Asteroid close approaches: keeping things in perspective



On July 25, the Sydney Morning Herald reported on a close approach of a newly discovered near-Earth object (NEO), asteroid 2019 OK. The asteroid was detected at what might appear, to the non-expert, the last minute (a couple of days before fly-by, I believe.) In actuality, the detection and observation of this NEO as it passed by Earth at 70,000 kilometers (43,496 miles) was routine – certainly nothing to panic about.

The Sydney paper quoted four Australian scientists – understandably, since it’s an Australian news outlet. None of those scientists actually observed the asteroid, as far as I can tell. Two of them, in my humble opinion, made much ado about nothing.

“[If it hit Earth] it makes the bang of a very large nuclear weapon – a very large one.”

It didn’t, and it posed no risk of doing so.

“It would have hit with over 30 times the energy of the atomic blast at Hiroshima.”

It didn’t hit. And it posed no risk of hitting. Not to mention that when asteroids do impact Earth, they do not release any nuclear radiation.

“It’s a city-killer asteroid.”

No it’s not. It did not pose any risk of impact with Earth.

“Definitely too close for comfort.”

This close approach did not make me uncomfortable.

Nonetheless, several other news outlets, ranging from (usually) reliable – such as the Washington Post – to flaky (U.K. tabloids), picked up this story, repeating the sensational framing.

On July 26, the Washington Post picked up on this story, surprisingly interviewing only the two seemingly panic-stricken Australian scientists who generated the comments above. The Post’s story reiterated the “city killer” and “nuclear” tropes, which most asteroid scientists I know tend to avoid. It seems odd that a Washington news outlet would not check in with Washington-based experts – such as my colleagues with the planetary defense program at NASA headquarters (for which I am a consultant, and, for the record, no one asked me to write this post). Oh well….

According to NASA’s public web site for planetary defense:

  • A near-Earth object (NEO) is an asteroid or comet whose orbit brings it into or through a zone between approximately 91 million and 121 million miles (195 million kilometers) from the Sun, meaning that it can pass within about 30 million miles (50 million kilometers) of Earth’s orbit.”
  • A potentially hazardous object (PHO) is a near-Earth object whose orbit brings it within 4.7 million miles (7.5 million km) of Earth’s orbit, and is greater than 500 feet (140 meters) in size.”
  • “A NEO close approach is of particular interest when it passes within the distance from the Earth to the Moon…. The Jet Propulsion Laboratory’s Center for NEO Studies maintains close approach tables that are updated daily.”
  • “Small asteroids a few meters in size are detected passing between Earth and the Moon’s orbit several times a month.”

According to NASA’s Center for NEO Studies (CNEOS), 2019 OK was estimated to be between 59 and 130 meters in size. Yes, an asteroid in this size range could cause damage IF it were to explode in the atmosphere or impact water or land. But, again, 2019 OK didn’t, and it posed no risk of doing so.

A global system is in place for finding, tracking, and characterizing asteroids and predicting their future orbits and any possible impact hazards. Detection and tracking of asteroid 2019 OK – though it may have seemed last-minute to some – is evidence that this global system is working just the way it’s supposed to.

Observers around the world – both professional and amateur – report detections to the Minor Planet Center (MPC), which is funded by NASA’s planetary defense program. The MPC analyzes and archives data received and relays observations to CNEOS, also funded by NASA’s planetary defense program. This is what occurred in the case of 2019 OK.

CNEOS verifies observations and predicts future orbits of the asteroid. (No known asteroid is on an impact course with Earth for the next 100 years.) In the case of asteroid 2019 OK, SONEAR, a Brazilian observation team, first detected this NEO and reported its observations to the MPC. Astronomers at McDonald Observatory in Texas also detected 2019 OK and reported its observations to the MPC. Other astronomers received notification of these observations and conducted follow-up observations, also reported to the MPC. The MPC has a public recordof these observations.

In addition to the MPC and CNEOS, the European Space Agency funds the NEODys-2 system, which performs the same functions as NASA’s CNEOS does using different methods, providing further verification of observational and orbit-prediction data.

The Sydney paper reported, “Asteroids this size tend to pass by once every decade.” According to CNEOS director Paul Chodas, a close approach by an object of the size of 2019 OK is predicted to occur perhaps a couple of times each century, and an impact of an object of this size might occur once every few thousand years. It’s important to note, as always, that considerable uncertainty underlies such predictions.

The International Asteroid Warning Network (IAWN) is a multinational organization of space agencies and observatories involved in finding, tracking, and characterizing asteroids, predicting their future orbits, and identifying any possible future impact hazards.

The multinational Space Mission Planning Advisory Group (SMPAG) is responsible for preparing for an international response to an actual asteroid impact threat (none have, as yet, been identified) through the exchange of information, development of options for collaborative research and mission opportunities, and the conduct of asteroid impact mitigation planning activities.

All of these organizations are in close communication with each other (and I have worked with representatives of all of them).

I realize that in the global, 24-7, news and information environment, where journalists’ deadlines are always NOW, we can’t expect to see as much careful and thorough reporting as we’d like to. In the case of the Sydney paper’s story, I don’t know who reached out to whom: reporter to scientists, or scientists to reporter…. I also realize that we’ll likely never wean journalists off grabby headlines and leads (city killer etc.).  After working on four workshops for the media on planetary defense over the past year, I can only hope that, over time, we might see some improvement.



What is the value of the human exploration of space?


Credit: the

With all the media brouhaha about this Saturday’s 50thanniversary of the Apollo 11 – stirred up in large part by NASA’s highly efficient public-affairs operation – it’s worth thinking about why the U.S. sent men to the Moon and why the current administration wants to repeat the feat and then send people on to Mars.

