National Aeronautics and Space Administration

NASA PLANETARY DEFENSE

STRATEGY AND ACTION PLAN

In support of the National Preparedness Strategy and Action Plan for 

Near-Earth Object Hazards and Planetary Defense 

APRIL 2023

Double Asteroid 

Redirection Test

Near-Earth 

Object Surveyor

www.nasa.gov
 NASA Planetary Defense Strategy And Action Plan | 2

National Aeronautics and Space Administration

NASA PLANETARY DEFENSE

STRATEGY AND ACTION PLAN

In support of the National Preparedness Strategy and Action 

Plan for Near-Earth Object Hazards and Planetary Defense 

NASA Planetary Defense Strategy &

Action Plan Working Group

Co-Chairs

Lindley Johnson, PDCO

Patrick Besha, OTPS

Assistant to the Co-Chairs

Renata Kommel, OTPS (contractor)

Members

Kelly Fast, PDCO

L.A. Lewis, PDCO (FEMA liaison)

Joshua Handal, PDCO (contractor)

Alyse Beauchemin, OTPS (contractor)

Nikolai Joseph, OTPS

Justin Treptow, STMD

Alvin Drew, OIIR

Kevin Conole, OIIR

Rebecca Levy, OIIR

DaMara Belson, OCFO

William West, OCFO

Rebecca Bresnik, OGC

Karen Reilley, OGC

Steven Mirmina, OGC

Karen Fox, OCOMM
 NASA Planetary Defense Strategy And Action Plan | 1

Summary of the 2023 National Preparedness Strategy and Action 

Plan for Near-Earth Object Hazards and Planetary Defense

In April 2023 the United States government released the National 

Preparedness Strategy and Action Plan for Near-Earth Object Hazards 

and Planetary Defense (National Planetary Defense Strategy)1

 to improve 

the United States’ preparedness to address the hazard of NEO impacts 

over a 10-year period, primarily by helping organize and coordinate 

interagency NEO-related efforts. 

The 2023 National Planetary Defense Strategy updates the United 

States’ first comprehensive Near-Earth Object Preparedness Strategy 

and Action Plan released in 2018. It builds on existing efforts by Federal 

Departments and Agencies to address the hazard of NEO impacts, 

includes evaluation of where progress has been made since 2018, and 

focuses future work on planetary defense across the U.S. government. 

The National Planetary Defense Strategy provides a road map for 

a collaborative and federally coordinated approach to developing effective technologies, policies, 

practices, and procedures for decreasing U.S. and global vulnerability to NEO impacts. 

When implemented, the National Planetary Defense Strategy will improve detection, research, mission 

planning, emergency preparedness and response, international engagement, and internal U.S. 

government coordination on planetary defense.

NEOs are asteroids and comets that come close to or pass across Earth’s orbit around the Sun. 

They range in size from small “meteoroids” only a few meters across, to much larger bodies several 

kilometers wide. When NEO orbits bring them into Earth’s atmosphere, smaller objects harmlessly 

fragment and disintegrate, while larger objects can cause local damage or even global devastation.

Figure 1: National 

Planetary Defense 

Strategy. available online.1

Venus Orbit

Earth Orbit

Mercury Orbit

Sun

Near-Earth Objects (NEOs)

Asteroids and comets with orbits that bring them 

within one-and-a-third times the distance from the 

Sun to Earth, or 1.3 astronomical units (blue zone)

Potentially Hazardous Objects

Orbit of Bennu

• NEOs with orbits that bring them 

within 4.7 million miles (7.5 million km) 

of Earth's orbit (dark blue zone) and

• Size that could do regional 

damage should they impact Earth 

(~500 feet or ~140 meters in size 

and larger)

• Example of Potentially

Hazardous Asteroid

• Target of NASA's

OSIRIS-REx mission

1 https://www.whitehouse.gov/wp-content/uploads/2023/04/2023-NSTC-National-Preparedness-Strategy-and-Action-Plan-forNear-Earth-Object-Hazards-and-Planetary-Defense.pdf

Figure 2: Near-Earth objects in the Solar System. (Source: NASA)
 NASA Planetary Defense Strategy And Action Plan | 2

The threat exists because our planet orbits the Sun amidst millions of objects that cross our orbit – 

asteroids and comets. Even a rare interstellar asteroid or comet from outside our solar system can enter 

Earth’s neighborhood. 

Characteristics of the estimated NEO population:

• Around 1,000 NEOs greater than one kilometer in size that are potentially capable of causing 

global impact effects. Approximately 95 percent of these bodies have been found and none are a 

current threat. 

• Around 25,000 objects larger than 140 meters in size, capable of causing regional devastation, 

are believed to exist. Less than 50 percent have been detected and tracked to date. 

• An estimated 230,000 or more objects exist that are equal to or larger than 50 meters in size and 

could destroy a concentrated urban area. It is estimated that fewer than eight percent of these 

have been detected. 

• Tens of millions of smaller NEOs exist. While most are small enough to likely break up in Earth’s 

atmosphere during an impact, those larger than 10 meters in size could potentially cause some 

surface damage. Less than one percent of these small bodies have been discovered.2

Figure 3: NEO size and hazard. (Credit: Johns Hopkins University / Applied Physics Lab)

2 National Academies of Science Planetary Science Decadal Survey 2023-2032
 NASA Planetary Defense Strategy And Action Plan | 3

Executive Summary

In April 2023 the United States released the National Preparedness Strategy and Action Plan for 

Near-Earth Object Hazards and Planetary Defense (National Planetary Defense Strategy).3

 This NASA 

strategy responds to the U.S. National Planetary Defense Strategy, and focuses Agency-level activities 

within NASA, describing existing efforts to survey the Near-Earth Object (NEO) population, assess risks and 

develop approaches to prevent or mitigate NEO impacts on Earth. It provides guidance to improve current 

efforts and charts a robust yet realistic path forward for planetary defense activities at NASA. 

NASA has been engaged in NEO research since 1998. In 2016, NASA formalized its planetary defense 

efforts with the establishment of the Planetary Defense Coordination Office (PDCO), under the Planetary 

Science Division (PSD) in NASA’s Science Mission Directorate, to oversee the ongoing NEO research 

and to coordinate activities with U.S. government agencies and international participants. The PDCO 

manages the NEO Observations Program and coordinates requirements for planetary defense missions, 

such as the Double Asteroid Redirection Test (DART) and the NEO Surveyor missions. 

In 2022, the National Academy of Sciences’ Origins, Worlds, and Life: A Decadal Strategy for Planetary 

Science and Astrobiology 2023-2032 prominently featured a section on planetary defense, noting 

that NASA’s PDCO was “the critical organization to advance U.S. planetary defense capabilities and 

initiatives in the next decade and beyond.” 

Significant progress in NEO detection has been made in recent years and the recently approved NEO 

Surveyor mission, designed to improve detection capabilities to greater than 90 percent of NEOs 140m 

or larger within about a decade of being launched in 2028, will roughly triple our current capability.

Despite this impressive progress, key challenges remain:

• Survey, detection, characterization and assessment: The global community wants a 

complete NEO survey catalog and sufficient ability to fully characterize NEOs. The ability to 

assess the risks that NEOs may pose to Earth, and support any mitigation efforts, could be 

significantly improved by a sufficient set of ground and space-based observations, modeling and 

prediction capabilities. (NASA Strategic Goals 1 and 2, see table below) 

• Mitigation: Technological preparedness would be improved with follow-on reconnaissance and 

mitigation demonstration missions. (NASA Strategic Goal 3) 

• International cooperation: With the expansion of international capabilities related to NEO survey 

and mitigation, planetary defense is poised to become a global effort. To realize this vision, NASA 

plans to foster greater international collaboration and engagement. (NASA Strategic Goal 4) 

• NASA support for interagency coordination: The National Planetary Defense Strategy 

recognizes a need for more stable, coordinated planetary defense activities across the United 

States government. NASA has a key role to play in spearheading this ongoing interagency 

coordination. (NASA Strategic Goals 5 and 6)

• NASA organization: While the NASA PDCO benefits greatly from the close coordination with 

planetary science activities by being part of NASA PSD, competing priorities in the Planetary 

Science portfolio, which currently includes development of several large missions, may limit 

opportunities for expanding planetary defense activities. However, competition for funding is likely 

to be an issue regardless of where the program is situated. (NASA Strategic Goal 7) 

3 https://www.whitehouse.gov/wp-content/uploads/2023/04/2023-NSTC-National-Preparedness-Strategy-and-Action-Plan-forNear-Earth-Object-Hazards-and-Planetary-Defense.pdf
 NASA Planetary Defense Strategy And Action Plan | 4

• Strategic communications: NASA should better integrate and disseminate information 

regarding NEO survey and mitigation work. (NASA Strategic Goal 8)

In support of the National Preparedness Strategy and Action Plan for Near-Earth Object Hazards and 

Planetary Defense, NASA developed this NASA Planetary Defense Strategy and Action Plan. It also 

complements the 2022 National Cislunar Science & Technology Strategy (e.g., Objective 3). The NASA 

strategy is organized around the paradigm of architecting from the right: envisioning desired end states, 

identifying key challenges and then developing actions to address them. Embedded within are the six 

National goals and two additional NASA-specific goals (NASA Strategic Goals 7 and 8). 

The NASA strategy provides additional details related to the Agency’s planetary defense work and 

specific actions to be completed by NASA organizations in response to the National Strategy and 

Action Plan (consistent with the leading/supporting agency roles identified in the National plan).

NASA Strategic Goals and Actions

Goal 1: Enhance NASA NEO detection, tracking, and characterization capabilities

Actions Timeframe

1.1 Continue to identify opportunities in existing and planned 

space domain awareness programs to improve detection 

and tracking by enhancing the volume and quality of current 

data streams, including from ground-based and space-based 

optical, infrared, and radar facilities.

Short term 

and ongoing

1.2 Identify technology and data processing capabilities and 

opportunities in existing and new telescope programs to 

enhance characterization of NEO composition and dynamical 

and physical properties. 

Short term

1.3 Continue and enhance multi-agency efforts to detect large 

meteoroids and small asteroids entering Earth’s atmosphere and provide 

rapid public notification. 

Short term 

1.4 Identify opportunities to leverage existing and planned cislunar 

space domain awareness capabilities to support detection, tracking, and 

characterization of NEOs, including through data sharing with planetary 

defense databases.

Short term

1.5 Support an interagency assessment to explore interest from key 

stakeholders in the coordinated development of current and future deep 

space radar facilities and identify where these facilities may be useful for 

planetary defense. 

Short term

1.6 Use the information developed in Actions 1.1, 1.2, 1.3, and 1.4 

to inform investments in space domain awareness programs and 

technology improvements to enhance completeness and speed of NEO 

detection, tracking, and characterization.

Long term
 NASA Planetary Defense Strategy And Action Plan | 5

1.7 Advance concepts for rapid characterization of a potentially 

hazardous NEO.

Short term 

and ongoing

1.8 Support analysis of emerging challenges in NEO survey and 

characterization in the upcoming decade, as well as solutions for 

mitigating and overcoming these challenges. 

Long term 

and ongoing

1.9 NASA should seek to apply maturing commercial capabilities 

to the challenge of planetary defense survey, characterization, and 

mitigation efforts.

Medium term 

and ongoing

1.10 Consider strengthening planetary radar partnerships, beginning 

with a study of desired capabilities in collaboration with National 

Science Foundation (NSF) and/or United States Space Force (USSF). 

Medium term

1.11 Consider potential designs for a bolide detector tech 

demonstration, such as a hosted sensor on a mission, which could be 

developed in partnership with other U.S. organizations.

Medium term

Goal 2: Improve NASA coordination on NEO modeling, prediction, and information integration

Actions Timeframe

2.1 Continue to support an interagency working group for coordination and 

enabling dissemination of the results of NEO threat modeling and analysis. Ongoing

2.2 Ascertain what information each participating organization requires 

for threat analysis on what timeframe. Identify gaps and develop 

recommendations for modeling improvements. 

Short term

2.3 Continue development and validation of a suite of computer 

simulation tools for assessing the outcome of deflection or disruption 

techniques applied to a NEO. 

