Having ignored all of the rules and risked his own safety in an attempt to save Damien in the aftermath of their unfortunate accident on the Moon, it seems as if this decision has backfired spectacularly (and not to mention dangerously) on Hibito.
The injured Damien can only watch on in horror as his colleague crashes to the ground after losing his footing trying to climb up and ensure his safety, and it's a horror that Hibito can only share once he comes around and both parties realise that his primary oxygen tank has been punctured, leaving him with only his backup tank for air. Thus, the countdown begins until Hibito runs out of air.
Even in this scenario, it seems that Hibito's priority remains saving Damien - once he calms down from the initial shock and panic of his situation, he goes about resuming his rescue attempt as before with little regard for the fact that this is simply causing his oxygen supply to deplete further still. Away from the scene of the accident, we flit between NASA and JAXA headquarters as they run through all of the possibilities and devise strategies to deal with whatever they find once Hibito and Damien's fellow astronauts reach the site. Even Mutta has some input on where he thinks the rescue attempt should focus - input based not on the documented protocol for astronauts, but rather his own knowledge of his brother and how he'd think in such a situation. But will NASA listen to what seems like such an off-base suggestion?
As per last week's episode, Space Brothers continues to nail down this current situation with aplomb - the tension of air running out or body temperature dropping too low, the simple human horror of finding yourself so far from home with rescue some way away, the nervous helplessness of being back on Earth with nothing to do but throw out ideas based on worst-case scenarios and so on. It's perhaps inevitable that this is the most compelling stuff that the series has brought us yet simply because of the emotions involved, but even then the way Space Brothers is handling the entire thing is worthy of the highest praise.