Guest contribution by Eric Worrall
NASA scientists conducting experiments on real asteroid fragments have come to conclusions about the limits of incoming asteroid deflection and the need to plan for multiple “bumps” if the asteroid is made of an inferior material.
Deflecting an asteroid before it hits Earth can take multiple shocks
After years of shooting down meteorites with a special NASA cannon, researchers have identified challenges for a preferred method of planetary defense.
By Katherine Kornei
August 25, 2021
There’s probably a large space rock out there somewhere that has the earth in its crosshairs. Scientists have actually discovered a candidate – Bennu, who has a slim chance of meeting our planet in 2182. But whether it’s Bennu or some other asteroid, the question will be how to avoid a very unwelcome cosmic rendezvous.
A team of researchers has been preparing for such a scenario for almost 20 years. Using a specially designed weapon, they repeatedly fired projectiles at meteorites and measured how the space rocks rebound and, in some cases, splinter. These observations shed light on how an asteroid might react to a high-speed impact designed to deflect it away from Earth.
Researchers presented the results of this high-profile marksmanship at the Meteoritical Society’s 84th Annual Meeting this month in Chicago. Their results suggest that it could depend on what type of space rock we are facing and how often we encounter it, whether we can knock an asteroid off our planet.
Read more: https://www.nytimes.com/2021/08/25/science/asteroid-deflection-collision.html
The research paper is below (original source here).
It’s nice to see NASA scientists getting their hands dirty and doing physics experiments instead of just rotating a series of models.
While the risk of a Earth impactor causing more than local damage is extremely small, a large impact could have serious consequences, causing widespread disruption of the food chain or worse.
Personally, I would like the Project Orion research program to resume.
The Orion project was one of the most powerful space engines ever conceived, a method of propelling a spaceship with nuclear explosions. The most powerful version could have been used to send a 100-year-old manned mission to Proxima Centauri at about 3% the speed of light – a slow journey, but not unthinkable.
For a while, Orion was a serious contender for the Apollo missions until politicians refused and chemically powered Saturn rockets were selected. An Orion-powered Apollo mission would have included a tour of the inner solar system with landings on the Moon and Mars and a visit to Venus.
So a lot of energy to carry space cannons or whatever into every corner of the solar system, all buildable with the technology of the 1950s.
Freeman Dyson, one of the directors of the Orion Project, was confident it was worth a try, based on actual physical testing with atomic explosions, but he had ongoing concerns about accelerated erosion of the center of the pressure plate due to turbulence in the atomic bomb explosion – a Issue that would have required a full physical test of a minimal size Orion spaceship to settle down.
Obviously, no one wants a return to regular atomic tests in the atmosphere. But after all of the testing in the 1950s, we could certainly endure some atmospheric detonations in some remote part of the Pacific Ocean just to see if this potential planet savior works before we have to try hard to actually build it. A single Orion launch would release far less radiation into the Pacific Ocean than the Fukushima meltdown, and such a launch would be invaluable in terms of developing planetary asteroid defense capabilities.
Video – Meteorite impact in Lapland.