Clark R. Chapman, planetary scientist
Credit: Alford Karayusuf

Pandemics and NEO Strikes – Instructive Parallels

By Clark R. Chapman, planetary scientist, Southwest Research Institute (retired), Boulder, Colorado

We are currently in the early-to-mid stages of what promises to be an exceptionally catastrophic worldwide pandemic. It isn’t early for China and a few other countries that practiced strict early social distancing, where the coronavirus disease has peaked and then dropped, though experts fear that there might be subsequent waves.

For the United States and other countries, the worst of the pandemic is still yet to come. This is also a rather rare catastrophe. It appears that no widespread disease of the potential magnitude of the 2020 coronavirus pandemic has happened since the 1918/1919 flu pandemic, just over a century ago.

I’ve spent several decades studying another rare but catastrophic potential disaster, the possibility that a kilometer-wide near-Earth asteroid might collide with the Earth. 

Credit: The Center for Space Policy and Strategy

Such near-Earth objects (NEOs) can come in any size, including tiny particles that produce meteors, house-sized bodies that can produce megaton blasts in the atmosphere (like Russia’s Chelyabinsk event of 2013 that sent 1,500 people to the hospital), up to the 10 kilometer wide asteroid that struck 66 million years ago and killed off the dinosaurs and many other species of life.

While pandemics and NEO strikes differ in many ways, there are some instructive parallels.

Crimson contagion 2019

For starters, even though President Trump has declared that “nobody ever expected” anything like the current coronavirus pandemic, pandemics have been the subject of much academic study for a long time, just as the rare NEO threat has been studied by scientists and engineers for forty years. Despite the fact that the Trump administration dismantled the group of pandemic experts in the National Security Council in early 2018, the threat of a major pandemic was actually modeled by experts convened by Trump’s Department of Health and Human Services (HHS) just last year.













An unpublished “Do Not Distribute” report finalized in October 2019, obtained and published by the New York Times — outlines a multi-month tabletop exercise (“Crimson Contagion 2019”) coordinated by the HHS Office of the Assistant Secretary for Preparedness and Response. It involved numerous federal agencies, including the National Security Council; the U.S. Departments of Agriculture, Commerce, Defense, Energy, Homeland Security, Interior, Justice, Housing and Urban Development, Labor, State, Transportation, Treasury, and Veterans Affairs; the Environmental Protection Agency (EPA), the U.S. General Services Administration (GSA), the Director of National Intelligence (DNI), the U.S. Office of Personnel Management (OPM) and the Small Business Administration (SBA); fourteen states; numerous tribal nations and pueblos; the City of Chicago; and dozens of non-governmental and private sector organizations (e.g. the Red Cross, hospitals, universities, health systems, insurance companies, pharmacies, and professional medical associations).

One might have expected the President and/or his top advisors to have been aware of the findings in the 63-page report and recommendations from this exercise, but apparently – through some kind of grotesque organizational oversight – they were not, or at least didn’t treat it seriously and have forgotten about it.

Global worry: Near-Earth Objects (NEOs).
Credit: Texas A&M

Tabletop exercises

Similarly, experts on the topic of potential NEO disasters have been performing analogous tabletop exercises since August 2013, when the first one was held at the Federal Emergency Management Agency (FEMA) Headquarters, organized by individuals from NASA Headquarters and its Jet Propulsion Laboratory, FEMA, The Aerospace Corporation, RAND Corporation, Sandia National Laboratories, and Lawrence Livermore National Laboratory.

Some of the exercises have been held in Washington D.C. and others at the every-two-year Planetary Defense Conferences held in, for example, Rome, Tokyo, and Maryland. Besides involving many international experts and agencies, the second tabletop exercise, also held at FEMA Headquarters, involved individuals from many U.S. federal agencies, including the Department of Defense (DoD), the White House Office of Science and Technology Policy (OSTP), the State Department, Department of Homeland Security, Department of Education, Department of Labor, the U.S. Forest Service, the Defense Advanced Research Projects Agency (DARPA), the Department of Veterans Affairs, etc.

