How do we make:
Fred Noonan as well-known as Amelia Earhart?
The other people killed by the Manson Family that night as well-known as Sharon Tate?
the other six Challenger astronauts as well-known as Christa McAuliffe?
All of those people are relatively famous for good reasons, though; they all stand out.
Amelia Earheart was already famous as the first woman to solo the Atlantic; Fred Noonan was much more boring: while he was fairly remarkable in his own right, he was definitely there to "accompany" Amelia Earheart on what was definitely
her expedition. And, frankly, the things he was remarkable for were boring to most people, as plotting commercial air routes isn't very sexy.
Sharon Tate, again, was very famous as a model and actress before her murder. The fact that she was very pregnant when she was killed also helped make it even more sensational. The others killed that night were largely unknown (Abigail Folger, heiress to the Folger Coffee fortune, may have been known, but wasn't particularly high profile).
Christa McAuliffe was an ordinary schoolteacher chosen as part of a publicity stunt, who gave lots of TV interviews and had her face plastered on every newspaper for months. The others to die on Challenger were, well, astronauts.
Interestingly, without McAuliffe to focus on, three of the others might well have become very well-known: Ronald McNair was an incredibly accomplished physicist and the second black astronaut; Ellison Onizuka was the first Asian-American astronaut (though otherwise fairly unremarkable, a USAF test pilot); Judith Resnik was the second woman astronaut and the first Jewish astronaut (note that for all of these, astronaut means "and not cosmonaut").
Make McNair the first black man or Resnik the first woman and you might make them be better known, at least among their respective constituencies, but...Christa McAuliffe was famous as
pho in the days leading up to Challenger.