space navigation, PNT, GPS, GNSS, Profile 

International Policy and Interplanetary Navigation

Joel Parker Lends Expertise to NASA Missions and the Global Navigation Community

By ​Danny Baird

April 12, 2022

NASA Navigation Engineer Joel Parker Credit: NASA

Prague. Munich. Sochi. Bremen. Vienna. Kyoto. Bangalore.

Maps neatly frame Joel Parker’s desk. Each creased leaflet marks a meeting conducted — a milestone crossed. He collects one for every city he visits while representing NASA as a Positioning, Navigation, and Timing (PNT) expert.

His work occupies the intersection of engineering and policy, working with domestic and international Global Navigation Satellite System (GNSS) providers to ensure reliable navigation signals from these systems are a robust option for high-altitude NASA missions as far away as the Moon. All the while, Parker serves as a flight dynamics engineer, guiding missions to their intended orbits so they can accomplish their science and exploration objectives.



At Mississippi State University, Parker attained graduate and undergraduate degrees in aerospace engineering while minoring in political science. Collegiate internships led him into aerospace’s private sector, to the halls of Congress, and then to NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Parker’s first assignment at Goddard was on the team developing the General Mission Analysis Tool (GMAT). GMAT, an open source mission-planning product for flight dynamics engineers, has a wide variety of uses for NASA, commercial industry, and the public at large. Parker helped take the software from beta to operational.

"GMAT captures the best of NASA’s flight dynamics experience," said Parker. "We’re embracing the NASA charter and publishing it as widely as possible, for the benefit of commercial industry and the general public."

After GMAT, Parker’s journey at NASA led him to the Transiting Exoplanet Survey Satellite (TESS) mission, for which he served as a flight dynamics engineer and ultimately the flight dynamics lead. TESS launched in 2018 and is now surveying the night sky, searching for the telltale signs of planets around other stars — the subtle dimming of the star as the planet passes in front of it.

During his work on TESS, Parker began working for the Space Communications and Navigation (SCaN) program office and the Exploration and Space Communications (ESC) projects division as a GNSS policy advocate for the agency.

SCaN oversees the agency’s work in PNT policy under Space Policy Directive 7 (SPD-7), which governs how PNT is managed government-wide. A particular focus is the Space Service Volume (SSV), the area of space where satellites can receive the faint signals that spill past Earth’s edge from GNSS satellites on the opposite side of the planet. Parker’s duties include serving on the U.S. delegation at the United Nations-managed International Committee on GNSS (ICG). He co-chairs its Space Use Subgroup, advocating for the space community and collaborating with U.S. agencies and international GNSS providers on policy and capabilities.

"We have really strong and collaborative relationships with GNSS providers and users around the world," said Parker. "It’s interesting to hear everyone’s needs and ideas for the future of GNSS in space, and I can’t stress enough how beneficial it is to build that future together as a community."

On Earth, GNSS signals enable navigation and provide precise timing in critical applications like banking, financial transactions, power grids, cellular networks, telecommunications and more. In space, spacecraft can use these signals to determine their location, velocity, and time, which is critical to mission operations.

Parker and his highly capable team of navigation engineers have shown that GNSS signals can be used reliably in lunar orbit. With specialized equipment, NASA exploration initiatives like the Artemis missions to the Moon could navigate cislunar and lunar space using GNSS signals in the same way one might navigate the highways with their phone.

To prove this capability at the Moon, NASA is collaborating with the Italian Space Agency on the Lunar GNSS Receiver Experiment (LuGRE), which will fly on a Commercial Lunar Payload Services mission to the Moon as early as 2024. Parker serves as the principal investigator for the experiment, which is planned to calculate the first-ever GNSS location "fix" on the lunar surface while using both GPS and Galileo, the GNSS constellation operated by the European Union.

Even as he works to extend the SSV, Parker continues in his role as a flight dynamics lead. His current mission, the Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission, will launch in 2024 into polar orbit.

PACE will assess ocean health by measuring the distribution of phytoplankton, tiny plants that sustain the marine food chain. The mission will also be an early adopter of Disruption Tolerant Networking (DTN), a communications innovation that could improve efficiency and reduce data loss.

When not at work, Parker stays busy raising his two daughters, caring for his elderly Labrador retriever, finding creative outlets in the kitchen, and working with his wife to restore their 1930s, Craftsman-style home in Maryland.