A digital processing device, intended to be embedded aboard a space platform, comprising a plurality of input and output ports, and having a multi-module modular architecture based on the use of one or more types (10, 12) of basic elementary modules, and on a connectivity matrix of predetermined size, said device comprising. - a first plurality of input ports (4 1, 4 2,..., 4 ne),. - a second plurality of output ports (6 1, 6 2,..., 6 ns), and. - a third plurality of at least four basic elementary modules (14 1, 14 2..., 14 k; 16 1, 16 2,...16 l; 18 1, 18 1, 18 2,..., 18 m; 20 1, 20 2,..., 20 n), characterised in that the third plurality of the elementary modules is split up according to a partitioning of at least two sub-assemblies (32; 34; 36; 38) of module(s) (14 1, 14 2..., 14 k; 16 1, 16 2,...16 l 18 1, 18 1, 18 2,..., 18 m; 20 1, 20 2,..., 20 n), each sub-assembly (32; 34; 36; 38) of module(s) containing one or more elementary module(s) (14 1, 14 2..., 14 k; 16 1, 16 2,...16 l; 18 1, 18 1, 18 2,..., 18 m; 20 1, 20 2,..., 20 n) and a different monobloc mechanical structure (42, 44, 46, 48) in which are integrated the one or more elementary modules (14 1, 14 2..., 14 k; 16 1, 16 2,...16 l; 18 1, 18 1, 18 2,..., 18 m; 20 1, 20 2,..., 20 n); and at least two sub-assemblies (32, 34, 36, 38) of modules of the partitioning of the third plurality are sub-assemblies of at least two modules, each defining a different islet of modules, and the digital processing device contains a harness of optical links (54, 56, 58, 62, 64, 66) for mutually interconnecting the sub-assemblies (32, 34, 36, 38) of modules whose interconnection lengths are compatible with interconnection runs between two interconnected islets (32, 34, 36, 38), said interconnection lengths being arranged so as to avoid, by sidestepping, one or more items of equipment external to the digital processing device, which are installed on the space platform and interposed between the two interconnected islets, and/or to distribute at least two interconnected islets over two heat exchange zones of the space platform that are separated by a separation distance of the scale of the size of the platform, at least one external interconnection length of the optical harness between two islets of modules being comprised between 1 metre and 50 metres, preferably between 1 and 7 metres.. - a first plurality of input ports (4 1, 4 2,..., 4 ne),. - a second plurality of output ports (6 1, 6 2,..., 6 ns), and. - a third plurality of at least four basic elementary modules (14 1, 14 2..., 14 k; 16 1, 16 2,...16 l; 18 1, 18 1, 18 2,..., 18 m; 20 1, 20 2,..., 20 n), the third plurality of the elementary modules is split up according to a partitioning of at least two sub-assemblies (32; 34; 36; 38) of module(s) (14 1, 14 2..., 14 k; 16 1, 16 2,...16 l 18 1, 18 1, 18 2,..., 18 m; 20 1, 20 2,..., 20 n), each sub-assembly (32; 34; 36; 38) of module(s) containing one or more elementary module(s) (14 1, 14 2..., 14 k; 16 1, 16 2,...16 l; 18 1, 18 1, 18 2,..., 18 m; 20 1, 20 2,..., 20 n) and a different monobloc mechanical structure (42, 44, 46, 48) in which are integrated the one or more elementary modules (14 1, 14 2..., 14 k; 16 1, 16 2,...16 l; 18 1, 18 1, 18 2,..., 18 m; 20 1, 20 2,..., 20 n); and at least two sub-assemblies (32, 34, 36, 38) of modules of the partitioning of the third plurality are sub-assemblies of at least two modules, each defining a different islet of modules, and the digital processing device contains a harness of optical links (54, 56, 58, 62, 64, 66) for mutually interconnecting the sub-assemblies (32, 34, 36, 38) of modules whose interconnection lengths are compatible with interconnection runs between two interconnected islets (32, 34, 36, 38), said interconnection lengths being arranged so as to avoid, by sidestepping, one or more items of equipment external to the digital processing device, which are installed on the space platform and interposed between the two interconnected islets, and/or to distribute at least two interconnected islets over two heat exchange zones of the space platform that are separated by a separation distance of the scale of the size of the platform, at least one external interconnection length of the optical harness between two islets of modules being comprised between 1 metre and 50 metres, preferably between 1 and 7 metres.