After an abortive attempt to get him there last week, Mutta has finally taken his brother up on the opportunity to tour NASA's Lyndon B. Johnson Space Centre - naturally, the phrase "kid in a candy store" is very much applicable here.
While Mutta gets to enjoy the sights and sounds of his tour, seeing Hibito continuing with his own training and hard work in preparation for taking to the moon stirs up another bout of competitive jealousy as he watches his younger sibling and "Samurai Boy" doing the rounds, while once again showing his blasé eye for detail in everything he does. Perhaps even more notable from Mutta's point of view is not how hard Hibito is working, but how popular he's become - not just within NASA itself, but also to the outside world as he does his PR bit of an American talk show, which seems to be going swimmingly until Mutta can't bear but to hide himself away as Hibito mentions him to the watching world.
Unfortunately for our protagonist, this is also the point where he learns that his past might just be catching up with, as news of his dismissal from his job in the past and the exact reason for that dismissal come to the attention of JAXA's selection committee. For most of those present, this automatically excludes him from the running in regard to qualifying for the next round of testing, but unbeknownst to him Mutta has a friend on the inside - a man who is familiar with the Nanba brothers and their dedication to all things space from their childhood. Thus, like some kind of surrogate parent, he stops at no lengths in clearing Mutta's name and proving that there's no reason that the incident in question should count as a red mark against his application. Will he succeed in presenting this argument to his colleagues? That's one for next week.
Once again, Space Brothers "just works" - it doesn't do anything sensational in this episode to grab the viewer or drag them towards the edge of their seat, but it continues to leave you cheering on Mutta regardless while genuinely enjoying the continued heart-warming plot points of the show, whether it's the two Nanba brothers and their respect, love and rivalry towards one another or Mutta's "guardian angel" on the selection committee who goes the extra yard out of his belief in a boy he's kept tabs on for decades. It's simply hugely enjoyable to watch - no further explanation can really be presented for it, such are the simple but successful qualities of the series to date.