A problem with NEO tabletop exercises is that they mostly involved space scientists and engineers playing roles; few experts on global finances, sociology, and psychology were involved to reliably predict how society would react. I imagine that experts in the trenches of the Department of HHS might have been more knowledgeable about how to simulate society’s response to a threatened pandemic than we were simulating an NEO disaster.

The reason such exercises are undertaken is to assess potential disasters and then propose steps that governments and other entities should take to be ready to deal with a disaster should it threaten. It is meaningless to hold such exercises if their reports are filed away so that leaders are unaware of their findings and recommendations when such a disaster threatens.

Credit: The Aerospace Corporation, via NASA/FEMA

Communications channels

In the case of NASA’s Planetary Defense Coordination Office, which is likely to be immediately well-informed about any relevant NEO observations or predictions, it has developed methods for communicating with relevant federal agencies (as specified by NASA Policy Directive NPD 8740.1) including the Executive Office of the President, the State Department, and FEMA.

How effective the communication might be has (fortunately) not yet been tested by a real NEO catastrophe, because none has occurred and none is likely to occur in our lifetimes. But it is evident that any communications channels that were supposed to be used to bring the “Crimson Contagion” recommendations forward in the early days of the Covid-19 pandemic failed, with terrible consequences.

Another similarity between the NEO and pandemic low-probability high-consequence disasters concerns non-intuitive aspects of “timing.”

For both pandemics and asteroid disasters, it is often vital to act immediately and never procrastinate.



It has become obvious in the case of Covid-19 what has been understood by pandemic experts for a century: strong, early actions are vital in slowing or stopping the spread of a pandemic. It is not clear on exactly which date President Trump’s advisors, or the President himself, became aware of the potential epidemic that began in Wuhan, China, during (or before) early December 2019. Surely there was some early denial in China. But the Wuhan disease cluster was identified by the end of December and was more widely recognized as a world health concern by mid-January 2020. The situation in Wuhan was bad and the city was put on lockdown on January 24th (South Korea was declared to be on the highest level of alert the previous day).

A week later, President Trump declared a public health emergency and clamped down on some air travel from China to the U.S., paralleling his other xenophobic travel bans. He then went into weeks of denying the seriousness of the developing pandemic. Even during late February, Trump was commenting almost daily that the pandemic was “like the flu” and the dozen known U.S. cases were getting better and the number would likely soon “go to zero.” On March 6th, Trump signed the Coronavirus Preparedness and Response Supplemental Appropriations Act, but he was still highly misinformed about the pandemic and downplaying it (it was on that day that he said that “anybody that wants a test can get it,” which still isn’t close to being true over six weeks later).

Meanwhile, it is clear that the relevant people in his administration were going slowly during the period late-January to early-March on necessary preparations for the pandemic. Thus it is widely opined by pandemic experts that effective testing and other preparations were delayed by four to six weeks because of apathy by the Trump administration.

Covid-19 virus illustration.
Credit: CDC/Science Photo Library

Relevance of time

Even after a national emergency was declared, it was evident that many politicians and news reporters failed to comprehend the relevance of “time” in understanding the exponential growth of the pandemic. For instance, a critical measure of the strength of the virus is the percentage of people who become infected who eventually die of the disease.

In the case of the ongoing seasonal flu, the ratio is about 0.1% (or one-in-a-thousand people who get the flu eventually die from it or its complications). Of course, in the case of the flu, vaccinations prevent many people (order half) from even getting it, and “herd immunity” protects many others. 

Because it is well understood, many people who get the flu and might otherwise die are successfully treated and recover. In the case of Covid-19, many reports took the number who have died in a particular country and divided by the reported cumulative number infected in that country as a measure of the lethality. But those who die don’t do so on the day they become infected.

A typical period of a month to six weeks elapses between infection and death. In between, there are other important durations: from infection to when the infected person becomes contagious, the common delay between becoming contagious and showing symptoms of the disease, the further delay until the symptoms become sufficiently severe that the patient is hospitalized, yet another duration between hospital admission and being placed on a ventilator, and the final duration – for those patients who die – between being placed on a ventilator and dying. With all these stages growing exponentially (and not necessarily at the same rate) it is simply wrong to look at statistics for any two stages on a particular date and compare them.

