Dangerous Near Earth Asteroids: Is Nuking them the Best Protection?

Recent Russian space rock explosion and same day close flyby of an asteroid is stirring up talk about dealing with the near-Earth object threat.

CREDIT: Texas A&M

If a dangerous asteroid appears to be on a collision course for Earth, one option is to send a spacecraft to destroy it with a nuclear warhead.

Such a mission, which would cost about $1 billion, could be developed from work NASA is already funding, a prominent asteroid defense expert says.

Bong Wie, director of the Asteroid Deflection Research Center at Iowa State University, described the system his team is developing to attendees at the International Space Development Conference in La Jolla, Calif., on May 23.

The annual National Space Society gathering attracted hundreds from the space industry around the world.

An anti-asteroid spacecraft would deliver a nuclear warhead to destroy an incoming threat before it could reach Earth, Wie said.

The two-section spacecraft would consist of a kinetic energy impactor that would separate before arrival and blast a crater in the asteroid.

The other half of the spacecraft would carry the nuclear weapon, which would then explode inside the crater after the vehicle impacted.

The goal would be to fragment the asteroid into many pieces, which would then disperse along separate trajectories.

Bong Wie

Bong Wie believes that up to 99 percent or more of the asteroid pieces could end up missing the Earth, greatly limiting the impact on the planet.

Of those that do reach our world, many would burn up in the atmosphere and pose no threat.

Wie's study has focused on providing the capability to respond to a threatening asteroid on short notices of a year or so.

The plan would be to have two spacecraft on standby — one primary, the other backup — that could be launched on Delta 4 rockets.

If the first spacecraft failed on launch or didn't fragment the asteroid, the second would be sent aloft to finish the job.

Wie admitted that sending nuclear weapons into space would be politically controversial.

However, he said there are a number of safety features that could be built into the spacecraft to prevent the nuclear warhead from detonating in the event of a launch failure.

A nuclear weapon is the only thing that would work against an asteroid on short notice, Wie added.

Other systems designed to divert an asteroid such as tugboats, gravity tractors, solar sails and mass drivers would require 10 or 20 years of advance notice.

Field tests in Mojave Desert pave way for human exploration of Asteroids and Small Moons

Top Image: 538 meter-long Near Earth Asteroid (25143) Itokawa imaged by Japan’s Hayabusa spacecraft. 

The asteroid is likely a loosely consolidated rubble pile 

Credit: JAXA

Bottom Image: Similar scaled Asteroid Hill at the National Training Center, Fort Irwin, California, the site of the April 2013 NASA Mojave Field Test. 

Note the graduation of large blocks of rock, down to a small gravel surface. The rocks and debris here is primarily made of granite tors and debris. 

Credit: NASA

A team of researchers from the SETI Institute, the Mars Institute, NASA Ames Research Center, and the space robotics company Honeybee Robotics, has successfully completed a first series of field tests aimed at investigating how humans will explore and work on Near-Earth Asteroids (NEAs) and eventually the two moons of Mars, Phobos and Deimos.

From 13 to 15 April 2013, field experiments were conducted at the U.S. Army's National Training Center (NTC) at Fort Irwin, California, to evaluate geotechnical methods and systems that will enable humans to be productive explorers in the low gravity environment of small rocky bodies.

Sub-kilometer sized NEAs, Phobos, and Deimos are among destinations currently considered by NASA for future human missions into Deep Space.

Pascal Lee

"Human missions to Near-Earth Asteroids and to the moons of Mars present us with the exciting challenge of exploring planetary bodies with extremely low gravity" says Pascal Lee, planetary scientist at the SETI Institute and leader of the field test.

"The goal of our field test was to learn how to characterize the physical properties of small body surfaces, and to test ideas that might enable humans to more productively explore these low-gravity worlds."

Pascal Lee (SETI Institute and Mars Institute) (left) measures the bearing capacity of gravelly soil at Asteroid Hill, National Training Center, Fort Irwin, California, using a static cone penetrometer, while Kris Zacny (Honeybee Robotics) drives an anchor into the same material to evaluate the system’s design and performance.

These field tests will help design surface exploration systems optimized for the exploration of Near-Earth Asteroids, Phobos, and Deimos. 

Credit: First Canyon Media

Kris Zacny

The Mojave field test included three investigations:

1. a study of whether conventional field tools commonly used to characterize the mechanical properties of soils on Earth are suitable for small bodies; 
2. an evaluation of how different anchoring systems might allow robotic spacecraft and astronauts to remain bound to a low gravity body; 
3. a study of how astronauts might conduct geological sampling on a small body while using anchors and tethers.

"It's important to analyze and understand how conventional civil engineering methods and systems perform in natural settings on Earth before adapting them to the exploration of small bodies" explains Kris Zacny, Director of planetary exploration robotics at Honeybee Robotics in Pasadena, California.

Honeybee Robotics is the company that developed the Rock Abrasion Tool (RAT) on NASA's Mars Exploration Rovers, Spirit and Opportunity, and the Sample Manipulation System (SMS) and Dust Removal Tool (DRT) on NASA's Mars Science Laboratory (MSL) rover, Curiosity.

Pascal Lee (SETI Institute and Mars Institute) (right) and Sgt Andre Pearson (U.S. Army, NTC) conduct “small body” geological sampling in simulated spacesuits while anchored and tethered on a steep boulder slope at Asteroid Hill, National Training Center, Fort Irwin, California. 

Credit: NASA

The Mojave field test was carried out on a small rocky hill at the NTC with many exposed blocks of weathered granite called tors. The site, now named "Asteroid Hill", is reminiscent of the blocky rock surface of Near-Earth Asteroid (25143) Itokawa, which was explored in 2005 by Japan's Hayabusa robotic spacecraft.

"While neither the composition of the rocks nor the gravity at Asteroid Hill are similar to what they are on NEAs, the relevance of the site resides in the similarity in terrain texture (gravel and block abundance and sizes), topography, and scale between Asteroid Hill and Itokawa" notes Lee.

Terry Fong

"This is an interesting analogue site for planning future NASA robotic and human asteroid exploration, as it not only resembles the surface of the only sub-kilometer NEA explored by spacecraft to date, Itokawa, but it is well supported logistically by the U.S. Army's National Training Center" said Terry Fong, Director of the Intelligent Robotics Group at NASA Ames Research Center.

Russia And Europe: Join Forces To Protect Earth From Asteroids

Russia And Europe May Join Forces To Protect Earth From Asteroids

Russian space officials and members of the European Commission will meet in early July to discuss joining forces against thousands of potentially hazardous asteroids, the head of the Russian Federal Space Agency Roscosmos said.

Despite the growing concern about the asteroid threat, no anti-asteroid defense programs have been developed in practice so far, with only several theoretical concepts being studied. At a meeting in Moscow on July 7, the European Commission will consider Roscosmos's proposal to start a joint anti-asteroid project with the European Union.

"I received a letter, in which the European Commission proposes to meet on July 7 in Roscosmos with scientists and engineers of the Federal Space Agency, the Russian Academy of Sciences and other institutions and organizations. At the meeting, the Russian bid to start a joint project with the EU will be considered," Anatoly Perminov said.

In his Wednesday's report to Roscosmos, the head of the Astronomy Institute at the Russian Academy of Sciences, Boris Shustov, said Russian scientists had detected a total of 6,960 near-Earth asteroids (NEAs) as of April 10.

The vast majority - 6,070 space bodies, or 87.2% of the total - are asteroids measuring from 100 meters to 1,000 meters in diameter. Others are 48 comets (1.2%) and 806 asteroids measuring more than a thousand of meters in diameter (11.6 %).