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Raumfahrt - After fireballs streaked across sky, space-junk sleuths got busy — and hit the jackpot in Washington

25.04.2021

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Meteorite hunter Robert Ward with a pressure tank that contained super-cold helium, part of the debris from the reentry of the upper stage of a SpaceX Falcon 9 rocket that fell in March at the Yakima military training range east of the Columbia River. (Courtesy of Robert Ward)

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People across the Pacific Northwest were awed on the evening of March 25 by an otherworldly formation of fireballs that streaked across the heavens, causing a social media sensation. Astronomers promptly demystified it as debris from a falling SpaceX Falcon 9 rocket.

Though such wayward rockets generally burn up in the atmosphere, this time substantial chunks fell to earth in Eastern Washington. At least one came uncomfortably close to hitting people.

Yet neither SpaceX nor the various federal agencies with some role in tracking space junk — the Federal Aviation Administration, NASA, and the U.S. Space Force — investigated what happened on the ground.

That was left to a self-motivated trio of sleuths who brought to the task a combination of sophisticated scientific ingenuity, a passion for space and an Indiana Jones-style appetite for adventure.

Software coder and American Meteor Society operations manager Mike Hankey used an app he developed to collect eyewitness reports and triangulate their location data. National Oceanic and Atmospheric Administration meteorologist Ken Howard analyzed data from weather radars.

Together they pinned down the flight path of the fiery space junk and the expected location of some fallen pieces. Then meteorite hunter Robert Ward provided the boots on the ground to go find them.

He tracked down where three 200-pound cylindrical tanks fell to Earth near a bend in the Columbia River east of Yakima. One landed 50 feet from a trailer home, where the owner pulled a shotgun on the stranger searching for space junk.

Heavier rocket pieces, traveling with more momentum, likely hit the ground much farther east in the state, the trio believes.

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Leading the hunt

The falling debris that lit up the Pacific Northwest skies was from a rocket SpaceX launched March 4 to lift a batch of 60 Starlink satellites into orbit.

Those satellites, designed and built by SpaceX in Redmond, are part of CEO Elon Musk’s plan to deploy a total of 12,000 satellites that will provide broadband Internet access worldwide. SpaceX currently has about 1,320 of the satellites in orbit, all launched on its Falcon 9 rockets.

Soon after the 45-foot-long, 3-ton upper stage of the rocket delivered the 60 satellites into orbit, SpaceX was supposed to steer it to a controlled descent into the ocean. But something went wrong and instead it slowly spiraled down from orbit over three weeks, finally breaking up and burning as it reentered the atmosphere. 

As the debris traveled eastward over the state, eventually the fiery glow went out, ending what scientists who study meteors call the “luminous flight path” as remaining chunks traveled on in a “dark flight” phase.

Federal officials seem to have lost interest when it left orbit. An FAA spokesperson said the launch license it grants SpaceX ended when SpaceX lost control of the rocket.

“Its subsequent uncontrolled, random reentry is not an FAA-licensed activity,” the spokesperson said. “The agency is not investigating it.”

A NASA spokesperson said the federal space agency does not track debris from “non-NASA missions” and directed inquiries to the 18th Space Control Squadron of the U.S. Space Force.

But that unit tracks only objects in orbit, said Space Force spokesperson Meaghan Dorroh, and “if they fall to the ground … it’s no longer the responsibility of Space Control to track them.”

She said the Federal Emergency Management Agency would be responsible for the recovery of such objects.

But at FEMA, a spokesperson said it “has not received a request for assistance from the state,” adding, “FEMA does not recover debris.”

SpaceX did not respond to repeated requests for comment about the incident.

Weather radar and software

Unlike SpaceX or the federal government, Howard, Hankey and Ward sprang into action.

Howard, 63, works for NOAA’s Oklahoma-based National Severe Storms Laboratory. He analyzes the data from the nation’s network of 160 Doppler weather radar stations, the same data that produces the animated weather forecast maps on local TV.

