President Obama has signed a bill guaranteeing that NASA astronauts can keep and sell memorabilia from their missions, laying to rest a recent controversy. H.R. 4158 says that any astronaut who participated in the Mercury, Gemini, or Apollo programs through the end of the Apollo-Soyuz Test Project has full ownership of expendable or disposable items they kept with them after landing. That doesn't include moon rocks, other lunar material, or anything NASA required people to return after a mission, and it doesn't cover astronauts from later programs like the Space Shuttle or the ISS. It does, however, lay to rest claims of ownership for many historic mission artifacts by clarifying that NASA cannot attempt to repossess them.
As CollectSpace points out, the law was a response to a growing number of disputes over whether astronauts could auction off space artifacts, which were made by NASA but would mostly have been destroyed or discarded. In 2011, NASA filed suit against Edgar Mitchell, who had brought back a camera from Apollo 14. Later, it challenged the sale of a notebook used in the Apollo 13 landing. This law seems to contradict some of the claims NASA has made in the past, but the space agency says it is "pleased ownership of flight mementos and other artifacts of the Mercury, Gemini, and Apollo astronauts is no longer in question."