Once you hit the Pegasus, it's done... especially with Morning Stars...
Basically, like in the nebula mission where you test it, you just have to hit it a few times before it's rendered useless... even with stealth, using Rockeyes and Morning Stars will definately allow you to gain the upper hand (until it gets out of sight).It's hard to keep up when you push it away so much...
They should have another weapon like the Morning Comet or something; instead of pushing it pulls.