Long time reader, first time poster, love the forum.

So, I started an Age of Rebellion campaign and we're now getting in to the nitty gritty of the story and I've had an idea to open the galaxy up to the players. The idea would be for there to be a number of 'Story' missions that would propel the campaign forward, as well as a number of 'side' missions that the team can freely take up or ignore if they wanted to. Some of these side missions would be character focused, bringing in their backgrounds and duty. In my head, it's basically taking an open world computer game style(specifically Mass Effect) and plonking it on the table (well, Roll20 in this case). I'll fill you in on where we are so far.

- The first mission saw the team working as part of an multi rebel cell assault on a recommissioned Republic base situated in a large asteroid field. The mission was to steal the cannons of a Gozanti cruiser that was dry docked, and attach them to a rebel CR-90. Intelligence showed that there would be minimal imperial presence on there, as it was just being used for refurbing old ships. Well, it wouldn't be that easy would it? There was a heavy presence on the base, and after fighting their way through, they managed to get hold of some information from the computers. This was all heavily encrypted, but they got the words 'Wraith', and 'Cloud Hammer' as well as that these were top secret imperial projects that the base could be used for. They managed to fight off a small group of Death Troopers, get the cannons on the CR-90 and escape in a U-Wing.

- The second mission saw the team recovering an undercover rebel asset on Batuu, who has fled from the Hutts after being discovered. His last transmission to his handler included information on an asset called 'Wraith' (I was hammering the plot thick at this point). When they arrived on Batuu, the team met with the operatives handler, who after hearing that there was a bounty hunter on it's way to capture the spy, sent him off on a transport to Coruscant. The handler gave them information that the Hutts had come in to contact with a defected imperial pilot, code named Wraith, who also came with an experimental TIE fighter and was willing to sell it to the highest bidder. Obviously, that would be a Hutt crime lord. The team had a run in with the Bounty Hunter and managed to escape.

- The third mission is long and has multiple parts for them to complete. The group were asked by Rebel command (their cell leader, they aren't part of the wider rebellion yet) to investigate the sudden comms silence from a friendly, but as of yet not rebelling, planet where a group of people fleeing Imperial rule have fled to. Rebel intel has shown a large movement of imperial resources to this planet, and nobody knows why, and they especially don't know why they have blocked all communications from the planet. Imperials have contracted out a lot of supply runs to local independent operators due to it's isolated nature. The job is to deliver them some weapons as a gesture of good will, and hopefully bribe them in to joining the rebel cell and boosting their numbers.
The players had a few options on how to proceed here. They needed transponder codes that would get them through the Imperial checkpoint and on to the planet, and they could either visit a handler on Kafreene who had a code and was willing to part with it, or locate one of the licensed freighters and get the code from a ship. The players chose to go to Kafreene.
The handler on Kafreene had the ability to acquire a code, but a mission needed doing first. The players had to visit one of the last legal podraces and stop a racer from finishing (but not kill him). This racer happened to be the son of an imperial governor and big bad of the campaign, Quondos Vorn. The players managed to pull this off in a very round about way (and creating a completely fictional sports station in order to infiltrate the arena), but their actions basically led to the outlawing of podracing entirely after the racer they were hired to stop almost died, and another pods engines ended up launching in to the spectator stands. It also, unknown to them, has attracted the attention of the Imperial governor. The players escape but are involved in a chase against a few TIE fighters and are damaged in the process.
The players get back to Kafreene, get the codes, manage to steal some additional weapons, and get to the planet pretty much without incident. They manage to get off the Imperial radar by faking an explosion in the middle of a very violent storm, and make it to the coordinates of the friendly village. Talking to the leader, they find out that this was an old sepratist mining facility, and that they were digging for Stygium crystals (Yeah, Wraith is flying the first TIE Phantom prototype) and that this planet wasn't even known for actually having them. The players went and scoped out the main mining facility, managed to infiltrate it after knocking out two scout troopers and stealing their bikes and uniforms, managed to get a comms decryptor that is basically a one shot device to talk to Cell command before the Empire notice an unortharised transmission and change frequencies. We left the last session with them deciding on where to go from here.

When this mission is complete, I intend to make the trail for wraith go cold for a session or two. I need the players to have to actively hunt him down and find out who is looking to buy the tech he's selling. I also have NO idea what Cloud Hammer is, it just sounded cool at the time so I threw it in and now have to make something fit. My initial idea was that it would be a satellite array that could cloak using the Phantom cloaking tech, and could essentially fry an opposing army/population without damaging the infrastructure. That seems pretty evil, and completely in keeping with the ideas I've already seeded in about Governor Vorn. I also have an idea of the team needing to go to Corellia (the home planet of one of my players characters) and kidnap a scientist working on the Phantom project. Other than that, I'm running a little dry on ideas for side missions that the players can do.

If anyone has any advice or suggestions, it would be a huge help.

Perhaps Cloudhammer was intended to be some kind of terraforming device intended to help make uninhabitable worlds inhabitable for colonisation?

Only it was far from ready for use, but the Empire aren't interested in its original function only that it can render an inhabitable world lifeless of sentient life but still perfectly fine to be mined for all its resources since there's no one left alive to argue about it.

Remember that code names for projects tend to have nothing to do with whatever the project is if the group assigning the name has the slightest idea about maintaining security. So this Project Cloudhammer could be something like development of a new dessert cake for Imperial field rations.

Plus it’s fun throw in an utter wild goose chase every now and again to keep PC’s ( and more importantly, the players themselves) guessing.