  Asteroid Impacts pose a major threat to all life on the Earth. Deflecting the
asteroid from the impact trajectory is an important way to mitigate the threat.
A kinetic impactor remains to be the most feasible method to deflect the
asteroid. However, due to the constraint of the launch capability, an impactor
with the limited mass can only produce a very limited amount of velocity
increment for the asteroid. In order to improve the deflection efficiency of
the kinetic impactor strategy, this paper proposed a new concept called the
Assembled Kinetic Impactor (AKI), which is combining the spacecraft with the
launch vehicle final stage. By making full use of the mass of the launch
vehicle final stage, the mass of the impactor will be increased, which will
cause the improvement of the deflection efficiency. According to the technical
data of Long March 5 (CZ-5) launch vehicle, the missions of deflecting Bennu
are designed to demonstrate the power of the AKI concept. Simulation results
show that, compared with the Classic Kinetic Impactor (CKI, performs
spacecraft-rocket separation), the addition of the mass of the launch vehicle
final stage can increase the deflection distance to more than 3 times, and
reduce the launch lead-time by at least 15 years. With the requirement of the
same deflection distance, the addition of the mass of the launch vehicle final
stage can reduce the number of launches to 1/3 of that of the number of CKI
launches. The AKI concept makes it possible to defend Bennu-like large
asteroids by a no-nuclear technique within 10-year launch lead-time. At the
same time, for a single CZ-5, the deflection distance of a 140 m diameter
asteroid within 10-year launch lead-time, can be increased from less than 1
Earth radii to more than 1 Earth radii.
