Today, 10 March 2021, there was an obituary for, Allan McDonald, one of the Morton Thiokol engineers, who worked so hard to keep the Challenger from being launched. There was a problem with the O ring design of the missile.
Here is an image of the missile they were using:

The solid-fuel booster rockets whose failure is a cause of the Jan. 28 explosion of the space shuttle Challenger were made by Morton Thiokol Inc. at a sprawling mountain production site a few miles east of Brigham City, and 10 miles from Promontory Point, where the western and eastern legs of the transcontinental railroad were joined in a historic ceremony May 10, 1869.
These solid fuel rockets were transported on railroad cars. And, the tunnels for these cars were built to cover the tracks that were built, the way the English built tracks. The English used the ox-cart tracks left by the Romans when they invaded England. Julius Cesar invaded in 55 BC and the Roman Empire was in England from 43 BC to 410 AD. So, the missiles were built to the width of ox-carts.
These missiles had O ring seals that could not be accurate when the launch occurred after an extended period of cold weather. These seals shrank too much to offer the protection that was needed to keep the missile together. The engineers and the scientists all knew that. NASA knew that.
The scientists and engineers could say what they wanted to say, but nobody was listening. It was like Trump with: “the pandemic will go away”. The politicians wanted that teacher in space so Reagan could show the world how COOL he was.
Because, the REAL cause of the disaster was that President Ronald Reagan intended to speak by radio to the teacher that NASA had placed on the astronaut’s crew, during his State of the Union speech that he intended to give on national TV on January 28th. I know that because WBAI reported it when this disaster struck. You can’t find it in the history of the disaster but the kids know how to do the hacking. They will find it!

The five astronauts and two payload specialists that made up the STS 51-L crew aboard the space shuttle Challenger in January of 1986. Crew members are (left to right, front row) astronauts Michael J. Smith, Francis R. (Dick) Scobee and Ronald E. McNair; and Ellison S. Onizuka, Sharon Christa McAuliffe, Gregory Jarvis and Judith A. Resnik.
Christa McAuliffe—Payload Specialist, Teacher
As the other payload specialist, McAuliffe was a social studies teacher at Concord High School in New Hampshire when she was selected from more than 11,000 applicants to join NASA’s Teacher in Space Project in 1985. She received a bachelor’s degree in history and education from Framingham State College in 1970 and eventually received her master’s in education, supervision, and administration from Bowie University in 1978.
While in space, McAuliffe was planning lessons to teach her students from the shuttle. Among the lessons, she was slated to give a presentation about space travel titled “Where We’ve Been, Where We’re Going, Why.” After the explosion and her death, several honors were bestowed on her posthumously.
The most serious impact of Ronald Reagan on education was his failure to affirm public education as an essential need for strengthening the nation. He wanted to talk to Christa McAuliffe on national TV to boost his image.