S01E01 Little Brother Hibito and Big Brother Mutta
The year 2006. Two brothers, Nanba Mutta (age 12) and Hibito (age 9), happen to spot a UFO headed for the moon. The experience inspires them to make a certain promise.
Space Brothers
S01E47: The First Promise
Mutta and the other astronaut candidates have arrived in Houston to begin training at NASA. First up is a social event to meet the other astronaut candidates from around the world.
Overview
When they were young, the brothers Mutta and Hibito promised each other they would become astronauts. Now, in 2025, Hibito has followed his dream to become the first Japanese on the moon, but Mutta has just been fired from his job. His brother reminds him of their childhood promise, and Mutta decides once again to aim for space.
Episodes
S01E02 My Shining Star
With his mother's assistance and Hibito's encouragement, Mutta has been accepted for the New Astronaut Selection Exam. However, unsure of his next step, he visits Sharon, who works at a nearby observatory. After receiving advice...
S01E03 The Man with the Advantage and the Running Female Doctor
After advancing to the second exam, Mutta realizes that the other applicants are much better prepared than he is. Desperate to prove himself, he stakes everything on the lung capacity test, as he has confidence...
S01E04 Next to Hibito
After a long week, only the final interview remains in the second JAXA exam. Mutta is drawing attention as Nanba Hibito's older brother, but he insists he won't spend his entire life as Nanba Hibito's...
S01E05 Days of Missing
After completing the second JAXA exam, Hibito invites Mutta for a free trip to Houston, Texas, through NASA's family support program. Upon arrival, he finds himself chased by a pug named Apo, and is then...
S01E06 Et Cetera in My Head
Mutta has arrived in America, but he's off to a rocky start with Hibito. Meanwhile, his future as an astronaut is in jeopardy because the headbutt incident has been brought to JAXA's attention.
S01E07 Dear Hibito
After learning that his former boss has told JAXA about the headbutt incident, Mutta has given up hope on passing the exam. To cope, Mutta falls back on his childhood habit of multitasking like crazy...
S01E08 Smoky Heaven
When the robber known as the fire extinguisher man strikes the restaurant where Mutta is, he's in trouble. But once the dust settles, Mutta has become a national hero for capturing the criminal. However, it...
S01E09 Individual Resolve
After passing the second JAXA exam, Mutta returns to Japan for the third. He's happy about the exam result, but on the flight back, a nightmare leaves him rattled. This is due to the letters...
S01E10 Running Bus
Mutta has learned that Kenji and Serika have strong reasons to become astronauts, while Mutta is simply trying to achieve a childhood dream. This causes Mutta to begin to question himself.
S01E11 Trapped Rivals
The third exam will take two weeks. Mutta and the other candidates are transported via sealed bus to a large, barren facility. Then they are led to an area that is known as the last...
S01E12 My Name Is Itou Serika
The fifteen remaining candidates have been divided into three teams of five. Each team will spend two weeks inside a sealed box, while completing various tasks. The first task is to determine the time.
S01E13 3-D Ant
The sealed box teams are assigned more tasks. These include Running Math, five minutes of mental math while running, and a typing test. Next, they're asked to write a letter of protest to a journalist...
S01E14 Broken Glasses and the Sole of the Foot
After five days in their sealed boxes, each team is exhibiting a pronounced personality. Mutta's Team A is rowdy, while Team C is quiet. However, Kenji's Team B appears to be a little gloomy.
S01E15 Let's Talk About Space
The exam in the sealed box is halfway over. Mutta's Team A suffered an accident when Fukuda's glasses were broken. But Furuya, the one who broke them, requested a new pair. Meanwhile, Team B must...
S01E16 Alarm, but No Clock
The third exam is halfway over. Mutta works on a completely white puzzle as he ponders why Fukuda-san would break the only clock in the sealed box.
S01E17 The Culprit Is in the Room
The third exam inside the sealed boxes has been underway for ten days. Each team has been experiencing unexpected problems, such as broken clocks and mysterious alarms that ring in the middle of the night....
S01E18 Roo-ra! Kenji!
The candidates have only a few days left in the sealed boxes. JAXA has been using green cards to create trouble, gauging each member's ability to respond to stress and trouble.
S01E19 The Day Before Goodbye
The teams have two days left in the sealed boxes. Mission Control has deliberately not given certain members of Kenji's Team B any green cards, leading to paranoia. Meanwhile, in Team A, Mutta announces that...
S01E20 The Worst Possible Punishment
It's their final day in the sealed box. Mutta has enjoyed his two weeks with the team, and he wishes to avert ruining their bond, as they make their final decision.
S01E21 A Long-Awaited Glimpse of the Sky
With the third exam finally over, Furuya takes the opportunity to visit the man who made his dream possible.
S01E22 Working on the Dream
The third astronaut selection exam has finally ended. Team A used rock-paper-scissors to select two members. Whose dreams are still alive?
S01E23 Father, Son, and Mutta Claus
Mutta has been picked to go to Houston for the final astronaut selection exam. But because his selection means that Kenji wasn't chosen, he has mixed feelings.
S01E24 The Worst Possible Interviewer
The final exam is set to take place in two months. Mutta heads to Houston, ahead of the other candidates to look after Apo and tour the Johnson Space Center. Meanwhile, Hibito is training hard...
S01E25 Sonic Little Brother Training Big Brother
With the final astronaut selection exam coming up, Mutta heads to Houston. However, Jennifer has some ominous news.
