10/27/2020 Debra Levey Larson
Written by Debra Levey Larson
After earning his bachelor’s degree in ’83 and master’s degree in ’84 from the University of Illinois he got a job at NASA’s Jet Propulsion Laboratory in Pasadena as a maneuver analyst for the Magellan Mission to Venus. In 1987, he decided to go back to grad school and received his Ph.D. from the University of Texas at Austin.
“The Air Force paid for my schooling, going to Eglin Air Force Base every summer,” D’Souza said. “About the time I was getting ready to graduate, they made me an offer to come work full time. I did research for them for five years on trajectory optimization and navigation. That’s when I first got involved with GPS.”
D’Souza said at that time GPS was just coming online and there were only a handful of satellites and GPS receivers were about the size of a car battery.
“I worked on the first reduction of a GPS receiver,” D’Souza said. “In the mid-90s, we were able to get it down to a card about six inches and that was quite revolutionary.”
It was about that time D’Souza learned sometimes the best career choice is to choose not to do something.
“They wanted me to go into management and I really didn't want to do that,” he said. “One of my buddies was a faculty member at MIT. He told me about the job opening at Draper. I was also getting pretty serious with a girl. I decided to accept the job and we moved to New England on our honeymoon.”
For about nine years, D’Souza worked for Draper as a guidance, navigation, and control systems engineer. He said although working for Draper was good, he spent three hours a day commuting and felt like it was time to make a change.
“I was offered at job at Draper in Houston to work on a project called the Space Launch Initiative,” he said. “Then a month after I moved down to Houston, the project was cancelled. The funding dried out so I had to scramble to find other work, still at Draper. It was frightening.”
That dramatic, stressful career move was what ultimately led D’Souza from guidance and trajectory optimization into navigation.
“I got to know some people at Johnson Space Center and got in on the ground floor of Orion,” he said. “And that was fun. The first year was a blast. We didn't have many meetings and no management oversight. They let me do my work. Nobody bothered me.”
Although everything worked out, D’Souza said leaving Draper to go to NASA was the most difficult career decision he had to make.
“In hindsight, it was the best decision I've made in my life, but it was an unknown. I had worked with the Air Force so I thought I knew what civil service was all about. It turns out NASA is very different. It’s very streamlined, and fun. The management is very much of a servant leadership model. There’s a lot of trust so it’s very empowering. They didn’t micromanage me. They encouraged me to do different things and spread my wings.”
During that time, he also began getting involved with numerous universities and developed a vision to grow the technical competence of people within the brand of navigation to be world class. He gives technical talks and wrote a book with Russell Carpenter form Goddard called Navigation Filter Best Practices. They give seminars across the country on navigation.
D’Souza said the interesting thing about navigation is it touches every area of the spacecraft.
“For example: thermal. The vehicle can’t get too hot. You need to point it in a certain direction, so the sensors and other systems can operate the way they’re supposed to. It affects propulsion, too. I need the vehicle pointing in a specific direction before a maneuver. So we are constantly interfacing with every other subsystem within navigation and other hardware. It’s a broader system.”
He said he actually learned navigation on his own. “People did orbit determination, but nobody taught me navigation and I never studied under a navigator.” Now he does the training.
“We bring in graduate students and tell them which schools they need to go to and who they need to study under. They come back here every summer and they work with us. Then after they graduate with a Ph.D. they’ll need another three years of training. It requires dedication. But if someone wants it, they can get it. If I can do it, anybody can.”
D’Souza describes navigation as very math heavy, requiring a knowledge of estimation theory, linear and nonlinear systems theory, and optimization theory. It involves a lot of numerical analysis. “I tell people who want to study navigation, they’d better be taking all these courses and going to a school that offers them. It’s very specialized, but if you want to have job security for the rest of your life, go into navigation.”
As a navigator, D’Souza’s is doing the work that astronauts can’t.
“They can’t do the calculations,” he said. “Even in the Apollo days of slide rules and charts, there were only a limited number of things they could do. They had to manually look through telescopes and sextants to do navigation. We have developed a system where we can do it when the astronauts aren't even there. In fact, the first mission we’re flying in a year is going to do this without any crew onboard. We have the requirements to return the vehicle safely to Earth, in case we lose communications with the ground. There won’t be people on board so it's got to be done automatically.”
D’Souza sees the work he is doing now as the groundwork for the future of spacecraft.
“We are designing systems to be ready for whatever comes in terms of human exploration in the next 30 years. It's going to be mature. It’s going to be flexible. It's going to be as technically competent as we can make it not knowing the future. That’s my goal. The next generation can take it and make improvements, but I don’t want anyone coming back saying, ‘what was Chris thinking’?”
He said when he was at U of I, a computer was a mainframe. “When I started at Illinois, my class was the first one that didn't use punch cards. We actually used terminals, and that was awesome.” He said because students today have better tools and training, he’s learning from them.