China's main spacecraft builder, the China Academy of Space Technology (CAST), may be hedging its bets on Long March 5 by developing a bigger version of its DFH-4 bus that, with a designed launch mass of 5.5 tons, is just small enough for launch to geosynchronous orbit by a current rocket, Long March 3B (see table). CAST is developing that larger bus, DFH-4E, along with a smaller derivative of the baseline DFH-4 called DFH-4S. The program is ahead of DFH-5, which state space marketing company China Great Wall Industry Corp. says “is still in its initial development phase.” In late 2010, DFH-5 was due to go into service in 2016 or 2017, but no firm target is given now. The DFH-5 bus will “meet the demand for new-generation large [geostationary] communications satellites and Earth-observation satellites.”
Long March 11 will launch much smaller satellites. With solid fuel, it will be ready for firing at short notice, offering the ability to send a reconnaissance spacecraft aloft almost as soon as a tactical need for one arises—for example, to sweep a patch of ocean for enemy ships. Liang describes Long March 11 as having value in civil missions such as post-disaster reconnaissance, but Chinese space officials routinely refer to non-military applications of equipment that have obvious military uses. One official last year said that the payload of a then-planned but unnamed solid launcher might be 1 ton.
Long March 7, the second member of the new liquid-propellant Chinese launcher family, has also been delayed, though perhaps not much. A year ago, it was due to fly late in 2013; now the target is 2014. It and a smaller relative, Long March 6, will use body and booster diameters of 3.35 and 2.5 meters, which Chinese industry is already adept at building for rockets dating back to the 1960s that use toxic hydrazine fuel.
Liang adds that Long March 7 may become China's manned launcher. As such, it would replace Long March 2F, a member of the hydrazine-fueled family that should ultimately be superseded by the group of rockets now under development. The authorities will surely not rush to anoint Long March 7 as their manned launcher, however. Apart from redundant and more robust systems, it will presumably need a long record of unmanned launches before it is trusted to carry people.
Long March 7 and Long March 6 will use kerosene fuel. Liang says the old hydrazine-burning Long Marches will serve alongside the new generation for 10-20 years. Long March 6 appears to be intended for launching reconnaissance satellites on polar orbits. A year ago, its program timing was close to that of Long March 7; the latest report makes no mention of it.
The state space industry is scheduled during the current five-year planning period, 2011-15, to request government approval to develop a launcher for manned Moon missions, China Daily says in the same report. Since that planning period is already well underway, the industry must hope to launch full-scale development no earlier than 2016. The Moon rocket, with an 8-meter diameter, would loft 100 tons to low Earth orbit, making it smaller than the U.S. Saturn V used in the 1960s and 1970s. The Tianjin space manufacturing base has been sized for diameters up to 10 meters.
The U.S. Apollo program experience suggests that a 100-ton throw weight to low orbit would not be enough to launch a lunar mission in a single shot, so Chinese space program managers appear to be considering at least two launches for each mission: one for the major part of their lunar spacecraft and one for the manned capsule. The Long March 7 is evidently a candidate for the separate launch.
CAST Satellite Buses
|Total mass (kg/lb.)||5,100/11,200||3,800/8,400||5,500/12,000||6,500–7,000/14,300-15,400|
|Payload mass (kg/lb.)||600/1,300||450/990||1,000/2,200||1,200-1,500/2,600-3,300|
|Total power (watts)||10,000||7,000||16,000||15,000–20,000 |
|Power supplied to payload (watts) ||8,000||4,000||11,000||Not available|
|Sources: CAST and China Great War Industry Corp.|