CRS-18 delivered the third International Docking Adapter, replacing the one lost in the CRS-7 failure four years earlier and giving the station a second modern docking port. With commercial crew flights approaching, having two ports rather than one provided essential operational flexibility.
The Dragon capsule was making its third flight, the first spacecraft in the programme to do so, having previously flown in 2015 and 2017. Each refurbishment cycle had been shorter than the last.
The cargo also included a biological experiment growing human tissue models to study drug responses, and a facility for producing high-quality protein crystals of pharmaceutical interest — the kind of research that justifies the station to a sceptical audience.
The first stage landed at the Cape, the landing zone having returned to service, and the flight proceeded without complication.
Around 2,300 kilograms was delivered. The adapter it carried has since received dozens of crewed arrivals, and the pair of ports it completed is what allows two commercial vehicles to be docked simultaneously.
