The explosion that doomed the Challenger space shuttle remains one of the most harrowing and heartbreaking moments in American history. On the morning of January 28, 1986, what was meant to be a seminal moment for NASA and the future of space travel turned into a disaster that was viewed on live TV by millions around the country. Further wall-to-wall coverage and years of retrospectives have seared the grainy image of a faulty rocket bursting into flames and the Challenger and its seven brave passengers veering off course into the national consciousness.

The Challenger had flown nine times before over the previous nine years and helped the United States reach several important milestones. The shuttle brought the first woman and African American into space, hosted the first space lab and enabled the first astronaut-run satellite repair. But it was the tenth and ultimately ill-fated launch from Kennedy Space Center in Florida that was by far the Challenger’s most anticipated, in large part thanks to the unique nature of the crew that was making the journey.

Any disaster of this magnitude is a great tragedy, but the Challenger’s doomed journey felt especially devastating because it carried a crew that reflected the diversity of the United States and multiculturalism that was beginning to emerge after the civil rights era. Most of the astronauts were making history of some kind, leaving many different communities in mourning.

Christa McAuliffe

Christa McAuliffe
Christa McAuliffe
Photo: NASA

Much of the excitement centered on Christa McAullife, a teacher from New Hampshire who was to become the first civilian to fly in space. She earned her spot on the shuttle by winning the Teacher in Space Project, a contest launched by President Ronald Reagan and NASA that received over 11,000 applications. The field was whittled down to 10 finalists and McAuliffe was ultimately chosen after medical tests and other evaluations.

A 37-year-old mother of two at the time of the flight, McAuliffe was a high school social studies and English teacher with 15 years of experience in the classroom. She became an overnight celebrity and the focus of extensive media attention, as did her family and students at Concord High School. McAuliffe trained for six months to join the crew as a payload specialist, and she was to both help with experiments on the space station as well as give two lessons that would be broadcast to classrooms across the country. Schools around the country tuned into the Challenger’s launch due to her presence on the shuttle.

The two lessons that McAuliffe had planned, titled “The Ultimate Field Trip" and "Where We've Been, Where We're Going, Why,” were later recorded on the International Space Station. Her legacy of curiosity, optimism and grace has been frequently honored since the explosion; awards, scholarships and schools all bear her name.

Ellison Onizuka

Ellison Onizuka
Ellison Onizuka
Photo: Space Frontiers/Archive Photos/Hulton Archive/Getty Images

The good-natured and very popular Ellison Onizuka was the first-ever Asian American and person of Japanese descent to travel into space. He was born and raised in Hawaii, and brought the islands’ culture along with him throughout his career in the military and with NASA, becoming an ambassador of sorts who delighted crewmates with large pig roasts during their time together in training.

Like many of his fellow Challenger astronauts, Onizuka was a trained engineer who served in the armed forces during the 1970s, serving as a test pilot throughout the decade. In 1978, he was one of 35 hopefuls chosen for NASA’s first new astronaut program since 1969, a group dubbed “The 35 New Guys,” despite the presence of six women in the class.

Onizuka flew on one previous space shuttle mission, the third flight of the Discovery in 1985. A hero in Hawaii and icon to Asian Americans, he was celebrated in parades after his first flight and now has streets, an Air Force station, an asteroid and a crater on the moon named in his honor.

WATCH NOW: Christa McAuliffe: Teacher in Space on HISTORY Vault

Ronald McNair

A remarkable mind and steely determination helped Ronald McNair to become the second African American to reach space. His biography usually begins with his insistence, as a 9-year-old child living in a low-income community in segregated South Carolina, to check out a library book despite the refusal of a racist librarian. The police were called, but even at 9 years old, McNair knew his rights, stood up for himself and he wound up checking out that library book.

McNair went on to read a lot more books, earning his Ph.D. in physics from MIT. Just a few years later, he was invited to join that class of ‘78 at NASA. No Black person had ever flown into space at that point — two had been chosen for the astronaut training program in the 1960s, but one was not selected to join NASA and the other, who was invited to become an astronaut, died during a test flight. The agency worked to recruit potential Black astronauts when it resumed its program, in part by using Nichelle Nichols, an iconic Star Trek cast member, in its commercials.

