UTC Orbit; is a time conversion utility for use with Earth orbital elements calculations for spacecraft. The application also contains a UTC alarm clock that is based on "Day of Year". UTC stands for "Universal Time Coordinated", but is also known as Zulu Time or GMT Time. The application allows the user to select any epoch time in the future or past via pick wheels and that time is then displayed as YYDDD.FFFFFF where YY=Two digit year, where DDD=day of the year (000 - 366), and where .FFFFFF is the decimal fraction of the day. This is the standard format for manipulation of spacecraft tracking TLE's (Two Line Element sets). The app also works in reverse where the user types in the epoch time and the pick wheels will spin to the human readable date. The alarm is set via the pick wheels and operates in the background for sound and screen notification as well as the foreground if application is running. The user must "allow notifications" for the background to function. A useful feature of the app is that if you rotate the iPhone you then have a large digit UTC clock. iPad large digit clock is selected by touching the button "UTC screen". Note that this locks the screen rotation on all devices and to return to the calculation screen you must touch "Back to main screen". This app is for iPhone 4s and newer and all iPads running IOS 8.0 or newer.