不时之需

不 = 丆 + 卜 : Bruno Bear (bu) is setting up a wind wheel (丆) with a voodoo staff (卜) in the space station's bathroom (Ø4). He also puts a "forbidden" sign (mnemonic symbol for 不) on it, to make clear that it may not (不) be stopped.

时 = 寸 + 日 : Mnemonic symbol: a giant pocket watch.

The sun (日) asks Sherlock Holmes (sh) out for a coffee in the space station's kitchen (Ø2). Looking at his pocket watch (时), Sherlock sees he has time, winks and "thumbs up" (寸).

之 = 丶 + Z : Mnemonic symbol: Sooo sleepy... "zZz" (the character looks like a "Z"). James II of England (zh) fell asleep in front of the space station (Ø1). He sleeps on a big petal leaf (丶), making loud "zZz" (之) sounds.

需 = 而 + 雨 : Mnemonic symbol: When it rains and you do not want to comb your hair again, you need a rain cape.

需 = 而 + 雨 : It is raining in front of the rain station. Because Xu Xian doesn't want to comb his hair again, he uses a rain cape to stay dry.