A Long March 11 solid-propellant carrier rocket, with a payload of seven satellites, blasts off from a mobile launch platform off Shandong province on Wednesday. ZHU XINGXIN/CHINA DAILY

China carried out its first seaborne space launch in its territorial waters in the Yellow Sea on Wednesday, opening a new chapter in its space industry.

A Long March 11 solid-propellant carrier rocket blasted off at 12:06 pm from a mobile launch platform - a modified submersible craft - off Shandong province, sending seven satellites into an orbit nearly 600 kilometers above Earth.

The mission - the world's first seaborne space launch in the past five years - showed China's possession of technologies and capabilities required for such an operation and also indicated the country has found an alternative to its ground-based launch centers.

It also showed that China is striving to expand its launch service portfolio and promote its carrier rockets to more countries, especially those that want their own satellite network at affordable costs.

Before the seaborne mission, China had conducted more than 310 carrier rocket launches at its four land-based space launch centers.

Compared with conventional, land-based launches, a sea mission has a lower risk of causing trouble for densely populated areas along the rocket's trajectory. The method also allows launches to be made near the equator, which increases the rocket's carrying capacity, lowers launch costs and extends the life span of some satellites, according to Li Tongyu, project manager for Long March 11 at the China Academy of Launch Vehicle Technology.

Wednesday's launch also marked the first time a Chinese private company - Beijing Aerospace Satelliteherd Science and Technology - has provided monitoring and tracking service during the entire launch and flight path of a space mission.

The Long March 11, designed and built by the China Academy of Launch Vehicle Technology, is the first and only solid-fuel carrier rocket in the Long March family, the pillar of the country's space programs.

The model is 20.8 meters long, with a diameter of 2 meters and a liftoff weight of 58 metric tons. It is capable of sending satellites to low-Earth orbit or sun-synchronous orbit, according to the academy, part of the State-owned space conglomerate China Aerospace Science and Technology Corp.

Its first flight was in September 2015 from the Jiuquan Satellite Launch Center in northwestern China's Gobi Desert, ferrying four satellites to a sun-synchronous orbit.

The rocket was used in six launches before the seaborne mission and had placed 25 satellites into space. All the previous missions began at the Jiuquan center and were successful.

The mobile platform used in Wednesday's launch was owned and run by a Chinese maritime engineering company, which asked not to be named in consideration of contractual obligations.

Li, the project manager, said the Long March 11 will continue conducting sea-based launches to verify the rocket's capacity for various types of orbits.

He said the academy plans to develop and construct a coastal port to support seaborne launch missions as well as a dedicated launch platform - instead of the current modified one - that will be capable of lifting not only solid-propellant but also liquid-propellant rockets, which usually are bigger and stronger than solid-fuel models.

Jin Xin, the rocket's deputy project manager, said that in the future, each mobile launch platform will be able to carry multiple rockets and launch them at suitable places in China's eastern and southern seas.

Designers have begun to develop an upgraded variant of the Long March 11 called the Long March 11A, Jin said, adding that the new type will be wider and taller than its predecessor and will have greater thrust.

It will be able to send a 1.5 ton payload to a sun-synchronous orbit at an altitude of 700 km, nearly four times the Long March 11's capacity in that orbit, he said.

The world's first launch at sea was made in April 1967 with a Scout B carrier rocket, developed by the United States, from the San Marco platform of Italian-owned Luigi Broglio Space Center, off the coast of Kenya.

The most recent sea launch before Wednesday took place in May 2014, when Sea Launch, a multinational joint venture, sent a Zenit-3SL rocket from the company's mobile launch platform Odyssey into orbit carrying a communication satellite.