Which spacecraft exploded during flight killing all astronauts?

In January 1986, five astronauts and 2 other passengers were killed when the spacecraft shuttle Challenger exploded shortly after its launch. It delayed more space exploration for about 32 months, I think.

On January 28, 1986, the NASA shuttle orbiter mission STS-51-L and the tenth flight of Space Shuttle Challenger (OV-99) broke apart 73 seconds into its flight, killing all seven crew members, which consisted of five NASA astronauts and two payload specialists.