Protecting the Planet

Protecting the Planet.
A brief review of real life scenarios and solutions.

After the Deep Impact and Armageddon movies came out, my children, highschoolers at the time, asked two questions.  Could it really happen?  And what could we do about it?  So I set about looking for the answers.  What I found were articles and papers that ranged from the boring technical dissertations, to wildly speculative, to the fatalistic, ostrich like, Oh well, there is nothing we can do about it.  So I wrote this to answer those questions, not only for my children, but also for the rest of us as well.

Space may be the original silent, but deadly environment.  The stray comets and asteroids that wander the solar system often cross paths with planets, sometimes to devastating effect.  The three near misses in the last year, for example.  Comet Shoemaker-Levy 9 also provided an uncomfortable reminder of that fact when it slammed into Jupiter in 1994.  The fragments of the disintegrating comet created enormous disruptions, some the size of Earth, in the giant planet's atmosphere, which were clearly visible from Earth.  And the Earth is not immune.  Barringer Crater near Winslow, Arizona; Hudson Bay, in Canada; and the Chicxulub crater on the Yucatan Peninsula in Mexico; present day evidence that the planet has been struck hard by asteroids or comets, many times in the past.  Indeed, we get struck several times a year by small meteorites.  In addition, the remains of hundreds of large impact craters, some thousands of meters across, have been identified all over the Earth.

First, let us define the terms used by the scientists.  We have three classes of objects to be considered, manmade, asteroids and comets.  Meteors are less than fifty feet in diameter and usually parts of asteroids or comets. Manmade objects are tracked as a matter of routine, and generally do not pose much of a threat.  Near Earth Objects, such as asteroids and comets are another matter altogether.

Asteroids are usually grouped as Amors, which lie outside the Earth’s orbit; Apollos, which cross the Earth’s orbit once a year or less, and Atens; which cross the Earth’s orbit more than once a year.  Comets with periods of less than twenty years are considered short period comets; from twenty to two hundred years, intermediate period comets; and over two hundred years, long period comets.  Asteroids are generally rocky and/or metallic, comets are thought to made of lighter, more volatile substances.

One of the things that bothered me was the constant reference to the long times between impacts on the scale of the one that killed the dinosaurs and changed the planet.  Fact is, impacts big enough to crush cities occur with amazing frequency.  The impact in 1908, in Tunguska, Siberia was not a planet killer, it exploded just above the ground, devastating thousands of acres in an unpopulated area.  Had it exploded above a large city, thousands, of people would have been killed.  A ten to twenty megaton blast is nothing to sneeze at.  So, I think potential city smashing asteroids are also worth our attention.  And the debate over whether it was the Yucatan impact, or the effects of the impact, that killed the dinosaurs, is moot.  Dead is dead.

So, the answer to the first question is yes.  It can happen.  It has happened.  And it most certainly will happen again.  Since 1970, the United States Air Force has detected more than twenty, nuclear sized blasts in our atmosphere, attributed to objects from space.  We have since learned that at least two, if not more, false alarms were triggered by some of these minor impacts, bringing us to the brink of nuclear war.

So what can we do about it?

The first is, of course, detection.  What is out there and where are they?

Astronomers all over the planet are helping in the search for Earth crossing objects of all sorts.  In fact, amateurs found the majority of objects discovered in the last few years.  This is a good thing, since even today, the total worldwide effort to search for NEOs amounts to fewer than a dozen paid full-time-equivalent workers!  Without the effort of these volunteer astronomers, most of the objects cataloged today would still be unknown.  NASA estimates that if we were to implement the Space guard plan, basically quadruple our efforts within the next few years, It is therefore reasonably likely that even the ‘next Tunguska’ projectile (20 megatons energy) will be found by the Space guard Survey if it is continued for several centuries. (Safeguard survey report, 1992).  Some NASA scientists think that between 15,000 to 300,000 Earth-crossing objects probably exist in this size range, with several passing between Earth and Moon each year.  With so many potential crossings each year, do we really have centuries?

Well, so far, we have cataloged many objects.  According to the late Eugene Shoemaker (U.S. Geological Survey) the 128 known ECAs (earth crossing asteroids) are comprised of 11 Atens (9 percent), 85 Apollos (66 percent), and 32 Earth-crossing Amors (25 percent).  Sixty-one of these have received permanent catalog numbers, implying their orbits are well established, while preliminary orbits are in hand for 51 others.  The remaining 16 are considered lost, meaning their orbits are not well enough known to predict the current locations of these bodies.  The thousand or so new finds of the last couple of years are awaiting confirmation and orbital determination.  Again, hats off to these volunteers for their countless hours of work, and to the professional astronomers, for their tireless devotion and support for the volunteers, often on their own time.

There is a big difference between 15,000 or more potentially dangerous asteroids, and 128 known ones.   And that is not even counting the Earth orbit crossing comets.  Some of the comets are bigger.  Say, diameters from about 100 m to 20 km; energies from 20 to 100,000 megatons.  That is more than enough potential damage to worry about.

There are many proposals to increase detection and tracking of these objects.  All required the building of telescopes and supercomputers that don’t exist right now.  All require huge amounts of money.

