Challenger explosion date?

Some people remember the Space Shuttle Challenger disaster occurring some time before 1986 - are they experiencing the Mass Memory Discrepancy Effect?

Even weirder are the reports the astronauts are still alive.

Many of those who remember it exploding earlier think it happened in 1984.

NBC even ran a piece back in 2011 about people misremembering the date.

The cause was determined to be a seal which wasn't tested for cold winter temperatures, but even that's being questioned because the ones who remember it as 1984 also remember it being in the summer. 

Markers

This Mandela Effect is one where people tend to use "markers" as reference point. For example, going to see the movie "Top Gun" at the same time as they heard about it, graduating, leaving home etc It's the same as people knowing where they were when they heard JFK died, or Pricess Diana etc.

Columbia

There's also a mystery surrounding the Columbia shuttle too - many people don't even remember it exploding on re-entry at all in 2003. This could be explained by the fact the earlier Challenger disaster recieved much more air time than the Columbia, but those who do remember the Challenger say the thing they particularly remember is the fact there was a female teacher on board.