The launch of a modified Long March 7A carrier rocket on Dec 23 that sent two experimental satellites into space marked the debut mission of China's tallest rocket.

The 60.7-meter-tall rocket blasted off at 6:12 pm from a coastal launch tower at the Wenchang Space Launch Center in Hainan province before placing the Shiyan 12-01 and 12-02 satellites into their orbits, China Aerospace Science and Technology Corp, the nation's major space contractor, said.

Developed by the company's China Academy of Space Technology in Beijing, the two satellites－whose name translates as experiment－are tasked with surveying the spatial environment and conducting related technological tests, the State-owned enterprise said in a brief statement issued after the launch.

It was the first time China had used one rocket to deploy two large satellites to high-altitude orbits. To make the flight possible, engineers at the company's China Academy of Launch Vehicle Technology in Beijing used a new fairing－the top structure on a rocket that contains satellites or other payloads－that was higher than those on the two previously launched Long March 7As, said Wei Yuanming, a chief designer of Long March 7A.

The original version of the Long March 7A is 60.1 meters tall, about 1.8 meters taller than the second-tallest Chinese rocket－the Long March 2F.

Pang Zhihao, a space industry observer in Beijing, said that extending the length of a rocket is not easy because engineers are then required to make many related modifications to the rocket.

The first Long March 7A was launched in March last year but the flight failed due to technical malfunctions. The rocket conducted its second mission in March this year, successfully deploying the New Technology Demonstrator 9 experimental satellite into orbit.

According to designers, the Long March 7A has a liftoff weight of 573 metric tons and a core-stage diameter of 3.35 meters. It is capable of placing a 7-ton spacecraft into geosynchronous transfer orbit.

Flight on Dec 23 also marked this year's 45th liftoff of the Long March rocket family, which is the pillar of China's space programs. All of the Long March rocket launches this year have been successful.

China has carried out more space missions than any other spacefaring nation this year, with 52 orbital launches.