Posted on August 12, 2021
Parker Solar Probe Observatory Scientist
University of California, Los Angeles
I started working in earnest on what became Parker Solar Probe as a member of the Science and Technology Definition Team (STDT) back in 2003. At the time, it was a different mission: a flight out of the ecliptic plane (where most of the planets in our solar system orbit), one or two flybys of Jupiter, and a 16-hour close-approach pass over the Sun’s poles. I remember fantastic discussions in convivial atmospheres and meetings at the Johns Hopkins Applied Physics Lab in Maryland, the Southwest Research Institute in San Antonio and Montana State University in Bozeman. I would also like to remember an APL scientist who is no longer with us, but whose friendship and whose insights on the solar magnetic field I miss greatly, Barry LaBonte.
When we realized the polar mission was no longer feasible, we were tasked to reexamine the scientific objectives to see whether the new fantastic orbits developed by APL’s Yanping Guo could work. We realized collectively how a mission in the ecliptic plane was actually far superior to previous probe incarnations, and the term “Solar Probe Plus” entered in use.
Working with the STDT all the way through 2008 was a high point in my career. A few hiccups in the early development, the need for momentum wheels to get longer periods of unperturbed data around closest approach (called perihelion), the issues of the shield charging, and the need to bring the perihelion just a bit farther away than 9.5 solar radii from the Sun’s center in the end turned out to be only minor stumbling blocks, and the excellence of the instrument teams did the rest.
Working on Parker Solar Probe also led me to become scientific friends with eventual mission namesake Gene Parker, something that had begun when I had worked on the question of why the solar wind is supersonic and the nanoflare scenario for coronal heating. It was a great joy to be with Parker himself at the launch, and be able to discuss with him as the mission I had followed and worked on for 15 years took flight!
Marco Velli (left) speaks with Eugene Parker – namesake of the Parker Solar Probe mission – during launch activities in August 2018.