Sample return mission

A sample-return mission is a spacecraft mission with the goal of collecting and returning with tangible samples from an location to Earth for analysis. Sample-return missions may bring back merely atoms and molecules or a deposit of complex compounds such as loose material ("soil") and rocks. These samples may be obtained in a number of ways, including a collector array used for capturing particles of solar wind or cometary debris, soil and rock excavation, mining, and any other possible way for retrieving samples in the environment.

Up to the present, humanity has collected samples of six identified Solar System bodies, as well as samples of the solar wind. These samples were acquired through three methods: The collection of samples of Earth itself, the collection of meteorites that have fallen on Earth, and the collection of samples through sample-return missions. Samples of Moon rock from Earth's Moon were collected both from meteorites and through unmanned and manned sample-return missions. The comet Wild 2 and the asteroid 25143 Itokawa were visited by unmanned spacecraft, which returned samples to Earth. Furthermore, samples for three identified Solar System bodies were only collected by means other than sample-return missions: samples from Earth itself, samples from Vesta in the form of HED meteorites, and samples from Mars in the form of Martian meteorites.

Samples available on Earth can be analyzed in laboratories, so we can further our understanding and knowledge as part of the discovery and exploration of the Solar System. Until now many important scientific discoveries about the Solar System were made remotely with telescopes, and some Solar System bodies were visited by orbiting or even landing spacecraft with instruments capable of remote sensing or sample analysis. While such an investigation of the Solar System is technically easier than a sample-return mission, the scientific tools available here on Earth to study such samples are far more advanced and diverse than those that can go on spacecraft. Analysis of samples on Earth allows to follow up any findings with different tools, including tools that have yet to be developed; in contrast, a spacecraft can carry only a limited set of analytic tools, and these have to be chosen and built long before launch.

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