Challenger Disaster Revisited

The NASA Space Shuttle Challenger disaster was 100% preventable. Why this claim, when cold weather is commonly cited as the cause of the O ring malfunctions that allowed hot gases from the solid rocket booster to penetrate the big orange liquid fuel tanks?

NASA engineers and rocket maker Morton Thiokol engineers had seen O ring failures on several previous shuttle solid rockets recovered after launch. The solid rocket booster bodies parachute back to earth, landing in the ocean in less than an hour after shuttle launch. The rocket bodies were designed to be recovered, refurbished and put back in use on a subsequent shuttle launch. It had been during several of these refurbishment procedures that engineers discovered that hot solid rocket gases had breached the O rings used to seal the joints between segments of the rocket body joined together to form the full solid rocket several hundred feet tall.

Rocket engineers had actually redesigned the joint between these segments. However, the solid rocket boosters on the January 1986 Challenger were from the last remaining remnants of the older original design, that had suffered O ring burn through on previous Shuttle launches. It was for this reason that engineers revised launch criteria to be ambient temperatures above 48 F degrees, to allow sufficient flexibility of the solid rocket motor body segment joint seals to prevent burn through during the solid rocket burn of the initial launch phase.

Engineers decided that the below freezing temperatures at the launch site and throughout that portion of Florida’s East Coast, during the night prior to launch, had rendered the O ring material too brittle to perform its ability to seal in hlt solid rocket gases during launch burn.

Their decision was scientifically based on what they knew and what they had previously observed. Delaying the launch of Challenger was a logical choice, and one the NASA Launch Team at the Florida launch site was more than capable of rescheduling and completing under more favorable weather and temperatures.

The executives who chose to ignore and then override the engineers’ decisions, did so out of what appears to have been a political gamble to make the then Republican President Reagan look good for the Jan 1986 nationally televised State of the Union Address before Congress that same evening. Their decisions were not based on science, engineering or observation.

The cold weather was not to blame, since cold weather is merely a natural phenomenon. Rather, it was the executives’ decision to override the engineers’ No Go decision because of the cold weather that was to blame for the Challenger disaster. This disaster was therefore 100% preventable and knowable beforehand.


The United States, the astronauts and their families, NASA and all humankind lost big that historically infamous morning due to the gamble of a small handful of politically motivated executives. And for what? Who could really doubt that Reagan would have rationally chosen to not delay the launch knowing that the temperatures at launch time were out of engineering criteria? Wouldn’t Reagan have chosen the safer course of action? Reagan was never known as a gambler.

Judgment to delay for weather is most often seen as wisdom in leadership. Here are some notable examples. General Eisenhower delayed D-Day for bad weather. British General Cornwallis delayed his retreat across the York River, from the attacking General George Washington due to bad weather. Napoleon and Hitler lost their military adventures into Russia due to ignoring the severe bad weather of winter.


The Challenger disaster was the very sad outcome resulting in a gambler’s decision to ignore the engineers who knew the physical limits of their equipment caused by the effects of bad weather.

Published by Capt. Paul Miller

Aviation safety expert with 43 years in the sky

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