CRS: sustain a laboratory through recurring deliveries

Commercial Resupply Services, or CRS, purchases cargo transport for the International Space Station. Food, equipment, spare parts and research material support the laboratory’s work, while disposal and return remove different kinds of cargo. NASA awarded the first contracts to SpaceX and Orbital Sciences in December 2008, before their development demonstrations were complete.

The first operational SpaceX CRS mission flew in October 2012. Cygnus Orb-1, launched in January 2014, was Orbital’s first operational delivery after its 2013 demonstration. NASA, station partners, launch providers, spacecraft teams and payload specialists had to coordinate schedules and interfaces for each mission, not merely select a company once.

Different vehicles and configurations offer different combinations of pressurized cargo, external cargo, disposal and return. Dragon can bring cargo back through controlled reentry and recovery; Cygnus’s normal mission ends in destructive reentry with disposal cargo. A kilogram delivered and a kilogram returned therefore describe different services.

Early Dragon and Cygnus missions used robotic capture and berthing — open definition at the station. Later Cargo Dragon missions docked autonomously. Architecture and generation matter when reading a photo or capability table. Do not apply one mission’s approach method or cargo capacity to every vehicle carrying the same broad commercial label.

NASA announced CRS-2 selections in January 2016 for Orbital ATK, Sierra Nevada Corporation and SpaceX. This historical selection does not prove that every selected vehicle flew on the original schedule. Company names, contract terms and mission plans can change, so a flight claim needs a dated mission record rather than the award announcement alone.

Service continuity also depends on inventory, alternative transport and recovery from delays or failures. A useful comparison states the type of cargo, destination, delivery and return requirements, and period being assessed. The program’s achievement is sustained support for station work through a sequence of actual services, with each mission evaluated by what it delivered.