Rockets of Today

LONG MARCH (Chángzhēng, 长征) — “classic” models — China, 1970

Long March 2F

The Chinese have put many different rocket models under this one name — so many that I’m going to put the newer ones in a separate article. Here we will look at models 1 through 4.

These older Long March rockets burn hypergolic fuel, like the Proton. Model 1 was a rather small rocket — they added a third stage to a ballistic missile (Dōng Fēng 3) and got a capacity of about 0.3 tons to low orbit, with which they launched their first two satellites. They quickly moved on to a more serious rocket, and used the Dong Feng 5 as a starting point. It was originally called the Fēng Bào (风暴), which means Storm, but then got dubbed Long March 2, with the name change coinciding with a move to a new manufacturer: the China Academy of Launch Vehicle Technology, commonly known as CALT, which is part of CASC, the China Aerospace Science and Technology Corporation. The success record was poor at first but improved with revisions. Model 2A could lift 1.8 tons, 2C could lift 2.4, and 2D (which was lengthened) did 3.1 tons. These use four gimballed engines on the first stage, and one with a large nongimballed bell on the second, with separate little vernier rockets for steering.

Then for the 2E, they added the feature which has been characteristic of China’s heavier rockets ever since: four liquid fueled side boosters with one engine apiece, doubling the thrust and bringing the LEO capacity up to about 9 tons. The smaller 2C and 2D models remain in use to this day, along with the 2F which replaced the 2E.

(Meanwhile the Long March 1 tried a comeback as the 1D, but nobody wanted it and it was only used for a few suborbital tests, which were probably military.)

The Long March 3 is similar to the 2 but with a hydrogen-burning third stage added for higher orbit capability. The second stage is shortened relative to the heavy version used in the 2. Again, models 3A, 3B, and 3C all remain in active use. They are used mainly for geosynchronous satellites. The 3C uses two side boosters instead of four; the different models are basically just optimized for different payload weights. The 3B has its own variations: 3B/E and 3B/G, with lengthened first stages and side boosters which made their first appearance in the 2F. There is also a 3C/E using the lengthened stages. The short stages have now dropped out of use, except in the lightweight Long March 4. This is an upgrade which omits the side boosters and uses small upper stages — the second is even shorter than the one used in the 3, and the third is a small hypergolic one rather than the hydrogen burner. Models 4B and 4C are in use.

All of these rockets essentially form a single modular system, mostly built around a single engine, the YF-20. One in each side booster, four in the core stage, and one with a large bell (plus a small vernier engine) in the second stage. Only the third stages use a different engine.

At times these rockets have had a much poorer reliability record than their American and Russian competition, but with maturity they showed a streak of 102 consecutive successful launches from 1996 to 2011, and a longer streak of successes ongoing now.

In 2003 a Long March 2F, now dubbed “Shénjiàn” (神箭, Heaven Arrow — a reference to ancient gunpowder rockets which were commonly attached to arrows), carried China’s first astronaut — er, taikonaut — into orbit. It was a punishing ride because the rocket’s vibration was exceptionally harsh. They’ve managed to reduce it since then. (The 2E was even worse; it was retired after it shook a couple of satellites apart.) Later, a 2F/Shenjian launched a small orbital habitat, and then another was able to rendezvous with it.

China has recently started developing a much more modern range of rockets which burn kerosene and hydrogen — some of them quite large. These continue to use the Long March name but are covered in a separate article in the Revival Era section. Of these, model 7 is the one which retains the classic design while modernizing the propulsion. Model 6 is smaller, and model 5 is larger — their first real heavy-lift rocket. But despite the obsolescence of models 2, 3, and 4, all three remain in heavy use, with a combined launch cadence which sometimes exceeds that of SpaceX, let alone Roscosmos. And now that China has a space station, the 2F/Shenjian is busier than ever.

