(Thunderbolts I#60 (fb) - BTS) - The mutant Solarr used his powers to become a mercenary.
(Thunderbolts I#62 (fb) - BTS) - After Earth's heroes left Counter-Earth Franklin, the planet suffered a series of natural disasters that led to global catastrophes. The problems didn't end even after Doctor Doom shifted the world from its pocket dimension to Earth-616's solar system. Throughout the ongoing crises, Germany remained one of the few nations that managed to maintain a thriving economy. As a result, the European country quickly rose to power and prominence.
(Thunderbolts I#62 (fb) - BTS) - Hoping to capitalize on Germany's newfound importance, the World Party took center stage, now claiming to be a political alliance with tentative ties to, among others, France and the United States. Baron Heinrich Zemo was tasked to head up an elite team of super powered operatives.
(Thunderbolts I#60 (fb) - BTS) - Zemo founded the Thunderbolts: a group of international heroes operating out of Germany, but fighting for all of Earth. With himself as leader, he recruited Solarr and his fellow American mercenaries Makeshift and Phantom Eagle. France's heroine Chain Lightning and Heinrich's son Helmut rounded out the team as Iron Cross.
(Thunderbolts I#62 (fb) - BTS) - The Thunderbolts operated together for at least eight months. Zemo assured the allegiance of Solarr and the others by making sure they lived in the lap of luxury.
(Thunderbolts I#62 (fb) - BTS) - Solarr and the other Thunderbolts were more than willing to help Baron Zemo spearhead a World Party approved plan to give Germany world dominance. The country planned to launch a satellite they claimed would help restore the global communications network. In reality, the satellite was designed to only allow Germany access, which would give nation unprecedented control over the world economy.
(Thunderbolts I#61 (fb) ) - The Thunderbolts utilized their individual powers and expertise to help construct the rocket. Solarr was seen using his heat generation for spot welding.
(Thunderbolts I#60 (fb) - BTS) - Solarr joined Zemo and the others on a mission to the former Soviet Union where they had to locate and secure a prototype fuel injector assembly for the rocket.
(Thunderbolts I#59) - While in Russia, they came across the unconscious bodies of the Thunderbolts who had just been transported to Counter-Earth following their fight against Graviton.
(Thunderbolts I#60) - Solarr stood back, allowing the paranoid Zemo to question the newcomers who he believed to be mercenaries sent to thwart their mission. The Fixer tried to buy time for his teammates to recover, using the weapons in his Tech-Pac to keep the Thunderbolts at bay. Moonstone managed to defuse the situation by claiming they were merely hired hands sent by the World Party to check if the Thunderbolts were doing their duty. Satisfied with this explanation, Zemo allowed them to leave.
(Thunderbolts I#60 - BTS) - Zemo's Thunderbolts retrieved the fuel injector and returned to Germany. When Earth's Thunderbolts learned of Germany's upcoming launch, they decided to hijack the rocket and use it to leave Counter-Earth.
(Thunderbolts I#61) - Zemo's
Thunderbolts continued to work on the rocket after returning from the
Soviet Union. Solarr and Makeshift were commenting in public on the true
nature of the rocket mission, which was overheard by Iron Cross who read
them the riot act.(Thunderbolts I#62 (fb) - BTS) - Earth's Thunderbolts made it from Russia to Germany hours before the rocket launch.
(Thunderbolts I#62 - BTS) - Moonstone, Jolt and MACH-3, using fake ids created by Fixer, infiltrated the base while Atlas tunneled a way through the ground to reach the launch platform. However, 46 minutes before the launch, the Fixer abandoned his allies to carry out a mission for Helmut Zemo whose digitized essence was stored inside his Tech-Pac. Zemo needed a new body and threatened to shut down the Tech-Pac's life-preserving systems if Ebersol didn't find him one.
(Thunderbolts I#62) - After entering their facility, Fixer used knock-out gas to take care of the German Thunderbolts, but only Solarr and Zemo were affected. Fixer managed to temporarily disable Makeshift, Chain Lightning and Phantom Eagle.Iron Cross attacked Fixer from behind, but that only gave him the opening he needed to start transferring Zemo's essence from his Tech-Pac to his new host.
(Thunderbolts I#62 - BTS) - The rocket launch went ahead as scheduled, but Earth's heroes made sure it exploded before it could deliver its payload. MACH-3 and Fixer then put out a worldwide broadcast, revealing Zemo and Germany's deception. Solarr and the surviving members of Zemo's Thunderbolts were presumably incarcerated (see comments).