The return-to-flight mission will carry an experimental, 300 Gbps telecommunications satellite based on a new, large DFH-5 satellite platform. Future DFH-5's will deliver 1 terabit per second, up from the current 20 Gbps with DFH-4.

China’s most powerful rocket will fly for the third time late this year, with success of the launch to be crucial to upcoming projects including a lunar sample return, space station module launch and a 2020 mission to Mars.

Speaking on the sidelines of the country’s annual parliamentary sessions in Beijing in early March, senior aerospace officials revealed to media — in piecemeal fashion — details of the return-to-flight of the Long March 5.

The launch will carry an experimental telecommunications satellite named Shijian-20, or ‘Practice-20’ in Chinese, based on a new, large DFH-5 satellite platform.

Zhang Hongtai, president of the China Academy of Space Technology (CAST), a developer and maker of satellites and spacecraft, stated that the Shijian-20 will increase the country’s high-throughput communications satellite capacity to 300 gigabits per second, up from the current 20 Gbps with the predecessor DFH-4.

After on-orbit technical verification of this first satellite, which he suggests would launch in November, Zhang states that future satellites using the DFH-5 platform will be able to supply capacity of 1 terabit per second.

Shijian-20 will also carry newly developed high-thrust ion propulsion developed by the Lanzhou Institute of Physics and test out laser communications. With a payload capacity of over 2,000 kilograms and a total mass of around 7 metric tons the satellite will be one of the largest sent to geostationary orbit.

Long March 5 is 1 for 2

The 5-meter-diameter, 57-meter tall Long March 5, capable of delivering around 14 metric tons to geostationary transfer orbit, debuted successfully in November 2016, launching from the new, purpose-built coastal Wenchang Satellite Launch Center on Hainan Island.

The second flight, in July 2017, suffered an apparent issue with its first stage engines, as seen from images and data relayed in live coverage of the launch, leading to the rocket and its large Shijian-18 high-throughput satellite payload reentering the atmosphere and crashing into the Philippine sea.

The third Long March 5 rocket had been due that August to leave the factory in Tianjin, north China, for shipping to Wenchang for a November launch of Chang’e-5, China’s first lunar sample return mission. That, and plans to launch the first module of the Mir-class Chinese Space Station in 2018 or 2019, were postponed until the root of the failure was determined.

Following an investigation, officials with the China Aerospace Science and Technology Corporation (CASC), the country’s main space contractor and parent company of CAST, at the start of the year stated that the cause of the failure had been isolated — without revealing its nature — and that tests were ongoing to verify that measures taken have been effective.

New YF-77 cryogenic engines, a pair of which power the first stage of the Long March 5, were last month successfully test fired in a ravine near Xi’an in north China, at facilities owned by a propulsion institute subordinate to CASC.

Change’e-5

According to the emerging schedule, a successful launch of the third Long March 5 will see the fourth rocket launch Chang’e-5 to the moon in 2019. The complex mission aims to land in Oceanus Procellarum and collect 2 kilograms of regolith. An ascent vehicle will then perform a robotic lunar orbit rendezvous and docking with the service module and head for earth, with a skip or boost-glide reentry seeing the return capsule set down in Inner Mongolia.

A successful flight this year will also allow the test flight of the Long March 5B, the 1.5-stage variant of the rocket designed for low Earth orbit launches — specifically, lofting the 20 metric ton modules for the planned Chinese Space Station.

Debut of the Long March 5B is slated for June 2019, a spokesperson for the China Manned Space Engineering Office (CMSEO) announced last week. It will carry an as-yet unspecified early version of a reusable successor to the Shenzhou crewed spacecraft capable of deep space travel. A nominal launch would clear the way for the launch of the core module of the space station the following year.

Tianhe hab module

Named Tianhe and housing the astronaut living quarters, the module is expected to launch sometime in 2020, Zhou Jianping, chief designer of China’s human spaceflight program, told Chinese state media. Current plans are for the two science modules to join Tianhe in orbit in a T-shape arrangement by the end of 2022.

The standard Long March 5 will also be in action for the country’s first independent interplanetary mission, launching a combined orbiter, lander and rover to Mars in the summer 2020 transfer window.

Zhou Weijiang, a researcher with CASC, said told Chinese newspaper Science and Technology Daily that simulated tests for Mars atmospheric entry, descent and landing had begun early this year.

Between government and emerging commercial companies China is aiming to attempt around 40 launches in 2018, almost double the national record of 22 set in 2016. The Long March 5 launch late in the year, which will be open to spectators and live coverage, will be by far the most significant, with China’s major upcoming space ambitions dependent on its success.