A Flying Trader that comes around every 5 years, stays 1-2 month and then leaves again. An upgraded trading dock and an upgraded beacon are necessary. The flying trader should dock at the trading dock for immersion. The offered volume is never more than 180 units of a resource and only researched resources can be traded. The more complicated the produce the higher the costs for the exchange. The player should be able to order one specific resource per trade interval. If an order is placed the trader will only offer the ordered resource and some basics. An Order has to be way more costly than a standard trade with contracts or with quick trade. Changing the order while the trader is away will not change the order placed. After the next visit the new order is accepted. Such a small amount of trade volume will not break the game-play with the contracts but can offer a moment of relief for a sparse resource an greatly increases the immersion for a game placed after a global crises.
Flying Trader for small orders and gameplay immersion.
Inspiring idea, but I see it differently. First, lore-wise, I'd call that ship "Travelling scavanger". It drops by occasionally (once in a few years average) docking at trading port for a month, only if there is beacon exist. There is a chance it may bring a desise, but that is the only disadvantage. Essentially, it is just a trading spot at your gate with random offers every time. It buys stuff u r able to produce by the time of arrival and offers some higher tier items like gold, microchips, servers - those are sold at disadvantageous rate; also it offers bulk quantities of scraps as a set of generous offers. In addition it has reputation, like a settlement. To increase it, u donate water and diesel, and the result will be discounts for the trade deals. Rep resets every visit.