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The activities that focus on the avoidance of collisions of small solar system bodies with the Earth belong to the topic called planetary defense. These activities began in earnest in the 1990s. Now, nearly 30 years later, there has been remarkable progress. More than 36,000 Near Earth Objects (NEOs) have been discovered so far, and spacecraft have been sent to more than 10 NEOs. Furthermore, in 2022, DART by NASA made the first attempt to change the orbit of an asteroid successfully. ESA Hera was also launched successfully on October 7, 2024, to investigate in detail the results of the DART impact as well as the characteristics of its target. Other NEO missions such as OSIRIS-APEX (an extended mission of OSIRIS-REx) of NASA, and Hayabusa2# (an extended mission of Hayabusa2) of JAXA are on their way to their respective target.
In 2029, the asteroid Apophis will come closer than Earth's geostationary satellite orbit to our planet, and is the target of both the RAMSES of ESA that just started officially its development until its formal approval in 2025 in order to be at Apophis a few months before its closest approach, and the OSIRIS-APEX that will visit the asteroid a few days after its closest approach to the Earth. Several concepts are also under study to visit Apophis, offering a great possible international synergy between these two missions and possibly other concepts. Internationally, a wide range of activities such as discussions in groups established under the United Nations, international conferences, and outreach activities are actively carried out. This lively situation motivates presentations on ongoing relevant activities in various areas covering ground and space based investigations, theoretical/technical research, as well as social science research on NEO and planetary defense. We will also discuss what kind of research or action, including international cooperation, should be undertaken from now on for the protection of our planet against an impact.