An in-game message tonight from FoxNext revealed that the Legendary Space Ace Event to unlock Star Lord will return on May 21st. The event will allow players to unlock the Guardian character who is also part of the popular Tech and Cosmic factions, or power him up to 6 or 7-stars.
Star Lord, aka Peter Quill, is one of a select Legendary Event characters in Marvel Strike Force and opens at 5-stars (310 shards).