If you've been waiting for Space Brothers to try on some actual space adventure, the wait is over. Hibito's moonside crisis is classic astronaut adventure, in the vein of mission-gone-wrong tales like Apollo 13 and… well, Apollo 13. The series' languorously slow pace—it's ever more obvious that the show is stretching its source material to the limit—keeps his ravine misadventure from truly soaring, but it more than gets by on winding tension, solid psychology, and attention to detail, as well as a honed sense for the wonder of its lunar setting.

It helps if you think about the arc, not as sci-fi action, but as a kind of near-future, astronautical procedural. It has the procedural's concern for process and detail, and professionalism and teamwork. It splits its time fairly equally between Hibito's heroic efforts on the ground—his sacrifices, difficulties, and improvised strategies—and the energetic but considered responses of the NASA command structure. It takes its time to detail the emergency procedures of the organization and the logic behind them, while fully acknowledging the ways real-life emergencies make a mockery of bureaucratic preparation. It gives a good sense of the resources a large organization can bring to bear on a rescue, as well as the potentially deadly inflexibility of rule-bound, regimented institutions. All of which the series parlays into a slowly but powerfully mounting tension; into dangers that are palpably real, and an equally realistic faith in the compounded ingenuity of a team of dedicated professionals to prevail in even the most daunting of circumstances. The arc's ending may push its emotions hard, be they triumphant or bittersweet, but by then it's earned the right to exult in the feelings of its cast.

No sooner has the moon arc proven the show's space-adventuring chops, however, than it plops the series right back into its old groove. Mutta's march through the desert is exactly the kind of stolidly entertaining astronauts-in-training tale that has long been the show's bread and butter. Not to disparage bread and butter. Like the astronaut testing episodes before them, these training episodes are slow and deeply conventional, but also full of fun new characters, potentially interesting challenges, and the sweet (but never saccharine) optimism that makes the show the uplifting treat it is. Best among the new arrivals is Amanti, a beautiful, possibly psychic candidate from India, who supplies the arc's running joke when she receives a bad premonition about Mutta and then lies poorly about it. Which dooms poor Mutta to a hell of superstitious anxiety. (“Don't worry,” she tells Mutta, “you won't be stung by a scorpion.” “So I will be stung by something else,” worries Mutta.)

The real star of this part of the march, however, is taciturn Nitta. The super-fit, super-reserved candidate from Japan has been a bit of thorn in Mutta's side, but the last four or so of these episodes greatly soften his personality, mostly by delving into his relationship with his own younger brother. In light of what we learn, Nitta's digs at Mutta and Hibito take on a whole new, and far more poignant, meaning. The episodes do no favors, however, for Nitta's estranged brother, who is far too petty and selfish and cowardly to justify the trouble Nitta goes through to reconnect with him.

The series' execution throughout this wavers little from the staid professionalism it has taken on of late. Little flashes of humorous verve can be spotted in the mischievous body language of deceased uber-astronaut Brian Jay, or in the Smokey and the Bandit getup Mutta buys for his trip to Houston, but mostly that kind of silly energy is confined to the opening sequence, which is an even weirder take on Georges Méliès' already surreal A Trip to the Moon. The show's other strengths remain strong, from the odd but believable appeal of Koji Yabuno's character designs, to the CG-assisted accuracy of its space-faring technology. Unfortunately it also maintains a stoically competent mix of stills, shortcuts, and actual animation, as well as the peculiarly attenuated pacing of a series whose source material is fast depleting.

The moon arc is by far the better at capitalizing on the series' artistic strengths, making good use of CG vehicles and the moon's otherworldly topography and even making an advantage of the series' stretched-out pacing by using it to ratchet up tension (and find space for more procedural detail). It takes its time to appreciate the beauty of space, even when space is killing its characters, and takes a turn for the almost-poetic at the end. The desert march, on the other hand, has to make do with some less-than-convincing desert scenery and the occasional dose of Mutta's goofy charisma and Serika's potently plausible beauty. Which is more or less an exact reflection of the two arcs' charms. The first is good all over; the second finds its grace notes mainly within its cast. Which, mind you, is not a bad place to find them.