In 1976 at the Hanford Site in Washington state, a 64-year-old chemical operations technician named Harold McCluskey was working on columns filled with special exchange resins in a glove box at the Plutonium Finishing Plant.

Europe’s first Mars rover—named Rosalind Franklin—was months away from a planned September launch when the European Space Agency (ESA) convened a meeting a few weeks after Russia’s February 2022 invasion of Ukraine. The ESA Council unanimously agreed on “the present impossibility” of working with Roscosmos as its launch partner and later decided to reboot its ExoMars mission with a new lander, new partners, and a new launch date.

ANS is celebrating Actinide Days by giving some exceptional radioisotopes the credit they deserve on social media, and today it’s double the fun, with both plutonium-238 and uranium-238 getting a turn in the spotlight. While the actinides may be buried in the bottom row of the periodic table, isotopes of these elements are hard at work in applications in medicine, industry, power, and space. Visit ANS on Facebook, Instagram, and Twitter to join the conversation and speak up for your favorite actinides.