Tapping the New Mission button will bring up the following screen:

Screenshot from Star Rangers' Mission Launch Screen

• First, you’ll want to enter your Callsign – either your real name or (more likely) a preferred nickname. (Remember, this name will be posted on the OpenFeint Leaderboards with your high score.) If you already have an OpenFeint user name, this will automatically be entered in for you.
• If you would like to change your OpenFeint user name, enter the OpenFeint panel from the Star Rangers main menu and go to Settings. Your Leaderboard listings, earned achievements and Friends list will not be lost for Star Rangers or any other OpenFeint games you have. You are limited to 20characters. [Note that ANALOGretro will monitor player Callsigns; any name we deem inappropriate may lead to a warning to change your name, or a ban from the service.]
• Mission ID defaults to Random. Every time you start the game, the Galactic Map layout of enemy ship, starbases and fuelbases (depending on your mission type) will be new. However, the Mission ID button also enables you to enter the 8-digit mission number next to a player’s Callsign from the Leaderboards and play the exact same map/mission layout as that player. Enter your friend’s last mission and see if you can beat his score!
• Select Mission. Slide the image sideways to access additional missions.
  • The main mission is Galaxy Defense. Protect your starbases and fuelbases as the enemy advances on them with only one goal — to destroy all of them.
  • Instant Action! Gives you immediate gratification if you simply want to play a quick game, or practice your Starfighter skills. (Note that completing levels in Instant Action will not unlock the same level in other missions.)
  • In The Last Starbase you must defend against a galaxy full of Lans-trinzini ships, all heading towards the one remaining Starbase in the galaxy!

• Select Difficulty — Slide the image to the left to play the increasingly more difficult levels… but only after you have earned the rank of Fighter Class 5 on Rookie!
  • Earn Fighter Class 5 on Rookie to unlock the Fighter difficulty level
  • Earn Warrior Class 5 on Fighter to unlock the Warrior difficulty level
  • Earn Ace Class 5 on Warrior to unlock the Ace difficulty level
• Tap Launch Fighter to begin your mission