Medium term

2.4 Improve a suite of computer simulation tools for assessing the local, 

regional, and global risks associated with an impact scenario. Continue 

to assess the sensitivities of these models to uncertainties in NEO 

dynamical and physical properties. 

Medium term

2.5 Develop an impact risk data pipeline to inform decision makers on 

results from integrated modeling of potential impact threats. Medium term

2.6 Continually assess the adequacy and validity of modeling and 

analysis of impact effects through annual exercises, test problems, 

comparison to experiments, and peer review activities. 

Ongoing
 NASA Planetary Defense Strategy And Action Plan | 6

Goal 3: Develop technologies for NEO reconnaissance, deflection and disruption missions

Actions Timeframe

3.1 Collaborate with interagency partners on technologies for rapid 

response, reconnaissance, and characterization of in-space objects. 

Evaluate the capabilities of current and projected launch vehicle 

infrastructure to support short-warning planetary defense missions.

Short term

3.2 Create plans for the development, testing, and implementation of 

NEO reconnaissance mission systems. Short term

3.3 Develop preliminary mission designs for future NEO deflection 

mission campaigns. Identify, assess the readiness, estimate costs, 

and propose development paths for key technologies required by 

NEO impact prevention concepts. Perform a risk analysis on planetary 

defense mission success under varying assumptions and circumstances. 

Medium term

3.4 Continue the study of circumstances when only use of a nuclear 

explosive device would provide the necessary force to mitigate an 

impending NEO impact threat, and the technologies, capabilities and 

operational considerations required for use of such devices. Assess the 

legal and national policy implications of such an option. 

Medium term

3.5 Continue flight demonstrations to validate NEO deflection and 

disruption system concepts. Long term

Goal 4: Increase NASA contributions to international cooperation on NEO preparation

Actions Timeframe

4.1 Continue to engage and inform foreign governments of the need for 

a collaborative and coordinated approach to preparing for a NEO event. Ongoing

4.2 Continue to demonstrate U.S. leadership in technical international 

NEO organizations, and increase awareness among all countries, in 

particular space agency officials, of the need to address NEO issues in 

major international bodies.

Ongoing

4.3 Continue to improve international collaboration on observation 

infrastructure and data sharing, as well as numerical modeling and 

scientific research. 

Ongoing

4.4 Support development of a plan for improving NEO monitoring 

through enhanced coordination (and potential expansion) of U.S. and 

key country ground-based telescopes. 

Short term

4.5 Continue to encourage countries to initiate and continue programs 

to develop space- and ground-based telescopes to detect, track, and 

characterize NEOs and coordinate via participation with the International 

Asteroid Warning Network (IAWN). 

Ongoing
 NASA Planetary Defense Strategy And Action Plan | 7

4.6 Continue to strengthen the IAWN and the Space Mission Planning 

Advisory Group (SMPAG) as the primary international technical bodies 

for addressing hazardous NEO response planning and mitigation.

Ongoing

4.7 Support and encourage participation in tabletop and physical 

exercises with global partners regarding preparedness, prevention, 

response, and recovery efforts. 

Medium term

4.8 Conduct exploratory discussions with international partners regarding 

U.S. participation and cooperation with upcoming foreign flight missions to 

NEOs such as a potential reconnaissance mission to Apophis. 

Ongoing

4.9. NASA will leverage existing and new research to develop longterm principles for NASA’s planetary defense activities that maximize 

transparency, multilateral cooperation, and promote the benefits of 

applied planetary science for all humanity. 

Short term 

and ongoing

Goal 5: Coordinate with FEMA and other agencies to strengthen and routinely exercise NEO 

impact emergency procedures and action protocols

Actions Timeframe

5.1 Support maturation of a set of real-world scenarios based on 

credible impact threats with observable parameters to inform planning 

and procedure development.

Medium term

5.2 Continue to improve protocols for notifying The White House 

and Congress (including briefing appropriate subcommittees), federal 

interagency, state and local governments, the public, foreign governments, 

and other international organizations, regarding NEO threats. 

Ongoing

5.3 Develop and share informational material for different audiences 

providing basic education, information on NEOs, impacts, uncertainties, 

and the scope of NASA’s role. 

Short term

5.4 Improve procedures and timeline for conducting a risk/benefit 

analysis for space-based mitigation mission options following a NEO 

threat assessment. 

Short term

Goal 6: Improve NASA contributions to ongoing interagency coordination on planetary defense 

Actions Timeframe

6.1 Convene an ongoing interagency group on planetary defense to 

address more detailed implementation issues than is common for a 

White House-level interagency working group. 

Short term

6.2 Work with agencies substantially involved with cooperation and 

collaborations outlined in the National Strategy and Action Plan to 

identify offices and points of contact (POCs) (expected to be only 

part-time for most agencies) tasked with responsibility and authority to 

address and advance the activities supporting planetary defense called 

for within the Action Plan. 

Short term
 NASA Planetary Defense Strategy And Action Plan | 8

6.3 Establish a small study effort to explore existing authorities and 

legislation (e.g., Economy Act) that could be leveraged to improve 

and enhance implementation of interagency collaborations related to 

planetary defense. 

Short term

Goal 7: Improve organization of NASA’s planetary defense activities

Actions Timeframe

7.1 Conduct an independent assessment of the organization of 

planetary defense activities at NASA. Short term

7.2 Formulate a budget and organizational plan to support the 

long-term sustainment, development and maturation of survey and 

mitigation capabilities. 

Short term

Goal 8: Enhance strategic communications related to planetary defense

8.1 Prepare a strategic communications plan related to 

planetary defense. Short term

8.2 Enhance leadership messaging of planetary defense to increase 

scientific knowledge, raise awareness and improve preparedness when 

addressing general public, Congress, media and partners.

Ongoing

This effort seeks to outline priorities and needs that would advance NEO physical characterization 

capabilities, pursue mitigation and prevention strategies beyond the DART demonstration, and 

coordinate planetary defense activities across the U.S. government, U.S. commercial industry, and with 

international partners.
 NASA Planetary Defense Strategy And Action Plan | 9

Table of 

Contents

Summary of the 2023 National Preparedness 

Strategy and Action Plan for Near-Earth Object 

Hazards and Planetary Defense

1

Executive Summary 3

Table of Contents 9

Background for Planetary Defense at NASA 11

Strategic Goals and Action Plan 13

Goal 1: 

Enhance NASA NEO Detection, Tracking, and 

Characterization Capabilities

14

NASA Action Plan 15

Goal 2:

Improve NASA Coordination on NEO Modeling, 

Predictions, and Information Integration 

17

Action Plan 18

Goal 3: 

Develop Technologies for NEO Reconnaissance, 

Deflection and Disruption Missions 19

Action Plan 20

Goal 4:

Increase NASA Contributions to International 

Cooperation on NEO Preparation 

22

Action Plan 23
 NASA Planetary Defense Strategy And Action Plan | 10

Table of 

Contents

Goal 5:

Coordinate with FEMA and Other Agencies to 

Strengthen and Routinely Exercise NEO Impact 

Emergency Procedures and Action Protocols 

25

Action Plan 26

Goal 6: 

Improve NASA Contributions to Ongoing 

Interagency Coordination on Planetary Defense 27

Action Plan 27

Goal 7: 

Improve Organization of NASA’s 

Planetary Defense Activities

28

Action Plan 29

Goal 8: 

Enhance Strategic Communications Related 

to Planetary Defense 

29

Action Plan 30

Appendix A: Acronyms 31

Appendix B: NASA Contributions to Planetary 

Defense & NEO Surveys 34

Appendix C: Examples of International Planetary 

Defense Programs 38

Appendix D: Support for Strengthening Planetary 

Defense Efforts at NASA 39

Appendix E: History and Evolution of Finding and 

Assessing the NEO Hazard 41
 NASA Planetary Defense Strategy And Action Plan | 11

Background for Planetary 

Defense at NASA

The 2023 NASA Planetary Defense Strategy and Action Plan focuses NASA efforts within the National 

Planetary Defense Strategy, providing additional details on NASA’s specific actions and the Agency’s 

current and future planetary defense work.

Planetary defense encompasses all the capabilities needed to detect and warn of potential asteroid or 

comet impacts with Earth and then to either prevent or mitigate their possible effects. The effort involves: 

• Finding and tracking NEOs that pose a hazard of impacting Earth (>10m);

• Characterizing each NEO to determine its precise trajectory, and also size, shape, mass, 

composition, rotational dynamics, and other parameters to assess the likelihood and severity of 

devastation if it has a potential Earth impact;

• Warning of the impact timing and potential effects, and advise of possible means to mitigate the 

impact; and

• Planning and implementation of measures to deflect or disrupt (break up) an object on an 

impact course with Earth, or to mitigate the effects of an impact if it can be prevented. Mitigation 

measures that can be taken on Earth to protect lives and property include evacuation of the 

impact area and movement of critical infrastructure.

Figure 4: Planetary defense as a decision cycle: planetary defense can be described as a cycle akin to the observe, orient, 

decide, act, and assess (OODAA) loop. This strategy and action plan entails efforts to detect and characterize NEOs, integrate 

information, plan action protocols, develop technologies to mitigate NEO hazards, and coordinate responses. Each of the six 

goals in this strategy address parts of the loop where the most impact can be made. (Source: NASA PDCO)
 NASA Planetary Defense Strategy And Action Plan | 12

The hazard of NEO impacts is challenging to assess when we do not have a complete NEO survey 

catalog. New survey projects, such as the space-based mid-infrared NEO Surveyor mission, would 

dramatically improve our risk assessment. When paired with new mitigation approaches, such as rapidresponse reconnaissance missions and targeted deflection missions, they can form the basis for a 

credible set of capabilities in response to actual NEO impact threats.

By statute, NASA is the lead U.S. Government agency for planetary defense. The 2005 George E. 

Brown Near-Earth Object Survey Act (51 USC Chapter 711) amended the NASA Act of 1958 to indicate 

that in the interest of U.S. “general welfare and security,” NASA will detect, track, catalogue, and 

characterize Near-Earth Asteroids (NEAs) and Near-Earth Comets (NECs) “in order to provide warning 

and mitigation of potential hazard of such near-Earth objects impacting the Earth.” This legislation 

also directed NASA to find at least 90 percent of NEOs that are at least 140 meters by 2020, however 

appropriations were not provided at the time to support this goal.

The 2017 NASA Authorization Act (Public Law 115-10) reiterated these goals, adding that NASA 

should “submit recommendations for carrying out the Survey program and an associated proposed 

budget, analyze options for diverting an object on a collision course with Earth, and provide the status 

of cooperation with other nations in a mitigation strategy in the event of a NEO threat.” The 2022 NASA 

Authorization Act (Public Law 117-167) further emphasized that NASA “shall continue the development 

of a dedicated space-based infrared survey telescope mission, known as the ‘Near-Earth Object 

Surveyor,’ on a schedule to achieve a launch-readiness date not later than March 30, 2026, or the 

earliest practicable date, for the purpose of accomplishing the objectives . . .” of the Survey.

The roles and responsibilities of the PDCO and NASA’s responsibilities to provide timely notification to 

the White House Office of Science and Technology Policy (OSTP) of close approaches of NEOs that 

may cause damage to the surface of the Earth are featured in NPD 8740.1. The Planetary Defense 

Officer leads the efforts of the PDCO. 

Significant progress in NEO detection has been made in recent years and the recently approved NEO 

Surveyor mission, designed to improve detection capabilities to greater than 90 percent of NEOs 140m 

or larger within about a decade of being launched in 2028, will roughly triple our current capability. 

In 2022, NASA’s DART mission successfully impacted an asteroid almost 7 million miles from Earth, 

altering its orbit and demonstrating our ability to respond to a potential asteroid threat for the first time 

via a kinetic impactor spacecraft.

