Scott Craven

The Arizona Republic

CASA GRANDE, Ariz. — Roughly south of here, in a vast expanse of desert dotted with scrub brush and devoid of footprints, riddles exist in plain sight.

Wander into just the right place, a pixel on a limitless plain, and it stands out like a beacon of improbability, a sliver of exactness in a random landscape.

Four tapered concrete slabs, roughly 30 feet long and 6 feet across at their widest point, radiate in each compass direction from a central point. It looks like an X that would mark the spot on a life-size treasure map.

But this cross, one of more than 100 that remain despite nature’s relentless effort to erase them, are part of a story of guile, intrigue and secrecy.

Corona spy satellite timeline

They date back to a time when the government could disguise a program requiring rockets as well as 16 square miles of desert. And without meddlesome blogs written by conspiracy theorists, that program remained a secret for more than 30 years.

Today, those crosses surrender their stories to the few willing to look for look for them.

Mystery in the desert

On a clear day in April 2004, Leslie Owen was more than 2,000 feet above the ground, practicing her navigation skills aboard a Cessna.

Checking her charts, she ticked off various landmarks, from peaks to canals or aqueducts. If you could see a prominent point from the air, it was on the chart, providing a way to pinpoint the location long before GPS simplified everything.

Something near the horizon caught Owen's eye. As she approached, the shape made less and less sense.

It was a cross, like a target. She looked through her charts, wondering how she could have missed it.

But she hadn’t.

“It was really strange,” Owen said. “If you can see it from the air, it goes on the charts. These weren't on any chart.”

Owen flew on, noting a few more crosses.

She returned to Ryan Field in Tucson with one thought: She had to call the one friend whose sense of adventure equaled hers. A few weeks later, Chuck Penson of Tucson was in the passenger seat, hoping to spot the unusual markings.

He needed little time to confirm Owen's sightings.

They were not so much a crosses as flowers, with four petals sprouting from a central disc. As Owen flew on, Penson saw several blossoming below.

How the Casa Grande crosses calibrated spy-satellite cameras

“I was intrigued by seeing crosses in a godforsaken part of the desert,” he said. “There had to be a reason.”

It occurred to Penson, a docent at the Titan Missile Museum in Sahuarita, Ariz., that the crosses were meant to be seen from the air. But a more thorough examination was needed.

A week later he and Owen, who then was working with the Flandrau Science Center and Planetarium at the University of Arizona in Tucson, returned to the area for ground-based reconnaissance, following the dirt roads they had noted from above.

They soon found what they were looking for: Maltese crosses that looked much bigger up close.

“They were huge — four concrete petals around a circle maybe 18 inches across," Penson said. "That’s when we noticed the disc in the center.”

Penson and Owen marveled at how its lettering was clear and distinct, noting the date stamped on the metal disc — 1966. "Corps of Engineers. U.S. Army Map Service."

A warning was even inscribed. “$250 fine or imprisonment for disturbing this mark.”

They hardly had an answer. But it was a clue.

“That gave us just enough information to start somewhere,” Owen said.

Pastor unravels Nazi spy's WWII terror plot

Noting the numbers on the discs, the pilots eventually discovered they were part of a large grid, perhaps targets of some sort.

It was a clue, but not an answer.

Penson sent an email to the Army Corps of Engineers. Weeks passed without a reply, so the two assumed the promising beginning was nothing more than a dead end.

NORAD's hidden bunker keeps the (data) snoops out

However, three months later, a history lesson arrived in Penson’s inbox with an apology.

“They were sorry it took so long,” he said. “They couldn’t find any records. They had to contact retirees to see if they might know anything.”

As Penson and Owen read the email, it all made sense. The markers were part of a top-secret spy program, one that would lay bare the Soviet Union’s arsenal.

But when Owen saw the name of the program, she couldn’t quite believe it. What were the odds that life would come full circle after catching a glimpse of something unusual in the desert?

Eyes in the sky

In the late 1950s, U.S. military officials feared that the Soviet Union was catching onto the U-2 spy plane, its high-altitude flights soaring over the Communist country’s most valuable targets.

Something better was needed: a photo-surveillance system impossible to detect. In the shadow of Sputnik, the answer was clear.

The brightest people in America’s budding space program went to work, designing satellites carrying high-tech cameras that could peer into the backyard of their Cold War nemeses.

The result was Corona, a satellite program so secret that its approval in April 1958 was not done in writing for fear it could be exposed, according to A Point in Time, a 1994 CIA documentary released after Corona was declassified.

