BeiDou Navigation Satellite System:

The first satellite, BeiDou-1A, was launched on 30 October 2000, followed by BeiDou-1B on 20 December 2000. The third satellite, BeiDou-1C (a backup satellite), was put into orbit on 25 May 2003. The successful launch of BeiDou-1C also meant the establishment of the BeiDou-1 navigation system.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". When was the BeiDou-1C satellite launched?
25 May 2003