Thus, if we are to build new systems, why not build them on the far side of the moon?  The moon is an ideal platform for detection equipment.  Without an interfering atmosphere, observation, and solar energy collection, will be far superior to Earth based systems.  In addition, the slow rotation and exposure away from Earth increases the ability of each instrument to observe and track an object, a thousand fold.  Not to mention the boon to astronomy.  And we have been to the Moon.  It is nothing new, does not require some new technology waiting to be invented.  In fact, our equipment is far better now, than thirty years ago.  It is easily doable now.

The United States Air Force already has the responsibility to watch over the sky, and near space, up to lunar orbit.  Since they already have the tracking computers, Space Command, and the experience, they would be the ideal group for such an assignment.  Protecting the nation is the military’s job, and I believe protecting the planet from catastrophe comes under that heading.  We should not expect the Air Force to do it alone.  Encourage businesses to bid on the construction of the bases, and support facilities. Offer contracts and grants, not for studies, but to actually do the work.  For example, the Colorado Bureau of Mining has already conducted and collected research into Lunar Mining.  There is no need to reinvent the wheel, so to speak, just use the information already there.  There are tons of researches on everything from metal and gas extraction, to Lunar concrete, to glass making, to biosystem technology.  There is more than enough information to effectively plan any construction project.  As the base grows, we can build shipyards and metal fabrication shops on Luna, as well as produce solar panels and glass works.  By dividing up the construction of the bases, production and support facilities, we can get the base built while allowing the Air Force, and Navy to do their job.

With the vast majority of equipment and supplies being produce on the moon, the only thing needed from Earth will be the personnel.  This will cut way back on launches, the biggest single expense of the Space Program by far.  If the military can arrange transportation, there are many people willing to go and work on the moon.  Imagine the boost to the economy and the sciences.  Better and more economical means of space transportation and construction are sure to grow out of these projects.  Researchers will be able to work on site, greatly expanding the range of their experiments.  We will be able to clean up and recycle the junk in Earth’s orbit, eliminating another threat to the expensive satellites and space stations in orbit.  Replacement satellites and space station components can be produced and launched at a substantial savings.

Many companies would be needed for this enterprise, creating many new jobs and businesses.  We will need mining operations, smelters, metal smiths, machine shops, factories, electronics, computers, batteries, clothing, construction, biosystem engineers (farmers e.g.), power companies, solar panel manufacturing and launch facilities.  That is just to name a few. Don’t forget stores, malls, restaurants and bars.

This is nothing new.  Historically, civilian contractors usually construct bases for the military, and support facilities and businesses tend to grow around the base, helping to supply some of the amenities of home.

Ok, so we can find them, now what?

The next step is to track the asteroids and comets, and deal with them when they pose a threat to the Earth.  To do this, I propose an even more ambitious step.  From the Lunar bases, we will develop a much more efficient life support system, the single biggest hurdle to human exploration of space.  We can build the next generation of spacecraft using mostly lunar material, to help relieve some of the strain on Earth’s resources.  From the moon, we can go to any point in the solar system, much easier and cheaper than from Earth’s surface.  In fact, we can build bigger, safer and more numerous ships for far less money.  Then we can establish a base on Mars.

Why Mars?  Simple.  Mars is closer to the asteroid belt.  Thus, one good reason for the Mars base is earlier detection and interdiction of any Earth threatening object.  Once the Lunar base has identified potentially hazardous objects, they can sent the list to the technicians at the Mars base, who can then tag that object with a transmitter, and if need be, mount thrusters to the asteroid and move it from harms way.  Remember that an asteroid or comet can cover the distance from Mars to Earth in about three to six months, though some are much slower.  It will take at least that much time for our current thrusters to move a threatening object out of harms way.  So we need to chart the orbits long in advance, to get sufficient warning.  In addition, anytime the objects collide, or come close to a planet, their orbital trajectories change, requiring new computations.  We will have our hands full just tracking these things.  Being able to move them will solve many uncertainties.

Why not blow it up?  Well for one, we would need at least a couple years notice to build, program and arm the weapons to do that.  The best we can do now is less than ninety days warning.   Second, we don’t have enough nuclear weapons on the Earth to destroy some of the bigger objects, or the means to fly them past Earth’s orbit.  And third, blowing it up would create a shotgun blast out of an artillery round.  It would still be dangerous, and sure to rain death and destruction somewhere on the Earth.  Moving it not only avoids this but also makes a good thing out of a bad thing.

How does that make it a good thing?

Move it somewhere we can use it.  NASA has developed various thrusters, even some that could be powered by solar panels, and use the material on the asteroid as reaction mass, to move it.  We would need to attach any thrusters, long before the asteroid reached Earth, due to the long time needed to have an effect on such a large mass.  The further away deflection begins, the less total power needed for moving it out of harm’s way.  So we can use that time to decide where to park the asteroid, or even move it to another orbit.  It would create another source of raw materials for us, even shipping some of the metal home, to Earth, with lunar silicate shielding.  There are companies willing to pay for asteroids moved to an orbit where they can be mined economically.  Leasing mining rights to an asteroid would be one way of getting a return on our investment.  Comets are sources of light elements and volatile materials.  We could even mine them for water, methane, ammonia, and etc., for use on the lunar base, space stations or even Mars.