In 2023, NASA established a Planetary Defense Strategy Working Group (PDSWG) co-led by the 

NASA’s Office of Technology, Policy & Strategy (OTPS) and PDCO to develop this first-ever NASA 

Planetary Defense Strategy in support of the 2023 National Planetary Defense Strategy

Challenges

The PDSWG identified several motivating challenges that this strategy aims to address: 

• Survey, detection, characterization and assessment: The global community wants a 

complete NEO survey catalog and sufficient ability to fully characterize NEOs. The ability to 

assess the risks that NEOs may pose to Earth, and support any mitigation efforts, could be 

significantly improved by a sufficient set of ground and space-based observations, modeling and 

prediction capabilities. (NASA Strategic Goals 1 and 2, see table below) 
 NASA Planetary Defense Strategy And Action Plan | 13

• Mitigation: Technological preparedness would be improved with follow-on reconnaissance and

mitigation demonstration missions. (NASA Strategic Goal 3)

• International cooperation: With the expansion of international capabilities related to NEO survey

and mitigation, planetary defense is poised to become a global effort. To realize this vision, NASA

plans to foster greater international collaboration and engagement. (NASA Strategic Goal 4)

• NASA support for interagency coordination: The National Planetary Defense Strategy

recognizes a need for more stable, coordinated planetary defense activities across the United

States government. NASA has a key role to play in spearheading this ongoing interagency

coordination. (NASA Strategic Goals 5 and 6)

• NASA organization: While the NASA PDCO benefits greatly from the close coordination with

planetary science activities by being part of NASA PSD, competing priorities in the Planetary

Science portfolio, which currently includes development of several large missions, may limit

opportunities for expanding planetary defense activities. However, competition for funding is likely

to be an issue regardless of where the program is situated. (NASA Strategic Goal 7)

• Strategic communications: NASA should better integrate and disseminate information

regarding NEO survey and mitigation work. (NASA Strategic Goal 8)

Strategic Goals 

and Action Plan

• Goal 1: Enhance NASA NEO detection, tracking, and characterization capabilities

• Goal 2: Improve NASA coordination on NEO modeling, prediction, and information integration

• Goal 3: Develop technologies for NEO reconnaissance, deflection and disruption missions

• Goal 4: Increase NASA contributions to international cooperation on NEO preparation

• Goal 5: Coordinate with FEMA and other Agencies to strengthen and routinely exercise NEO

impact emergency procedures and action protocols

• Goal 6: Improve NASA contributions to ongoing interagency coordination on planetary defense

• Goal 7: Improve organization of NASA’s planetary defense activities

• Goal 8: Enhance NASA’s strategic communications related to planetary defense

A set of strategic actions support each goal within NASA. Each action includes a desired timeline for 

completion and a list of relevant mission directorates and offices within NASA, with the recommended 

lead organization listed first. The timeline is described as short term for less than two years, 

medium term for two to five years, long term for five to ten years, and ongoing if expected to 

be repeated within the ten-year horizon of this NASA strategy and action plan. The lists of relevant 

organization are not meant to be exhaustive or limiting. The commitment of resources to support 

activities outlined in this document will be determined through the regular budget process and 

subject to the availability of appropriated funds.
 NASA Planetary Defense Strategy And Action Plan | 14

Goal 1

Enhance NASA NEO Detection, Tracking, and 

Characterization Capabilities

Why is this important?

Early detection and characterization of hazardous NEOs provide the greatest leverage to adequately 

respond in time to prevent loss of life and damage to critical infrastructure. Providing years to decades 

of warning increases the time available to make decisions and take effective mitigating action, enabling 

use of more benign options to prevent the impact. Once detected, early characterization of objects that 

are potential impact threats is key to reducing uncertainties, providing critical information for decision 

making, and developing an informed mitigation strategy.

What is NASA doing?

NASA has conducted a NEO survey and research program since 1998 and is the global leader in 

detecting, tracking, and characterizing NEOs. NASA PDCO’s Near-Earth Object Observations Program 

currently sponsors and leverages largely competed projects that use ground- and space-based 

telescopes around the world to search for NEOs, track them to determine their orbits, and study the 

characteristics, such as size, shape, rotation, and physical composition. Current major projects include 

the Catalina Sky Survey (CSS) and the Panoramic Survey Telescope and Rapid Response System 

(Pan-STARRS) for NEO detection and tracking, Spacewatch for NEO follow-up, and NASA’s Infrared 

Telescope Facility and Goldstone Solar System Radar for NEO physical characterization. Critical data 

management and analysis facilities include the Minor Planet Center and the Center for Near-Earth 

Object Studies. A more comprehensive list of current and planned NEO detection, tracking, and 

characterization projects and missions with NASA involvement can be found in Appendix B.

What are the challenges?

While these projects have enabled significant advances in the field of planetary defense, less than 

half of the estimated 25,000 NEOs that are 140 meters and larger in size (capable of causing regional 

devastation) have been detected and tracked to date. A complete NEO survey catalog and sufficient 

ability to fully characterize NEOs is required in order to detect and understand all potential impact threats.

How we will solve challenges

The ability to assess the risks that NEOs may pose to Earth, and support any mitigation efforts, can be 

significantly improved by a sufficient set of ground and space-based observation, modeling and prediction 

capabilities. In the next decade, NASA will significantly improve national capabilities for NEO detection, 

tracking, and characterization to reduce current levels of uncertainty and aid in more accurate modeling and 

more effective decision-making. A mix of ground-and space-based assets are required, and completion of 

planned ground and space-based wide-field sky survey assets will enable achievement of this goal. 

New survey projects, such as the space-based mid-infrared NEO Surveyor mission, launching not 

later than 2028, would dramatically improve our risk assessment. NEO Surveyor is designed to 

improve detection capabilities to greater than 90 percent of NEOs 140m or larger within about a 

decade of being launched (roughly tripling the current capability).4

4 Additionally, the Vera C. Rubin Observatory, a joint National Science Foundation (NSF) and Department of Energy (DOE) multidisciplinary facility, is slated for first light in 2024, with full operations in 2025. NSF: https://www.nsf.gov/about/budget/fy2023/

pdf/37_fy2023.pdf.
 NASA Planetary Defense Strategy And Action Plan | 15

The ability to more rapidly characterize objects that represent potential impact threat once detected 

is also critical. To realize this, existing radar capabilities could be augmented with a next generation 

deep space radar for potentially hazardous object (PHO) ranging and imaging, which may require 

interagency collaboration and partnership.

100

90

Potentially Hazardous Asteroids

Lvl 1 Req

2024 2026 2028 2030 2032 2034 2036 2038 2040

90%

Completion %

Time

80

70

60

50

40

Existing 58.7%

Existing + Rubin 75.6%

Existing + NEOS 93.7%

All Surveys 94.7%

Figure 5: Predicted NEO survey completeness, combining current capabilities with projected contribution by the Vera Rubin 

Observatory and then NEO Surveyor after 5 years of operations. (Source: NASA PDC)

NASA Action Plan

The following actions support Goal 1:

Improve NASA capabilities for NEO detection, tracking, and remote characterization

1.1 Continue to identify opportunities in existing and planned space domain 

awareness programs to improve detection and tracking by enhancing the volume and 

quality of current data streams, including from ground-based and space-based optical, 

infrared, and radar facilities. Existing and planned space situational awareness assets, including 

commercial systems and public-private partnerships, can also contribute to accelerate NEO detection 

and tracking. Existing and planned telescope programs should include those designed exclusively for 

NEO detection, tracking, and characterization and those that can be leveraged for this purpose. Solicit 

proposals for relevant capabilities through the ROSES Yearly Opportunities for Research in Planetary 

Defense peer review cycle. [Short term and Ongoing; PDCO]

1.2 Identify technology and data processing capabilities and opportunities in existing 

and new telescope programs to enhance characterization of NEO composition and 

dynamical and physical properties. Continue efforts to leverage opportunities in automation 

and analytical software, deployed sensor systems, data processing capabilities, and investigation 

into any existing national capabilities that could aid in asteroid characterization. Improving 

these capabilities will inform NEO impact threat assessments and enhance decision-making 
 NASA Planetary Defense Strategy And Action Plan | 16

by aiding better estimation of size, shape, rotation period, pole orientation, mass, mineralogical 

composition, hydration state, internal structure, and other properties. Continue investigation 

of approaches to use data from disparate and diverse sensors, in a standardized and defined 

format, into a database that is accessible to the widest available section of science, academic, 

government, and commercial entities, as applicable, allowing for development and use of evolving 

data analytics or emergent behaviors. Solicit proposals for relevant capabilities through the 

ROSES Yearly Opportunities for Research in Planetary Defense peer review cycle. [Short term; 

PDCO, Office of International and Interagency Relations (OIIR)]

1.3 Continue and enhance multi-agency efforts to detect large meteoroids and small 

asteroids entering Earth’s atmosphere and provide rapid public notification. These 

events occur worldwide a few times per month and create very bright meteors called bolides, aka 

“fireballs,” detectable by a variety of monitoring systems. These events provide opportunities to 

collect more extensive information on the very nearest-to-Earth natural objects. Rapid notification 

of such events to the world-wide science community enables further data collection, provision of 

information to calm the general public, and potential for timely collection of meteoritic samples of 

the object before contaminated by the terrestrial environment. [Short term: PDCO, OIIR]

1.4 Identify opportunities to leverage existing and planned cislunar space domain 

awareness capabilities to support detection, tracking, and characterization of NEOs, 

including through data sharing with planetary defense databases. Publicly shareable 

cislunar space domain awareness (SDA) information, space situational awareness (SSA) information, 

and space traffic coordination are key to promoting safety of access and use of space, supporting 

NASA, private industry, and international missions to the Moon, as well as providing additional data 

relevant to NEO detection and characterization. Identify synergies in systems developed to enable 

these missions, sharing associated data, in an accessible format, for planetary defense. Leverage 

architectures and data standards for SSA to support the interoperability of planetary. Leverage 

architectures and data standards for SSA and best practices from Department of Commerce’s 

Traffic Coordination System for Space (TraCSS) to support the interoperability of planetary defense 

data, including a widely accessible database catalog. [Short term and Ongoing; PDCO, OIIR] 

1.5 Support an interagency assessment to explore interest from key stakeholders 

in the coordinated development of current and future deep space radar facilities 

and identify where these facilities may be useful for planetary defense. Provide data 

to support the newly established interagency group on existing and planned deep space radar 

capabilities, informing key priorities, investment, and operational opportunities. [Short term; 

PDCO; OIIR, Space Technology Mission Directorate (STMD) in supporting roles]

1.6 Use the information developed in Actions 1.1, 1.2, 1.3, and 1.4 to inform 

investments in space domain awareness programs and technology improvements to 

enhance completeness and speed of NEO detection, tracking, and characterization.

To the extent possible, develop methods to coordinate roadmap development across countries, 

independent commercial investment, and U.S. Government investment to prioritize cost, reduce 

redundancy, identify gaps, and leverage worldwide achievement. [Long term; PDCO] 

1.7 Advance concepts for rapid characterization of a potentially hazardous NEO.

Developing and exercising a plan for rapid characterization of a NEO will inform development of other 

capabilities and further aid in meeting Goals 2 and 3. Periodic exercises should serve to identify and 
 NASA Planetary Defense Strategy And Action Plan | 17

correct any issues with the timeliness, quality, and quantity of information provided to the modeling 

group and decision makers. Such exercises could be in collaboration with the International Asteroid 

Warning Network which NASA/PDCO also coordinates. [Short term and Ongoing; PDCO]

1.8 Support analysis of emerging challenges in NEO survey and characterization 

in the upcoming decade, as well as solutions for mitigating and overcoming these 

challenges. New challenges have emerged in the detection and characterization of NEOs, 

including impacts to optical and infrared telescopes from the recent increases in the number of 

new and proposed large constellations of satellites in Low Earth Orbit (LEO). Many factors impact 

the observed brightness of these satellites, including their altitude, orientation, and design. Work 

is ongoing, including in collaboration internationally with the International Astronomical Union, to 

fully characterize the impact to NEO surveys and characterization, and to work cooperatively to 

identify mitigations between ground-based observers and satellite owner-operators. [Long term 

and Ongoing; PDCO, SMD] 

1.9 NASA should seek to apply maturing commercial capabilities to the challenge of 

planetary defense survey, characterization, and mitigation efforts. [Medium term and 

ongoing; STMD, PDCO]

1.10 Consider strengthening planetary radar partnerships, beginning with a study of 

desired capabilities in collaboration with NSF and USSF. [Short term; PDCO]

1.11 Consider potential designs for a bolide detector tech demonstration, such as a 

hosted sensor on a mission, which could be developed in partnership with other U.S. 

organizations. [Medium term; PDCO, STMD]

Goal 2

Improve NASA Coordination on NEO Modeling, 

Predictions, and Information Integration

Why is this important?

