I completed one solution based on the challenge instructions and getting an equivalent output to the solution value;
I then added in an extra "End of Transmission" character at the end of the message (as per the list of possible characters in the "HEX Table" input, as well as adding a 1 second break between characters to give time for the result to be read and recorded.
So this is a conceptual challenge. and the phrasing of the question was a little misleading.
The gem I took from it was the last sentence:
If the question card is sitting at 0 degrees and the 16 other letters (0-9, A-F) are ordered around the rover, the camera can only pan at 4 degrees per second, how long will it take for the rover to return the following message: “We are sending another mission. It will take 42 months.”?
There's mention of only 16 cards but there are 21 characters being used, if you factor in using a lower case w and i. So this made me doubt the question, thus I spaced the 128 hex master file around 360 degrees. It worked out to be 2.8125 degrees per sign.
We use the RegEx tool with "\w|\d|\s|\.|\?" as the regular expression without the quotation marks.
We join build out the hex table to show the distance between signs reflected by degrees.
We join by character and symbol.
We are missing - start of text and end transmission. So we inserted them in the character order as 0 and count of characters +1 (end of transmission)
We then use a multi row formula - for some reason it was returning nulls when negative; thus I used absolutes to can calculation differences between the signs. Then we applied an abs(degrees - 360) and then we compared the original degree difference to this secondary value because we're dealing with a circle and we can rotate back and forth, so we're getting the best bang (distance) for our buck (time).
We get a list of distances by degrees. We then calculate based on 4 degrees per second to extrapolate 939 seconds or 15 minutes. This is very different to the end result by the challenge solution. But the concept is the same, we'd just switch out what signs are used and their spacing!