HELSINKI — A Long March 5B rocket launched a prototype crewed spacecraft Tuesday, demonstrating the launcher’s capability to carry space station modules to low Earth orbit.

Liftoff took place at 6:00 a.m. Eastern from the coastal Wenchang Satellite Launch Center on Hainan island. Separation of four side boosters occurred around three minutes into the flight.

The China Aerospace Science and Technology Corp. (CASC) confirmed launch success around 20 minutes after launch. The prototype new-generation spacecraft entered its predetermined orbit 488 seconds after liftoff. 

The nominal launch of the near 22-metric-ton payload clears the Long March 5B for lofting modules for China’s planned space station into LEO. Launch of the Tianhe core module may now follow in early 2021.

The success also allows China to proceed with a July mission to send an orbiter and rover to Mars. China suffered two launch failures in March and April, bringing a temporary halt to launch activity and adding pressure on the mission.

The 8.8-meter-long, 21.6-ton uncrewed prototype spacecraft will use its own propulsion to raise its orbit to an apogee of around 8,000 kilometers (4,970 miles).

It will then attempt a high-speed reentry to test new heat shielding. The mission also will test avionics, performance in orbit, parachute deployment, a cushioned airbag landing, and recovery.

Reentry is expected May 8 following on-orbit testing. Planned partial reusability — by replacing the heat shielding — will also be tested. 

Experimental cargo reentry spacecraft were also aboard the flight, officials announced at a post-launch conference.

A pair of YF-77 cryogenic engines and four kerolox side boosters lifted the 849-metric-ton Long March 5B off the pad. 

A YF-77 turbopump failure in 2017 grounded the standard Long March 5 for more than 900 days. This also delayed the Long March 5B variant test launch and China’s space station plans.

The spacecraft will be able to carry up to six astronauts, or three astronauts and 500 kilograms of cargo to LEO. The three-module Shenzhou can carry three astronauts to LEO and has been used for all six of the country’s crewed missions.

The spacecraft has two variants of around 14 and 21 metric tons respectively. The mission will test the latter, which is designed for deep space.

China's prototype new-generation crewed spacecraft undergoing testing.
China’s prototype new-generation crewed spacecraft undergoing testing. Credit: CAST
China’s prototype new-generation crewed spacecraft undergoing testing. Credit: CAST

The 53.66-meter-long Long March 5B has a takeoff mass of 849 metric tons. The payload capacity is greater than 22 metric tons to LEO, according to the China Academy of Launch Vehicle Technology (CALT), the launcher’s designer.

It is a variant of the standard Long March 5, which had an inaugural flight in late 2016. The The Long March 5B lacks the second stage of the former. The payload fairing measures 20.5 meters in length with a diameter of 5.2 meters.

The Long March 5B is part of a new generation of Chinese launch vehicles. The Long March 5, 6 and 7 variants use combinations of liquid hydrogen or kerosene fuel with liquid oxygen. These could eventually replace the older, hypergolic Long March launchers.

The 5-meter-diameter core stage is powered by two YF-77 hydrolox engines. Each of four 3.35-meter-diameter side boosters are powered by a pair YF-100 kerolox engines.

Tuesday’s test launch was the first of numerous launches required for China’s three-module space station.

“China has planned about 12 flight missions for the construction of China’s space station. The first flight mission of [the] Long March-5B rocket is also to verify its performance,” Hao Chun, director of the China Manned Space Engineering Office, told state media in January.

Launches of modules, Tianzhou cargo and refueling craft and crewed Shenzhou missions make up the flight list.

Article updated with expected prototype spacecraft reentry date.

Andrew Jones covers China's space industry for GBTIMES and SpaceNews. He is based in Helsinki, Finland.