate shows that over the last few years, I’ve tested the landing system for about 1800 hours – the equivalent of testing around the clock for 75 days non-stop. It’s more time than I’ve spent with any family member or friend during the same period.
It is through this experience that the spacecraft turns from a two-dimensional inanimate object into a three-dimensional being with its own personality and style.
When I think back to my mentor’s words, I resonate with the feeling of the spacecraft being so much more than the metal it is built from and the code that runs through it computer – I feel how it has come to life and developed a personality, becoming so much more than just a vehicle. But it doesn’t feel like a child to me – it feels like an equal, or a friend.
As we approach the Mars 2020 launch in a few days, it feels like seeing a good friend starting their dream job or going on a trip they’ve been talking about for a decade.
When July 30th rolls around, I’m sure I’ll be filled with tears of joy and fear, rooting for my friend as she blasts through the atmosphere and begins her months long journey to Mars. I plan to revel in those emotions for a day or two before jumping back into a test, so I can learn even more about her before landing on February 18th, 2021.
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