Another Kind of Planetary Threat 

                                                          PWJ January 2023

Scientists analyzing the history of our planet Earth have described profound climate and biological changes due to meteoroid collisions. Major collisions have contributed to or directly resulted in extinction for certain then-existing plant and animal species.    

Meteoroids are fragments from asteroids, comets, planets or moons that range in size down to very small dust particles that burn up in the millions entering the Earth’s atmosphere each year. Much larger fragments or rocks can survive atmospheric burning as meteorites. 

Astronomer Gonzalo Tancredi has estimated that space rocks measuring about 33 feet wide can be expected to enter Earth's atmosphere every six to 10 years. Fortunately, meteoroids as large as the Tunguska, Russia event in 1908 occur much less frequently. The mere grazing effect of this passing meteoroid, estimated at 300-600 feet diameter, flattened 800 square miles of Siberian forest with an energy blast about 180 times the effect of the Hiroshima atomic blast of 1945. The consequences from Earth-bound meteoroids depend on the angle of atmospheric entry and location of their impacts, as well as their size and composition.  

The last decade has brought increased concern related to scientific forecasts concerning potential meteoroid collisions with Earth. There is even an annual Asteroid Day on June 30. The day is part of a UN-sanctioned global awareness campaign starting in 2014 to educate people about asteroids and possible means to protect our planet from very damaging meteoroid impacts. 

A truly significant accomplishment for our NASA space program occurred on September 26 of this year. A space mission called DART (Double Asteroid Redirection Test) resulted in a bulls-eye hit on the small asteroid Dimorphos to determine if this impact could shift the space rock’s pathway. Dimorphos is about 525 feet in diameter and orbits a five-time larger asteroid called Didymos that is 6.8 million miles from Earth. 

The Planetary Science Division of NASA was elated by this successful space vehicle collision, but their much more important goal was to shift the asteroid’s pathway or orbit. According to NASA, DART’s minimum goal for successful orbit change of Dimorphos around Didymos was 73 seconds. Early data suggests that this minimum benchmark was exceeded by more than 25 times. Dimorphos’ approximately 12-hour previous orbit was reduced by about 32 minutes. 

International coordination has been obvious throughout this vital space mission. The Light Italian Cube Satellite for Asteroid Imaging provided by the Italian Space Agency flew within 35 miles and a few minutes after DART’s impact on Dimorphos to survey the impact and consequences. The HERA Project by the European Space Agency is planned in about four years to do much more detailed surveys of the two asteroids, particularly Dimorphos’ crater from DART’s impact. 

Many of us grew up fascinated by the mission and exploits of the Federation in the sixties TV program, Star Trek. The DART mission represents a first-ever human feat, successfully changing the pathway of a celestial body, if only for a tiny asteroid and in a small way. The implications of this “small step” and “giant leap” by humanity might be almost as profound as Neil Armstrong’s words from the Moon in 1969. We might be able within a reasonable period to spot very damaging meteoroids threating Earth and to be able to divert these.  

I was hardly a scientist or much of an engineer long ago, and I eventually settled more into a policy analyst role. Policy analysts study potential institutional goals and the various programs or means that might be undertaken to reach these goals. NASA space exploration has many potential worthwhile goals. Which goals and programs have more desirable results given obstacles and the vast resources that must be expended?  

The glitter of commercial space exploration by Musk, Bezos, and others can be intriguing, but the space missions and actual accomplishments of American and global governments interest me more. Corporate or private interests obviously accomplish important human goals, but these interests can be overly self-serving and myopic at times. Witness the “greenwashing” by certain corporations in proclaiming environmental accomplishments. 

Think tanks and policy analysts study governmental agencies such as NASA to determine their capabilities and weaknesses to perform key social functions relative to the potentials offered in the private sector. Certain social priorities do not generate significant marketable interest in the private sector, and for a variety of reasons.    

The public’s confidence in governmental institutions, even our judicial or court system, has declined markedly in recent decades or years. It’s easy to find fault and be frustrated at their inability to conduct more effective and efficient usage of taxpayer funds. Perhaps though, we can fail to recognize their major accomplishments and celebrate these. NASA receives much more positive recognition than many other government agencies that also make key contributions to the quality of American life. You have to be a “devil’s advocate” these days to say much of a good word about government programs. Yet we depend so critically on many of these programs and resources that simply badmouthing these from an uninformed distance accomplishes very little. I salute those who are able to maintain their sanity and try to make federal government initiatives more responsive and effective for the public.