Hachirota "Hachimaki" Hoshino (often shortened to just "Hachi") is the protagonist of the anime as well as the manga. He is from Kujukuri, a city on the east coast of Japan and near Tokyo. His father, Goro, is also an astronaut and his mother is a housewife. He's twenty-five years old. Hachimaki starts out a little full of himself as he trains Ai Tanabe to perform EVA work, while his ego and hotheadedness are not exactly an asset he is able to provide her with a solid mentor figure in addition to a good understanding of EVA operations. His own mentor was former astronaut and fellow debris hauler Gigalt Gangaragash, who gave him the nickname of "Hachimaki". As the series progresses Hachi enlists himself into the Jovian expedition in an attempt to join the crew of the nuclear fusion powered spacecraft, the Wernher von Braun, on its history-making voyage to Jupiter.
- Goro Hoshino
- Hachimaki's father. He is the Chief Engineer of the Von Braun Jupiter Exploration Spacecraft. He is portrayed as an eccentric genius, and seeks to constantly irritate his eldest son. He plays the part of the "dirty old man" but is generally harmless. Goro was a pioneer in space exploration, as he was on a mission to build a human settlement on Mars among other exploits before joining the Von Braun.
- Hachimaki's younger brother, currently a high school student on Earth and an amateur rocket maker. Kyutaro considers Hachimaki an "insincere astronaut", as he feels that Hachi's role as a debris hauler does not warrant the title and the connotations that come with it. This echoes a sentiment expressed early on by (a completely inexperienced) Ai Tanabe. Any conversation between the two almost always degenerates into a brawl as they argue over their differing perspectives on space. Kyutaro hopes to eventually become an engineer to design larger and more powerful rockets that would allow humanity to push its boundaries further into the solar system.
- Formerly his teammate, then girlfriend, Hachimaki married Ai Tanabe just before he left for the seven year trip to Jupiter. Hachi first encountered Tanabe as a hard working but largely unskilled new hire assigned to Debris Section. Over the course of her training Tanabe's defining sense of right and boundless enthusiasm is able to leave an impression on even the ever-pessimistic Hachimaki. Despite their initial frustration with each other, they develop mutual respect for one another which forms the basis of their friendship and eventual romantic relationship. Tanabe is also noteworthy for being easily the most directly affected by Hachimaki's obsession with the Jovian mission, it causing her significant personal hardship.
|Characters of Planetes|
| Main characters: Hachirota "Hachimaki" Hoshino • Ai Tanabe • Fee Carmichael • Yuri Mikhalkov|
Minor characters: Claire • Hakim • Gigalt • Nono • Philippe Myers • Edelgard Rivera • Arvind Ravi • More…