12.5 Typical Application of System Integration and Assembly
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(1) Transshipment with assembly parking bracket was the simplest and most
reliable way. At the same time, it could also be applied in system assembly, test,
experiment, examination and propellant loading. It was also the most common way
of transshipment of spacecraft and hardware. The only shortcoming was that aid of
operators was necessary in small turn.
(2) The Air-cushion vehicle could transship super heavy spacecraft, which was
suitable to the development of large spacecraft. The air-cushion truck could be used
in different facility and implement “zero” turning radius. The height of air-cushion
vehicle was only several tens of millimeters, which would have almost no impact
when it moves and stops. The disadvantage was that the requirement for flatness of
passage in facility is high and there should be large gas source.
(3) AGV was a type of transshipment equipment with guide and high positioning
accuracy. It could be manually controlled in all directions and move automatically along a predefined path. It should have adequate safety protection and could
automatically identify obstacles in the path.
(4) Mecanum wheel could also implement transshipment in all directions. Its
advantage was movement in all directions within compact space environment, flexible and easy to operate. However, its structure was too complex and the effective
contact area of its wheels was small, which made that its effective load capacity was
small, the efficiency was low, it was easy to be damaged, and the movement accuracy
was relatively low.
The total mass of the Chang’E-3 lunar lander after propellant was loaded was about
3.8 tons, while less than 1.2 tons without propellant. At the same time, the transshipment distance in the facility was relatively short. Therefore, assembly parking
bracket was applied for the Chang’E-3 lunar lander, which was simple and reliable.
2. Transportation
Generally, the transportation of spacecraft and hardware is transshipment between
different assembly facilities, test sites and launch site. There are road transportation,
railway transportation, air transportation and sea transportation. The characteristics
of each transportation method are different.
(1) Road transportation. It is the major transportation method of spacecraft and
hardware in close range. Its advantages are convenient and no time restriction. The
disadvantage is that road transportation of large spacecraft may be affected by the
height of roads and bridges and the width of highway toll stations. Generally, special
transportation vehicle is applied in road transportation, which is very long, wide and
lower chassis.
(2) Railway transportation. It is the general transportation method of spacecraft
and hardware in long distance, and most ground support equipment is also transported
by railway. The advantage is that it is not limited by road; the disadvantages are
slow and poor transport environment. There are several types of railway carriages:
instrument carriage, flatbed truck, gondola truck and tank truck. The crucial hardware
shall be placed in the instrument carriage with temperature control.
(3) Air transportation. It is a general transportation method of spacecraft to launch
site. The greatest advantage of air transportation is fast. Its disadvantage is that it is
429
(1) Transshipment with assembly parking bracket was the simplest and most
reliable way. At the same time, it could also be applied in system assembly, test,
experiment, examination and propellant loading. It was also the most common way
of transshipment of spacecraft and hardware. The only shortcoming was that aid of
operators was necessary in small turn.
(2) The Air-cushion vehicle could transship super heavy spacecraft, which was
suitable to the development of large spacecraft. The air-cushion truck could be used
in different facility and implement “zero” turning radius. The height of air-cushion
vehicle was only several tens of millimeters, which would have almost no impact
when it moves and stops. The disadvantage was that the requirement for flatness of
passage in facility is high and there should be large gas source.
(3) AGV was a type of transshipment equipment with guide and high positioning
accuracy. It could be manually controlled in all directions and move automatically along a predefined path. It should have adequate safety protection and could
automatically identify obstacles in the path.
(4) Mecanum wheel could also implement transshipment in all directions. Its
advantage was movement in all directions within compact space environment, flexible and easy to operate. However, its structure was too complex and the effective
contact area of its wheels was small, which made that its effective load capacity was
small, the efficiency was low, it was easy to be damaged, and the movement accuracy
was relatively low.
The total mass of the Chang’E-3 lunar lander after propellant was loaded was about
3.8 tons, while less than 1.2 tons without propellant. At the same time, the transshipment distance in the facility was relatively short. Therefore, assembly parking
bracket was applied for the Chang’E-3 lunar lander, which was simple and reliable.
2. Transportation
Generally, the transportation of spacecraft and hardware is transshipment between
different assembly facilities, test sites and launch site. There are road transportation,
railway transportation, air transportation and sea transportation. The characteristics
of each transportation method are different.
(1) Road transportation. It is the major transportation method of spacecraft and
hardware in close range. Its advantages are convenient and no time restriction. The
disadvantage is that road transportation of large spacecraft may be affected by the
height of roads and bridges and the width of highway toll stations. Generally, special
transportation vehicle is applied in road transportation, which is very long, wide and
lower chassis.
(2) Railway transportation. It is the general transportation method of spacecraft
and hardware in long distance, and most ground support equipment is also transported
by railway. The advantage is that it is not limited by road; the disadvantages are
slow and poor transport environment. There are several types of railway carriages:
instrument carriage, flatbed truck, gondola truck and tank truck. The crucial hardware
shall be placed in the instrument carriage with temperature control.
(3) Air transportation. It is a general transportation method of spacecraft to launch
site. The greatest advantage of air transportation is fast. Its disadvantage is that it is