The innovative FRIPON network will engage professionals and the public in the hunt for space rocks.

FRIPON camera
One of the FRIPON all-sky cameras stands watch outside the Paris Observatory.

On February 15, 2013, the world awoke to dramatic news as an asteroid roughly 20 meters across exploded over Chelyabinsk, Russia. The asteroid approached Earth unannounced from a sunward direction, and weeks went by before researchers could analyze all the dash-cam footage, determine the rock's trajectory, and recover debris from the surviving meteorite.

Now, imagine a network of all-sky observing sentinels that speeds this whole process up to just days or even hours.

That's the goal of the Fireball Recovery and InterPlanetary Observation Network (FRIPON). A collaboration between the Observatory of Paris, the National Center of Scientific Research (CNRS), the University of Paris-South, the French National Museum of Natural History, and the Aix-Marseille University, this network of 100 cameras and 25 radio receivers provides continuous all-sky coverage over all of France. Catching a meteorite's fall from various angles from known coordinates enables researchers to quickly and accurately determine the location of a possible strewn field for an organized search campaign.

"If tomorrow a meteorite falls in France, we will be able to know where it comes from and roughly where it landed," says Jérémie Vaubaillon (Paris Observatory) in a recent article.

Sourcing Meteorites

Most meteors seen in the night sky are just grains of dust, remnants of various comets' passages, that burn up in our atmosphere without ever hitting the ground. French researchers estimate that 10 meteorites fall in France every year, but a meteor sighting followed by a subsequent meteorite recovery has been a once-a-decade affair. The rolling countryside of France isn't exactly prime real estate for meteorite hunting — ancient stones from space stand out better against the sands of the Sahara or the pristine ice shelf of Antarctica.

Now, FRIPON will give French meteorite hunters an edge, enabling them to recover meteorites before the space rocks are lost to erosion and earthly contamination.

With FRIPON researchers hope to accomplish a ground recovery within 24 hours of a bolide sighting. To accomplish this, the cameras are placed 50 to 100 kilometers apart, many of them at educational and research facilities throughout France.

FRIPON trajectory calculation
Calculating a meteorite's trajectory requires at least two images from two different stations. Additional stations can help get a clearer view during inclement weather. Even if the trajectory is initially well known, wind can strongly affect the location of the strewn field. Estimating the location becomes more complicated when the meteorite burns out, going dark before it falls.

You can see a searchable map of the FRIPON network, including two cameras based on Corsica, a French island in the Mediterranean sea, and one each in Vienna, Austria, and Bucharest, Romania.

Researchers hope to expand the FRIPON network into Germany, Switzerland, the Netherlands, and other European countries in the coming years. Other networks are already operating in Europe, including the United Kingdom Monitoring Network (UKMON) and the Spanish Meteor Network. NASA also has its own network in the United States named the All-Sky Fireball Network, with three clusters of cameras across the U.S.

In addition to aiding recovery, FRIPON will document the trajectory and direction of a meteorite's fall, allowing researchers to estimate its final orbit and, perhaps, its source.

Researchers with a FRIPON camera mounted atop the Natural History Museum in Vienna, Austria.

FRIPON is the first high-density, fully automated meteor observation system connected over a single network, says principle investigator François Colas (Paris Observatory). Other networks, such as one based in Australia, cover a larger area but with a more spread out cameras. Also, while most networks connect cameras that are privately owned and on separate networks, FRIPON's central computer can look at the same detection from several different cameras on the same network. That means it can quickly estimate a meteorite's strewn field down to a rectangular box that's about 1 kilometer by 10 kilometers.

It will be possible to get very fresh material with the least possible alteration due to our atmosphere,” says Colas. “The goal is to get the meteorite within 24 hours. This is also really new compared to other networks.”

Expanding the Hunt

Although only trained scientists will scout for meteorites initially, FRIPON hopes to invite the public to the hunt with the Vigie Ciel ("Sky Watch") project. This will allow educators and amateur meteor hunters to gain access to FRIPON data so citizen and professional teams can quickly scour the countryside.

French history is littered with tales of meteorites and meteorite falls. A stony meteorite fell near the town of Ensisheim in the Alsace region on November 7, 1492, and is now on display in the town's small museum. Another meteorite fall on April 26, 1803, showered 3,000 fragments over the small town of L'Aigle. That find ended the controversy as to whether meteorites were of volcanic or extraterrestrial origin, and it gave rise to the science of meteoritics.

Strangely, the number of meteorites recovered from France in the 20th century was about one per decade, a drop from one every two years in the 19th century. FRIPON may reverse this trend in the 21st century. So far FRIPON hasn't resulted in a ground recovery yet, but it has already resulted in a few preliminary orbital calculations, and the project is continuing to mature.

"In the end, we want to connect a meteorite with a parent body,” says Colas. “We are ready to search for meteorites!”




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June 24, 2016 at 4:29 pm

The drop in the number of French meteorites surprises me also. In the half century from 1801-1851 28 meteorites fell, but in the half-century from 1966-2016 only four! Difficult to explain.

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