9 months ago - Rocket - Direct link
New Frontiers, for the first time, allows all its missions to be played either in open world directly, or as the normal mission mode. You can take existing prospectors into the world (Prometheus) in the New Frontiers expansion.

Note that until the next big update, Exotics currently cant be earned on these missions. We just wanted more time to test, to make sure everything works fine with the missions before exotics are turned on for open world.