I realize this is not very Traveller, but it's the kind of thing that some of us like and hopefully I can build into our games. I am curious though, some people have hinted at game systems that do have more of a "hard scifi" feel to them for which this sort of thing would be built into the game mechanics. What games would those be?

(I'm personally more in favor of just modifying Traveller as I like the setting, but want to know what others like to play that might be more like this).

I'm Traveller through and through (not lack of interest, just lack of time), so if it's not Travelleresque at least, I'd probably be interested to see it existed and move on.

As for creating some game mechanics, this would be of interest (and for your reentry calcs as well), but for me it would need to focus on the game play rather than the maths. While doing a square root in the pub on game night wouldn't be a deal breaker (just the one, mind you), I'd rather not. A table would suit fine.

However, I wouldn't expect to use it often. But I can see that in one adventure where it was relevant, it could add some fun and interest. In fact, while the details of the rest of your email eluded me (I've never considered tactical twilight before!), just reading it through was making me think that it might be fun to have a bit of a ground adventure dependent on where orbital comm support was. As long, as usual, as I remembered to keep focussed on the human story rather than the details.

So if you produced something along the lines of the Keith brother's environment supplements but for the ground/orbit interface - comms coverage, drop times, how big/bright is orbital item x from given point on ground, can I see ship y landing from z distance, how far to the horizon for world size/height above ground etc - then that would be of great interest.

(That last example I've already done as it happens for an adventure I hope will see light of day this year. I ought to see if I can dig out the table when i get up so others can check my math. (Found the calcs on internet and worked out a table for world sizes and various heights for the particular distance I was interested in IIRC). Again, focussed on playable usability rather than exact simulation of, ummm, rocket science.). :-)

If that helps?