S01E26 Painful Interview
Seven days remain before Hibito takes off on a journey to become the first Japanese person to walk on the moon. Meanwhile, Mutta prepares for the final astronaut selection exam at Johnson Space Center.
S01E27 One Question
The final NASA interview was a decoy to trick the candidates into relaxing, so the astronauts could evaluate them. However, the candidates have yet to realize this.
S01E28 Miracle of Doha
With four days before the launch, Mutta and his family arrive at Kennedy Space Center for one last meal with Hibito before he heads into space. Mutta uses this opportunity to hand Hibito a very...
S01E29 Night Before Launch
Two days are left before launch. First, the lunar lander Artemis goes into space on Mars V. Afterwards, Hibito and the rest of the crew will head into space on Mars I.
S01E30 Dog, Old Man, and Alexander
It's finally the day of the launch, but the weather doesn't look good. On top of that, Apo's run off, so Mutta has to go find him. While searching for Apo, Mutta comes across a...
S01E31 Rocket Road
Mutta, Apo, and the strange old man watch as Hibito launches off into space. Afterwards, Mutta reminisces about the road taken by Hibito to reach this point.
S01E32 A Private Place
Hibito has made it safely into space, and he's on his way to the moon. Meanwhile, Mutta runs into Azuma and his family, and he decides to approach them.
S01E33 Moon Rabbit
Hibito and the CES-51 crew finally land on the moon. However, Mutta is worried that Hibito will embarrass their country when he takes his first step.
S01E34 Pug and Hug on a Moonlit Night
Hibito and the CES-51 crew have landed on the moon. Meanwhile, Mutta has returned to Japan to await his final exam results. He's especially concerned about using up his luck before the results are announced.
S01E35 From the Little Corner of a Big Facility
JAXA has begun announcing the results of the final astronaut selection exam. Makabe Kenji receives the first phone call. As Kenji waits to learn his fate, he reflects on his motivation for wanting to be...
S01E36 Dancing Astronaut
While Mutta waits to hear if he will become an astronaut, Kenji has received good news. The next candidate to get a call is Serika.
S01E37 Two Men in the Park
Two hours have passed since JAXA was supposed to notify the candidates, and Mutta hasn't received a call. When the phone finally rings, he's told to go to a nearby park. What will his fate...
S01E38 Eleventh E-mail
After a long wait, Mutta learns that he passed the final exam. With no time to enjoy the moment, he is immediately whisked to the press conference, where the other new astronauts wait.
S01E39 Lunar Illusions
Mutta has begun his life as an astronaut. First, he must undergo a month of JAXA training and orientation. Meanwhile, Hibito and Damian head out in a lunar rover to track down a missing probe.
S01E40 Heaven and Hell
Damian and Hibito leave Moonbase in search of a missing unmanned probe. However, an accident occurs, stranding them inside a ravine.
S01E41 Eighty Minutes to Live
After a buggy accident, Hibito and Damian are stuck at the bottom of a ravine. Damian's spacesuit is damaged, and he's losing body heat quickly. The odds are against them, but Hibito decides that the...
S01E42 Hibito's Choice
Hibito manages to bring Damian back to the surface by using Gibson, but he's running out of time, as his oxygen supply dwindles. Will Freddy and Buddy find him in time?
S01E43 Brian
Hibito is able to save Damian, but he's running out of oxygen. Freddy and Buddy are trying to catch him, but they won't arrive before his oxygen depletes. Is this the end?
S01E44 Three Astronauts
Oxygen generation system Brian arrives just in time to save Hibito. Once he and Damian are rescued and back at Moonbase, he reflects on the astronauts who saved him.
S01E45 Five Blue Rangers
Mutta and the other astronaut candidates have finally finished their Japanese training. Before they head to Houston, they receive a gift from Director Nasuda.
S01E46 Number One Restless Guy
The JAXA astronaut candidates head to Houston, to begin training at NASA. However, Murakami-san appears to have a surprise in store for Mutta.
S01E47 The First Promise
Mutta and the other astronaut candidates have arrived in Houston to begin training at NASA. First up is a social event to meet the other astronaut candidates from around the world.
S01E48 Always Have a Pedometer in Your Heart
The first astronaut candidate task is undergoing a survival training course consisting of a six-day trek through the desert. Meanwhile, Mutta is still worried about Amanti's reaction after she read his fortune.
S01E49 Nitta the Leader
The astronaut candidates continue their survival training in the desert. Team E has fallen behind the others, but after Nitta takes the lead, they try to pick up the pace.
S01E50 Nitta and Mutta
As the survival training draws to a close, Nitta suddenly tells the team he needs to backtrack due to losing his cell phone, but Mutta stops him. However, Mutta appears to have an idea in...
S01E51 Living Stone
Mutta and Nitta backtrack through the desert, looking for Nitta's cell phone. But Nitta cannot find it in time to answer his little brother's call. Has he lost another chance to reach him?
Cast
Hiroaki Hirata
Mutta Nanba (voice)
Miyuki Sawashiro
Mutta Nanba (voice)
KENN
Hibito Nanba (voice)
Masayuki Katou
Kenji Makabe (voice)
Miyuki Sawashiro
Serika Itou (voice)
Masako Ikeda
Sharon Kaneko (voice)
Yuko Sanpei
Hibito Nanba (voice)
Shô Ryûzanji
Tadashi Hoshika (voice)
Ryou Naitou
Yasushi Furuya (voice)
Shintaro Asanuma
Yamato Mizoguchi (voice)
Takanori Hoshino
Reiji Nitta (voice)
