Watch an exclusive clip from the CNN' 'Space Shuttle Columbia: The Final Flight' finale (video)

Other than the national tragedy of the Apollo 1 command capsule fire that took the lives of astronauts Gus Grissom, Ed White and Roger Chafee on Jan. 27, 1967 during a launch rehearsal at Cape Kennedy, NASA's darkest hour up to that point occurred 19 years later when the space shuttle Challenger exploded 73 seconds after launch on Jan. 28, 1986, causing the deaths of all seven astronaut aboard. 

Then on Feb. 1, 2003 disaster struck once again after the space shuttle Columbia broke apart during its reentry flight over Texas, sadly killing its STS-107 crew of seven brave astronauts, bringing the program to a shuddering halt.

"Space Shuttle Columbia: The Final Flight" is a riveting new four-part series that debuted April 7, from CNN Originals and co-produced by BBC and Mindhouse Productions, and we have an exclusive interview clip to share from the two-episode series finale landing on CNN on Sunday, April 14.

Related: 'Space Shuttle Columbia: The Final Flight' documentary to conclude on CNN

Here's the docuseries' official synopsis:

"Columbia was the first Space Shuttle to launch and redefined space travel – it took off like a rocket, landed like a plane, and was reusable – making the dream of routine space flight a tangible reality. Across four episodes, the story of the ticking-clock of Columbia's final mission is told in dramatic detail, beginning months before the troubled launch, unfolding across the sixteen days in orbit, and concluding with the investigation into the tragic loss of the seven astronauts' lives. Weaving together intimate footage shot by the astronauts themselves inside the orbiter, exclusive first-hand testimony from family members of the Shuttle's crew, key players at NASA – some of whom have never spoken before – and journalists who covered the story on the ground, the series paints an intimate portrait of the women and men onboard and uncovers in forensic detail the trail of events and missed opportunities that ultimately led to disaster. 

"With wide-ranging access to NASA's archives, including previously unseen footage and findings from the official investigation, 'Space Shuttle Columbia' is the definitive telling of this national tragedy and the inside story of one America's most iconic institutions, uncovering how financial pressures and a culture of complacency may have contributed to the events of February 1, 2003. The series also reflects on the legacy of the Space Shuttle era, serving as a timely exploration of the challenges and inherent dangers that remain relevant to space travel today."

Our exclusive clip above features interviews with former NASA Photo Analysis Manager Bob Page, Wayne Hale, former NASA Manager, Shuttle Program and CNN Analyst Miles O'Brien regarding the past ongoing issues at NASA where people were afraid to speak up and offer dissenting opinions in a bureaucratic system ill-equipped for good communication across all integrated departments.

CNN's "Space Shuttle Columbia: The Final Flight" premiered Sunday, April 7 at 9 p.m. ET/PT with its first two installments. The docuseries' final two episodes both air Sunday, April 14 at 9 p.m. ET/PT. Its executive produced by Emma Tutty and Emma Whitehead for Mindhouse, and Amy Entelis and Lyle Gamm for CNN Original Series.