Hi, it's me again!
I notice you guys are having some troubles, which I encourage you to work through, but allow me to offer a couple suggestions for things that I notice tend to make ME RPs die off before they begin, and things that can help keep things going.
The first is that most ME RPs I see start everyone off as strangers on the ship; don't do that! Every time I see an RP start off that way, people lose interest or things get bogged down with characters interacting without knowing each other, and the minute somebody vanishes while another player is trying to interact with them, the game grinds to a halt. If you have players who vanished, do NOT wait for them indefinitely. You have to keep things moving, even if it kills off a conversation right in the middle of it. What's worked for Nova (we've kept this incarnation going since I think June last year?) is having the characters have known each other for an indeterminate amount of time BEFORE the RP starts. That way, instead of stumbling around trying to meet as many people as you can before a mission, there's already that familiarity with them. Do some OOC in-character activities to kind of flesh out how characters behave and act around each other before the game even starts, it should help everyone mesh right away and build a bond before you even start.
One thing that's worked EXTREMELY well for us is having all the players kind of have GM powers during missions and what not where they're free to create or alter encounters as they come. It keeps players invested, and believe it or not, back before Nova became Nova, it was a game called Mass Effect: Surge where the GM disappeared indefinitely, leaving the small handful of players behind. We decided to just push on, since we knew what the mission was, and we literally winged the details as a group. From there, everything really gelled with the players and we started alluding to character history as a team that never was roleplayed; somebody would mention something that happened (say, a bar fight) and another player/character would flesh out details from their perspective. It actually was a lot of fun doing that, and I think it made the group gel really well and it gave birth to some of my favorite character moments in any of the incarnations of the game.
Either way, anyone who's in this thread reading this; don't give up on your RP just yet. Work together to see if you can't give it the boot in the ass to continue as you need to!
I also want some stuff to read when my games slow down, so do it for your audience. ;D