Lunar module and mechanical clock: what they have in common

1. Step 1. Lunar module — has part — Liquid-propellant rocket engine. A descent engine.
2. Step 2. Liquid-propellant rocket engine — is part of — Space Shuttle. Hydrogen-fuelled main engines.
3. Step 3. Space Shuttle — is made of — Silica (sand). The heat-shield tiles are silica fibre.
4. Step 4. Silica (sand) — is material for — Quartz clock. The resonator is a quartz crystal.
5. Step 5. Quartz clock — evolved from — Mechanical clock. Quartz clocks replaced mechanical ones: a vibrating quartz crystal took the place of the pendulum and balance.

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