As the current administration is pushing NASA to return people to the Moon by 2024 “by any means necessary,” I wonder – what is the point? The administration has directed NASA to focus its attention on the human exploration of space, which currently consumes close to half of NASA’s $20 billion annual budget. What is the public purpose, the value, of the human exploration of space?

On July 11, the results of a C-SPAN-Ipsos public opinion poll were published, showing that NASA funding is less popular with the public than NASA itself is.  This finding replicates the findings of decades worth of public opinion polls. NASA has done a great job at promoting its “brand,” but public interest has not translated into public support for a larger space program. In June, the results of an Associated Press-NORC Center for Public Affairs Research poll were published, showing that on a list of nine priorities for the U.S. space program, respondents ranked returning astronauts to the Mars #6, returning astronauts to the Moon #7, and establishing a permanent human presence on other planets #8. In June 2018, the Pew Research Center published the results of a poll asking respondents to rank in order of priority nine goals in space exploration: sending astronauts to Mars ranked #8, and sending astronauts back to the Moon ranked #9. For decades, NASA and successive administrations have offered the similar rationales for human exploration, as re-articulated by Vice President Mike Pence in December 2017, when he said, “America will lead in space once again on all fronts…space is the ‘next great American frontier’ – and it is our duty – and our destiny – to settle that frontier with American leadership, courage, and values.” Does this message resonate with the taxpayers who are financing the human exploration of space? In the current political environment, NASA’s priorities in space exploration do not appear to reflect the public interest.

As a scholar of space history, I have studied how, and why, NASA has worked on garnering public attention to the space program – especially its human exploration activities. This post is based on a chapter I contributed to a NASA history book marking NASA’s 50thanniversary.*

Even before NASA was created, U.S. engagement in space exploration was being shaped by political concerns about public image. U.S. activities in space were intended to be seen an assertion of scientific and technological expertise, political power, and global dominance. And they still are. From its inception, NASA was part of larger national political effort aimed at “winning hearts and minds” in a bifurcated world of free and Communist nations. Today, NASA is competing, and cooperating, with many space-faring nations. But the political impetus behind the space program is still, put simply, “USA, #1.”

Early NASA information policy documents cited the Agency’s statutory responsibility to “provide for the widest practicable and appropriate dissemination of information concerning its activities and the results thereof.”This policy, on paper and in practice, also aimed to control the flow of information to the public, including the mass media. At the same time, the media were invited in, by design, to help tell the story of U.S. leadership and conquest in space. This is still the intent of NASA’s public affairs operations.

From NASA’s start, there was a tension between the agency’s democratic task of informing the public and its political objective of controlling image and message: making America look great. This is still the case. The role of appointees is to make the President look good, by making NASA, headed by a leader of the President’s choice, look good. Civil servants have the task of fulfilling the Agency’s statutory responsibility to disseminate information on all of its activities. They are also compelled to keep their appointee bosses happy – a tough order on some days.

 In assessing public opinion about, interest in, and knowledge of the space program, NASA and the space community have typically taken an advertising and marketing approach to the task. NASA has repeatedly turned to the advertising and marketing sector for help in “branding” and “selling” the space program. The result has been a string of similar studies and similar findings – including the finding that public knowledge of NASA is a mile wide and an inch deep – and a series of attempts to cultivate favorable public opinion, along with the increased public support that is erroneously assumed to accompany that favorable opinion, by pitching NASA to the public. A C-SPAN-Ipsos public opinion pollconducted this year showed that while many reaspondents said they have been touched by the space program, a much smaller number identify as space enthusiasts. About one in five Americans classify themselves as “very interested” in space exploration, and only about a third believe the benefits are greater than the costs.

For all of its 60 years thus far, NASA has claimed a high level of public interest and a good reputation with “the public.” It is not clear how much of this good feeling among citizens is a product of NASA’s public affairs efforts and how much is due to other social factors – that is, the social and cultural context for the space program. Over the past 25 years, I have observed that when NASA and other members of the space community talk about public interest and understanding and engagement, they are usually talking about their desire to expand public support. Public opinion research and studies of public understanding of science and technology have shown how and explored why public interest does not equate to public understanding and how and why neither interest nor understanding equates to public agreement or support.

Today the range of issues people are thinking about may be different – for example, poll respondents now rank planetary defense and climate change research as high priorities for the space program – but the situation is the same. While many people may view the space program as a salient issue, they typically do not put it at the top of their list of things they need to think about. NASA continues to struggle to make space exploration relevant to people’s lives. In the 21stcentury, people know NASA by its representations – its space-walking heroes and their spaceships, the Hubble Space Telescope, and anthropomorphized rovers on Mars. What is missing in this pastiche of of spectacles is the meaning of NASA for all of its publics.

What people seem to care about is space exploration, in the broadest possible sense. People appear to care as much about the idea of space exploration, the idea of human and robotic presence in space, as they do about the mechanics, the reality, of these things. When asked to place a value on the idea of space exploration, people rate it highly. When asked to put a price tag on the reality of space exploration, a different picture results.

NASA exists in a social reality where special interests – political and economic and business interests – will continue to ensure, for better or worse, the continuation of the civilian space program. At the same time, most citizens arguably do not “get” space exploration in the same ways that special interests in the space community do. NASA and its advocates are framing space as a resource-rich environment to exploit for economic gain, as a money-making enterprise, as a new home for the endangered human species. While this messaging receives wide attention in the mass media, I wonder – does it resonate with taxpayers?

* Linda Billings, “Fifty years of NASA and the public: What NASA? What publics?”, pp. 151-182 in S.J. Dick, Ed., NASA’s First 50 Years: Historical Perspectives(NASA SP-2010-4704), NASA History Division, Washington, D.C., 2010. Available free online at