China claims progress in new landing technology for crewed spacecraft, Mars landings
This article originally appeared in the June 25, 2018 issue of SpaceNews magazine.
China is claiming progress on a number of reentry and landing technologies for human spaceflight and Mars missions, underlining apparently significant plans for deep space exploration.
The Beijing Institute of Space Mechanics and Electronics (BISME) announced in May that it had performed an airdrop test of a parachute for two new-generation crewed spacecraft, which will be larger successors to the current Shenzhou capsules. The test was reported to have verified the strength and function of the parachute.
The new-generation crewed spacecraft, according to previous announcements from the China Aerospace Science and Technology Corporation, will come in two variations – a 20- metric ton version for lunar missions, and a 14-metric-ton version for potential Mars and deep space exploration.
Zhang Bainan, a chief engineer at the China Academy of Space Technology (CAST) which is developing the spacecraft and owns BISME, said in March that the crew capsule will be able to hold four to six astronauts. The spacecraft design will be modularized, allowing adaptation to the specifics of a mission profile.
China carried out the test of a scale return capsule for the new crewed spacecraft in 2016 with the test flight of the Long March 7 rocket, successfully returning the spacecraft to a site in Inner Mongolia. The craft had a flat top and sloped sides, unlike the bell-shaped Shenzhou.
In June 2019, the variant of the Long March 5 rocket for low Earth orbit launches, the Long March 5B, will lift off for the first time from the Wenchang Space Launch Center on Hainan island carrying another test spacecraft for the project.
No indication has been given as to what will be tested next year, but a larger version of the 2016 test capsule could fly if progress on the parachute has been significant.
Rajeswari Pillai Rajagopalan, head of the Nuclear and Space Policy Initiative at the Observer Research Foundation in New Delhi, India, says testing parachutes could be for any number of Chinese missions — a crewed space capsule, lunar or Mars missions.
“China has announced its plans for lunar landings, Mars probe and a space shuttle. China plans for multiple Mars missions including to orbit and land in the first instance and a second probe to bring back samples from the red planet. Manned lunar missions are also very much on the Chinese radar,” Rajagopalan says.
Parachute testing is also important in the context of developing reusable rocket technologies, which the China Academy of Launch Vehicle Technology (CALT) recently announced it was pursuing, Rajagopalan adds.
BISME followed this announcement with two more, claiming a breakthrough with tests of a vented airbag system for soft-landing spacecraft, and Inflatable Reentry and Descent Technology (IRDT), similar to the Low-Density Supersonic Decelerator tested by NASA which aims to increase the mass of payloads that can be landed on Mars.
The saucer-shaped IRDT craft aims to integrate the functions thermal protection, deceleration, and landing systems and allow more massive craft to land.
Pang Zhihao, a scientist with CAST, told the Chinese language Science and Technology Daily that IRDT could allow craft with a mass of up to 15 metric tons to soft-land on Mars.
“This looks like China is pumping a lot of effort and money into Mars entry descent and landing systems to land significant payloads, possibly people,” says Alex Ellery, a professor of mechanical and aerospace engineering at Carleton University in Ottawa, Ontario.
However, some of these developments are in the early stages. From images of the airbag tests, Ellery assesses that it, “looks like they are doing a simple drop test—at early stages of design—of the airbags.”
Commenting on an image released by CAST, Ellery says the IRDT system, “looks rather fragile and tiny in comparison with the bushes – they are designed for large payloads.
“One of the problems the Europeans had in testing this technology over a decade ago was that large IRDT systems can be unstable due to unequal internal pressurization—which is high to impart sufficient rigidity—in a large system.
“It’s a very promising technology if it can be made to work but the picture reveals something tiny which would not tackle the issue,” Ellery continues. While the evidence of progress being made is lacking, the announcements do have some importance.
“I am very skeptical about the pictures – they are staged in such a way that they do not indicate that the Chinese have tackled these technologies seriously yet,” Ellery says. He adds however that the releases indicate that these are technologies that China will be tackling as a matter of priority and could soon lead to see major progress.
The Science article also stated that China plans to launch its first spacecraft using the IRDT technology in 2019.