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.

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