ronald erwin mcnair (october 21, 1950 – january 28, 1986) was an american nasa astronaut and physicist. his first space mission was sts-41-b aboard space shuttle "challenger" in 1984. after this mission, he was again on "challenger" for sts-51-l. he died at the start of this mission when the space shuttle was destroyed during the launch. he was the second african american in space.