With the extremely delayed testing in the U.S. and the large fraction that are pre-symptomatic, it is difficult to know when the early stages began for most people, or how many in fact developed the disease. Even the final stages are uncertain: it is sometimes unclear if a particular severely ill patient, or a deceased patient, had Covid-19 or just the flu (which itself kills tens of thousands of U.S. citizens each winter season). Planning for numbers of hospital beds or ventilators requires estimated extrapolations from the number identified as having the disease (enhanced by an uncertain factor due to inadequate testing) to the number expected to need ventilators some weeks later. People unfamiliar with exponential growth have often complained that the quantities of supplies ordered by state governors are exaggerated when in fact they may be underestimated due to uncertainties in the rates of growth.

The Panoramic Survey Telescope & Rapid Response System (Pan-STARRS) 1 telescope on Maui’s Mount Haleakala, Hawaii.
Credit: University of Hawaii Institute for Astronomy/Rob Ratkowski

Early action

There are analogous, non-intuitive timing issues involved in planning a response to any future NEO impact threat. For example, soon after it was discovered in 2011, it was noted that NEO 2011 AG5 had a tiny but significant chance of impacting Earth on February 5, 2040. With a diameter estimated between 100 and 300 meters, such an impact – with potential explosive energy ranging between 100 and 900 megatons – could devastate a whole country or even a whole continent. A 29-year advance warning might seem like a long time in the future, hardly meriting immediate action. But it turned out that, for non-intuitive technical reasons, early action was likely to be required.

The 2040 impact would be preceded by a 2023 passage of the NEO through a “keyhole.” (A keyhole is a small region of space rather near the Earth which, if entered by an asteroid, would result in a significant change in its orbit by Earth’s gravity that would bring it back to strike the Earth many years later, e.g. on February 5, 2040.)

Disturbing results

Simulations of space missions that could deflect the NEO (e.g. by slamming into it so that it would miss the Earth rather than impact) had disturbing results. It would be theoretically simple to deflect the NEO prior to 2023 so that it would miss the keyhole and hence miss striking the Earth in 2040. But after keyhole passage, it would tax the capabilities of even the largest, most effective launch vehicles to get a spacecraft to 2011 AG5 well before 2040 (with launches between 2026 and 2029) to deflect it away from impacting Earth.

By early 2012 it was calculated that the chances of impacting the Earth (most likely in Latin America) in 2040 were about 1-in-500. While those odds might seem small, such chances of destroying several countries and killing millions would hardly seem acceptable to people living in those countries. Yet NASA concluded that with such low probabilities it would be premature to begin planning for such an expensive deflection mission.  It would prefer to wait for more observations of the asteroid, which would likely improve knowledge of the body’s orbit and probably render a deflection mission unnecessary. Unfortunately, in 2012 the NEO was so far away from Earth and hence so faint that it would be difficult to re-observe it until autumn of 2013.

Credit: The Center for Space Policy and Strategy


But just as with the coronavirus, you can’t procrastinate in developing a mission that could deflect 2011 AG5 before its 2023 keyhole passage.

Mission calculations showed that the spacecraft would have to strike the asteroid in the beginning of 2021, requiring a launch of the deflector spacecraft at the beginning of 2020, and it would take years to develop and build that mission. But, in addition to the deflector, another spacecraft would need to orbit around the NEO in order to observe the deflection operation and make precise course-corrections if needed because of the uncertain results of the big slam.

The orbiting spacecraft would be a so-called Gravity Tractor which could further modify the NEO’s orbit to ensure that it would miss the keyhole. It takes much longer to orbit an asteroid than to just slam into it, so the Gravity Tractor would have to be launched in early 2017 to get into orbit before the deflector would arrive. Since it would take at least four years to develop and build the Gravity Tractor in time for an early-2017 launch, development would have to begin in early 2013, nearly a year before astronomers could again observe 2011 AG5 to assess whether it was still headed for the keyhole.