Given the difficulty of accounting for the many uncertainties involved and the direct testing of 

large hypervelocity impacts of asteroids and comets, computational modeling is critical to better 

understanding potential NEO impact threats and mitigation scenarios. NEO modeling, prediction, and 

information integration capabilities support effective mitigation strategies by informing decision makers 

about: 1) predicted Earth impact probabilities, 2) impact timing and location, 3) impact effects and 

consequences, and 4) options for impact prevention. 

What is NASA doing?

There are several existing efforts within NASA to support NEO modeling, prediction, and information 

integration. The Center for NEO Studies (CNEOS), hosted by NASA’s Jet Propulsion Laboratory (JPL), 

is responsible for computing high-precision asteroid and comet orbits and their potential for impacting 

Earth. CNEOS developed and improved tools to compute high precision orbits, future motions, and 

assess NEO deflection techniques, including an NEO deflection simulation tool.
 NASA Planetary Defense Strategy And Action Plan | 18

The Asteroid Threat Assessment Project (ATAP) team at NASA Ames Research Center leads efforts to 

model the potential damage and devastation that could occur from a NEO impact. By simulating the entry 

and passage of a natural object through Earth’s atmosphere, given a range of initial conditions about its 

trajectory, size and composition, the ATAP Probabilistic Asteroid Impact Risk (PAIR) modeling can assess the 

potential for any given impact scenario object to survive the passage through the atmosphere and produce 

destructive effects at any selected location on Earth’s surface, within a range of possible outcomes driven 

by the uncertainties in input parameters such as the object’s physical properties. The interagency NEO 

Action Plan Modeling Working Group (MWG), led by the ATAP, was established in late 2019 and includes 

participation by Goddard Space Flight Center and the Department of Energy National Laboratories. The 

MWG developed initial computer simulations and held asteroid impact exercise meetings in 2019 and 2020. 

What are the challenges?

The ability to assess the risks that NEOs may pose to Earth, and support any mitigation efforts, can 

be significantly improved by a sufficient set of ground and space-based observation, modeling, and 

predication capabilities. As a result, rapid assessments via modeling the variation of outcomes of potential 

NEO impact threats may be required while the specific properties of the NEO remain largely unknown. 

In the event of an impending NEO impact, newly created foreign and domestic sources of information 

and analysis may become available. NASA needs to further improve the ability it has developed to 

coordinate, collect, assess, and then rapidly deliver verified and validated information to enable informed 

decision making and manage public awareness needs.

How will we solve challenges?

NASA will continue to coordinate with other relevant agencies on the development of validated 

modeling tools and simulation capabilities that aid in characterizing and mitigating NEO impact risks. 

NASA and its partners will also push to integrate hazard models into an operational risk assessment 

pipeline, so in the event of an impact threat we can be better prepared. 

Action Plan

The following actions support goal 2:

Sustain and expand interagency NEO impact modeling group

2.1 Continue to support an interagency working group for coordination and enabling 

dissemination of the results of NEO threat modeling and analysis. This group will update 

plans for the management of modeling and analysis efforts, including a list of all contributing and 

affected organizations, and will help manage the tasking and flow of modeling and analysis results 

to relevant officials and organizations. [Ongoing; PDCO]

Advance development and integration of computational tools for modeling NEO impact 

risks and mitigation techniques

2.2 Ascertain what information each participating organization requires for threat 

analysis on what timeframe. Identify gaps and develop recommendations for 

modeling improvements. This includes an assessment of the adequacy of current modeling 

capabilities. [Short term; PDCO]

2.3 Continue development and validation of a suite of computer simulation tools for 

assessing the outcome of deflection or disruption techniques applied to a NEO. 

This analysis includes but is not limited to understanding how variations in NEO physical 
 NASA Planetary Defense Strategy And Action Plan | 19

properties affect the effectiveness of a deflection or disruption technique and the largest deflection 

a NEO can tolerate (especially so-called “rubble pile” NEOs with little intrinsic strength) before 

beginning to disrupt. [Short term; PDCO] 

2.4 Improve a suite of computer simulation tools for assessing the local, regional, 

and global risks associated with an impact scenario. Continue to assess the 

sensitivities of these models to uncertainties in NEO dynamical and physical 

properties. Probabilistic Earth impact consequence models should link to existing infrastructure 

mapping capabilities to achieve a suite of simulation tools that predicts potential impact damage 

and can provide, for a detected NEO on a potential impact trajectory, a list of at-risk infrastructure 

and associated probability of damage. This analysis includes but is not limited to understanding the 

level of damage that could be caused by an airburst over or impact on land and in ocean areas, 

particularly those effects on coastal areas. [Medium term; PDCO] 

2.5 Develop an impact risk data pipeline to inform decision makers on results from 

integrated modeling of potential impact threats. The seamless integration of hazard 

models into an operational risk assessment pipeline is needed to fully understand (characterize) 

the wide range of possible consequences, especially cascading hazards, that could result from an 

asteroid impact event. This action should include the possibility for longer-term hazards that result 

from triggering events, such as high winds or extreme precipitation. The pipeline output should be 

in a format that is readily usable for emergency managers, resource managers and planners, and 

research scientists involved in mitigation and recovery efforts. [Medium term; PDCO]

Exercise, evaluate, and continually improve modeling and analysis capabilities

2.6 Continually assess the adequacy and validity of modeling and analysis of impact 

effects through annual exercises, test problems, comparison to experiments, and 

peer review activities. Structure exercises to identify gaps, formulate needed improvements, 

test connections within the national framework, and improve operational readiness. This action 

should include an annual lessons learned document and plan for increasing operational readiness to 

be shared among interested parties. [Ongoing; PDCO] 

Goal 3

Develop Technologies for NEO Reconnaissance, 

Deflection and Disruption Missions

Why is this important?

Developing technologies for NEO reconnaissance, deflection, and disruption before an imminent 

threat arises will strengthen our ability to adequately respond and pursue efforts to prevent NEO 

impact disasters. An effective deflection or disruption mission will most likely require more detailed and 

accurate information about the incoming NEO than existing and currently planned remote observational 

capabilities can provide. A capability to responsively build and launch a spacecraft to rendezvous or fly 

by the NEO to perform reconnaissance may be needed.
 NASA Planetary Defense Strategy And Action Plan | 20

What is NASA doing?

In 2022, NASA’s DART mission successfully impacted an asteroid almost 7 million miles from Earth, 

altering its orbit and demonstrating our ability to respond to a potential asteroid threat for the first 

time via a kinetic impactor spacecraft. PDCO also funds modeling studies of additional deflection 

technologies, some in coordination with U.S. national laboratories.

What are the challenges?

Preparing to respond effectively to a NEO impact threat scenario includes developing and maturing 

capabilities for both deflection and disruption before the need arises to deploy them in an actual 

threat scenario. NASA’s technological preparedness would be improved with further study of potential 

mitigation demonstration capabilities. In addition to the kinetic impactor approach, other NEO mitigation 

approaches may be more effective in different scenarios. For example, multiple technologies may 

be suitable for more benignly preventing NEO impacts that are predicted decades in advance, while 

deflection or disruption via a nuclear explosive device may be the only feasible option for NEOs that are 

very large or come with a short warning time.

How will we solve challenges?

NASA will advance technology development and programmatic processes that could support 

an effective mitigation campaign. Conceptual studies, early-stage technology development and 

engagement with international partners on such a mission can help fulfill this goal. NASA’s Planetary 

Defense efforts should consider recommendations from the scientific community. The National 

Academies’ Origins, Worlds, and Life: A Decadal Strategy for Planetary Science and Astrobiology 

2023-2032, released in April 2022, provides recommendations from the Planetary Science 

community on priorities for Planetary Science, including Planetary Defense. For example, the 

upcoming close approach of Apophis, an asteroid estimated to be approximately 330 meters in size, 

represents a significant opportunity for international collaboration to achieve major scientific benefits, 

at relatively low cost. Apophis is expected to pass within 31,600 kilometers of Earth’s surface in 

April of 2029, offering a rare opportunity in this decade for advancing science in support of planetary 

defense. NASA is not planning any mission to Apophis before 2029, but is currently conducting 

conceptual studies and collaborating with international partners to identify opportunities for studying 

Apophis during its close encounter with Earth.

Action Plan

The following actions support goal 3:

Develop technologies and designs for rapid-response NEO reconnaissance missions

3.1 Collaborate with interagency partners on technologies for rapid response, 

reconnaissance, and characterization of in-space objects. Evaluate the capabilities 

of current and projected launch vehicle infrastructure to support short-warning 

planetary defense missions. This collaboration should include evaluation of reconnaissance 

via spacecraft flyby or rendezvous, as well as mission concepts in which the reconnaissance 

spacecraft could also carry out deflection or disruption actions. This collaboration should consider 

both commercial-off-the-shelf parts and new hardware development. The launch vehicle infrastructure 

evaluation analysis should include consideration of both rapid-response reconnaissance and 

deflection/disruption missions, recommending processes for accomplishing rapid response planetary 

defense launch, accounting for integration and testing processes, launch vehicle procurement, 

authorization processes, and methods to prepare payloads for rapid launch, including technology 
 NASA Planetary Defense Strategy And Action Plan | 21

development, contracting, and storage considerations. Begin to investigate how the U.S. government 

would authorize DoD/USSF to prepare and use responsive launch and/or other existing capabilities to 

support an emergent NEO threat situation. [Short term; PDCO, STMD]

3.2 Create plans for the development, testing, and implementation of NEO 

reconnaissance mission systems. These plans should lead to establishment of timely NEO 

reconnaissance capabilities, including rapid response. [Short term; PSD, PDCO, STMD]

Develop technologies and designs for NEO deflection and disruption missions

3.3 Develop preliminary mission designs for future NEO deflection mission campaigns. 

Identify, assess the readiness, estimate costs, and propose development paths for key 

technologies required by NEO impact prevention concepts. Perform a risk analysis on 

planetary defense mission success under varying assumptions and circumstances. 

Technology assessments should include the most mature in-space concepts—kinetic impactors, 

gravity tractors, ion beam deflection—as well as less mature NEO impact prevention methods. This 

action includes preliminary designs for demonstration of a gravity tractor NEO deflection mission 

campaign, and/or an ion beams deflection campaign. Mission designs should include reconnaissance 

spacecraft and methods to measure the achieved deflection. Include an assessment of the value of 

alternative planetary defense approaches, to include pre-deployment of NEO deflection capabilities 

in space prior to an identification of an actual impact threat. They should consider contemporary 

work, including potential synergies with relevant private industry interests (e.g., asteroid mining), 

as well as NEO impact scenarios that may have received insufficient attention thus far (e.g., binary 

asteroids, high-speed comets). Ground-based facilities useful to support these missions should also 

be identified. Solicit for mission concept study proposals through the ROSES Yearly Opportunities 

for Research in Planetary Defense peer review cycle. Continue to encourage and incentivize creative 

and new ideas from diverse sources for NEO deflection and disruption technology through alternative 

methods, such as prizes, university grand challenges, STEM outreach, centers of excellence, gaming, 

etc. The risk analysis will address current deficiencies in understanding how rapidly the U.S. can 

deploy planetary defense missions while maintaining acceptable reliability and mission success 

probability, and with sufficient redundancy. [Medium term; PDCO, STMD]

3.4 Continue the study of circumstances when only use of a nuclear explosive device 

would provide the necessary force to mitigate an impending NEO impact threat, and 

the technologies, capabilities and operational considerations required for use of 

such devices. Assess the legal and national policy implications of such an option.

Studies have shown that at this time in our understanding of the potential NEO impact hazard it is 

still possible that discovery of either even a relatively small object less than a few months to years 

before impact or a relatively large or fast-trajectory object would create a situation when only use 

of a nuclear explosive device (NED) would provide sufficient force to either deflect or disrupt the 

impactor in time to mitigate devastating effects on Earth. Therefore, it is still prudent to continue 

the research on the potential for NEDs to be used for PHO deflection and disruption missions. 