These radar receivers also are used to predict turbulent storms that could affect airplanes and to assess the spread of forest fires, forming “the critical backbone to this country’s monitoring of weather and natural disasters,” Howard said.

“And it just so happens that they also pick up birds, bugs, bats and objects falling from the sky,” he added.

As part of his job at NOAA, Howard is studying how to discriminate on radar between storms and non-weather features like bird migrations or meteorites — or space junk.

“As space becomes more crowded, obviously the odds go up of having more things reentering the atmosphere,” he said. “My interest in all of this is, can these technologies that are used for weather help us with tracking space debris re-entering the atmosphere — and then potentially issuing warnings of debris falls.”

However, because vast quantities of real-time radar data are continuously logged, Howard can only process the data on a specific incident if he knows where and when it happened. For that, he needed Hankey’s expertise.

Hankey, 49, is a software entrepreneur working out of his home in Monkton, Maryland.

An English major in college, he learned to program at a young age and in the 1990s formed his own boutique software company. He sold it when the Internet boomed late in that decade, freeing him since then to spend time on pet projects.

About 10 years ago, Hankey said, “I stumbled into astronomy.” Now he spends much of his time “meteorite hunting and tracking fireballs.”

Working with the American Meteor Society, a nonprofit that promotes astronomical research, he developed a Web app that takes eyewitness reports of fireballs in the sky and cross-references them to pin down the trajectory of the object.

“We collect dozens, sometimes hundreds of reports from multiple people, and triangulate them and mathematically solve to get the location,” he said. “We automated all that.”

That’s what Hankey did after the March 25 light show over Seattle and Portland, using 68 distinct eyewitness reports. Then Howard used that trajectory to look at the weather radar data on that precise path at that precise time.

Sure enough, blips on the radar tracks indicated pieces of the space debris falling away from the rocket as it disintegrated, and arcing southward due to the wind. Those included what looked like four pieces with similar radar signatures falling near the Columbia River.

Searching desert and farmland

Briefed by Hankey, with whom he collaborates regularly, Ward booked a flight from his home in Prescott, Arizona, and arrived in Yakima three days after the skyfall.

Ward, 44, has no scientific credentials and says he’s “largely self-taught” about meteors and space debris through working with experts over the years.

His family has money from land investments, so Ward doesn’t need to make a living. He described himself as “a full-time planetary science field researcher” and said he has “found over 600 meteorites, on every continent except Antarctica.”

He said he honed his field search skills “growing up on ranches, rockhounding and hunting fossils,” and on annual visits to southern Africa where he hunted big game with his father.

At home in Arizona, Ward keeps a large private collection of meteorites in “one whole wing of the house, in a climate-controlled, high-security vault”; it’s open to visits from collectors, scientists and enthusiasts. On a slick personal website, he showcases parts of his collection and describes his global meteor-hunting expeditions.

He said he donates some of his finds to interested institutions, such as Chicago’s Field Museum and Arizona State University, and trades or buys from other collectors.

Following the trajectory map developed by Howard and Hankey, Ward drove from Yakima about 70 miles to an area just north of the Hanford Reach turn in the Columbia River.

The radar signatures suggested the objects that had fallen there were about the size of the cylindrical pressure tanks used in the Falcon 9 rocket propulsion system. These are filled with super-cold helium that is released to maintain pressure in the fuel tanks as their mix of oxygen and kerosene burns up.

The science got Ward to the general area, but he needed gossip to lead him further.

He asked around in one of the local hangouts — the Carquest auto parts store in Mattawa. Showing locals a photo of one such helium tank that fell in Brazil in 2014, he handed out his card to start building a network of potential informants.

Bingo. Minutes after he drove away, he got a text — with a photo — saying one had landed in a yard on the outskirts of the town of Beverly.

By the time Ward got there, the Grant County sheriff had already come and taken the tank away. The Sheriff’s Office did not respond to questions about what was done with it.