These circumstances motivated several of us to see if it might be possible to observe the faint NEO and refine its orbit before early 2013. We found that it was marginally possible to observe the asteroid using one of the world’s largest telescopes. Dave Tholen of the University of Hawaii used the very large 8-meter Gemini telescope on Mauna Kea in Hawaii to observe the asteroid in October 2012. The new data showed that the asteroid would just miss the keyhole in 2023 and so it could not come nearer to the Earth in 2040 than twice the distance to the Moon.

Stop the disaster

Thus just as a death from infection by a virus doesn’t occur until weeks or months later, the mounting of a successful NEO deflection mission often requires years or decades of planning, development, launch, impact on the asteroid, and then waiting for the NEO to drift far enough away from its previous impact trajectory to miss the Earth.

In the case of 2011 AG5, a critical early step had to be taken more than 27 years before the devastating catastrophe might have happened.

Credit: NASA/JPL-Caltech

An attribute that the NEO hazard shares with pandemics, but is rare for natural hazards, is that human beings can potentially stop the disaster from happening.  Hardly any other natural hazard can be totally prevented. Explosives can be used to trigger avalanches, rendering them harmless. But bad effects of most natural hazards can only be partially mitigated by measures like hardening buildings to withstand earthquakes, restricting building in flood plains, issuing evacuation warnings, etc.

In the case of potential NEO disasters, search programs – when fully implemented – can identify any large NEO headed our way and then a space mission can be launched to deflect the NEO away from striking the Earth (large comets are very rare exceptions). Or, if time is too short, ground zero can be precisely specified and people can be provided with many days, weeks, or more to evacuate. It is very unlikely that a regionally destructive NEO would not be found before striking Earth, especially once several search projects being developed are completed and become operational.

Usually, warnings to evacuate from oncoming tornadoes, hurricanes, and floods are much shorter, although the effectiveness depends on the promptness of alerts. In the case of Hurricane Katrina, a Hurricane Watch wasn’t issued until the probability of a hurricane striking New Orleans had risen to 20%, just two days before it struck…too late for effective evacuation. In the case of the Covid-19 pandemic, there were perhaps two months of warning before the pandemic reached serious levels in the United States, but the predictions were dismissed by President Trump until it was too late to take effective action such as testing and contact-tracing, wasting up to six weeks.

DART mission schematic shows the impact on the moonlet of asteroid (65803) Didymos. Post-impact observations from Earth-based optical telescopes and planetary radar would, in turn, measure the change in the moonlet’s orbit about the parent body.
Also shown is planned ride-along CubeSat, the Italian Space Agency’s Light Italian CubeSat for Imaging of Asteroid (LICIACube).
Credits: NASA/Johns Hopkins Applied Physics Lab

Levels of redundancy

Another attribute of NEO planning that should have been employed in the weeks leading up to the Covid-19 pandemic is redundancy.

Decades of experience with failed rocket launches have led the aerospace community to adopt multiple levels of redundancy into space missions. Sometimes limited funding doesn’t permit adequate redundancy, which unfortunately can result in failures of satellites and space missions. But in the tabletop exercises for NEO defense, the prospects of terrible devastation from an impact always mandated multiple levels of redundancy in missions to deflect (or destroy) the threatening NEO. Multiple deflection missions are developed and launched in case one or more fail.

Unfortunately, in the case of Covid-19, the decision was made to develop only one approach to testing.  Despite opportunities to purchase tests developed in other countries, and recommended by the World Health Organization (WHO), a single-string approach to testing developed by the U.S. Centers for Disease Control and Prevention (CDC) was all that was relied on (other labs were even forbidden by the Food and Drug Administration (FDA) from doing any testing).When the CDC test was found to be flawed, there was a lengthy delay before a revised test could be developed and distributed widely throughout the country and before the FDA relaxed its restrictions.

I don’t know if earlier plans and tabletop exercises for pandemics addressed the need for redundancy, but there have been extremely deadly consequences from the failure to implement redundancy in developing Covid-19 tests in the U.S.

— Clark R. Chapman, planetary scientist, Southwest Research Institute (retired), Boulder, Colorado

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