As if we haven’t had enough doomsday fatigue from Mayan calendar, Nostradamus, and biblical scripture soothsayers, the Russian news agency, Ria Novosti, reported last week: “Russian Astronomers Predict Apophis-Earth Collision in 2036.”
Popularized by Apollo 9 astronaut Rusty Schweickart, the 1,300-foot long near-Earth asteroid Apophis has been widely reported as a “doomsday asteroid.” It has projected razor-thin near-misses with our frail blue planet in 2029, 2036, 2056, 2068, and beyond.
But a reading past the sensationalistic headlines of the Russian article explains that the astronomer, Professor Leonid Sokolov of the St. Petersburg State University, isn’t really telling us something that NASA folks don’t already know.
Both Sokolov and our planetary scientists agree that on Friday, April 13 of 2029 the asteroid is predicted to brush by Earth at 18,000 miles altitude, below the height of Earth’s geosynchronous satellites.
Per the article: “Sokolov went on to say the chance of a collision on Easter Sunday in 2036 was extremely slim, predicting that the asteroid would likely disintegrate into smaller parts and smaller collisions with Earth could occur in the following years.”
The bottom line is that asteroids are featherweight objects compared to other solar systems bodies. Gravitational forces and even the pressure of sunlight can shove them around. There are so many dynamical uncertainties affecting asteroid trajectories that Apophis will haunt us right up to 2036, and well beyond.
In his State of The Union message before Congress last week, President Obama announced that this generation’s “Sputnik Moment” has arrived. He was referring to the United States’ need to invest in research and development to revive the economy and ensure future stability.
But the real Sputnik Moment — when the Soviet Union established technological preeminence by hurtling a the world’s first artificial satellite into Earth orbit — was an evolutionary game-changer. It ushered in an age when we would begin the conquest of space as the first “extra-terrestrial” generation.
So here’s my Sputnik Moment: Launch an international space program to ensure the long term survival of the human species by building and testing a robust asteroid deflection capability.
The first target of choice is that pesky Apophis, which now hangs like a sword of Damocles — though it is not massive enough to be in the dinosaur-killer category.
Here are some of the Earth protection strategies that are on the table:
Hot Spot: Use a space mirror or laser to heat the surface and boil off material that acts as a small jet and reroutes the asteroid.
Gravity Tractor: Fly in formation with the asteroid for a long period and the gravitational attraction between the two bodies induces a small force that deflects the asteroid.
Asteroid Tug: Rendezvous with the object, make physical contact, and give it a nudge.
Photon Pressure: Make one side of the asteroid jet black or snow white (perhaps using reflectors) the extra absorption or reflection of sunlight will impart a net change of photon pressure on the object, altering its trajectory.
Physicist Daniele Farigon of the University of Rome has a bold proposal straight out of an Arthur C. Clarke science fiction novel. She suggests landing multiple nuclear powered “mass-driver” rocket motors onto an asteroid’s surface. Like a drywall toggle screw, these devices would burrow into the asteroid’s surface until they are rigidly anchored. They would then in unison eject mass, like a rocket exhaust, and thereby alter the object’s trajectory.
The beauty of the concept is that by using a cluster of half-ton rocket motors would have redundancy and stability should one or more rockets fail to work, or properly anchor into the asteroid.
Once implanted into the surface, each so-called “screw-engine” would have one or more drills that would dig out dust from the asteroid’s interior. This would provide the fuel for a nuclear-electric powered mass driver that would use a powerful electromagnetic rail to catapult buckets-full of dust off the asteroid’s surface. This would act the same as a rocket’s hot exhaust, except that the mass is not heated to a plasma but remains in solid form. Newton would have never imagined that his laws of motion would be used for such an exotic task.
The thrust from a cluster of the screw-engines strategically placed on an asteroid like Apophis could be timed and vectored for precision control over the asteroid’s trajectory.
Landing and positioning of the engines in Apophis’ micro-gravity field would be tricky. The engines would essentially have to spiral down to the surface and gently dock with the crust. A thruster would have to keep pushing down on an engine until it mechanically anchored itself into the surface.
The installation would be largely autonomous. But I can’t image doing this without an astronaut command center flying formation with Apophis. Astronaut servicing for malfunctioning engines or any number of technical glitches may be a necessity until the entire array is configured. I can easily visualize a cigar chomping Bruce Willis character tending to the screw-engine drilling fields.
Such a complex endeavor would be the “Apollo-on-steroids” mission that former NASA Administration Michael Griffin once talked about. The public would be enraptured with HD video images of the mining operation from millions of miles away. And the consequences would affect all of humanity, not just the curiosity of the scientific world.
We don’t have the power to deflect hurricanes or shut off volcanoes. But we do have the technological smarts to prevent a “Space Katrina” — the impact of Apophis that would unleash twice the energy of the 1883 eruption of the monster volcano Krakatoa. But do we have the political will and resources to undertake such a grand space project for all mankind?
Image credits: NASA, D. Farigon, Lockheed-Martin