Houston, We Have Liftoff (Solution)
by Alex Irpan
The solved first grid is below. The solution has been checked as unique by computer.
When solved, the top-left to bottom-right diagonal spells CONUNDRUM, while the other diagonal spells SCRANBLED (which is as close to SCRAMBLED as is possible.)
As hinted by the flavor text (countdown, 30 seconds) and the diagonals, each row should be replaced by a scrambled conundrum from the game show Countdown. The conundrum used is the one from the launch date of the Shuttle mission noted on the side.
As an example, the first row
is associated with the mission STS-51-A. The unsolved conundrum that aired on the same date as that mission was TMGIBIYAU.
Applying the transformation in the second grid gives the row
(This row matches the row generated by the colored squares from the first grid.)
Doing this to each row in the second grid gives the following grid, which has the same property as the first grid. Solving the second grid in the same way as the first gives the following. The solution has been verified as unique by computer.
The diagonal gives ANSWERALI, so the puzzle answer is ALI. The other is gibberish.