Satellite Senshi History
It wasn't until the reign of Serenity X that the Satellite Senshi were formally acknowledged as fighting forces.
The chain of command is as follows: The Leader of Earth's Moon as Prime Satellite Senshi (Generally some version of Queen Serenity/Sailor Moon), the respective planet's Sailor Senshi (i.e.: Sailor Jupiter, Sailor Uranus), the leader of the planet's satellite senshi (i.e.: Sailor Io for Jupiter, Sailor Zephrius for Quinox), and the rest of them.
Depending on how large a planet's batch of satellite senshi is, they might be split up further into ranks (as is the case with Saturn and Jupiter, they have several different groups and ranks).
Formation and History
During the expansion of colonies and outposts in 19,103 B.C., moons are also set upon and colonized by their respective planetary colonizers.
Between 12,540 B.C. and 12,510 B.C., satellite senshi are born in the Jupiter, Saturn, Uranus, Neptune, and Haumea planetary systems.
After the banishment of Selenity X by Serenity I in 10,557 B.C., the Satellite Senshi's top of command was gone. For the that time she ruled, Serenity I discarded the title of Prime Satellite Senshi and cut off ties to the satellite senshi of the rest of the solar system. With their prime leader gone, the satellite senshi devoted theirs lives soley to their respective leaders and the communities of their planetary system. Gone were the days where satellite senshi of one planet freely associated with those of another planet.
Serenity I ignored and excluded the Satellite Senshi of their former role. She chose to focus on her own kingdom and those of the planets of the solar system and not their satellite senshi.
During the 10,600's, a series of interplanetary satellite senshi battles occurred. The planetary armies and respective satellite senshi fought one another. The reasons behind the animosity and hatred betwixt them has been lost to time. It is known that hundreds perished (i.e. - the crown prince of Europa, Prince Kenzo).
With the births of the princesses of their respective planets between 8,123 B.C. and 8,120 B.C., the satellite senshi finally had someone to pledge their allegiance and loyalties to. They finally had someone they would die to protect.
Since the beginning life in the Solar System, Sailor Charon has been there to weigh and support the lives of these beings upon her shoulders, as is her role in life.
Having grown weary of her mandatory position in life, the immobile Sailor Charon took it upon herself to set a plan into motion. Using a very small amount of power, she sent an orb to bring to her the most malleable satellite senshi she could find; it was Sailor Io. After some heavy persuasion and brain washing, Sailor Io became Sailor Charon's minion.
Going back to Jupiter, Sailor Io began in infect the minds of her fellow satellite senshi, though it was very subtle and not likely to be noticed. The two ambassador senshi of Jupiter (Sailor Callisto and Sailor Ganymede) made their way to the Saturn System and then Neptune system, which then attempted to infect the Uranus system. Once the two arrived, they began to infect the other planet's ambassador senshi and the infection grew amongst those systems. Once the infections began spreading through the planetary systems, the ambassador senshi who had been traveling returned back to their respective planetary systems and joined in the slaughter of their fellow Satellite Senshi, civilians, and others.
Some senshi were not susceptible to the brainwashing virus. There were very few that noticed it right away and, as was the case of Sailor Enceladus, killed themselves, rather than be infected.
When Queen Beryl's forces make their attack on 12:01 a.m. 12/15/8012 B.C. Sailor Charon took that as her cue to activate the brainwashing virus she had infected into so many satellite senshi.
What resulted were massive Civil Wars between the affected satellite senshi and the unaffected satellite senshi. They fought each other to the death, brainwashed satellite senshi trying to take out as many civilian lives as possible. This is known as the Satellite Civil Wars.
Unlike the prior satellite senshi wars, the Satellite Civil Wars had satellite senshi fighting against their own planetary satellite senshi and not others. (Ex: Uranus' Ariel fighting Umbriel, Saturn's Tarvos vs Polydeuces)
The fighting didn't end until the cleansing wave of Sailor Saturn's attack, killing all life that had remained in the solar system.
With all life obliterated, Sailor Charon was able to roam free until the next life forms appeared.