astroengine writes "The Earth has one permanent moon — you know, "The Moon" — but at any given time there are thought to be two temporary interlopers that were once asteroids, but get captured by our planet's gravity to become mini-moons for a few months or even years. They eventually get flung back out into interplanetary space. This ultimate "catch and release" provides an interesting opportunity for any future asteroid mission. So now astronomers want to find them, possibly using the newly-minted Hubble-class spy telescopes donated to NASA by the National Reconnaissance Office."
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