10.12.023

LandSpace has launched its third ZhuQue-2 rocket on Friday, Dec. 8, at 23:40 UTC. The launch, just like the first two, took place from Launch Site 96 at the Jiuquan Satellite Launch Center in China.

Earlier this year, ZhuQue-2 performed its second launch, in which the rocket successfully reached orbit. After the initial launch in December 2022, which failed due to a second-stage issue, the second launch made LandSpace the first company in the world to reach orbit with a methane-based rocket platform. 

The ZhuQue-2 rocket

ZhuQue-2 (Redbird 2) is a medium-sized launch vehicle, developed by the Chinese private company LandSpace. It stands 49.5 meters tall, with a diameter of the common-in-China 3.35 meters due to transport limitations. Right now, the rocket features the performance to carry up to 1.5 tons to a 500km Sun-synchronous orbit (SSO), with future upgrades of ZQ-2 increasing that capability to up to 4 tons.

The first stage of the rocket, which is decorated by the signature red bird, is powered by four TQ-12 liquid methane engines. The engines run on a gas generator cycle, and are, just like the rocket, constructed with as many off-the-shelf parts as possible. Together as a module of four, the TQ-12 engines are referred to as a TQ-13 first-stage engine pack.

At liftoff, the engines produce a thrust of 2,680 kN, which brings the thrust-to-weight ratio of the rocket stack to about 1.22, depending on the mass of the payload. Each of the engines has a nozzle diameter at the end of 1.5 meters, has a specific impulse at sea level of 284.5 seconds, and operates on a mixture ratio of 3.5 parts oxygen to methane.

The development of these engines moved quickly for a modern rocket, with the first complete test firing being performed in May 2019 after just a few years of development. The engine was tested at the LandSpace engine test facility in Huzhou, Zhejiang. From day one, the engine was designed to be produced at a rapid pace, as LandSpace has the ambition to produce up to 15 ZQ-2 rockets a year.

The second stage still features a TQ-12 engine, which is assisted by four TQ-11 vernier engines. It was initially expected that the third flight of the rocket may debut the TQ-15A engine module, which would eliminate the vernier engines; however, based on early statements by LandSpace, this change seems to be planned for further down the line.

After the second stage has performed its main burn, the four TQ-11 vernier functions as a kick stage after the main engine shuts down. They will perform the final orbital insertion of the payload.

Zhang Changwu, CEO of LandSpace, told Chinese media in an interview that this launch is used to further prove the reliability of the ZhuQue-2 rocket. After the third flight, LandSpace will transfer to a model of mass production, which will pave the way for up to four flights of ZhuQue-2 in 2024, and up to 15 a year in later years.

ZhuQue-2 flight 3 featured no major upgrades but did boast some improvements based on the learning experiences of the first and second flights. This includes process optimizations and adjustments to further improve the reliability and safety of the rocket. It likely also features the improvements made from flight 1 to flight 2, which prevent another failure of the second-to-kick stage transition. 

It is not known when LandSpace will transition to a reusable rocket down the line. The company is already test-firing the TQ-12A engine, which is designed for multiple first-stage relights. This capability is required for a propulsive landing method of recovery, like what SpaceX performs with the Falcon 9 rocket.

The history of ZhuQue-2

ZhuQue-2 flew for the first time on Dec. 14, 2022. After a flawless performance of the first stage and second stage, the rocket failed during the final moments of flight, in which the second stage shuts down and the four vernier engines take over the flight.

In an investigation report, LandSpace confirmed that the issue was a low-pressure liquid oxygen pump outer casting that broke during the main engine shutdown maneuver as it was experiencing a high impact force.

During the shutdown, a connection at the LOX inlet pipe broke, which was not properly reinforced for the heavy shutdown event. LandSpace conducted a series of tests on the ground before flight two to verify the fix that was implemented in the second stage.

Flight one featured a series of smaller payloads, which were all lost due to the vehicle not reaching orbital velocity. The rocket only achieved five kilometers per second, while roughly seven are needed for a stable orbit.

Flight two featured the aforementioned upgrades and lifted off on July 12, 2023. This flight went off without any issues, making the rocket the first vehicle to reach orbit using liquid methane as a fuel. The second flight, which was flown to an SSO just like the first one, did not feature any payloads and was solely a demonstration of the return to flight.

ZhuQue-2s third flight

The preparation for flight 3 of ZhuQue-2 seemed steady from the outside. In late October, the company confirmed on Chinese social media that the rocket had left the factory and was on its way to Jiuquan.

At the same time, ground testing at the pad was already underway, as the pathfinder was rolled out to the pad just days later. This pathfinder structure has so far always been used by LandSpace ahead of a flight to verify the pad and systems ahead of the actual rocket. Harry Stranger confirmed the pathfinder was vertical on Nov. 11 using satellite imagery.

Satellites on top of ZhuQue-2 Y3. (Credit: LandSpace

Initially, the rocket had a launch planned for Dec.  5; however, a Chinese travel agency confirmed the launch slipped to Dec. 7 just a few days later.

On Dec. 1, Harry Stranger acquired another satellite image showing the third set of flight hardware rolling out to Pad 96 at Jiuquan. Just days later, the rocket was confirmed vertical and the sponsor for the mission was announced. It features decals from the toy company Pop Mart, which are featured on the body of the vehicle.

Released photos of the rocket show multiple satellites being integrated into the vehicle as well. However, the company has not detailed which payloads were launched on the rocket for the third flight. Based on published photos, it seems that there might be four or more payloads.

The NOTAM for the mission lasted 82 minutes and, based on previous flights, indicated a launch time of around 23:45 UTC.

The Future of LandSpace

In the future, LandSpace plans to evolve ZhuQue-2. A stretched version with upgraded engines, tanks, and a larger payload fairing, called ZQ-2A, is in development. This rocket is also planned to feature 3- and 5-core variants called ZQ-2B and ZQ-2C, respectively. 

Based on the 9% thrust increase of TQ-12A to about 2,921.2 kN per core, the three-core variant would boast a thrust of 8.7 meganewtons, and the five-core variant would feature 14.6 meganewtons.

After ZhuQue-2, LandSpace plans to develop a reusable stainless steel rocket called ZhuQue-3. This rocket would feature the capability to launch 20 tons of payload in an expendable configuration and 16.5 tons when landing on a barge. If completely returned to the launch site, it would be able to lift more than 11 tons.

So far, LandSpace has not communicated a timeline for these development steps. However, it has shown in the past that it can achieve rapid rocket development, even though ZhuQue-2 slipped two years from 2020 to 2022.

Quelle: NSF