A man of many talents, McNair was a six-degree black belt in karate and an accomplished saxophone player. His first flight was aboard the Challenger in 1984, and on that journey, he became the first person to play music in space. He had planned to become the first person to play a concert via live feed during the Challenger mission that never made it past the Earth’s atmosphere.

Judith Resnik

Judith Resnik was just 28 when she was asked to join NASA as a part of the 1978 class. She scored a perfect 1600 on the SAT, attended Carnegie Mellon for undergraduate and then earned a Ph.D. in electrical engineering from the University of Maryland. In between her two degrees, she worked for RCA, helping on high-level projects for major clients (including NASA) and then went on to work for the National Institutes of Health as a biomedical engineer.

She was so impressive that she joined NASA just a year after receiving her doctorate and spent the next five years training to be an astronaut and working on other space-related projects. She had a bubbly personality and big head of curly hair that made for fun photo opportunities in zero gravity.

Resnik made her first flight into space aboard the Discovery in 1984. In doing so, she became the first Jewish woman and first American Jew to make it off-planet. She was also the second woman ever to make it into space, following in the footsteps of her ‘78 classmate, Sally Ride.

Dick Scobee

The commander of the Challenger on that fateful morning in late January, Lt. Col. Francis Richard Scobee had a remarkable career in both the Air Force and NASA. He served in the Vietnam War, flying in combat missions for three years before returning to the United States and becoming a test pilot for cutting edge aircraft through the late 1970s.

After that, he was chosen as a candidate to become an astronaut in 1978, in the same class as Onizuka, McNair and Resnik, and aced all of the training and exams. That was no surprise, because not only was he a great pilot and aerospace engineer, Scobee was something of a polymath. His official NASA biography detailed a long list of hobbies, including flying, oil painting, woodworking, motorcycling and racquetball.

Scobee’s first trip to space also came aboard the Challenger, when he served as its pilot during its fifth flight in April 1984. He was known for his prowess in the sky and cool demeanor. After the investigation into the crew’s final minutes concluded that they likely survived until the compartment hit the ocean, a close friend and fellow astronaut named Robert Overmayer said he was certain that Scobee gave everything he had in the fight for survival.

“I not only flew with Dick Scobee, we owned a plane together, and I know Scob did everything he could to save his crew,” Overmayer said. “Scob fought for any and every edge to survive. He flew that ship without wings all the way down.”

Gregory Jarvis

The only other crew member who didn’t come through traditional astronaut training, Gregory Jarvis was an engineer who wound up on the Challenger through hard work and a lot of bad luck.

Jarvis spent his whole career in and around aeronautics, beginning with his joining the Air Force during the Vietnam War and working in the space division, with a specialty in satellites. After his discharge, he began to work for Hughes Aircraft, a major military and NASA contractor and eventually worked on space-related crafts. After nearly a decade of working for Hughes, he applied for and beat out 600 other engineers at the company for the opportunity to work on a NASA space shuttle. Technically, he was to be a payload specialist, which is the blanket term for any non-astronaut who goes up into space on a NASA mission.

Jarvis was twice bumped from the flight roster by politicians. He was first billed to make his journey into space in April 1985 but was replaced by Senator Jake Garn (R-UT) and then got pushed back in line by Rep. Bill Nelson (D-FL) in early January 1986. Instead, he was put aboard the Challenger’s fateful late January flight.

Michael J. Smith

Like Scobee, who piloted the fifth Challenger mission, Michael J. Smith was a Vietnam vet and joined NASA at the turn of the decade. He was known as a bright student and impressive athlete who spent much of the 1980s helping the space agency develop new parts and procedures for the space shuttle program.

Smith wound up piloting the Challenger after nearly two years of being short-listed for shuttle flights. In 1984, he was assigned to pilot the Space Shuttle Atlantis’ second flight in November 1985, and he nearly replaced the pilot who wound up flying an earlier Challenger mission, this one in January 1985, a year before the shuttle’s fateful flight.

The married father of three seemed to know almost instantly upon the Challenger’s liftoff that they were in trouble; his voice was the last captured on the flight deck recorder, uttering an understated and apocryphal concern: “Uh oh.”

Christa McAuliffe smiles as George Bush announces that she will be the first non-astronaut to fly in space on July 19, 1985 in Washington, D.C.