[meteorite-list] Military intelligence-- still an oxymoron.

[Darren Garrison]

http://www.space.com/news/090610-military-fireballs.html

Military Hush-Up: Incoming Space Rocks Now Classified
By Leonard David
SPACE.com's Space Insider Columnist
posted: 10 June 2009
05:35 pm ET

For 15 years, scientists have benefited from data gleaned by U.S. classified
satellites of natural fireball events in Earth's atmosphere – but no longer.

A recent U.S. military policy decision now explicitly states that observations
by hush-hush government spacecraft of incoming bolides and fireballs are
classified secret and are not to be released, SPACE.com has learned.

The satellites' main objectives include detecting nuclear bomb tests, and their
characterizations of asteroids and lesser meteoroids as they crash through the
atmosphere has been a byproduct data bonanza for scientists.

The upshot: Space rocks that explode in the atmosphere are now classified.

"It's baffling to us why this would suddenly change," said one scientist
familiar with the work. "It's unfortunate because there was this great
synergy...a very good cooperative arrangement. Systems were put into dual-use
mode where a lot of science was getting done that couldn't be done any other
way. It's a regrettable change in policy."

Scientists say not only will research into the threat from space be hampered,
but public understanding of sometimes dramatic sky explosions will be
diminished, perhaps leading to hype and fear of the unknown.

Incoming!

Most "shooting stars" are caused by natural space debris no larger than peas.
But routinely, rocks as big as basketballs and even small cars crash into the
atmosphere. Most vaporize or explode on the way in, but some reach the surface
or explode above the surface. Understandably, scientists want to know about
these events so they can better predict the risk here on Earth.

Yet because the world is two-thirds ocean, most incoming objects aren't visible
to observers on the ground. Many other incoming space rocks go unnoticed because
daylight drowns them out.

Over the last decade or so, hundreds of these events have been spotted by the
classified satellites. Priceless observational information derived from the
spacecraft were made quickly available, giving researchers such insights as
time, a location, height above the surface, as well as light-curves to help pin
down the amount of energy churned out from the fireballs.

And in the shaky world we now live, it's nice to know that a sky-high detonation
is natural versus a nuclear weapon blast.

Where the space-based surveillance truly shines is over remote stretches of
ocean – far away from the prospect of ground-based data collection.

But all that ended within the last few months, leaving scientists blind-sided
and miffed by the shift in policy. The hope is that the policy decision will be
revisited and overturned.

Critical importance

"The fireball data from military or surveillance assets have been of critical
importance for assessing the impact hazard," said David Morrison, a Near Earth
Object (NEO) scientist at NASA's Ames Research Center. He noted that his views
are his own, not as a NASA spokesperson.

The size of the average largest atmospheric impact from small asteroids is a key
piece of experimental data to anchor the low-energy end of the power-law
distribution of impactors, from asteroids greater than 6 miles (10 kilometers)
in diameter down to the meter scale, Morrison told SPACE.com.

"These fireball data together with astronomical observations of larger
near-Earth asteroids define the nature of the impact hazard and allow rational
planning to deal with this issue," Morrison said.

Morrison said that fireball data are today playing additional important roles.

As example, the fireball data together with infrasound allowed scientists to
verify the approximate size and energy of the unique Carancas impact in the
Altiplano -- on the Peru-Bolivia border -- on Sept. 15, 2007.

Fireball information also played an important part in the story of the small
asteroid 2008 TC3, Morrison said. That was the first-ever case of the
astronomical detection of a small asteroid before it hit last year. The fireball
data were key for locating the impact point and the subsequent recovery of
fragments from this impact.

Link in public understanding

Astronomers are closing in on a years-long effort to find most of the
potentially devastating large asteroids in our neck of the cosmic woods, those
that could cause widespread regional or global devastation. Now they plan to
look for the smaller stuff.

So it is ironic that the availability of these fireball data should be curtailed
just at the time the NEO program is moving toward surveying the small impactors
that are most likely to be picked up in the fireball monitoring program,
Morrision said.

"These data have been available to the scientific community for the past
decade," he said. "It is unfortunate this information is shut off just when it
is becoming more valuable to the community interested in characterizing near
Earth asteroids and protecting our planet from asteroid impacts."

The newly issued policy edict by the U.S. military of reporting fireball
observations from satellites also caught the attention of Clark Chapman, a
planetary scientist and asteroid impact expert at Southwest Research Institute
in Boulder, Colorado.

"I think that this information is very important to make public," Chapman told
SPACE.com.

"More important than the scientific value, I think, is that these rare, bright
fireballs provide a link in public understanding to the asteroid impact hazard
posed by still larger and less frequent asteroids," Chapman explained. 

Those objects are witnessed by unsuspecting people in far-flung places, Chapman
said, often generating incorrect and exaggerated reports.

"The grounding achieved by associating these reports by untrained observers with
the satellite measurements is very useful for calibrating the observer reports
and closing the loop with folks who think they have seen something mysterious
and extraordinary," Chapman said.