[Medium term; PDCO, STMD, Office of General Counsel (OGC), OIIR in supporting role]

3.5 Continue flight demonstrations to validate NEO deflection and disruption system 

concepts. Following the successful pathway demonstrated by the DART mission for the kinetic 

impact deflection technique, NASA will study whether future flight demonstrations should focus on 

test and validation of deflection/disruption system concepts on benign NEOs and identify design 

issues for correction. Results will inform decision-making processes during an actual NEO threat 

scenario. [Long term; PSD, PDCO]
 NASA Planetary Defense Strategy And Action Plan | 22

Goal 4

Increase NASA Contributions to International 

Cooperation on NEO Preparation

Why is this important?

The potentially cataclysmic and existential consequences of a NEO impact coupled with the impact’s 

indifference to borders and geopolitical dynamics presents a global challenge and a unique opportunity 

for engagement with the international community. Planetary defense is an intrinsically global endeavor, 

drawing upon telescopes and capabilities on every continent and in orbit. 

What is NASA doing?

NASA and other programs share observations and research and explore how to coordinate our 

responses. For example, NASA’s DART mission involved an Italian satellite, LICIACube, to flyby and 

provide observational analysis of the Didymos asteroid binary system after impact on Dimorphos. 

Additional ground-based observations of the orbital period change were contributed from every 

continent on Earth. NASA is also currently collaborating with the European Space Agency on its Hera 

mission, planned for 2024, which aims to further investigate the Didymos asteroid system.

NASA PDCO works with the IAWN and the SMPAG, international organizations dealing with NEOs 

whose establishment was recommended by the United Nations Committee on the Peaceful Uses of 

Outer Space (UNCOPUOS) and endorsed by the UN General Assembly. These expert bodies promote 

coordination among astronomers, scientists, space agencies, lawyers, and policy makers seeking 

to detect, characterize, and respond to potential NEO impacts. NASA coordinates IAWN including 

observational campaigns to test worldwide capabilities in detection, tracking, and characterization. The 

most recent campaigns in 2021 and 2022 more fully characterized the asteroid Apophis and tested the 

accuracy of NEO position measurements by the world’s observatories.

What are the challenges?

While the NASA and U.S. partners provide a significant majority of the world’s NEO preparedness 

infrastructure, international capabilities for NEO observation and research are expanding, opening up 

the possibility of a truly global planetary defense effort. With the expansion of international capabilities 

related to NEO survey and mitigation, planetary defense is poised to become a global effort. To realize 

this vision, NASA needs to foster greater international collaboration and engagement.

How will we solve challenges?

NASA will continue to enhance its leadership role in fostering global collaboration and leveraging 

international capabilities to improve NEO preparedness and response. Increased outreach to 

other nations, both bilaterally and through relevant multilateral fora, is necessary to foster a better 

understanding of potential NEO impact risks and to muster the necessary resources, expertise, and 

capabilities to address those risks. Focusing resources on identifying and improving existing relevant 

international institutions can begin to improve our collective situational awareness, predictions, and 

overall preparedness for NEO events. Furthermore, by collaborating on and leveraging upcoming foreign 

planetary defense missions, NASA can advance its own goals and potentially avoid incurring some 

technology development costs. 
 NASA Planetary Defense Strategy And Action Plan | 23

Action Plan

The following actions support goal 4:

Build international awareness of potential NEO impacts as a global challenge

4.1 Continue to engage and inform foreign governments of the need for a 

collaborative and coordinated approach to preparing for a NEO event. Underscore 

U.S. positions in relevant international NEO impact initiatives and promote awareness in other 

international organizations and meetings. This action should include delivering an annual 

U.S. statement under the NEOs agenda item of the UNCOPUOS Scientific and Technical 

Subcommittee (STSC) ; special technical presentations on NEOs at UNCOPUOS and other 

relevant international fora (e.g., the International Astronautical Congress (IAC), workshops, 

symposiums, etc.); developing and implementing a plan for outreach and education to other 

countries to promote understanding of NEO impact effects by relevant international disaster 

management bodies to aid in decision-making; encouraging more countries to join SMPAG and 

the existing SMPAG members to increase their participation based upon coordination with their 

national governments; and adding NEOs as an agenda item in bilateral consultations, including 

existing space policy dialogues with spacefaring nations with relevant capabilities. These 

engagements can be informed by the talking points developed by Department of State and NASA 

within the Near-Earth Object Impact Threat Emergency Preparedness (NITEP) working group. 

In addition, the U.S. should continue to include NEO-related efforts in important national and 

international documents, such as the 2021 U.S. Space Priorities Framework and the 2021 UN 

General Assembly resolution “Space2030: Space as a driver of sustainable development,” (A/

RES/76/3), which calls for the world to “strengthen international cooperation and preparedness to 

respond to the threat posed by near-Earth objects.” [Ongoing; OIIR, PDCO]

4.2 Continue to demonstrate U.S. leadership in technical international NEO 

organizations, and increase awareness among all countries, in particular space 

agency officials, of the need to address NEO issues in major international bodies.

This action should include making NEO issues an agenda item at scientific and technical meetings 

as appropriate, as well as at major international conferences. In addition, the U.S. should continue 

participation within SMPAG, IAWN, and any other international organizations dealing with NEOs. 

[Ongoing; PDCO, OTPS, OIIR]

Increase international engagement and cooperation on observation infrastructure, 

numerical modeling, and scientific research

4.3 Continue to improve international collaboration on observation 

infrastructure and data sharing, as well as numerical modeling and scientific 

research. Since 2018, worldwide participation in the IAWN has increased from 13 to 50 

signatories. The U.S. will continue working to encourage more countries to join IAWN so that 

it can serve as an effective body for international collaboration on observation infrastructure, 

scientific data sharing, numerical modeling, and scientific research. NASA will seek to expand 

bilateral or multilateral international cooperation on future NEO-related missions, such as 

the CubeSat provided by the Italian Space Agency for the Double Asteroid Redirection Test 

mission and cooperation with the European Space Agency’s Hera mission, which will perform 

a detailed post-impact survey of the target asteroid, Dimorphos. It will be important to 
 NASA Planetary Defense Strategy And Action Plan | 24

include strong identity, access control, accuracy, integrity and auditability capabilities for the 

reporting and information sharing and dissemination capabilities to mitigate risks associated 

not just with the malicious use of such reporting and alerting to spread panic, but to also with 

authorized but unintentional incorrect alerting or reporting. [Ongoing; PSD, PDCO, OIIR]

4.4 Support development of a plan for improving NEO monitoring through enhanced 

coordination (and potential expansion) of U.S. and key country ground-based 

telescopes. This plan should focus on existing telescopes but could look at coordinating new 

and planned hardware to optimize the range of capabilities. This action could include holding an 

international workshop on the use of ground-based telescopes to improve global NEO monitoring 

in conjunction with each International Astronautical Congress. [Short term; PDCO, OIIR]

4.5 Continue to encourage countries to initiate and continue programs to develop 

space- and ground-based telescopes to detect, track, and characterize NEOs and 

coordinate via the IAWN. This could include sponsoring sessions at international astronomical 

conferences on how to initiate and conduct programs for NEO observation, addressing both existing 

capabilities and needs. In addition to these conferences, the U.S. should work to initiate internationally 

coordinated global NEO exercises through its coordination of the IAWN. [Ongoing; PDCO, OIIR]

Foster consultation and coordination on NEO impact planning, mitigation, and response

4.6 Support strengthening of the IAWN and SMPAG as the primary international 

technical bodies for addressing hazardous NEO response planning and mitigation. 

Provide continued support and engagement to make both international bodies more effective. 

This action should include developing and implementing a plan to broaden and enhance U.S. 

interagency participation in these forums, and a list of actions to inform other nations about the 

activities, consistent with law. A template e-mail and briefing may be developed and used to 

demonstrate the value of joining IAWN and SMPAG to other countries. [Ongoing; PDCO, OIIR] 

4.7 Support and encourage participation in tabletop and physical exercises with 

global partners regarding preparedness, prevention, response, and recovery efforts.

Include realistic modeling data from the integrated suite of computational tools developed in 

Goal 2 and the scenarios developed in Action 5.1 to ensure high fidelity in the exercise. This 

action could include sponsoring a workshop for global and international disaster management 

organizations on NEO preparedness, response, and recovery. [Medium term; PDCO, OIIR] 

4.8 Conduct exploratory discussions with international partners regarding U.S. 

participation and cooperation with upcoming foreign flight missions to NEOs such 

as a potential reconnaissance mission to Apophis. The upcoming close approach of the 

Apophis asteroid in 2029 represents an opportunity for international collaboration on technology 

demonstration missions for planetary defense with major scientific benefits, at relatively low cost. 

[Ongoing; PSD, PDCO, OIIR] 

4.9. NASA will leverage existing and new research to develop long-term 

principles for NASA’s planetary defense activities that maximize transparency, 

multilateral cooperation, and promote the benefits of applied planetary science 

for all humanity. NASA will share these principles in multilateral and scientific fora. [Short 

term and ongoing; OTPS, PDCO, OIIR]
 NASA Planetary Defense Strategy And Action Plan | 25

Goal 5

Coordinate with FEMA and Other Agencies to 

Strengthen and Routinely Exercise NEO Impact 

Emergency Procedures and Action Protocols

Why is this important?

Following identification of any potential NEO impact, NASA, in coordination with other relevant Federal 

Agencies and Departments, will assess the nature of the threat and inform subsequent communications 

and mitigation decision making. Coordinated communications and notifications within the U.S. 

Government and with foreign governments, as needed, will improve impact emergency preparedness and 

reduce the physical and economic harm to the Nation. Developing and exercising thresholds, procedures, 

and action protocols to support decision-making and communications will aid agencies in preparing 

options and recommending courses of action, enabling timelier and more effective implementation of NEO 

impact response and mitigation measures. 

What is NASA doing?

NASA serves as both the lead agency and a supporting agency in this national effort. For example, 

NASA is the lead for providing timely and accurate information of a potential impact threat and analysis 

to support a coordinated response. NASA Policy Directive 8740.1 describes the process of providing 

timely and accurate reporting of a very close approach or predicted NEO impact. Overseen by NASA’s 

PCDO, it includes receipt and analysis of observations by the Minor Planet Center, transmission of 

potential impact analysis results by the JPL Center for NEO Studies, and formal notification to OSTP. 

The NITEP interagency working group, established in 2019 and co-chaired by NASA, made significant 

progress towards strengthening and routinely exercising NEO impact emergency procedures and action 

protocols. These included the establishment of procedures and timelines for conducting NEO impact 

threat assessments and risk/benefit analyses for space-based mitigation options, as well as providing 

NEO threat notifications to government and nongovernment entities. NITEP also developed benchmarks 

for determining when to recommend NEO reconnaissance, deflection, and disruption missions.

Exercises and workshops have been successful means to articulate communication requirements. 

NASA, the Federal Emergency Management Administration (FEMA), and the asteroid-impact MWG 

have conducted various tabletop exercises to date to familiarize officials with the hazard and improve 

NASA’s ability to communicate information.

What are the challenges?

Ensuring that information can be quickly exchanged and the public can be accurately informed of credible 

threats is a challenge. Current approaches provide a sound basis upon which to build, but agency awareness 

of NPD 8740.1 and NITEP recommendations is limited, and continued work is needed to further refine 

and strengthen these procedures and protocols. Periodic reviews are needed to ensure that notification 

protocols include all relevant agencies, including updated contacts, and account for the full range of potential 

circumstances. Additionally, there are opportunities for more extensive national-level exercises, potentially 

including media participants, non-governmental organizations, and international partners as observers.

How will we solve challenges?

Procedures for rapidly collecting, assessing and exchanging information about NEO threats within NASA 

and to the White House and Congress, state and local governments, the public, foreign governments, 
 NASA Planetary Defense Strategy And Action Plan | 26

and other international organizations can be streamlined and improved. As noted in Goal 2, advancing our 

ability to provide rapid cost/benefit risk analysis of NEO threats would be of great benefit to the nation. 

