AviationWeek.com/awst AVIATION WEEK & SPACE TECHNOLOGY/MARCH 30-APRIL 12, 2015 33Bradley Perrett BeijingLong Wait
Long March 7 progress stalls again
I
t is not unusual for complex development programs to slip.
But delays do not usually mount as steeply as they have
for Long March 7. In March 2012 the rocket, China’s future
workhorse space launcher, was sup-
posed to be about 20 months away from
flight. Three years later, that first launch
is still at least 10 months away.
Work on Long March 5, meanwhile,
has progressed as far as assembling the
first airframe; engines have apparently
not been installed. That launcher, the
largest of the three in China’s new family
of carrier rockets, will also be ready for
flight in 2016, while the smallest, Long
March 6, should lead its siblings with a
first liftof in the middle of this year.
In one configuration, Long March 7
is designed to throw 13.5 metric tons
(29,800 lb.) to low-inclination low Earth
orbits; it will replace the larger versions
of the current Long March 2, 3 and 4 se-
ries. It may also become China’s manned
launcher, replacing Long March 2F.The largest version of Long March 5, the one that has been
assembled, is supposed to throw 14 tons to geostationary
transfer orbit, while Long March 6 has variously been cred-
ited with a throw-weight to Sun-synchronous polar orbit of
500 kg (1,100 lb.) or more than 1 ton.
The latest schedule for the three rockets—under develop-
ment together because they share airframe modules and en-
gines—was given by Tan Yonghua, president of the Academy
of Aerospace Propulsion Technology (AAPT). Tan is prob-
ably happy to discuss the matter because the Long March 7
delay is unlikely to be the fault of his organization. AAPT is
providing the engines, which have long been confirmed as
mature and ready for service.
“The Long March 7 and our most powerful rocket, the
Long March 5, will make their first flights next year, and they
will also use the new engine,” the China Daily quotes Tan as
saying. The engine is the 120-ton-thrust YF-100. Its develop-ment was completed before 2012, when series production of
the engine began. So it has been waiting at least three years
for its first flight on one—any—of the new launchers. Long
March 6 will provide the occasion.
The launcher family is made up of three airframe mod-
ules, in varying lengths. Two of the modules—3.35 meters
(11 ft.) and 2 meters in diameter—are powered by one or two
YF-100s, which burn kerosene with liquid oxygen. Those two
modules serve as core first stages for Long March 6 and 7
and boosters for Long March 7 and 5. The 5-meter-dia. Long
March 5 core modules burn liquid hy-
drogen with liquid oxygen.
Tan’s schedule for Long March 5
and 6 confirms an Aviation Week re-
port from December, but at that time
it appeared that Long March 7 would
make its first flight in 2015. Late last
year, the airframe of the first Long
March 7 had been built, but the en-
gines had yet to be installed. Before
that, the developer and manufacturer,
the China Academy of Launch Vehicle
Technology (CALT), overcame dif-
culties that had arisen in the propel-
lant supply system (but not in the
engines) by making more than 10
changes to the Long March 7 design.
It appears, then, that some new prob-
lem may have emerged to push the
first flight into 2016.
The schedule has slipped by a to-
tal of more than two years during the
three years of program execution.
The first airframe underwent
tests at a launch site that was not
in the Chinese interior, says China
Aerospace Science and Technology
Corp. (CASC), the country’s main
space industry organization. Since
the airframe traveled by sea, that site was presumably the
new launch base on Hainan. The tests were successful, says
CASC, apparently referring to a set of evaluations that late
last year were expected to verify compatibility of onboard
and of-board systems.
The airframe was built at Beijing, the home of CALT, and
at a new space manufacturing base at Tianjin.
CALT is also developing Long March 5. Sibling organization
Shanghai Academy of Spaceflight Technology (SAST) is han-
dling Long March 6, which has been expected to be the easiest
of the three to develop, because it is the smallest and simplest.
An ofcial photograph of the first Long March 5 (above,
right) shows the 5B version, the most powerful, featuring two
core stages and four boosters of the largest diameter.
The core modules of the first Long March 5 were being
built late last year, by which time the boosters were ready. The
next step was to be assembly of the complete airframe with-
out engines. That appears to be the stage that has now been
reached. The photograph of the airframe, shown on China
Central Television, reveals no sign of the engines.
“Whole-rocket” tests have been conducted successfully on
the assembled launcher, says CASC. In February, the Xinhua
news agency reported that the program had completed a
ground test on the power system of the Long March 5. cCASCSASACChinese engineers
have assembled
the first Long
March 5 airframe.The core of the first Long March 7 airframe in testing.