Title text: We're going to have to work together to get over our hangups if we're going to learn to move on Catan's hexagonal grid. It's bad enough that we lost our crew of pawns when we passed within firing range of Battleship.
The typical representation of explorers has them travel from their homeland aboard a ship to unknown distant places. The travel can get very long, implying the need for food supplies on the ship; and the fact that the crew members have to live together with little room (the ship) for such a long time, with possibilities of failure, getting lost or dying for various reasons, can often lead to tensions between some of them. In the Age of Exploration the explorers were mainly sailors from Europe traveling on the sea to other continents, whereas in space exploration they are astronauts or robots from Earth traveling in space to other planets (or whatever celestial bodies), but the general concepts of exploration remain the same.
Here the explorers are two chess pieces, a knight and a bishop; they have left their "home board", presumably a full 8x8 chess board, aboard a smaller "capsule" made of a small 3x3 chess board in motion. It could be drifting in the sea; rolling along a hard surface on wheels or casters, as indicated by the small circles by each corner; or flying through space with the circles as rockets. The drawing is somewhat ambiguous. They are apparently headed for a Settlers of Catan board, and already passed near a Battleship board, so these game boards are like islands or regions which the chess pieces explore, coming from a chess board.
Ba3, Nc3 and Ke5 are the identification of chess pieces and their respective position: Ba3 is a bishop on the A3 square, Nc3 a knight on the C3 square, and Ke5 a king on the E5 square. Chess is pretty much a representation of the structure of medieval European society (with the king and queen being the most crucial pieces, the bishops representing the somewhat powerful clergy, the knights corresponding to the armies, the rook alluding the castles, and the pawns being, as the medieval working classes, the most numerous and disposable assets); so chess pieces exploring other places, approaching the "coast of Catan", and reporting to the king ("calling Ke5"), is reminiscent of explorers from Europe who under their king's jurisdiction set sail to other continents during the Age of Exploration.
In chess, the knight and the bishop have different move constraints. The knight can only move two squares horizontally and one square vertically, or two vertically and one horizontally, so on the capsule the knight explorer can only go from one corner square to a black square, or vice-versa. The bishop can only move diagonally, so this bishop is bound to move only on the white squares. The knight is also the only piece that can "jump" over other pieces, which seems to annoy the bishop, hence the "hopping around"; apparently the bishop put all the food onto the middle square, which the knight can't reach, because the knight was taunting him about his not being able to get onto a black square.
The two pieces are from the opposite chess camps (one black and the other white). This can be a reference to multinational space mission crews, where formerly opponent nations joined their efforts on space missions. But in chess it also means they can capture each other, by getting on the square where the other stands. Here, with the chess turn-by-turn gameplay, the knight won't be able to capture the bishop (except of course in case of error or dumb move), since the bishop will always be able to escape, whereas the bishop is actually one or two moves away from capturing the knight. So saying that he's "this close" to capturing him is a play on words, he is "this close" as in a few moves away, as well as "this close" as in severely annoyed and about to act on it.
Finally, the title text adds two jokes. The Settlers of Catan board has an hexagonal grid, which means the chess pieces will have difficulty to move on it, since they are used to moving on a squared grid. This can draw a parallel with explorers facing, in distant lands, weather conditions, wild animals, atmosphere or whatever condition, to which they are not used at all in their homeland. Battleship is a game where players send shots on the opponent's board, which is why the chess capsule received shots when it passed within firing range of a Battleship board; in pure chess style, it's the pawns of the crew, the least valuable and most disposable chess pieces, who took the shots.
- [A black bishop, Ba3, and a white knight, Nc3, are on a three by three chessboard. Both are on white squares. There is a heap of supplies at b2, also a white square. The chessboard is mounted on rockets and appears to be flying through the air.]
- Ba3: Mission Control, come in. This is Ba3 on the capsule calling Ke5 on the home board. We're on track and approaching the Coast of Catan. Our ETA is—
- Nc3: Control, this is Nc3. Bishop put all our food in the center so I can't get it. I demand—
- Ba3: Control, knight will get his food back when he stops hopping around bragging about how comfy the black squares are. I swear to God, I'm this close to capturing him and completing the mission alone.