Integer Overflow When Enemies Attack Sphereworld.

[Suicide Junkie]

I did some beta testing on this:
It sounds like the Sphereworld has more than an unsigned INT of hitpoints, and therein lies the problem.

If you break up the designs of your defenses, you should be able to avoid the crash; try to not let any one group of units exceed 64K hitpoints.
You can make two or more identical designs, and build an smaller number of each.
As an example, a platform design with 2000 hitpoints (incl armor AND shields) can only be used in 30 unit stacks. A second identical design allows you to add another 30 platforms, and so on.

For the short term, launch any sats and/or fighters into space, and build carrier starbases to hold excess fighters
Medium term, start replacing weapon platforms as above.
Long term, install the next patch that will come out.