Technical problems and the Challenger accident in 1986 delayed the mission for seven years.

Twenty-one years after the Challenger accident, she finally got her chance to go into space.

The search for new space goals began in earnest after the Challenger accident.

Since the Challenger accident, many folks here have begun thinking about where they are in their careers.

Anyone who had lived through the Challenger accident, he said, "is never going to take anything for granted."

The shuttle fleet has been grounded since the Challenger accident last year.

The best that they had managed to do before the Challenger accident was a launching rate of nine missions in 1985.

Several hundred sensors have been added since the Challenger accident.

The agency never came close to 50 shuttle missions a year - or even the 24-a-year goal after the Challenger accident in 1986.

They were built before the Challenger accident to serve as spare parts.