SCIM (Sample Collection for Investigation of Mars) is a low-cost low-risk Mars sample return concept. SCIM returns dust and air samples without landing or orbiting, by passing through the atmosphere as it collects samples. The design utilizes heritage from the successful Stardust and Genesis sample return missions. SCIM was studied by the Mars Scout Program, which successfully landed Phoenix in the north polar region of Mars.
A pass through the atmosphere about 40 km (25 miles) above Mars would result in millions of particles being encountered. The particles would be captured in an aerogel similar to Stardust's.