NASA will continue to strengthen and exercise procedures and protocols for assessing NEO threats, and 

for communication—from protocols within NASA to public and international community engagement. 

This includes periodic reviews and updates of procedures and protocols, as well as biannual interagency 

tabletop exercises, including a more extensive national level exercise in the next five years.

Action Plan

The following actions support goal 5:

Strengthen protocols for coordinated communications and notifications regarding NEO 

threats and incorporate NEO impacts into all-hazards response and recovery plans

5.1 Support maturation of a set of real-world scenarios based on credible impact 

threats with observable parameters to inform planning and procedure development. 

NASA should work with FEMA to lead biannual Interagency Tabletop Exercises (TTX), including 

a more extensive interagency TTX in the next five years, and include media participants, nongovernmental organizations, and international partners as observers. [Medium term; PDCO, OIIR]

5.2 Continue to improve protocols for notifying the White House and Congress 

(including briefing appropriate subcommittees), Federal interagency, state and 

local governments, the public, foreign governments, and other international 

organizations, regarding NEO threats. Re-evaluate and validate the current notification 

protocol chain-of-command. Adjust accordingly the protocols for notifying and communicating 

from PDCO through NASA and within the Federal Government regarding NEO threats. Develop 

appropriate modifications to existing emergency alert protocols based on specific NEO impact 

factors, as creating a new system for just the NEO impact scenario is not warranted. This action 

should culminate in an action flowchart, specific notification checklists, and a specific joint annex 

to the NASA Policy Directive 8740.1 as a joint memo covering these procedures between NASA 

PDCO and FEMA. Enhance and exercise existing NASA PDCO and IAWN plans for exchange 

of information among national and international emergency response stakeholders. Participate 

in tabletop exercises that determine effectiveness with emergency managers at local, state, and 

national levels. [Ongoing; PDCO, OIIR, Office of Legislative and Intergovernmental Affairs (OLIA)]

5.3 Develop and share informational material for different audiences providing 

basic education, information on NEOs, impacts, uncertainties, and the scope of 

NASA’s role. This action should include developing an integrated information and education 

package with social media, internet, and traditional press release formats for relevant information. 

[Short term; PDCO, Office of Communications (OCOMM)]

Establish protocols for recommending space-based reconnaissance 

and mitigation missions

5.4 Improve procedures and timeline for conducting a risk/benefit analysis for spacebased mitigation mission options following a NEO threat assessment. [Short term; PDCO] 
 NASA Planetary Defense Strategy And Action Plan | 27

Goal 6

Improve NASA Contributions to Ongoing Interagency 

Coordination on Planetary Defense 

Why is this important?

The National Planetary Defense Strategy sets out that planetary defense is an initiative that involves 

many elements of Federal, state, and local governments. With NASA in a key coordinating role, the 

stable, long-term development of U.S. planetary defense capabilities will require a collaborative and 

coordinated approach among various Federal Agencies and Departments with relevant expertise and 

capabilities in developing effective technologies, policies, practices, and procedures.

What is NASA doing?

NASA PDCO and OIIR play key coordinating roles in this effort. Activities include the use and 

support of astronomical observatories operated by NSF, data sharing and modeling efforts with 

USSF, collaborations with U.S. National Laboratories, emergency exercise planning with FEMA, and 

cooperation with other U.S. agencies. 

What are the challenges?

Despite the best intentions of all involved, it is often difficult to coordinate and make effective progress 

on collaborative projects across agency boundaries for a mission whose level of endeavors fall short 

of requiring a joint program office. Substantial differences in processes and procedures, both real and 

perceived, often mire such endeavors in the respective bureaucracies. As a result, strategic, sustained, 

and enhanced coordination is needed to develop a stable, long-term planetary defense capability that 

can effectively decrease U.S. vulnerability to NEO impacts.

How will we solve challenges?

NASA will work to enhance ongoing interagency coordination and collaboration in planetary defense by 

seeking to improve communication channels, including new interagency groups, as needed, and exploring 

ways to leverage existing authorities that could facilitate implementation of collaborative efforts.

Action Plan

The following actions support goal 6:

6.1 Convene an ongoing interagency group on planetary defense to address 

more detailed implementation issues than is common for a White House-level 

interagency working group. This interagency group should begin with quarterly meetings to 

address issues and progress of ongoing work under this Action Plan. [Short term; PDCO, OIIR]

6.2 Work with agencies substantially involved with cooperation and collaborations 

outlined in the National Planetary Defense Strategy to identify offices and POCs 

(expected to be only part-time for most agencies) tasked with responsibility and 

authority to address and advance the activities supporting planetary defense called 

for within the Action Plan. This Action will clarify who has responsibility within these agencies 

for both contact on issues by the other agencies and for monitoring and assessing progress on 

actions and addressing any issues within the agency. These POCs would represent their respective 

agency on the interagency group established in Action 6.1. [Short term; OIIR, PDCO]
 NASA Planetary Defense Strategy And Action Plan | 28

6.3 Establish a small study effort to explore existing authorities and legislation 

(e.g., Economy Act) that could be leveraged to improve and enhance 

implementation of interagency collaborations related to planetary defense. One 

objective would be to seek approaches to effectively partition actions required to achieve 

project objectives or streamline interagency funding transfers and assisted procurements when 

calling for work efforts across government agencies. Studies will also investigate gaps and 

authorities for agencies involved in planetary defense work. [Short term; Office of the Chief 

Financial Officer (OCFO), PDCO, OTPS]

Goal 7 

Improve Organization of NASA’s 

Planetary Defense Activities

Why is this important?

For NASA to effectively implement this Strategy and Action Plan, NASA needs to examine the budget, 

staffing and structure of NASA’s planetary defense activities to ensure they are sufficient. 

What is NASA doing?

NASA established the PDCO in 2016, and the roles and responsibilities of the office, and the Agency’s 

responsibilities to provide timely notification of close approaches of near-Earth objects that may cause 

damage to the surface of the Earth to Executive Office of the President (EOP)/OSTP are featured in NPD 

8740.1. In recent years, NASA increased funding for PDCO to enable the development of DART, NEOOP 

and the NEO Surveyor mission. 

What are the challenges?

While the NASA PDCO benefits greatly from the close coordination with planetary science activities by 

being part of NASA Planetary Science Division, competing priorities in the Planetary Science portfolio, 

which currently includes development of several large missions, may limit opportunities for expanding 

planetary defense activities. However, competition for funding is likely to be an issue regardless of where 

the program is situated. 

How will we solve challenges?

Based on the strategic goals and actions outlined in this strategy, NASA should formulate a stable 

program of record that features continued support for existing and planned survey and mitigation efforts 

that can also enable long-term development and maturation of technical capabilities. SMD should assess 

the scope of planetary defense activities and ensure there are appropriate staffing resources to meet the 

challenge. Planetary defense efforts at the agency may also benefit from greater engagement and support 

from other mission directorates, centers and offices. As noted previously, a worldwide trend is the rapid 

expansion of planetary defense capabilities and activities, and NASA can improve its capacity to lead and 

coordinate global efforts. Finally, NASA should seek to conduct an independent assessment of activities 

within SMD as part of its future budget formulation work. 
 NASA Planetary Defense Strategy And Action Plan | 29

Action Plan

The following actions support goal 7:

7.1 Conduct an independent assessment of the organization of planetary defense 

activities at NASA. Results of the study will be provided to leadership to guide organization, 

reporting structure or other modifications. [Short term; OTPS]

7.2 Formulate a budget and organizational plan to support the long-term sustainment, 

development and maturation of survey and mitigation capabilities. [Short term; PDCO]

Goal 8

Enhance Strategic Communications Related 

to Planetary Defense

Why is this important?

Raising public awareness about realistic concerns for potential impacts of NEOs to Earth can help improve 

emergency preparedness in the event of an incident and contribute generally to the Agency’s goals of 

educating the public about science and technology. 

What is NASA doing?

The DART mission was a milestone in the application of planetary science to a complex planetary defense 

technology demonstration. The success of the mission positively resulted in increased public awareness 

for planetary defense.

For mission-specific communications that do not rise to the level of a full-length web feature or press 

release, NASA uses its various blogs. Currently, the PDCO has a NEO Surveyor blog, a DART blog, 

and an overarching Planetary Defense blog. NASA also announces releases, features, and blogs 

posts and disseminates other information through its NASA Asteroid Watch Twitter account.

What are the challenges?

There is a challenge in getting information on activities and often time-sensitive updates about NEO 

observations, including potential threats, published externally. A more regular cadence of messaging 

could raise public awareness of the issue. 

How will we solve challenges?

NASA informs and educates the public, Congress, and stakeholders in government about the NEO impact 

hazard and planetary defense. NASA will prepare a strategic communications plan to ensure timely and 

accurate information can be disseminated quickly in the event of potential NEO incident (e.g., NPD 8740.1). 

NASA should also consider bolstering its communications resources to ensure established communications 

procedures in place and ready should a NEO impact threat be discovered.
 NASA Planetary Defense Strategy And Action Plan | 30

Action Plan

The following actions support goal 8:

8.1 Prepare a strategic communications plan related to planetary defense. Include 

procedures and protocols in event of a potential NEO impact threat. [Short term: PDCO, OCOMM]

8.2 Enhance leadership messaging of planetary defense to increase scientific 

knowledge, raise awareness and improve preparedness when addressing general 

public, Congress, media and partners. Highlight the 2023 National Planetary Defense 

Strategy, NASA’s own planetary defense strategy, and unique NASA planetary defense programs 

and initiatives in public communications. [Ongoing; Office of the Administrator, SMD Associate 

Administrator, OTPS, OCOMM, OIIR, OLIA; PDCO in a supporting role]
 NASA Planetary Defense Strategy And Action Plan | 31

Appendix A: 

Acronyms

Acronym Definition

ATAP Asteroid Threat Assessment Project

ATLAS Asteroid Terrestrial-Impact Last Alert System

Caltech California Institute of Technology

CNEOS Center for Near-Earth Object Studies

CSS Catalina Sky Survey 

DART Double Asteroid Redirection Test

DOD Department of Defense

DOE Department of Energy

EOP Executive Office of the President

FEMA Federal Emergency Management Agency

GSFC Goddard Space Flight Center

IAC International Astronautical Congress

IAU International Astronomical Union

IAWN International Asteroid Warning Network

IRTF (NASA) Infrared Telescope Facility

JAXA Japan Aerospace Exploration Agency

JPL Jet Propulsion Laboratory

LEO Low Earth Orbit

LICIACube Light Italian Cubesat for Imaging Asteroids

LINEAR Lincoln (Labs) Near-Earth Asteroid Research

MANOS Mission Accessible Near-Earth Objects Survey

MIT Massachusetts Institute of Technology

MPC Minor Planet Center

MWG (NEO Action Plan) Modeling Working Group

NAC NASA Advisory Council
 NASA Planetary Defense Strategy And Action Plan | 32

Acronyms

Acronym Definition

NAS National Academy of Science

NEA Near-Earth Asteroid 

NEC Near-Earth Comet

NED Nuclear Explosive Device

NEO Near-Earth Object

NEO Surveyor Near-Earth Object Surveyor infrared telescope

NEOOP Near-Earth Object Observations Program

NEOWISE NEO Wide-field Infrared Survey Explorer

NITEP NEO Impact Threat Emergency Protocols

NNSA National Nuclear Security Administration of the Dept. of Energy

NPD NASA Policy Directive

NSF National Science Foundation

OCFO (NASA) Office of the Chief Financial Officer

OCOMM (NASA) Office of Communication

OGC (NASA) Office of the General Counsel

OIG (NASA) Office of Inspector General

OIIR (NASA) Office of International and Interagency Relations

OLIA (NASA) Office of Legislative and Intergovernmental Affairs

OMB Office of Management and Budget

OODAA Observe, orient, decide, act, and assess loop

OSTP (White House) Office of Science and Technology Policy

OTPS (NASA) Office of Technology, Policy, and Strategy

PAIR Probabilistic Asteroid Impact Risk

Pan-STARRS Panoramic Survey Telescope and Rapid Response System

PBR President’s Budget Request

PDCO Planetary Defense Coordination Office

PDSSBN Planetary Data System Small Bodies Node
 NASA Planetary Defense Strategy And Action Plan | 33

Acronyms

Acronym Definition

PDSWG Planetary Defense Strategy Working Group

PHA Potential Hazardous Asteroid

PHO Potential Hazardous Object

POC Point of Contact

PPBE Planning, Programming, Budgeting, and Execution

PSD Planetary Science Division

ROSES Research Opportunities in Space and Earth Science

SAO Smithsonian Astrophysical Observatory

SBDB Small-Body Database

SDA Space Domain Awareness

SMD Science Mission Directorate

SMPAG Space Mission Planning Advisory Group

SNL Sandia National Laboratories

SSA Space Situational Awareness

SST Space Surveillance Telescope

STMD (NASA) Space Technology Mission Directorate

STSC Scientific and Technical Subcommittee of UNCOPUOS

UNCOPUOS United Nations Committee on the Peaceful Uses of Outer Space

UNOOSA United Nations Office of Outer Space Affairs

USGS U.S. Geological Survey

USSF U.S. Space Force

YORPD Yearly Opportunities for Research in Planetary Defense

ZTF Zwicky Transient Facility
 NASA Planetary Defense Strategy And Action Plan | 34

Appendix B: NASA Contributions to 

Planetary Defense & NEO Surveys

Assets used for NEO surveys include both ground-based and space-based systems. The main 

capabilities and demonstrations to support planetary defense in the U.S. in the next decade are 

highlighted below. 

