ScienceDaily
Sample return
Bringing a piece of somewhere else back to a laboratory on Earth.
Instruments that fit on a spacecraft are always a compromise; the ones that fill a building are not. A returned sample can be re-examined for decades with equipment that did not exist when it was collected, which is why Apollo material is still producing results. Hayabusa2 brought back 5 grams of Ryugu, OSIRIS-REx about 120 grams of Bennu, and Chang'e 5 and 6 returned lunar material including the first from the far side. Mars is the hard case: the samples Perseverance has already sealed are sitting on the surface waiting for a retrieval mission whose cost and schedule are, at present, unresolved.
Where it has come up lately
NASASpaceflight
The Planetary Society
Related terms
Gravity assist
Stealing a fraction of a planet's orbital momentum to go faster for free.
Regolith
The layer of broken rock and dust covering an airless world — and a serious engineering problem.
Opposition and conjunction
The two alignments that decide when a planet is worth looking at and when it is unreachable.
Tidal locking
When a body's spin has been dragged into matching its orbit, so one face never turns away.
Questions
What is Sample return?
Bringing a piece of somewhere else back to a laboratory on Earth.
Why does it matter?
Hayabusa2 brought back 5 grams of Ryugu, OSIRIS-REx about 120 grams of Bennu, and Chang'e 5 and 6 returned lunar material including the first from the far side. Mars is the hard case: the samples Perseverance has already sealed are sitting on the surface waiting for a retrieval mission whose cost and schedule are, at present, unresolved.