NASA’s Near-Earth Object Observations Program is keeping a close eye on 2011 AG5, an Earth-crossing asteroid that could hit the Earth on February 5, 2040.

2011 AG5 is 140 meters in diameter. In the unlikely event of an impact, it would strike with the force of a 100-megaton bomb. NASA is sufficiently concerned that it held a Potentially Hazardous Asteroid Workshop at NASA Goddard Space Flight Center last month.

The probability of 2011 AG5 hitting Earth is currently estimated at 0.2%, but the estimate is still being refined. The probability will change when the asteroid passes through a gravitational keyhole on a pass by Earth in February 2023.

If 2011 AG5 is on a course toward Earth, further data could raise our certainty to 70%. Such data could be used to plan an intercept mission, which could occur either before or after the 2023 keyhole event.

Unfortunately, it’s currently impossible to observe 2011 AG5 because its relative position is too close to the Sun. It will not be possible for astronomers to observe 2011 AG5 again until fall of 2013.

Observing objects that appear close to the Sun will be one of the key missions for suborbital telescopes, such as the Atsa Suborbital Observatory which is slated to fly on the XCOR Lynx Mark III. The Atsa Observatory won’t be flying in time to help with the 2011 AG5 problem, but it will be valuable for studying similar asteroids in the future.

XCOR Lynx with Atsa Suborbital Observatory space telescope

A robust plan for dealing with potentially hazardous asteroids will require a range of in-space capabilities, from suborbital observatories to deep-space intercept and deflection techniques.

Suborbital spacecraft are being developed in the private sector and do not require government investment – but what about the intercept and deflection problem?

Apollo 9 astronaut Rusty Schweickart, who created the B612 Foundation to develop asteroid-deflection techniques, does not think NASA is doing enough. Schweickart discusses 2011 AG5 and possible deflection techniques in the following video.


Written by Astro1 on June 18th, 2012 , Astronomy, Planetary Defense, XCOR Aerospace

Brilliant Pebbles was a system of ballistic-missile interceptors proposed by Lawrence Livermore National Laboratory as part of the Strategic Defense Initiative in the 1980’s. Brilliant Pebbles was a kinetic-energy interceptor. The name derives from the descriptive term of “smart rocks,” which was previously used to describe guided kinetic-energy weapons. Brilliant Pebbles took advantage of miniaturized electronics to make the interceptors much smarter, smaller, and cheaper to build – hence  “pebbles” rather than “rocks.”

Now, two researchers from the University of Strathclyde in Glasgow, Scotland have suggested that smart pebbles might find a use against a different target, according to the New Scientist. At the Astrobiology Science Conference, held recently in Atlanta, Dr. Alison Gibbings and Dr. Massimiliano Vasile stated that a swarm of smart pebbles could be used to deflect an Earth-approaching asteroid.

According to Gibbings and Vasile, a 500-kilogram swarm of pebbles, each the size of a fingernail, could deflect the course of a 250-metre asteroid by almost 35,000 kilometers. The calculation assumes some advanced warning. The swarm would to hit the asteroid about eight years before the expected impact.

Dr. Vasile is also investigating the use of brilliant pebbles to remove space debris in Earth orbit.

Written by Astro1 on May 6th, 2012 , Innovation, Planetary Defense

NASA’s Radiation Belt Storm Probes arrived at Kennedy Space Center on May 1. The two probes, built at Johns Hopkins University Applied Physics Laboratory in Laurel MD and managed by Goddard Space Flight Center under the Living With a Star program, are scheduled for a predawn launch on August 23 aboard a United Launch Alliance Atlas V 401 rocket.

The two probes will be enter into nearly identical, eccentric orbits that cover the entire radiation belt region, lapping each other several times over the course of the two-year mission. Observations from the two probes will enable the development of empirical and physics-based models for the radiation belts. The empirical models will be used by engineers to design radiation-hardened electronics, while the physics-based models will be used by forecasters to predict space weather and alert astronauts and spacecraft operators to potential hazards.



Written by Astro1 on May 1st, 2012 , Planetary Defense, Space Medicine and Safety

Due to their possible effects on Earth’s climate, supernovae have been viewed as potential killers and linked to past extinction events.

That may not be the whole story, however. A new study by Professor Henrik Svensmark of the Technical University of Denmark (DTU) suggests that supernovae are, on balance, good for life on Earth.

Examining the geological and astronomical record for the past 500 million years, Prof. Svensmark found that the diversity of the Earth’s ecosystem tended to be greater in eras when nearby supernovae were plentiful. Prof. Svensmark hypothesizes that this is because the colder climate caused by cosmic rays results in a greater variety of habitats between polar and equatorial regions and creates stress that prevents ecosystems from becoming locked into fixed patterns.

The picture is mixed, however. While supernovae have generally had positive effects on Earth’s biosystem, Svensmark says they have also caused prolonged glacial periods and sudden falls in sea level by 25 meters or more.


Written by Astro1 on April 30th, 2012 , Planetary Defense, Space Medicine and Safety

As the emerging commercial space industry enables more people to travel into space, and we become more dependent on satellite systems for military and commercial purposes, accurate and timely space weather forecasts are a matter of growing importance.