Another advantage to a base on Mars would be, there is a slight atmosphere, and it is possible to grow food on there, in green houses.  Martian farmers could sell food to the bases on the moon and Mars.  In addition, the added benefit of mining on Mars, and creating colonies there, will provide scientists with a new base to operate from.  Instead of pouring over a few bits of meteorite from Antarctica, they could lease time at the Mars base, or pay for samples to be sent back.  No telling what we might find on Mars, once we start digging and building there. Repair parts and rocket fuel can also be made on Mars.  Maybe even build space ships for private enterprises, like asteroid mining or satellite repair.  Think of the new economic and tax base we would be creating out there.

Again, we should not expect the USAF to shoulder the burden alone. For going to Mars, and expanding operations into the asteroid belt, the United States Navy has more experience in both navigating in a three dimensional environment, and long duration missions.  The Navy does that every time a submarine, or any other ship for that matter, leaves port.  So they have the crews already trained for such a mission.  And the resulting contracts for base construction and supplies will again expand our commercial and economic base.  Building a permanent base would make more sense, and cost less in the long run, with much greater benefits, than sending a few astronauts to look around for a little while and come home.  And it would be safer.  By having the military handle the asteroid and comet problem, NASA could open up Mars and Lunar offices, and do what they do so well, research and explore.  Help would be a lot closer for the astronauts, and a lot faster, should something go wrong.  NASA has worked hard and done an outstanding job of getting the information and research for this new venture.  It is time to put that hard-earned knowledge to work.

We need to start somewhere.

Let’s allow the United States Air Force to build the far side observatory, in conjunction with the universities, NASA, ESA, Great Britain and Japan.  Since those organizations and countries have their own plans for building an observatory, we can either pool resources, or lease time to them.

Let’s encourage private enterprise to bid on and build the base and support facilities.  Not only for the economic benefits, but to help protect the planet.

Imagine the pride each worker would have in knowing they helped protect the world, not just for their children, but for their children’s children and their children after that.  Each person would return from working off world, with a new appreciation for our fragile little world and the life on it.

Let’s encourage the Navy to get involved and begin gearing up for Mars.  We need their help in this endeavor.  The experience and know how the Navy has is invaluable.  Finally, we can begin watching for Earth grazers earnestly, and soon we will be able to do something about them.

I would like to thank all of the people who took the time to respond to my inquiries, and to list some of the sources for this document.

• Friends and fellow members of Adapting To Space, and Space Colonization & Commercial Development communities at MSN. Many of these ideas have been and are being discussed in these forums. Keep up the great work, guys.
• Doug Adams (Designing a Lunar Mining Colony)
• Maria Antonietta Barucci (University of Pisa)
• Edward Bowell (Lowell Observatory, USA)
• Clark Chapman (Planetary Science Institute, USA)
• Jim Benson, CEO of Space Dev,
• Louis Friedman (The Planetary Society, USA)
• Tom Gehrels (University of Arizona, USA) Editor, Hazards Due to Comets and Asteroids, University of Arizona Press, Tucson, Ariz., 1994.
• Gerhard Hahn at Institute of Space Sensor Technology and Planetary Exploration of the German Aerospace Center (DLR) in Berlin-Adlershof, Germany.
• Eleanor Helin (Caltech/NASA Jet Propulsion Laboratory, USA)
• Brian Marsden (Harvard/Smithsonian Center for Astrophysics, USA)
• David Morrison (NASA Ames Research Center, USA) The Safeguard Survey: Report of the NASA International Near-Earth-Object Detection Workshop, Jet Propulsion Laboratory, Pasadena, Calif., 1992.
• R. Rajamohan (Indian Institute of Astrophysics, India)
• Ken Russell (Anglo-Australian Observatory, Australia)
• Eugene Shoemaker (U.S. Geological Survey, USA): The flux of periodic comets near Earth: in Hazards Due to Comets and Asteroids ;Shoemaker, E. M., Weissman, P. R. and Shoemaker, C. S., 1994,
• Space Studies Board, National Research Council, An Integrated Strategy for the Planetary Sciences: 1995-2010, National Academy Press, Washington, D.C., 1994
• Solar System Exploration Division, Office of Space Science, Report of the Near-Earth Objects Survey Working Group, NASA, Washington, D.C., 1995
• Duncan Steel (Anglo-Australian Observatory, Australia)
• Faith Vilas (NASA Johnson Space Center, USA)
• Donald Yeomans (Caltech/NASA Jet Propulsion Laboratory, USA)
• Brigadier General S. Pete Worden (United States Air Force, for his article NEOS, Planetary Defense and Government: A view from the Pentagon; in Space Views.)
• Robert Zubrin and Richard Wagner, The Case for Mars, Touchstone Books, 1997
• Colorado School of Mines: the school also maintains an entire library on space mining and extraction techniques.

And the many others who took the time to talk with us.

This page was last updated on Friay, November 11, 2005 10:14:25 AM EDT