|First appearance:||"What a Difference a Day Makes"|
|Last appearance:||"Children of the Revolution"|
Ashenfelder and his Artemis crew participated in the Battle of Ubessi in orbit of the neutral planet Ubessi during the tail-end of the Federation-Cardassian War in 2362. Due to a Starfleet starship slamming into the planet's surface, resulting in the total ecological collapse of the planet's ecology that weighed heavily on his first officer John Greene's conscience, Greene, with Anne Lansing and Daniel Radke's help, convinced Ashenfelder to break battle lines and proceed to Ubessi to assist. This was after Ashenfelder spoke personally with self-appointed Ubessian leader Yaghim Thau to assure him the Federation would assist as soon as they could get to the planet.
After an away team led by Greene returned to the Artemis from Ubessi, they found Thau had a Galor-class warship under his command, and, with Cardassian forces also approaching, Ashenfelder ordered the Artemis to the safety of Federation-controlled space, despite the urging of Greene to continue to the Ubessians' new planet to convince Thau to accept their assistance. (Star Trek: The Prospect Chronicles: "What a Difference a Day Makes")