Being a particularly dumb fellow layman but seeing no other comments after 18h…

I’m picturing a ruler thrown into gravity waves and another ruler somehow measuring the parts of the first one where millimeter markers stop being one millimeter apart.

Now for Gemini’s summary:

Space-based gravitational wave detection is the study of ripples in spacetime using observatories positioned in orbit rather than on Earth. While ground-based detectors like LIGO and Virgo have already proven these waves exist, they are limited by their size and Earth’s seismic “noise.”

How It Works

Space-based detection uses laser interferometry across millions of kilometers of vacuum.

• The Formation: LISA will consist of three spacecraft flying in a triangular formation, roughly 2.5 million kilometers apart, orbiting the Sun behind the Earth.

• The “Arms”: Each spacecraft contains “test masses” (gold-platinum cubes) that float freely in a vacuum, shielded from solar wind and radiation.

• The Measurement: Lasers are fired between the spacecraft to monitor the distance between these cubes. When a gravitational wave passes through the formation, it causes the fabric of space to stretch and squeeze, changing the distance between the cubes by a fraction of an atom’s width.

… Honestly I’m feeling reasonably good about my dummy understanding. The “rulers” are lasers being shot between satellites all around the Earth, but I think it sounds roughly right?

Not sure this honors the spirit of the question, but I think GrapheneOS may be something you’re looking for.