  Recent years have seen unprecedentedly fast-growing prosperity in the
commercial space industry. Several privately funded aerospace manufacturers,
such as Space Exploration Technologies Corporation (SpaceX) and Blue Origin
have innovated what we used to know about this capital-intense industry and
gradually reshaped the future of human civilization. As private spaceflight and
multi-planetary immigration gradually become realities from science fiction
(sci-fi) and theory, both opportunities and challenges are presented. In this
article, a review of the progress in space exploration and the underlying space
technologies is firstly provided. For the next, a revisit and a prediction are
paid and made to the K-Pg extinction event, the Chelyabinsk event,
extra-terrestrialization, terraforming, planetary defense, including the
emerging near-Earth object (NEO) observation and NEO impact avoidance
technologies and strategies. Furthermore, a framework of the Solar
Communication and Defense Networks (SCADN) with advanced algorithms and high
efficacy is proposed to enable an internet of distributed deep-space sensing,
communications, and defense to cope with disastrous incidents such as
asteroid/comet impacts. Furthermore, the perspectives on the legislation,
management, and supervision of founding the proposed SCADN are also discussed
in depth.