By the time Corona was halted in 1972, panoramic cameras had captured 520 million square miles on film, exposing military stockpiles in the Soviet Union, China and their allies.

The satellites were crude compared to today’s standards. Orbiting roughly 100 miles up, the cylindrical spacecraft housed a camera in its body and the film in the cone. The camera shot one frame after another, recording observations on several pounds of film.

The problem: getting that precious film into the hands of analysts. Technicians devised a then-ingenious method in which the film-carrying cone ejected and propelled itself to a point where gravity could snatch it.

As the canister floated downward on a parachute, a plane would intercept it midair, a plan that did not always work. Some canisters were lost to the ocean, others to parts unknown.

And once, in July 1964, farmers in southwestern Venezuela found an errant capsule. Word spread of the find and a few weeks later, CIA agents posing as Air Force officers purchased the “science experiment” gone awry.

N. Korea draws visitors seeking peek at reclusive regime

Once the film was secured and developed, analysts interpreted the shapes scattered about the frames. Resolution was so poor at first that objects measuring 40 feet across appeared as a single dot. As cameras improved, a single dot comprised 6 feet, so more distinct shapes emerged.

Still, for the sake of complete accuracy, one last problem remained: How could analysts precisely determine the size of a jet or missile or submarine photographed from a camera 100 miles high?

The answer would be found in the middle of the Arizona desert.

Calibration targets

On Oct. 9, 1968, a front-page story in the Casa Grande Dispatch announced an unusual, though hardly mysterious, project about to undertaken nearby.

In the next six months, crews would install 267 concrete crosses 50 feet across to the south and west of Casa Grande, then an agricultural town of about 9,000 people, the article said. The markers — destined for federal, state and private lands — would be used to test aerial cameras.

To secure the 48 plots of state property needed, the U.S. Army Corp of Engineers paid $2,000 a year to the Arizona State Land Department, according to department spokeswoman Molly Bonsall. The plots were 100 by 100 feet, and leases did not reveal the purpose of the project.

All leases were canceled by 1984, she said.

The Dispatch reported that the area was chosen for the $250,000 project because of its “extremely clear weather.” Few other details were released.

By 1968, Corona’s cameras had advanced far beyond the rudimentary ones on the earliest flights. The latest devices captured color, depth and infrared light. The earlier images seemed like blurry snapshots in comparison.

The innovations made focus that much more critical. What was needed as a “ground truth” target.

To ensure accurate, distortion-free photos, reconnaissance cameras take shots of areas and targets where size and distances are known, said Paul Schaya, a retired CIA image analyst. The desert is perfect for such calibration grids because the air is dry and skies usually clear.

Such “ground truth” targets must be precisely designed and built. Deviations could affect calibration.

The Corona targets were to be exactly 1 mile apart, off by no more than the width of a pencil lead. according to one report.

When the work was done — a garden of concrete flowers 17 miles wide and 17 miles long — Casa Grande landed directly in the crosshairs of the Cold War.

Family ties

Corona.

Owen immediately recognized the name. An arcane bit of Cold War history to most, it was an integral part of her family history.

While growing up in Palo Alto, Calif., Owen knew little about her dad’s job beyond the fact he was with the Discovery project, which launched science experiments into space. He would mention something about payloads but said little more than that.

That changed in early 1995 when President Bill Clinton declassified the satellite program. Owen learned the Discovery program was a cover for Corona.

She reached out to her father and after keeping the secret for more than 25 years, Sid Owen opened up about his job.

He worked on a satellite designed to carry a high-tech camera over the most sensitive areas on the planet. He and his co-workers were responsible for gathering the kind of information that could alter history.

His daughter listened proudly because until that moment Leslie Owen had no idea about the role her father played during the Cold War. Intrigued by a past concealed for so long, she eventually read a book about the Corona spy satellites.

She understood why he had to be so secretive.

As years went by, his tales — so thrilling at first — faded into family lore.

Spy shoes to drones: How U.S. surveillance changed

Yet a decade later, those stories bloomed amid concrete flowers in the desert.

“I couldn’t believe the connection,” Leslie Owen said. “My dad had no idea there was anything in the desert. It was news to him, too.”

Her discovery prompted the family again to ask Sid Owen about working at Lockheed and Itek, which designed and built the cameras. Though her father had nothing more he knew, Leslie Owen still enjoyed the stories.

Atlas V launches eye in the sky into orbit

Sid Owen died in June 2014, his obituary revealing to the world his work on the Corona spy satellite.

The concrete flowers spread across the desert also tell the tale, at least to those willing to seek them out.

Follow Scott Craven on Twitter: @Scott_Craven2