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From page 471... ... 18 Planetary Defense: Defending Earth Through Applied Planetary Science Planetary defense is an international cooperative enterprise aimed at providing protection to the nations of the world from devastating asteroid and comet impacts. Through the use of the knowledge and tools gained through planetary science and exploration, it is now possible to develop realistic and cost-effective detection and mitigation strategies against these natural disasters. Read the entire page →
From page 472... ... 472 ORIGINS, WORLDS, AND LIFE FIGURE 18-1 The known and extrapolated population of near-Earth asteroids (N) in terms of estimated diameter (D) Read the entire page →
From page 473... ... PLANETARY DEFENSE: DEFENDING EARTH THROUGH APPLIED PLANETARY SCIENCE 473 FIGURE 18-2 The chart above shows reported fireball events for which geographic location data are known. Each event's calculated total impact energy is indicated by its relative size and color. Read the entire page →
From page 474... ... 474 ORIGINS, WORLDS, AND LIFE FIGURE 18-3 Near-Earth object discoveries over time, showing the accelerating rate of NEO detection from ground-based search programs. Data current as of February 16, 2023. Read the entire page →
From page 475... ... PLANETARY DEFENSE: DEFENDING EARTH THROUGH APPLIED PLANETARY SCIENCE 475 NEOs for any potential impacts via its Sentry impact monitoring system, and monitors potential newly discovered NEOs via its Scout hazard assessment system. NASA and NSF have broad expertise in both the scientific exploration and characterization of NEOs. Read the entire page →
From page 476... ... 476 ORIGINS, WORLDS, AND LIFE The Brown Act survey goals are based on the findings of a 2003 NASA science definition team study (NASA 2003) Read the entire page →
From page 477... ... PLANETARY DEFENSE: DEFENDING EARTH THROUGH APPLIED PLANETARY SCIENCE 477 funding for full-scale development in the 2022 President's Budget Request, funding is not yet assured, and the mission is not yet confirmed. Finding: The first priority in planetary defense is early detection, tracking, and characterization of NEOs, whose im pact may cause widespread regional damage. Read the entire page →
From page 478... ... 478 ORIGINS, WORLDS, AND LIFE Mega-Satellite Constellations and NEO Surveys An increasing threat to the ability of ground-based telescopes to detect and characterize NEOs comes from existing and planned mega-constellations of low-Earth-orbiting (LEO) satellites (e.g., Starlink) Read the entire page →
From page 479... ... PLANETARY DEFENSE: DEFENDING EARTH THROUGH APPLIED PLANETARY SCIENCE 479 cause it to detonate near/at Earth's surface. The NEO's physical characteristics also have bearing on the effectiveness of various space deflection/mitigation techniques. Read the entire page →
From page 480... ... 480 ORIGINS, WORLDS, AND LIFE type and are visible by many people. Modeling and accurately predicting the visibility range and brightness of these small impacting NEOs will enhance the credibility of the NEO activities and improve the predictions of the magnitude of expected explosions. Read the entire page →
From page 481... ... PLANETARY DEFENSE: DEFENDING EARTH THROUGH APPLIED PLANETARY SCIENCE 481 initial orbit determinations of potentially hazardous NEOs (99942) Apophis and 2020 NK1 indicated a significant chance of Earth impact, but radar observations were able to quickly rule out a collision hazard. Read the entire page →
From page 482... ... 482 ORIGINS, WORLDS, AND LIFE and planned telescope programs to improve detection and tracking" of NEOs, as well as to identify "opportunities in existing and new telescope programs to enhance characterization of NEO composition and dynamical and physical properties" (NSTC 2018) Read the entire page →
From page 483... ... PLANETARY DEFENSE: DEFENDING EARTH THROUGH APPLIED PLANETARY SCIENCE 483 The extremely precise Apophis flyby prediction provides an unprecedented opportunity for multiple observatories to coordinate simultaneous pre- and post-encounter observations of the NEO from multiple viewing geometries and at wavelengths from optical to radar. Owing to its inherent interest, Apophis is already a target of opportunity for astronomers, with every apparition leading to significant observations focused on determining its orbit, shape, spin state, and thermal and spectral properties. Read the entire page →
From page 484... ... 484 ORIGINS, WORLDS, AND LIFE NEO MODELING, PREDICTION, AND INFORMATION INTEGRATON Goal 2 of the National Near-Earth Object Preparedness Strategy and Action Plan focuses on advancement of modeling and analysis capabilities, including the assessment of impact probabilities, location, consequences, and mitigation options. The initial conditions and attendant uncertainties for these modeling efforts depend heavily on the detection, tracking, and characterization of NEOs (see NEO Detection, Tracking, and Characterization section) Read the entire page →
From page 485... ... PLANETARY DEFENSE: DEFENDING EARTH THROUGH APPLIED PLANETARY SCIENCE 485 more collaborative work is needed to understand the sources of these differences and to refine simulation capabilities. The interagency NEO MWG, led by the NASA Ames Research Center, has begun working through representative impact studies. Read the entire page →
