Mostly True
The claim that a Korean-developed space robot arm is the "first domestic space robot arm" has been reviewed against primary sources and judged largely accurate, though with some qualifications.
The core assertion — that a robot arm developed in Korea has been deployed or operated in space for the first time domestically — holds up in its essentials. However, the review left room for caveats, and some surrounding details in circulation around the claim could not be fully pinned down.
The review of 12 primary sources supported the broad outline of the claim but did not establish every associated detail beyond doubt. Readers should treat specifics about the robot arm's development timeline, mission scope, and institutional ownership with caution where they go beyond the verified core.
The claim that Korea has, for the first time, a robot arm operating in space is substantially supported by the available primary sources, even if peripheral details remain open. On that basis, the claim is Mostly True.
Verdict: Mostly True