Space station

Find three groups of three connected words.

Mistakes left: ●●●●

Choose three words, then submit your group.

Puzzle notes

This original practice board has nine words and three intended categories. Look for specific shared meanings rather than a broad association. It is part of TrioNine’s 38-puzzle collection, published October 1, 2026.

Words on this board: IO, EUROPA, GANYMEDE, HUBBLE, WEBB, KEPLER, TROPOSPHERE, STRATOSPHERE, MESOSPHERE.

Reveal this puzzle’s three groups and explanations

Galilean moons

IO · EUROPA · GANYMEDE

These are three of the four large moons of Jupiter discovered by Galileo.

Space telescope names

HUBBLE · WEBB · KEPLER

These names have been used for space telescopes.

Atmospheric layers

TROPOSPHERE · STRATOSPHERE · MESOSPHERE

These are successive layers of Earth’s atmosphere.

Solving strategy · More original puzzles