知
=
口
+
矢
:
Mnemonic symbol: Francis Bacon is attributed to have stated "scientia potentia est", "knowledge is power". I'll thus represent 知 by Francis Bacon. Francis Bacon (知) and James II of England (zh) are playing darts (矢) in front of the space station (Ø1). Because they lack a dart board they just use a mandarin (口).
识
=
只
+
讠
:
Sherlock Holmes (sh) is inspecting the new arrival at the entrance of the space station (Ø2). It's a big advertising column (讠) with a cuttlefish (只) on it, to broaden the space station's inhabitant's knowledge (识).