See the National Planetary Defense Strategy, available online,5

 for a complete list of U.S. governmentfunded capabilities and systems. 

Ground-Based NEO Observations Program Detection & Characterization 

Minor Planet Center (MPC)

Under the auspices of Division F of the International Astronomical 

Union (IAU), the MPC designates all minor bodies discovered in the 

solar system (e.g., comets, asteroids, and natural satellites) and 

collects, computes, and disseminates astronomical data concerning 

the positions of these bodies to the world-wide planetary astronomy 

community. The MPC is fully funded by NASA as a sub-node of its 

Planetary Data System Small Bodies Node and is hosted by the 

Smithsonian Astrophysical Observatory (SAO) in Boston, MA.

Center for NEO Studies (CNEOS)

CNEOS is hosted by NASA’s Jet Propulsion Laboratory and uses 

small body position data collected on NEOs at the MPC for its 

analyses. It is responsible for computing high-precision asteroid 

and comet orbits and their potential for impacting Earth to support 

NASA’s PDCO. NEO parameters computed by CNEOS are 

archived in the JPL Small-Body Database (SBDB).

Catalina Sky Survey (CSS)

The CSS is a NASA-funded NEO discovery project based out of the University of Arizona’s Lunar 

and Planetary Laboratory. Its primary assets consist of two wide-sky-field survey telescopes and 

one telescope for astrometric follow-up in the Catalina Mountains of Arizona. 

Panoramic Survey Telescope and Rapid 

Response System (Pan-STARRS)

Pan-STARRS is a two-telescope system for wide-field 

astronomical imaging developed and operated by the 

University of Hawai’i. Located on Haleakala, Maui, NASA 

provides funds to Pan-STARRS for NEO search and 

discovery operations. Figure 6: Pan-STARRS. (Source: 

University of Hawaii and Ratkoski)

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Asteroid Terrestrial-Impact Last Alert System (ATLAS)

Developed and run by the University of Hawaii, ATLAS is a relatively small telescope automated 

hazardous asteroid impact early warning system funded by NASA with telescopes in South Africa, 

Chile, and Hawai’i (Maui and Hawai’i Island). 

Lincoln Near-Earth Asteroid Research (LINEAR)

MIT Lincoln Laboratory’s LINEAR program has searched for and categorized Near-Earth Objects 

using data provided by U.S. Air Force R&D optical telescopes in partnership with NASA since 

1998. Asteroid and comet data are now retrieved from the Space Surveillance Telescope (SST), 

which is now in operations on a site located in Western Australia.

Goldstone Solar System Radar

The Goldstone Solar System Radar originated in 1958. It features radar integration and a fully 

steerable 70-meter dish for high-resolution ranging and imaging of planetary and small-body 

targets, supporting both science objectives and planetary defense. Goldstone is located in 

Barstow, California and operated by JPL through NASA Deep Space Network funding. 

Spacewatch

Spacewatch began independently as a NEO survey project, but currently operates as an NEO 

astrometric follow-up project funded by NASA. Spacewatch primarily uses two University of 

Arizona telescopes on the grounds of Kitt Peak National Observatory in Arizona.

Magdalena Ridge Observatory

The Magdalena Ridge Observatory is located at 10,600 feet in the Magdalena Mountains in New 

Mexico. It is built and operated by the New Mexico Institute of Mining and Technology. Continuing 

programs launched in 2008 include NASA- and NSF-funded research in astrometric follow up and 

spin rate determination of near-Earth asteroids and comets.

Astronomical Research Institute

The Astronomical Research Institute operates privately owned telescopes in Illinois and on the 

grounds of Cerro Tololo Inter-American Observatory in Chile. The project, funded via a NASA 

grant, performs astrometric follow-up of NEO discoveries in the northern and southern skies.

The Mission Accessible Near-Earth Objects Survey (MANOS)

The Mission Accessible Near-Earth Objects Survey first began in August 2013 with the task 

of physically characterizing the large population of sub-kilometer NEOs, which are more easily 

accessible by spacecraft mission but also pose the highest likelihood of impacting the Earth. 

Funded by NASA, the data from MANOS observations is used to understand the NEO population, 

provide planetary science data, and help develop impact risk assessments. 

The Infrared Telescope Facility (IRTF)

The IRTF is a NASA telescope optimized for near-IR observations, located at an altitude of 13,600 

feet on Hawai’i Island. It is operated and managed by the University of Hawai’i’s Institute for 

Astronomy under NASA contract. Approximately 50 percent of the observing time is used for 

NASA planetary mission support and solar system science, including comets and asteroids. 
 NASA Planetary Defense Strategy And Action Plan | 36

Zwicky Transient Facility (ZTF)

ZTF is a wide-field survey camera based at Palomar Observatory performing a systematic study 

of the optical night sky, including near-Earth asteroids. It is funded by NSF and an international 

collaboration of partners, with grant support from NASA for data mining of NEOs, and funding 

from Caltech and the Heising-Simons Foundation.

Flight Programs

Double Asteroid Redirection Test (DART)

DART was the world’s first mission to demonstrate asteroid deflection technology by altering the 

orbital period of a celestial body via a kinetic impactor spacecraft. It successfully impacted its 

target asteroid Dimorphos in 2022, changing the orbit period around its primary Didymos by 32 

minutes (~5 percent), with post-impact analysis continuing. 

NEOWISE

NASA’s NEOWISE project has repurposed the Wide-field Infrared Survey Explorer space 

telescope since 2013 to continue to survey for NEOs and other small bodies using its remaining 

non-cryogenic infrared channels. It was launched in 2009 (as the Wide-Field Infrared Survey 

Explorer mission), with extended operations planned until at least June 2023. 

Near-Earth Object (NEO) Surveyor

NEO Surveyor is a space-based, mid-infrared telescope in development for the purpose 

of rapidly accelerating the rate at which NASA can discover NEOs. From its vantage point 

at the L-1 gravitation stable point on the sunward side of Earth, it will be able to survey 

along Earth’s orbit both ahead and behind the planet and closer to the direction of the 

sun than possible from the ground. By using two heat-sensitive infrared imaging channels, 

NEO Surveyor will be able to detect dark asteroids, which are the most difficult type to find, 

and it will be able to make significantly more accurate measurements of NEO sizes directly 

from these observations regardless of the amount of sunlight they reflect. NEO Surveyor is 

expected to launch no later than June 2028.

Asteroid Impact Threat Modeling and Simulation Resources 

Asteroid Threat Assessment Project (ATAP)

The ATAP team at NASA Ames Research Center leads efforts to model the potential damage 

and devastation that could occur from an NEO impact. By simulating the entry and passage of a 

natural object through Earth’s atmosphere, given a range of initial conditions about its trajectory, 

size and composition, the ATAP Probabilistic Asteroid Impact Risk (PAIR) modeling can assess the 

potential for any given impact scenario to survive the passage through the atmosphere and produce 

destructive effects at any selected points on Earth’s surface, within a range of possible outcomes 

driven by the uncertainties in initial conditions. ATAP is assisted in this comprehensive modeling 

effort by the NASA High Performance Computing Center at Ames and expertise at the DOE NNSA 

Laboratories, USGS and other agencies.
 NASA Planetary Defense Strategy And Action Plan | 37

Figure 7: Large NEO discoveries by survey. (Source: NASA)

1995 2000 2005 2010 2015 2020

0

100

200

300

400

500

600

0

100

200

300

400

500

600

LINEAR

NEAT

Spacewatch

LONEOS

Catalina

Pan-STARRS

NEOWISE

ATLAS

Other-US

Others

~140m and larger NEAs (as of 2023-Apr-12)

Near-Earth Asteroid Discoveries by Survey

Discovery Date

Number Discovered

https://cneos.jpl.nasa.gov/stats/ Alan Chamberlin (JPL/Caltech)
 NASA Planetary Defense Strategy And Action Plan | 38

Appendix C: Examples of International 

Planetary Defense Programs

Double Asteroid Redirection Test (DART) Worldwide Observing Campaign

Global network of assets that participated in observing DART’s post-impact effects, including 

documenting impact plume evolution and assessing the change in orbital period of Dimorphos about 

Didymos – critical to DART’s mission success and to assessing the effectiveness of the world’s first test 

of an asteroid deflection technique. 

International Asteroid Warning Network (IAWN)

The UN-endorsed IAWN collaboration currently consists of 50 signatories in 20 countries. IAWN is organized 

by NASA which supports the website at http://www.iawn.net/. U.S. signatories are NASA (contributed 

assets include all funded NEO survey, follow-up, characterization, and orbit determination and data center 

capabilities of NASA’s NEO Observations Program), the Zwicky Transient Facility, and independent amateur 

astronomers at Squirrel Valley Observatory, Toole Observatory, and Farpoint Observatory.

In-Space NEO Encounters

Flight programs to conduct space-based observations have been conducted by space agencies since the 

launch of ISEE 3/ICE in 1978, which targeted the near-Earth object 21P/Giacobini-Zinner, passing through 

its plasma tail in September 1985. NEO encounters have also included multiple flyby missions as Halley’s 

Comet passed through our solar system in the mid-1980’s. Near-Earth Asteroid Rendezvous-Shoemaker 

made history by landing on an asteroid in 2001. Japan Aerospace Exploration Agency (JAXA’s) Hayabusa, 

Hayabusa 2, ESA’s Rosetta and NASA’s EPOXI, OSIRIS-Rex and Double-Asteroid Redirection Test missions 

all encountered near-Earth objects. 

There are additional flight missions under development for launch this decade: the European Space 

Agency’s Hera mission may launch as early as 2024 to the asteroid Didymos and study the impact site of 

DART mission on the smaller nearby asteroid Dimorphos. The mission features two small satellites capable 

of sensing the interior of the asteroids to map their geological structure and chemical composition.

Figure 8: Locations of observatories that supported the DART observation campaign. 

(Source: Johns Hopkins University Applied Physics Lab)
 NASA Planetary Defense Strategy And Action Plan | 39

Appendix D: Support for Strengthening

Planetary Defense Efforts at NASA

Biden-Harris Administration

In April 2023 the White House released the National Preparedness Strategy and Action Plan for Near-Earth 

Object Hazards and Planetary Defense (National Planetary Defense Strategy), which is available online.6

The Biden-Harris Administration also highlighted the importance of planetary defense in the 2021 U.S. 

Space Priorities Framework: “The United States will lead, in cooperation with commercial industry and 

international allies and partners, in efforts to enhance warning of and mitigation against potential nearEarth object impacts.” 

On August 9, 2022, the President signed the “CHIPS and Science Act” which affirmed a commitment to “...

continue the development of a dedicated space based infrared survey telescope mission [NEO Surveyor] on a 

schedule to achieve a launch-readiness date not later than March 30, 2026, or the earliest practicable date...”

