I think it said something like recommended power level of 140+. Ridiculous that at almost twice that and my Titan goes down no sweat. After about an hour of trying, I said to hell with it and went back to orbit. I've got my Sturm (thankfully, the target for that is NOT the end boss).
What's even stupider is that this week's Nightfall is that same mission...with a time limit of 15 minutes. Ya...good luck with that.