I read on TVTome that she was in the final eps part of the mission control, I watched the final eps yesterday and I saw a woman who looked like her but I'm not sure if it really was her, at one point I heard her say "Way to go Steve!" and it sounded just like Payton, her appearance was uncredited. Can anyone help me out?

she wasn't harriet though she should have been but that was her at mission control

Yeah that was her. She looked terrible, I thought and could barely recognize her. It wasn't until I heard the voice that I realized it was her.

I have always wondered why she decided to do that guest scene but wouldn't do the rest of the series.

At least we can say that she was in the final eps, but I'd also like to know why she was there.