• Small bodies are not geologically active • They provide “fossil” record of early solar system – Asteroids • Mostly from region between Mars and Jupiter • Left over small debris from accretion, never assembled into a large planet • Meteorites come mostly from asteroids – Comets • “Stored” on large elliptical orbits beyond planets • Thought to be “planetesimals” from Jovian planet region, almost ejected from solar system in its early history • Meteorites provide only samples besides Apollo – With sample in hand, can perform very detailed analysis: detailed chemistry; radioisotope age; other isotope info