A tremendous loss, as was the loss of the Challenger crew.
Quote:The first Space Shuttle Disaster was Challenger which was lost during an explosion as it took off from Cape Canaveral on January 28, 1986, killing all seven people on board. NASA suspended shuttle flights for two years.

The Space Shuttle Challenger Mission (Flight STS-51L) was the 25th Space Shuttle mission and the 10th launch of the Space Shuttle Challenger.
It was launched from Pad 39B at Kennedy Space Center in Florida at 11:38am EST. This mission was highly publicized because it was the first time a school teacher was allowed to travel in space. Christa McAuliffe, a high school teacher from New Hampshire was to be the the first civilian in space. She was selected from more than 11,000 applicants.
The crew of Space Shuttle Challenger consisted of 7 astronauts:
- Francis R. Scobee - Mission Commander
- Michael J. Smith - Pilot
- Gregory B. Jarvis - Payload Specialist 1
- Christa McAuliffe - Payload Specialist 2
- Judith A. Resnik - Mission Specialist 1
- Ellison S. Onizuka - Mission Specialist 2
- Ronald E. McNair - Mission Specialist 3
This item of philatelic space memorabilia was produced relatively early in the shuttle program. This cover was flown aboard Challenger on the eighth space shuttle flight.