2:30 PM - 2:45 PM
[PPS03-21] Planetary defense activities at JAXA
Keywords:Planetary defense, Near earth object, asteroid, Hayabusa2, Hera
It is about 30 years since the activity of the planetary defense (spaceguard), has started in the 1990s. The planetary defense is an activity that deals with the problem of collisions of celestial bodies with the Earth. During this period, the number of discovered near-Earth objects (NEOs), which was several hundred, has increased to about 30,000 and several small celestial body explorations were conducted. As a consequence, the understandings of small solar system bodies have changed significantly. On the other hand, discussions on the issue of NEO collisions with the Earth have also become active internationally and many discussions at the United Nations, international conferences, and outreach events have been held. In this situation, JAXA is also engaged in various activities related to the planetary defense. Here, we will introduce our current and future activities.
In the planetary defense, firstly it is important to discover hazardous celestial bodies that collide with the Earth. Regarding NEO's discovery observations, the majority of discoveries are by US projects. In JAXA, we have developed a method called the stacking method in order to discover small and fast moving asteroids that are passing near the Earth. Using this method, JAXA has succeeded in discovering 11 NEOs with a small telescope with a diameter of about 20 cm. The discovery contains four 10m-class objects. JAXA also has the Bisei Spaceguard Center, which is equipped with a telescope with a diameter of 1 m. So we are planning to apply the stacking method to observations with a larger telescope.
It is also important to avoid the Earth collision, when a celestial body that collides with the Earth is discovered. There is much debate about collision avoidance methods, but in any case it is important to know the characteristics of the colliding asteroids. To do this, it is necessary to send spacecraft to asteroids for investigation. JAXA sent the spacecraft Hayabusa and Hayabusa2 to asteroid Itokawa and Ryugu to investigate these objects, which are NEOs, in detail. As a result, it was found that these asteroids have rubble pile structure, which is important information for planetary defense.
For Hayabusa2, an extended mission is being carried out, and after a flyby of 2001 CC21in 2026, it will arrive at 1998 KY26 in 2031. These two asteroids are also NEOs, and in particular, 1998 KY26 is estimated to be about 30 m in size. Since such small body collisions with the Earth could actually occur in the near future, the exploration results are important from the point of planetary defense. In addition, JAXA will cooperate in Hera, a planetary defense mission of ESA, by providing an infrared camera. Hera will investigate an asteroid after DATR, which is a mission of NASA, will collide to it.
NASA and ESA have specialized sections to deal with the issue of the planetary defense. In Japan as well, various activities related to the planetary defense are being carried out, so we think it is time to deepen domestic discussions and organize future activities for the planetary defense.
In the planetary defense, firstly it is important to discover hazardous celestial bodies that collide with the Earth. Regarding NEO's discovery observations, the majority of discoveries are by US projects. In JAXA, we have developed a method called the stacking method in order to discover small and fast moving asteroids that are passing near the Earth. Using this method, JAXA has succeeded in discovering 11 NEOs with a small telescope with a diameter of about 20 cm. The discovery contains four 10m-class objects. JAXA also has the Bisei Spaceguard Center, which is equipped with a telescope with a diameter of 1 m. So we are planning to apply the stacking method to observations with a larger telescope.
It is also important to avoid the Earth collision, when a celestial body that collides with the Earth is discovered. There is much debate about collision avoidance methods, but in any case it is important to know the characteristics of the colliding asteroids. To do this, it is necessary to send spacecraft to asteroids for investigation. JAXA sent the spacecraft Hayabusa and Hayabusa2 to asteroid Itokawa and Ryugu to investigate these objects, which are NEOs, in detail. As a result, it was found that these asteroids have rubble pile structure, which is important information for planetary defense.
For Hayabusa2, an extended mission is being carried out, and after a flyby of 2001 CC21in 2026, it will arrive at 1998 KY26 in 2031. These two asteroids are also NEOs, and in particular, 1998 KY26 is estimated to be about 30 m in size. Since such small body collisions with the Earth could actually occur in the near future, the exploration results are important from the point of planetary defense. In addition, JAXA will cooperate in Hera, a planetary defense mission of ESA, by providing an infrared camera. Hera will investigate an asteroid after DATR, which is a mission of NASA, will collide to it.
NASA and ESA have specialized sections to deal with the issue of the planetary defense. In Japan as well, various activities related to the planetary defense are being carried out, so we think it is time to deepen domestic discussions and organize future activities for the planetary defense.