In 2022 the White House Office of Science and Technology Policy hosted the DART Mission team to 

brief senior leaders across the White House on the successful mission results.

Congress

The 2005 George E. Brown Near-Earth Object Survey Act directed NASA to find at least 90 percent of 

NEOs that are at least 140 meters by 2020. Since 2005, the number of NEOs catalogued in this range 

has almost tripled, while the total number of catalogued NEOs has increased by almost five times. In 

November 2022, the U.S. House Committee on Science, Space and Technology wrote to Administrator 

Nelson reiterating its strong support for planetary defense. 

American Public

Support for planetary defense among the American public is extraordinary, with 62 percent ranking 

it among NASA’s top priorities. Only climate change research was deemed a higher priority (Pew 

Research Center, 2019). A 2021 survey showed sustained support, with 62 percent of the public again 

placing it among the agency’s most important priorities, above many of NASA’s exploration goals 

(Morning Consult, 2021). 

Further evidence of public interest in planetary defense was illustrated during the DART mission: 

• DART’s asteroid impact event was covered by 338 domestic newspapers and featured on 35 

domestic front pages. Similarly, the news was covered by 153 international newspapers and 

featured on 5 international front pages.

• The DART impact broadcast, which was streamed on the agency’s YouTube account, has 

accumulated over 5.5M views and was the agency’s #1 trending video at the time of release. At 

peak viewership, the DART impact broadcast garnered nearly 1.1 million concurrent viewers and 

was NASA’s largest live viewing audience since the Perseverance rover landing in February 2021.

6 https://www.whitehouse.gov/wp-content/uploads/2023/04/2023-NSTC-National-Preparedness-Strategy-and-ActionPlan-for-Near-Earth-Object-Hazards-and-Planetary-Defense.pdf
 NASA Planetary Defense Strategy And Action Plan | 40

National Academies of Science and Planetary Science community

The National Academy of Sciences (NAS) highlighted planetary defense in the 2023-2032 Planetary 

Science and Astrobiology Decadal Survey. Notably, their recommendations included: 

• NASA should fully support the development, timely launch and subsequent operation of 

NEO Surveyor.

• Subsequent to DART and NEO Surveyor, the highest priority mission should be a rapid-response 

flyby reconnaissance missions to a challenging near-Earth object.

• NASA’s Planetary Defense Coordination Office should be funded at adequate levels to 

conduct a robust program of necessary planetary defense-related activities, technologies, and 

demonstration missions launching on a regular cadence.
 NASA Planetary Defense Strategy And Action Plan | 41

Appendix E: History and Evolution of 

Finding and Assessing the NEO Hazard

This is re-printed from the 2023 National Preparedness Strategy and Action Plan for Near-Earth Object 

Hazards and Planetary Defense.7

Observations of celestial bodies and comets have been recorded for thousands of years across civilizations, 

but the development of near-Earth object astronomical observation including asteroids is a comparatively 

recent development (and the understanding of the need to pursue capability to mitigate their impact risks 

even more recent!) The discovery of Ceres in 1801 by astronomer Giuseppe Piazzi was the first observation 

of an asteroid (later reclassified as a dwarf planet). The first near-Earth asteroid, 433 Eros, wasn’t discovered 

until 1898 by Gustav Witt. 

In 1973, Eleanor Helin and Gene Shoemaker at the California Institute of Technology started the first major 

systematic search for NEOs. Their Palomar Planet-Crossing Asteroid Survey mapped the orbits of 65 NEOs 

until the project finished in the mid-1990s.8

 Their legacy led to a new era of NEO searches: application of 

computers, digital imagers, and automated searches revolutionized NEO discovery efforts starting in the 

1990s; hundreds of NEOs were being discovered per year by the 2000s.9

The importance of asteroids to Earth’s geologic history and their current hazard became apparent in the 

1980s as scientists began to hypothesize that an approximately 10 km-wide asteroid likely caused a 

mass extinction on Earth and killed off non-avian dinosaurs about 65 million years ago, and that this event 

corresponded to the age of Chicxulub impact crater.10 The asteroid impact theory, attributed to the Alvarez et 

al. team, became widely (though not universally) accepted within the scientific community, signaling the need 

to establish “applied planetary science” as a discipline to guide effective planetary defense strategies.

After the very public near-Earth miss of the sub-kilometer asteroid FC 1989,11 NASA issued a 1992 

Spaceguard Survey Report recommending a goal to find 90 percent of NEOs one kilometer and larger. The 

impact of comet Shoemaker-Levy 9 with Jupiter in 1994 further raised public awareness to the asteroid and 

comet impact hazard and encouraged Congress to authorize the “Spaceguard Goal” of finding 90 percent 

of kilometer-size NEOs. In 1998, NASA initiated a Near-Earth Object Observations Program and formally 

adopted the original Spaceguard Goal (which was successfully completed by 2011).12

In 2003, as the original Spaceguard efforts were underway, a NASA-commissioned NEO Science Definition 

Team recommended expanding discovery efforts to include 140 meter and larger asteroids within five million 

miles of Earth’s orbit.13 The Science Definition Team identified 140 meters as the size that could cause severe 

7 https://www.whitehouse.gov/wp-content/uploads/2023/04/2023-NSTC-National-Preparedness-Strategy-and-Action-Planfor-Near-Earth-Object-Hazards-and-Planetary-Defense.pdf

8 Caltech. Palomar history graphical timeline. https://sites.astro.caltech.edu/palomar/about/timeline.html

9 Conway, Erik M, Rosenburg, Meg, Yeomans, Donald K. 2022. A History of Near-Earth Object Research, 10. https://www.

nasa.gov/sites/default/files/atoms/files/a_history_of_near-earth_object_research_tagged.pdf

10 See for example: Alvarez et al, “Extraterrestrial cause for the Cretaceous-Tertiary extinction,” Science, 1980; Hildebrand et 

al, “Chicxulub crater: a possible Cretaceous/Tertiary boundary impact crater on the Yucatán peninsula, Mexico,” geology, 

1991; and Schulte et al, “the Chicxulub asteroid impact and mass extinction at the Cretaceous-Paleogene boundary,” 

Science, 2010.

11 House Hearing, 110th Congress. November 8, 2007. Near-Earth Objects (Neos)—Status of the Survey Program and 

Review of Nasa’s 2007 Report to Congress. https://www.govinfo.gov/content/pkg/CHRG-110hhrg38057/html/CHRG110hhrg38057.htm

12 NASA Office of Inspector General. 2014. NASA’s Efforts to Identify Near-Earth Objects and Mitigate Hazards, 24. https://oig.

nasa.gov/docs/IG-14-030.pdf

13 Near-Earth Object Science Definition Team. Study to Determine the Feasibility of Extending the Search for Near-Earth 

Objects to Smaller Limiting Diameters. Prepared at the request of the NASA Office of Space Science Solar System 

Exploration Division, August 22, 2003. https://cneos.jpl.nasa.gov/doc/neoreport030825.pdf
 NASA Planetary Defense Strategy And Action Plan | 42

regional devastation leading to national economic and societal upheaval. Two years later, the George E. 

Brown, Jr. Near-Earth Object Survey Act, directed NASA to find 90 percent of PHOs 140 meters and larger 

in 15 years. Additionally, the Act updated NASA’s mission to make NEO detection, tracking, and research 

one of the Agency’s seven explicit missions.14 

By 2010, a memorandum by the White House Office of Science and Technology Policy (OSTP) began 

pivoting the Federal government towards a broad official planetary defense program, rather than one 

focused solely on NEO discovery.15 The memo presented an interagency plan of action in the event of a PHO 

impact threat discovery, and recommended that NASA initiate a research program to assess mitigation and 

deflection technologies, continue to detect hazardous NEOs, and notify relevant Federal agencies in the case 

of a potential NEO impact threat. This would eventually lead to a broader NASA planetary defense program 

that includes planning for deflection and impact mitigation of PHOs in addition to just detection. A 2010 

NASA Advisory Council (NAC) task force amplified these changes within NASA. 

In February 2013, an undetected asteroid roughly the size of a house exploded over Chelyabinsk, Russia, 

injuring approximately 1,600 people. The incident dramatically raised global public awareness of the NEO 

threat.16 In 2014, the United Nations Office of Outer Space Affairs (UNOOSA) endorsed the creation of the 

IAWN and the SMPAG, formally bringing to bear many of the world’s space observatories and expanding 

planetary defense into a global effort.17 By 2016, NASA established its Planetary Defense Coordination Office 

(PDCO) to organize and oversee planetary defense efforts. 

In 2017, the NASA NEO Science Definition Team published an updated report, finding that a space-based 

NEO surveillance system would be needed to complete the George E. Brown Jr. Survey before 2033.18 And 

in 2022, for the first time, the National Academies of Sciences, Engineering and Medicines (NASEM) Decadal 

Survey for Planetary Science prominently featured a section on planetary defense, recommending that 

NASA’s PDCO should be “robustly supported as the critical organization to advance U.S. planetary defense 

capabilities” for at least the next decade.19

Today, a new era is starting: in 2022, NASA’s DART mission successfully demonstrated the ability to alter the 

orbit of an asteroid. After thousands of years observing celestial bodies, this was the first demonstration of 

an ability to shift a potentially hazardous asteroid. Two revolutionary NEO search capabilities will come online 

soon, the NSF/DOE-supported Vera C. Rubin Observatory (beginning operations in 2024-2025), and the 

NEO Surveyor space telescope (anticipated for launch by 2028).20 Planetary defense initiatives have also 

yielded unexpected scientific discoveries: NASA’s NEO Observations Program-funded Pan-STARRS project 

discovered the first known interstellar object passing through our Solar System, ‘Oumuamua, opening a future 

field of scientific inquiry into interstellar objects. Looking ahead, the asteroid Apophis is predicted to pass within 

about 31,600 km of Earth’s surface in 2029, presenting a serendipitous opportunity to further advance Earth’s 

planetary defense through technology demonstrations and international collaboration. 

14 S.1281 NASA Authorization Act of 2005, public law no.: 109-155. Sec. 321: George E. Brown, Jr. Near-Earth Object 

Survey. https://www.congress.gov/bill/109th-congress/senate-bill/1281/text

15 Issued in response to a Congressional tasking in the 2008 NASA Authorization Act. Holdren, John P. OSTP Letter Report on 

NEOs. 15 October 2010. https://www.nasa.gov/sites/default/files/atoms/files/ostp-letter-neo-senate.pdf

16 NASA. Five Years after the Chelyabinsk Meteor: NASA Leads Efforts in Planetary Defense. 15 February 2013. https://www.

nasa.gov/feature/five-years-after-the-chelyabinsk-meteor-nasa-leads-efforts-in-planetary-defense

17 UNOOSA. Near-Earth objects, 2011-2012. 21 December 2012. https://www.unoosa.org/oosa/oosadoc/data/

documents/2013/aac.105c.1l/aac.105c.1l.329_0.html

18 Near-Earth Object Science Definition Team. September 2017. Update to Determine the Feasibility of Enhancing the Search 

and Characterization of NEOs. https://cneos.jpl.nasa.gov/doc/2017_neo_sdt_final_e-version.pdf

19 National Academy of Sciences, Engineering, and Medicine. Origins, Worlds, and Life: A Decadal Strategy for Planetary 

Science and Astrobiology. 2023-2032, (Washington D.C.: National Academies Press) 2022.

20 In 2022, NASA approved the NEO Surveyor space telescope to begin mission development for launch by 2028. The NASA 

Authorization Act of 2022 passed by Congress also reaffirmed the George E. Brown, Jr. Survey goal and directed NASA 

to continue development and deployment of NEO Surveyor without further delay or diverted resource allocations to other 

missions. See: H.R. 4346 CHIPS and Science Act, public law no.: 117-167. Sec. 10825: Planetary Defense Coordination 

Office. https://www.congress.gov/bill/117th-congress/house-bill/4346/text?r=2&s=2. 
 NASA Planetary Defense Strategy And Action Plan | 3

NASA PLANETARY DEFENSE

STRATEGY AND ACTION PLAN
 NASA Planetary Defense Strategy And Action Plan | 4

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