The mission of  the rotating space station technology demonstrator is: first, to acquire knowledge on the behaviour, operation and control of a giant revolving structure in space for the first time; and second, to simulate Moon, Mars, Earth and other Solar System gravities for research in Earth orbit also for the first time. The design envisions a truss structure formed into a giant open ring 220 metres in diameter that resembles a hula-hoop. It dispenses with the hub-and-spoke approach of traditional revolving station concepts by resolving all rotational structural loads through the ring structure. This has an octagonal cross-section eight metres across and comprises six ring segments that fold up into compact payloads for launch and then extend and deploy in space. Crewed spacecraft visits occur when the ring is at rest at 0-g. At mission end, the ring is dismantled and the curved segments straightened for other applications.

The ring operates like a traditional Ferris wheel, spinning up and down as desired. Eighteen low-thrust solar ion engines powered by xenon gas provide the rotational power. The engines enable the ring to spin up very slowly from 0-g to 1-g and back through a range of angular velocities that simulate different Solar System gravities. Rotational acceleration or deceleration can halt to spend time at any gravitational point for research. The engines also provide attitude control and stationkeeping.  Each payload segment stows as a flat pack inside the Starship fairing with the propulsion tank and retracted solar ion engines at the top of the stack. The ring structure consists of 120 structural bays with octagonal bulkhead frames connected by longerons and X-braces that fold up inside the bulkheads for launch and deploy in space. Each bulkhead has a 'clamshell' design with two hinged frames opened by electric actuators to an angle of 3° to induce the ring's curvature throughout its 120 bays. Each payload is an independent spacecraft with its own propulsion, guidance, navigation and control enabling it to rendezvous with the orbital assembly site. It closes with the aft end of a previously deployed segment where it is grappled by a robotic arm and brought in for a hard berthing under control from the ground. 

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