T he sample return capsules from the Genesis and Stardust missions represent the newest collections of space-exposed hardware being curated at the Johnson Space Center. These missions are unusual in that they have returned materials exposed to the space environment outside of low Earth orbit. While the sample return capsules have a number of features in common, they witnessed considerably different flight paths and space environments. Each is a valuable resource for understanding these environments and their effects, but even more so when taken together.
The Genesis spacecraft orbited L1 for more than 2 years, collecting solar wind for return to Earth. The interior surfaces of the open capsule were sun pointing at all times during this phase of the mission, making these materials a unique repository of information on the effects of direct solar exposure. They are also witness to a region of space witnessed by no other returned samples.
The Stardust spacecraft, on the other hand, traveled outward in the solar system, covering nearly 3 billion miles in 7 years. The interior of the capsule was exposed only three times - during the encounter with Wild 2 and the two interstellar dust collection periods lasting several months each. Only the exterior of the capsule was exposed in transit.