Yes, the Honeywell Alert was used to provide energy management info to the X-15 pilot, so he could arrange to be at the right altitude to make a power-off landing at Edwards AFB after going mach <crazy> at a couple hundred thousand feet over the California desert.
They had some kind of range navigation system so they could figure out how many miles they were from the strip, and add in altitude and you have all the info you need to inform the pilot.
If too high, he can circle around, but if just a little too high, he needs to burn off energy with S-turns and such so he doesn't overshoot the runway.
Unlike most systems, I was able to get an incredible 2-volume document on the history of the project. This was a contemporary of the Apollo Guidance Computer project, which started just a bit earlier than the Alert, but finished later. That was most likely due to the large amount of software needed for Apollo.
The Computer History Museum has already expressed interest in this relic. I just don't want to let it go just yes, as it is a bit too neat.
Jon