BEIJING, Oct. 16 (Xinhuanet) -- China's maritime space tracking technologies have achieved substantial progress over the past 27 years and reached the advanced levels in the world, an official in charge of the operation said Sunday.

The maritime space surveying and controlling operation, which has been tracking China's second manned spacecraft Shenzhou-6 since the lift-off on Wednesday, has made a number of breakthroughs since it was initiated in 1978, according to Jian Shilong, director in charge of the program.

China is able to carry out maritime measuring and controlling on objects at sea, under the surface of water, on international satellites, and manned spacecrafts, said Jian.

However, during the initial stage, China was only able to measure and control objects at land, on the surface of water, domestic satellites and unmanned spacecrafts, he recalled.

The operation, equipped with four "Yuanwang" tracking ships, has accomplished some 50 key scientific researches and tasks with no hitches or failures for the past 27 years.

The "Yuanwang" ships have involved in China's past five Shenzhou space flight missions during 1999-2003, conducting measuring and controlling operations including the orbit transfer,attitude adjustment, video and audio transmission for China's first manned spacecraft Shenzhou-5 in 2003.

The tracking ships have accomplished designed tasks, including orbit maintenance for the record-making Shenzhou-6, despite rough sea weather on Friday and Saturday.

The four ships boast advanced technologies in terms of the functions and precision of measuring and controlling, automatization and reliability, said Jian.

The ships and some 20 surveying stations on land jointly build up China's space telemetry network. Enditem