Things were a lot less rosy in the old days. Launch sites were built in areas with people living under the flight path, and also living uncomfortably close to the launch complex itself. In the days before they got to a good level of reliability, this was far from safe. In 1996, there was a mishap where a 3B taking off from Xichang (which is in a mountainous part of Sichuan province) went sideways and crashed. It wiped out an apartment building. That building was properly evacuated but the grounds around it were not, as local people were watching the launch from outside the fence. The officially stated death toll was six but many believe that it was actually hundreds, making it the deadliest spaceflight accident ever, covered up by the government.

Even on successful launches, downrange areas can be pelted with falling boosters, so those living in the impact areas may experience toxic fires or smashed houses. I have not been able to get any kind of count on such instances, but I have found reports of three significantly nasty incidents just since 2015. It may be that we are only recently seeing the full extent of the harm, as poor villagers gain the ability to upload video of the damage. Procedures have improved but those badly located inland launch sites still have many years to go before they can be phased out. In the meantime they are starting to add grid fins to the boosters to steer them away from harm as they fall.

Long March 2F: mass 464 t, diam 3.3 m (7.8 at base w/o fins), thrust 6500 kN, imp 2.8 km/s, gas generator (UDMH), payload 8.4 t (1.8%), cost $15M/t?, record 169/4/10 (10 crewed) as of February 11, 2023.
Long March 3B/E: mass 459 t, diam 3.3 m (7.8 at base), thrust 5900 kN, imp 2.8 km/s, gas generator (UDMH), payload 12 t (2.8%), cost $6M/t?, record 138/0/7 as of February 11, 2023.
[Show stages] (LM 2 and 3)
Stage name L-45 L-186 L-86 (LM-2) * L-54 (LM-3) H-18 (LM-3) * Yuanzheng
Role (pos) count booster (S) ×2|4 core (1) upper (2) upper (2) kick (3) kick (3|4), opt
Diameter (m)   2.25   3.30   3.30   3.30   3.30
Liftoff mass (t) 48.5 199    91   52   19.2
Empty mass (t)  4.0 13.0  4.8  2.8  0.9
Fuel mass (t) ~14.3  ~60    ~27.1  ~15.5  ~3.0
Oxidizer mass (t) ~30.2  ~126     ~59.1  ~33.7  ~15.3 
Fuel type UDMH UDMH UDMH UDMH hydrogen UDMH
Engine YF-20C YF-21C
(20C ×4)
YF-24E (22E +
23F vernier)
YF-24E (22E +
23F vernier)
YF-75 ×2 YF-50D
Power cycle gas gen gas gen gas gen gas gen gas gen ?
Chamber pres. (bar) 71   71   71   71   38  
Ox./fuel ratio   2.12   2.12   2.18   2.18   5.10
Thrust, vac max (kN) 810    3300     830    800    160     6.5
Thrust, SL initial (kN) 740    2960    
Spec. imp, vac (km/s)   2.83   2.83   2.97   2.97   4.30   3.09
Total imp, vac (t·km/s) 491    513    255    147    78.4
Long March 4C: mass 250 t, diam 3.3 m, thrust 3000 kN, imp 2.6 km/s, gas generator (UDMH), payload 4.2 t (1.7%), cost $12M/t?, record 95/0/2 as of February 11, 2023.
Stage name L-176 L-36 L-14.5
Role (pos) count core (1) upper (2) kick (3)
Diameter (m)   3.30   3.30   3.30
Liftoff mass (t) 188    37.4 15.5
Empty mass (t) 12.3  2.0  1.0
Fuel mass (t) ~56    ~11.1  ~4.6
Oxidizer mass (t) ~119    ~24.3  ~9.9
Engine YF-21C
(20C ×4)
YF-24E (22E +
23F vernier)
YF-40B rs
Power cycle gas gen gas gen gas gen
Chamber pres. (bar) 71   71   46  
Ox./fuel ratio   2.12   2.18   2.14
Thrust, vac max (kN) 3300     800    101   
Thrust, SL initial (kN) 2960    
Spec. imp, vac (km/s)   2.83   2.97   3.00
Total imp, vac (t·km/s) 485    105    43.4