A segmented radial seal assembly comprising: a first segment (12; 212; 312; 412; 512; 612; 712; 812) comprising: a first segment first end (42; 142; 542) opposite a first segment second end (48; 148; 548); a first segment radial outward-facing outer surface opposite a first segment radial inward-facing contact face; and a first segment axial contact surface (26; 126; 526) extending between the first segment outer surface and the first segment radial contact face; and a second segment (12; 212; 312; 412; 512; 612; 712; 812) comprising: a second segment first end (42; 142; 542) opposite a second segment second end (48; 148; 548); and a second segment radial outward-facing outer surface opposite a second segment radial inward-facing contact face; wherein: the first segment first end (42; 142; 542) comprises a protruding feature (44; 144; 244; 344; 444; 544; 644; 744; 844); the first segment first end (42; 142; 542) defines a tangential vector (34; 134; 234; 334; 434; 534; 634; 734; 834) from a circumferential ring that is formed by the segmented radial seal assembly; the protruding feature (44... 844) defines a curved face (46; 146; 246; 346; 446; 546; 646; 746; 846) having at least a first axis of curvature, the first axis of curvature being parallel to the tangential vector (34... 834); the second segment second end (48; 148; 548) includes a recessed feature (50; 150; 550) that is matingly engageable to the first segment first end (42; 142; 542), thereby forming a first radial seal segment joint; and the segmented radial seal assembly is configured to surround a shaft; characterized in that: the curved face (46... 846) comprises a cross-sectional shape as viewed into circumferential tangential vector (34...834) that is an arc of an ellipse which extends from the first segment axial contact surface (26; 126; 526) to the first segment radial contact face. a first segment (12; 212; 312; 412; 512; 612; 712; 812) comprising: a first segment first end (42; 142; 542) opposite a first segment second end (48; 148; 548); a first segment radial outward-facing outer surface opposite a first segment radial inward-facing contact face; and a first segment axial contact surface (26; 126; 526) extending between the first segment outer surface and the first segment radial contact face; and a first segment first end (42; 142; 542) opposite a first segment second end (48; 148; 548); a first segment radial outward-facing outer surface opposite a first segment radial inward-facing contact face; and a first segment axial contact surface (26; 126; 526) extending between the first segment outer surface and the first segment radial contact face; and a second segment (12; 212; 312; 412; 512; 612; 712; 812) comprising: a second segment first end (42; 142; 542) opposite a second segment second end (48; 148; 548); and a second segment radial outward-facing outer surface opposite a second segment radial inward-facing contact face; a second segment first end (42; 142; 542) opposite a second segment second end (48; 148; 548); and a second segment radial outward-facing outer surface opposite a second segment radial inward-facing contact face; wherein: the first segment first end (42; 142; 542) comprises a protruding feature (44; 144; 244; 344; 444; 544; 644; 744; 844); the first segment first end (42; 142; 542) defines a tangential vector (34; 134; 234; 334; 434; 534; 634; 734; 834) from a circumferential ring that is formed by the segmented radial seal assembly; the protruding feature (44... 844) defines a curved face (46; 146; 246; 346; 446; 546; 646; 746; 846) having at least a first axis of curvature, the first axis of curvature being parallel to the tangential vector (34... 834); the second segment second end (48; 148; 548) includes a recessed feature (50; 150; 550) that is matingly engageable to the first segment first end (42; 142; 542), thereby forming a first radial seal segment joint; and the segmented radial seal assembly is configured to surround a shaft; the first segment first end (42; 142; 542) comprises a protruding feature (44; 144; 244; 344; 444; 544; 644; 744; 844); the first segment first end (42; 142; 542) defines a tangential vector (34; 134; 234; 334; 434; 534; 634; 734; 834) from a circumferential ring that is formed by the segmented radial seal assembly; the protruding feature (44... 844) defines a curved face (46; 146; 246; 346; 446; 546; 646; 746; 846) having at least a first axis of curvature, the first axis of curvature being parallel to the tangential vector (34... 834); the second segment second end (48; 148; 548) includes a recessed feature (50; 150; 550) that is matingly engageable to the first segment first end (42; 142; 542), thereby forming a first radial seal segment joint; and the segmented radial seal assembly is configured to surround a shaft; characterized in that: the curved face (46... 846) comprises a cross-sectional shape as viewed into circumferential tangential vector (34...834) that is an arc of an ellipse which extends from the first segment axial contact surface (26; 126; 526) to the first segment radial contact face. the curved face (46... 846) comprises a cross-sectional shape as viewed into circumferential tangential vector (34...834) that is an arc of an ellipse which extends from the first segment axial contact surface (26; 126; 526) to the first segment radial contact face.