HRABOVE, Ukraine--Angela Rudhart-Dyczynski slipped off her shoes, covered her feet in white socks and crunched through a field tinged with the sick-sweet smell of death to reach a wing of downed Malaysia Airlines Flight 17.

She and her husband arrived Saturday from Australia after an exhausting three-day journey that left her feet too swollen for shoes. They braved this war zone in search of a lost passenger: Fatima, their only child.

"We're standing here at the wing in the field," Jerzy Dyczynski, a cardiologist, said into his phone, as the wind blew. "This is where we thought she was sitting. We're trying to picture her."

Among the locusts and wildflowers, images of their daughter, a 25-year-old aerospace engineering graduate student at the Delft University of Technology in the Netherlands who had been on her way home for a visit, overwhelmed them.

They knew where they were, but they still couldn't believe it. "We're lost," Mr. Dyczynski said.

The attack on Flight 17 has traumatized the loved ones of the 298 passengers and crew traveling aboard the Boeing 777 from Amsterdam to Kuala Lumpur.

Eleven days later, pieces of the plane have been moved. Most of the bodies have been flown to the Netherlands but others are still here. Fighting has crept closer to the crash site. Rain and heat have tarnished what remains.

The chaos that followed--disputes over the handling of the site, fighting between Ukrainian forces and pro-Russia rebels, and an uncertain probe--has added the worry that families will never learn exactly what happened.

The prospect offends Mr. and Mrs. Dyczynski, trained scientists who hold the search for truth as a fundamental pillar of their lives. They want to identify positively their daughter's remains and establish her death to scientific standards of proof.

As parents, they are here, determined to see the facts for themselves. For them, it is too early to reach conclusions. Mrs. Rudhart-Dyczynski asked: "Who can I trust?"

Fatima Dyczynski, born and raised in Germany until her family moved to Australia seven years ago, inherited from her parents a wanderlust of the mind. For the family of three, life had long been about exploring the limits of human capacity--whether through data architecture or homeopathic medicine.

As a young woman, Fatima was fascinated with technology and outer space. She earned her undergraduate degree at Delft and became interested in space flight, eventually helping design a satellite as part of a university-funded research project.

At a TEDx talk in Groningen last year, she projected confidence onstage. Dressed in a black business suit, she energetically described the goal of a company she founded: to launch a constellation of nano-satellites that would communicate with personal cellphones, alerting people to nearby emergencies.

She called herself a futurist. She wanted to go to Mars.

A former classmate, Nir Kalush, said she was the kind of person who would call in the middle of the night and suggest a trip to Paris. She was someone comfortable emailing with NASA astronauts or voicing new ways of thinking about the world and life. "Fatima's laughter was the loudest in the world," he said.

She was also disciplined. Her mother recalled how she would talk with her daughter from Australia over Skype, as Fatima did her engineering work or built presentations. Among other topics, Mrs. Rudhart-Dyczynski remembered her daughter studying the structural disintegration of aircraft.

Fatima urged her friends to keep on moving and keep on dreaming in a July 6 post on Facebook. Two days later, she wrote, "I love my life. Infinite potential. Multidimensional. Intergalactic." She finished, "Always remember. Don't let gravity hold us back."

On the evening of July 17, Fatima's parents were sitting on their sofa in front of a fire when they learned their daughter's plane had gone down in eastern Ukraine.

Their immediate response was incredulity. "No experts were there. No one had credible data," Mrs. Rudhart-Dyczynski said.

As hours marched on, the mother rattled off emails to Fatima's aerospace engineering colleagues, her daughter's acquaintances at NASA and the family's biologist friends. Could the human body survive a fall from more than 30,000 feet?

Given that Fatima was a trained hang-glider, could she have landed safely? Could a passenger fall and then survive in a coma on the ground?

No one immediately replied. Then the parents packed and flew from Perth to Amsterdam, followed by Kiev, Dnipropetrovsk and finally war-torn Donetsk. They decided they needed to find the answers themselves.

In Donetsk, they found a ghost city, where artillery fire echoed off the sides of Soviet-era buildings devoid of half their residents.

An hour-and-a-half drive, through checkpoints manned by pro-Russia militants, brought them to the villages where the remains of Flight 17 still littered the ground.

The parents laid bouquets near a crumpled section of the plane's wing, close to where their daughter had sat.

Roughly 300 yards away, the overhead compartment above their daughter's seat--20D--rested, just out of their view, in a tangle of weeds and purple-and-white wildflowers. The Dyczynskis didn't see the piece of evidence. They only learned of it a day later.

Back in Donetsk on Saturday evening, Mrs. Rudhart-Dyczynski appeared in a swirl of perfume and energy. She overflowed with ideas and concepts about the scientific process of investigating the crash, showing flashes of her daughter's expansive thought process.

Mr. Dyczynski was largely silent. The bearded doctor stared at the sunflowers the couple had brought back from the crash site, the big faces of the blossoms bent in the gloom of a deserted lobby.

Long before the crash, the family had once discussed how much time would be required to escape an airplane falling to Earth. "She would have needed 10 seconds," Mr. Dyczynski said. He asked if his daughter would have had that much warning, realizing as he spoke the answer was most likely no.

His wife took out her white Toshiba laptop and showed photos of her daughter. "You're in for a shock, a good shock," Mrs. Rudhart-Dyczynski said as she flipped through them. "She is the most beautiful."

She found a photo of Fatima next to astronaut Leroy Chiao. A proud mother was smiling behind her. "That's me," Mrs. Rudhart-Dyczynski said. She promised to replace the lecture Fatima was scheduled to give at an aeronautics conference this fall with a panel discussion on the science of aircraft attacks. She hoped her daughter's science would live on in a new advance.

Mrs. Rudhart-Dyczynski, a psychologist and scientist, said she didn't want condolences: "I want the facts."

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