Topic summary
Upmass
Extracted from the Wikipedia article Space logistics.
Downmass
While space logistics often emphasizes upmass, referring to the delivery of payloads from Earth to orbit, many space activities also require the return of material, referred to as downmass. Downmass capacity is important for scientific sample return, on-orbit research and manufacturing, hardware refurbishment, and waste management, and can represent a critical constraint in mission and campaign design.