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Written by Astro1 on April 26th, 2012 , Nanosatellites, Planetary Defense, Space Medicine and Safety

A new study suggests that giant stars may not be necessary for supernovae.

This is a bit discomforting. Nearby supernovae are suspects in a number of past extinction events. Scientists think that a gamma-ray burst from a supernova may have been responsible for the Ordovician extinction which killed off 60% of all marine species 450 million years ago. A supernova has also been suspected in the extinction of the mammoth just 13,000 years ago.

The gamma-ray burst from a supernova is not likely to kill off organisms from direct biological effects unless the supernova is very close by (unrealistically close). A gamma burst could damage the ozone layer, however, causing species extinctions due to increases in ultraviolet radiation. It could also trigger changes in the Earth’s climate that lead to a new ice age.

Until now, scientists thought they knew which stars were candidates for supernovae. If that is changing, we may need to take another look at the stars in our own neighborhood. The risks may be greater than we think.

Still, we’re probably at far greater risk, individually and collectively, from the star which is closest to us and sustains our lives: the sun. A solar superstorm could damage or destroy power grids, pipelines, and communication satellites, plunging us back into the dark ages. Even a much smaller storm could endanger the lives of space travelers, including spaceflight participants on the suborbital vehicles many of us hope to be flying in a few years. Fortunately, there steps that can be taken to understand and prepare for bad space weather. Citizen scientists can help improve space-weather forecasting by participating in the Royal Greenwich Observatory’s Solar Storm Watch.

Written by Astro1 on March 21st, 2012 , Planetary Defense

Los Alamos National Laboratory has used a massively parallel supercomputer to simulate the effects of a nuclear weapon on an Earth-crossing asteroid.


Written by Astro1 on March 12th, 2012 , Planetary Defense Tags:

Solar Storm Threat Analysis is an interesting paper on the damage potential of solar storms.

Written by Astro1 on March 9th, 2012 , Books and Resources, Planetary Defense, Space Medicine and Safety

NASA’s Advanced Composition Explorer, which is critical to space-weather forecasting, is nearing its end of life. Satellite operators fear the end could come at any time, according to Irene Klotz of Discovery News.

ACE provides advanced warning of high-energy particles from solar storms and changes in the solar wind. This information is critical for space-weather predictions that help ensure the safety of ISS astronauts, high-latitude airline flights, and future suborbital space travelers as well as unmanned satellites and the terrestrial power grid. Pipelines are also vulnerable, especially those at high latitudes like the Alaska Pipeline.

There is currently no backup for the satellite. The National Oceanic and Atmospheric Administration and the US Air Force are hoping to launch a replacement, the Deep Space Climate Observatory (DSCOVR), before ACE fails. At the moment, however, the launch its not yet scheduled and the DSCOVR satellite is in storage at NASA’s Goddard Spaceflight Center.

This report is especially timely. The news came just as Earth was being hit by the biggest solar storm in years.

X-Class Solar Foare

Written by Astro1 on March 9th, 2012 , Planetary Defense, Space Medicine and Safety

When scientists someone mentions “planetary defense,” most people think about asteroid impacts. Asteroids are not the only space hazard that poses a risk to life and civilization here on Earth, however.

Space weather, caused by the unstable behavior of the sun, affects life on Earth in many ways. It creates the colorful auroras that are enjoyed in higher latitudes, but it can also interfere with communications. Space weather can create increased radiation risks for space travelers and even air travelers. Most people don’t realize that airlines routinely monitor space weather forecasts and sometimes need to reroute flights that normally go over the polar regions, due to increased solar activity.

Large solar storms could have much more serious effects. They could damage or destroy communications, weather, and GPS navigation satellites, as well as the terrestrial power grid. In 1989, a solar storm took down the Quebec power grid leaving 6 million customers temporarily without power. A larger storm could create more widespread, catastrophic damage which could take years to repair. A single storm could damage or destroy electrical power plants throughout an entire hemisphere. The economic impact of such an event is estimated at one trillion dollars per year. Fortunately, we have not seen a really large storm since 1859.

IEEE Spectrum looks at the potential effects of a solar superstorm and some measures that might be taken to protect the planet. There are some relatively simple modifications that can be made to protect power plants, but we also need better space weather forecasting and monitoring.

Written by Astro1 on March 4th, 2012 , Planetary Defense, Space Medicine and Safety

Dr. Clark Chapman of the Southwest Research Institute Department of Space Science puts the risk of asteroid impacts in perspective:

The average American’s chances of dying as a result of an asteroid impact is about the same as an average American’s chances of dying in a tornado….  the chances of death and destruction by cosmic impact are on the same order for Americans as death by airliner crash, flood, tornado, and other hazards society takes seriously, it is reasonable that the impact hazard be taken seriously. In fact, an asteroid impact is a much more serious hazard, statistically speaking, than many other hazards we have experienced in the last few decades, including death by terrorism, by nuclear power plant accident, by shark attacks, etc. And cosmic impacts – if large enough – are nearly unique (along with nuclear war and perhaps some “Andromeda Strain” pandemic) of having the possibility of sending civilization back into a Dark Age or even exterminating our species…

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Written by Astro1 on February 20th, 2012 , Planetary Defense Tags: