Does anyone have an idea how far work on the ground-launched BGM-136B got? And, for that matter, on the ground-launched MGM-137B TSSAM variant?
I don't know for sure, but I'll risk a guess (well, two guesses, actually
The TACIT RAINBOW was essentially a USAF program, and I wouldn't be surprised if the Army's BGM-136B variant was more like a formal statement saying "See, this is a joint
program, so we deserve more money ..". In reality, I've never read anything about the ground-launched variant except that it "existed" (formally, at least).
As for the ground-launched TSSAM, I'd guess that this reached the flight test stage. The Army was in the program for 7 years (1986-93), and it would be rather strange if they had just watched the development of the air-launched missile all the time. Unfortunately, it appears to be rather difficlut to get any firm information on TSSAM at all, including e.g. a decent photo.
Also, why the ground-launched Tacit Rainbow was designated BGM and the TSSAM MGM although they both were to be launched from MLRS launchers?
Theoretically, it could mean that the ground-launched TACIT RAINBOW had only few modifications, so that it was still air-launchable as well. This would justify the B letter (denoting "Multiple Launch Options"). OTOH, it could also (and at least as likely) be just another screwed-up designation