Ward did find a 5-foot-long dent in the earth, 4 inches deep, where the tank had hit. A pickup was parked just 15 feet away.

The woman who lived there seemed unconcerned that this 200-pound tank might have hit her trailer home and worried only that her underground septic tank might be damaged. But their conversation was cut short, he said, when “her husband came unglued.”

“I guess her husband was upset that people were on the property,” Ward said. “He came out on the porch with a shotgun and told me to go back to my truck, and then in some very colorful language, to get in it and leave.” Ward quickly complied.

The couple could not be reached. The Grant County Sheriff’s Office in a tweet informed the media that “the property owner simply wants to be left alone.”

In the following days Ward drove more than 100 miles northeast, and talked to people who had watched the fireball trail. Their accounts suggested to Ward that some heavier pieces might have fallen somewhere between the towns of Odessa and Reardan, in Lincoln County.

Denser parts such as engine cores may even have reached the mountains on the border between Montana and Canada.

Ward left his contact information with dozens of farmers and asked them to get in touch if they found anything.

Then he doubled back to the Beverly area. He knew the Falcon 9 carried four of those helium pressure tanks — all the same size, shape and weight so they were likely to have fallen not too far apart.

Within a day, driving around in remote locations, with binoculars “and a really good eye,” he found two more. One had fallen in sage brush where the desert met some irrigated fields. Another was across the river inside the Army’s Yakima training range, where he got permission to roam in an area open to the public.

The tanks come wrapped in carbon fiber composite that partly shredded during the violent reentry. “It’s a very nasty material,” said Ward. “It’s basically like fiberglass times 20. It gets in your fingers and it’s like ants biting you.”

Wearing protective gloves and mask, he manhandled both tanks onto his rented pickup.

Later, Ward changed the drop-off location for his rental truck and drove the tanks all the way back to Prescott, where he cleaned them and wrapped them in tarps for storage.

He’s unsure what he’ll do with them. Hankey sent a Facebook message to an acquaintance at SpaceX, but so far without response.

Hankey and Ward both say they are “pretty sure” the fourth tank is also on the military training range, but in an area closed to the public, “where they blow things up.”

And they have a report of a piece of twisted metal, likely a part of the rocket’s fuselage, that was found much farther south than the tanks.

Monitoring the danger

NOAA’s Howard said the March 25 rocket reentry “should not be considered an isolated incident but rather a trend, given the vast amount of space craft and debris entering and exiting” orbit around the planet.

The U.S. estimates that nearly 1,800 rocket bodies are currently orbiting Earth among tens of thousands of smaller objects.

Howard believes the world needs to add more camera, radar and telescope monitoring for space junk or meteorites that may land in populated areas.

“We were lucky that none of those tanks Robert found landed on a structure or freeway or was encountered by a commercial aircraft,” he said. “I’m all for commercial use of space because it furthers the scientific mission of what I do, but it has to be managed for the public’s safety.”

Hankey is doing his part: Working with the American Meteor Society, he’s developed the hardware and software for a computer-linked network of high-resolution cameras to track meteors and anything else falling from the sky.

So far, he has Maryland covered and a few cameras scattered elsewhere. Nothing in the Pacific Northwest.

The FAA spokesperson said that agency is in the early stages of initiating rules “to address space debris and reentry risks.”

Yet on this occasion, there was zero official reaction.

The pass-the-buck response from government agencies and silence from SpaceX brings to mind the Tom Lehrer song about Wernher von Braun — the former Nazi rocketeer who after the Second World War led development of the U.S. missile and space rocket programs.

As the chorus goes, “‘Once the rockets go up who cares where they come down, that’s not my department,’ says Wernher von Braun.”

Hankey, Howard and Ward care.

This week, Ward is back in Eastern Washington to resume his hunt and encourage farmers there to pay close attention when they next plow their fields.

Quelle: The Seattle Times

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