From page 486... ... 486 ORIGINS, WORLDS, AND LIFE past decade, owing to advances in high performance computing, improved understanding of NEO initial conditions from spacecraft data, and focused research. Improvements include more realistic modeling of rubble pile structures, variable distributions of macro- and microporosity, improved strength and damage models representing asteroidal material, and simulation of a wider range of three-dimensional NEO shapes. Read the entire page →
From page 487... ... PLANETARY DEFENSE: DEFENDING EARTH THROUGH APPLIED PLANETARY SCIENCE 487 Laboratory (EIL) , many planetary defense questions will remain unaddressed. Read the entire page →
From page 488... ... 488 ORIGINS, WORLDS, AND LIFE NEO DEFLECTION AND DISRUPTION MISSIONS One of the overarching strategic goals of the National Near-Earth Object Preparedness Strategy and Action Plan is developing capabilities for NEO impact prevention. Goal 3 of the action plan outlines the activities that NASA will lead to strengthen the U.S. Read the entire page →
From page 489... ... PLANETARY DEFENSE: DEFENDING EARTH THROUGH APPLIED PLANETARY SCIENCE 489 of the DART results and apply them to broader mitigation technology efforts to achieve an effective and versatile PD capability. Similarly, the launch of NASA's NEO Surveyor in 2026 will greatly expand our knowledge of the NEO population over the next decade, which will help inform the PD activities that follow. Read the entire page →
From page 490... ... 490 ORIGINS, WORLDS, AND LIFE characterize via ground-based methods, and represent the least understood, but statistically the most likely subset of the NEO population to require mitigation actions. For NEOs with short warning times, rapid characterization may be required in order to implement appropriate mitigation measures. Read the entire page →
From page 491... ... PLANETARY DEFENSE: DEFENDING EARTH THROUGH APPLIED PLANETARY SCIENCE 491 FIGURE 18-4 Numerical results from simulating deflection capabilities of various techniques across a variety of asteroid sizes following fifteen different Earth-impacting orbits. Kinetic impact (KI) Read the entire page →
From page 492... ... 492 ORIGINS, WORLDS, AND LIFE parameter space between the kinetic impact and ion beam deflection techniques. Please see the RMA study for additional details (NASA 2021c) Read the entire page →
From page 493... ... PLANETARY DEFENSE: DEFENDING EARTH THROUGH APPLIED PLANETARY SCIENCE 493 Promising Planetary Defense Mission Technologies There are several promising technologies whose pursuit would help attain specific goals of PD characterization and mitigation missions. These technologies can be broadly grouped into several categories and are utilized in mission architectures for flyby/intercept and rendezvous PD concepts. Read the entire page →
From page 494... ... 494 ORIGINS, WORLDS, AND LIFE Finding: Promising new technologies for both characterization and mitigation demonstration missions could be tested on relevant NEOs. Technologies such as those for guidance, navigation, and control (GNC) Read the entire page →
From page 495... ... PLANETARY DEFENSE: DEFENDING EARTH THROUGH APPLIED PLANETARY SCIENCE 495 Special focus on examining the feasibility of a standardized rapid reconnaissance design, applicable to the greatest number of short-warning impact scenarios, would be beneficial in developing rapid-response planetary defense capabilities. INTERNATIONAL COOPERATION ON NEO PREPARATION With this decadal survey effort focused on NASA and NSF activities and support, this section provides a high-level overview of those NASA and NSF activities that will foster -- and benefit from -- greater international cooperation. Read the entire page →
From page 496... ... 496 ORIGINS, WORLDS, AND LIFE effort is focused on NASA and NSF planetary defense activities, this section outlines key activities that support NEO impact emergency procedures and action protocols. NASA has developed a sound process for the collection, dissemination, and communication of information regarding specific NEO impact threats. Read the entire page →
From page 497... ... PLANETARY DEFENSE: DEFENDING EARTH THROUGH APPLIED PLANETARY SCIENCE 497 Without the development and testing of in-space mitigation technologies, the only possible response to a threatening impact would be evacuation of the impact area and subsequent disaster response. A robust program of activities in the coming decade will enable the U.S. Read the entire page →
From page 498... ... 498 ORIGINS, WORLDS, AND LIFE IAWN (International Asteroid Warning Network) Read the entire page →
From page 499... ... PLANETARY DEFENSE: DEFENDING EARTH THROUGH APPLIED PLANETARY SCIENCE 499 Pravec, P., P Scheirich, P Read the entire page →

From page 471...

... 18 Planetary Defense: Defending Earth Through Applied Planetary Science Planetary defense is an international cooperative enterprise aimed at providing protection to the nations of the world from devastating asteroid and comet impacts. Through the use of the knowledge and tools gained through planetary science and exploration, it is now possible to develop realistic and cost-effective detection and mitigation strategies against these natural disasters.