Ships disappearing from space/planets in 1.7

[djr5899]

Hello,

I have run into an issue where I am seeing ships disappear from my Sandbox mode save.  And what I mean by disappear is, I have a number of craft that are in orbit and landed on planets.  Now, I've never been very ambitious about having a bunch of craft out in space at the same time, and yet, I've seen dozens of screenshots from players with lots and lots of ships.  In 1.7, I seem to be running into an issue going above 10 ships.

In my current Sandbox game, I have the following ships out in space

• 3 satellites in geosync orbit around Kerbin
• 1 resource satellite around Minmus
• 1 relay satellite around Minmus, to help prevent signal outage zones
• 2 ore drilling rigs on the surface of Minmus (first two craft put on Minmus)
• 1 rover mainly for transporting ore from drillers to ore processor (3rd craft on Minmus)
• 1 ore processing craft (4th craft added to Minmus)
• 1 additional rover, just for moving fuel from ore processor to fuel storage rig (5th craft added to Minmus)

The 5 ships on Minmus are all in the same location, with 500m of each other.  All of those ships were working just fine, no issues.  Yesterday, I went to launch a another ship to the surface of Minmus, a fuel storage vessel.  When I got there and  started my decent to land, I noticed that there were only 3 craft showing on the ground (1 ore rig, 1 rover, 1 ore processor), instead of the 5 that should have been there.   1 rover (3rd craft on Minmus surface) and 1 ore rig (1st or 2nd craft placed on Minmus) were gone.  No sign of them, no pieces of them, no listing of them in the tracking station.

I attempted to launch a new rover to the Minmus, and when I got there, my other rover (5th craft added to Minmus) and my other ore rig (1st or 2nd craft on the planet) were now gone.  Unfortunately, because these were missions to Minmus and relatively close, I didn't keep a lot of saves like I would for longer missions.  I have no saves available with no craft missing.  I do have a save of me landing 

Mods in place:

KER, ScanSAT, Surface Lights, RCS Build Aid, [X] Science

Anyone else comes across something similar?  Very frustrating as I get limited time to play KSP anymore, and, getting all my satellites in place, and my different craft refined through several versions of each took me about a month to complete.