Complex sentence: On 12 February 1999, the first tests were performed at Kapustin Yar in Astrakhan which were reported to be successful; therefore, the S-400 was scheduled for deployment in the Russian army in 2001.
Split into simpler sentences: On 12 February 1999, the first tests were performed at Kapustin Yar in Astrakhan which were reported successful. As a result of this, the S-400 was scheduled for deployment in the Russian army in 2001.