Project 921, China studies reusable rockets that can be "lassoed"

Gianluca Riccio

Spazio

The space race gets interesting, and "ambitious" projects accelerate: the latest Chinese rockets show a strange method of reuse.

China's space program is based on years of meticulous planning, or at least that was the case until recently. Reusable rocket technology has allowed it to more rapidly develop its capabilities in this sector, as demonstrated by a “mysterious” rocket seen at a recent airshow.

China's space program has been focused on the same goals since the 90s: launching a manned spacecraft (done, with Shenzhou 5, in 2003). Building a space outpost (done, in 2019), develop a permanent crew by 2020 (here there is a hint of delay, but very little: the Tiangong space station is about to be completed). What comes next?

The next steps

I told you about manifest intentions a few days ago: China seems to point to 2028 as a date for a human outpost: a settlement on the Moon. To achieve this, it has been testing various solutions for some time: we know one, and it is a huge rocket called Long March 9 (LM-9). Other solutions are currently much more "discreet", if you pardon the euphemism.

Two things are certain: first, the current technology exhibited by China (that of the powerful Long March 5 rockets) is not capable of carrying out human missions to the Moon. Second, the technology of the Long March 9 also appears to need a lot of tweaking before the final launch.

We are left with the last hypothesis, the "secret" one: a reusable rocket similar to a spaceship with a cryptic name: Project 921.

reusable rockets
Names on the rockets are not seen, numbers are: 921.

Reusable rockets that can be captured "with a lasso"? It's not science fiction

From the few reports available, development of the “921” began in 2017 . When completed, it will be available in two versions: one “single-core” to bring materials and vehicles into orbit, and the other “triple-core” to go… well, further.

The central core of these rockets can reach a height of almost 90 meters. According to recently released specifications, the single-core variant will be capable of carrying 18 tons and will replace all, or almost all, Chinese launch vehicles.

Many elements (reuse of projects that have already started, or engines in an advanced stage of testing) suggest that the Chinese are really racing on the project. And the date scheduled for the first test flight (2026) confirms these impressions. In summary, Project 921 is not a paper rocket or a concept.

Large, capacious, reusable

Though not right away, engineers are working to make the 921 design reusable by 2032, with reuse technology already being tested now. Like the Falcon 9 rocket from SpaceX, will use it to head in fall towards a landing platform on the ocean.

Unlike the Falcon 9, however, China plans to abandon the landing "legs" in favor of an innovative capture system. Landing legs have proven to be a difficult engineering challenge for reusable rockets: they create drag and add significant weight, reducing payload capacity. 

SpaceX also completely abandoned the landing legs for Starship's first stage, hoping instead to "catch" it upon landing using the launch tower itself. China's approach is similar in principle but potentially much simpler.

New promotional video for the 921 shows a double layer of parallel cables or attachments tightening around the rocket as it approaches landing. The cables, presumably with some degree of elasticity, provide the necessary shock absorption needed to cushion the rockets with no moving parts.

Supposedly, these cables can “tighten” in different directions/positions if the rocket doesn't land exactly on the landing pad. A sort of "lasso" that envelops the rocket until it stops. Even if to me they look like wires for hanging clothes. Will they work?

Reusable rockets, an exciting future

Ultimately, China's approach to landing and reusing rockets will benefit the industry and humanity as a whole. More innovation and competition in this nascent industry will continue to drive down launch costs and hopefully open the door to a brighter future for space exploration.