Pujiang-2 & Tiankun-2 | Long March 6A

Featured image credit: CNSA

Lift Off Time	March 29, 2022 – 09:50 UTC | 17:50 BST
Mission Name	Pujiang-2 and Tiankun-2, the first flight of the Long March 6A
Launch Provider (What rocket company launched it?)	China Aerospace Science and Technology Corporation (CASC)
Customer (Who paid for this?)	Shanghai Academy of Spaceflight Technology and CASC
Rocket	Long March 6A
Launch Location	Taiyuan Satellite Launch Center, China
Payload mass	Unknown, no more than 4 tonnes
Where did the satellites go?	The satellites were placed into a 605 x 588 km low-Earth polar orbit at 97.79º
Did they attempt to recover the first stage?	No, the Long March 6A is not capable of first stage recovery
Where did the first stage land?	The first stage crashed into land in Eastern China
Did they attempt to recover the fairings?	No, the Long March 6A is not capable of fairing recovery
Were these fairings new?	Yes
This was the:	– 1st launch of the Long March 6A – 9th launch of the Long March 6 (any variant) – 32nd orbital launch attempt of 2022 – 412th flight of the Long March series of rockets
Where to watch	Unofficial Replay

How Did It Go?

The China Aerospace Science and Technology Corporation successfully launched the Pujiang-2 & Tiankun-2 satellites into a low-Earth polar orbit on the debut launch of the Long March 6A. Lifting off from the Taiyuan Satellite Launch Center, in China, this marked the first time China used solid rocket boosters (SRBs) on a flight.

Pujiang-2

Like the majority of Chinese satellites, little is known about the Pujiang-2 satellite, a follow up to the Pujiang-1 satellite, which was launched in 2015. The satellite’s main use is scientific research of land and resources, surveilling them to monitor population density, weather, traffic, and crop growth.

The Pujiang-2 satellite is able to communicate with other satellites in low-Earth orbit; it is possible, but not confirmed, that the CASC is using the two sister Pujiang satellites to communicate with one another, similar to SpaceX’s Starlink satellites.

Tiankun-2

The Tiankun-2 satellite is a follow up to the Tiankun-1 satellite, which launched in 2017. The family of satellites are technology test satellites developed by the Second Academy of Aerospace Science and Industry of China; the Tiankun-1 satellite was launched to verify the satellite bus design and ensure that the foldable solar arrays work. The Tiankun-2 satellite builds on this, delivering the same functionality for cheaper, less mass, and smaller size.

Tiankun-2 is going to be used to validate these design changes, demonstrate on-orbit attitude control, and perform on-satellite computation of photos.

Long March 6A

Capable of lofting 4 tonnes into low-Earth orbit, the Long March 6A is a significantly larger version of the Long March 6. The Long March 6A is a two stage rocket that stands at 50 meters tall, has a core diameter of 3.35 meters (11 feet), and has a wet mass of 530 metric tonnes (1.2 million lb). Surprisingly, this is roughly the same lift-off mass as the Falcon 9, which can lift over 16 tonnes to low-Earth orbit, while being recovered.

The Long March 6A is made up of a center core, four side solid rocket boosters, and a second stage.

Core Stage

Equipped with two YF-100 engines–which run on RP-1 and liquid oxygen–the core stage of the Long March 6A produces 2,376 kN of thrust at liftoff. Each of the YF-100 engines is a LOx-rich staged combustion cycle engine that produce 1,200 kN of thrust at sea-level with 300 seconds (2.9 km/s) of specific impulse and 1,340 kN of thrust in a vacuum with 335 seconds of ISP (3.29 km/s). As with all rocket engines, despite the turbo-pump running LOx rich, the main combustion chamber (MCC) runs fuel rich.

The core stage burns for just under four minutes.

Side Boosters

Attached to the center core are four SRBs. Each SRB is 2 meters in diameter and produces 1,214 kN of thrust, for just under 5 MN of thrust in total. The Long March 6A is the first Chinese vehicle to launch with SRBs. The SRBs burn for 114.5 seconds, before burning out and being disposed of at 117.5 seconds.

With the SRBs, the first stage produces 7.2 MN of thrust, making the vehicle fly off the pad with a thrust-to-weight-ratio of 1.38.

Second Stage

The second stage is equipped with a single YF-115 engine which produces 180 kN of thrust while having an ISP of 341.5 seconds (3,350 m/s). Similar to the YF-100, the YF-115 is a closed cycle staged combustion engine that has a LOx-rich turbo pump and a fuel rich MCC. Additionally, the YF-115 is capable of gimbaling, providing the second stage with attitude control.

Stage two burns for over 500 seconds before playing its payloads into orbit.

Fairings

Like with all Chinese rockets, the Long March 6A also has an expendable payload fairing. Deployed about 3 minutes into flight, the 4.2 meter payload fairing protects the payloads during ascent from the aero-thermal loads from the atmosphere.