After all that walking, hearing Nitta exclaiming that he wants to go back is hardly music to the rest of his group's ears - a fact not really improved by his explanation that he needs to backtrack to retrieve his lost mobile phone.
Although Nitta is prepared to turn tail and walk back alone, leader of the day Mutta is having none of it, and in a rare assertion of his authority he takes control of the situation entirely, insisting that the group travel onwards to their next food ration drop-off point and setting up camp before returning to look for Nitta's phone. Despite Nitta himself being far from happy with this decision, it's clear that this is the smartest course of action for all concern.
Thus, once camp has been set up, Nitta and Mutta retract their steps to find the missing phone - a situation which also gives Mutta, and us, an opportunity to learn about the all-important phone call which Nitta has been waiting for and expects tonight. In short (and as hinted heavily at a few episodes back), Nitta does in fact have a brother - a brother who is something of a genius when it comes to his knowledge of space, but this is a knowledge that is being wasted as Kazuya is both a drop-out and a shut-in, refusing to leave his room or speak to anyone. With Kazuya having promised to call his brother at long last after having not spoken to him for two years, can Nitta retrieve his lost phone in time?
Perhaps the biggest problem with this particular plot point is - if Nitta hasn't spoken to his brother in two years, why wait until a week where you're trekking across the desert to suggest that said brother call him? Putting this to one side, this week's episode of Space Brothers was mostly enjoyable on account of Mutta's role in charge of his group - for all of his frequent depictions as something of a bumbling eccentric, it was nice to see him in a position of power taking charge of the situation and getting things done in the most effective manner to add a little extra depth to his character. I just hope we don't get too overly caught up in Nitta's current situation, as I get the feeling that the series has far more interesting fare that it could be bringing to the fore.