The United Launch Alliance plans to kick off its first mission of the year with the launch of its Atlas V rocket from Cape Canaveral, Florida, this evening. The vehicle will be sending an infrared surveillance satellite into a high orbit for the US Air Force.

Take off was initially scheduled for yesterday at 7:46PM ET, but ULA had to delay the launch in order to work on an issue with sensors on the rocket. The launch was then scrubbed due to an aircraft in range of the mission. Tonight’s launch time is set for 7:42PM ET, but ULA can launch anytime until 8:22PM ET.

Called the SBIRS GEO-3, the satellite going into space tonight is part of the Defense Department’s Space-Based Infrared System, or SBIRS. It’s a surveillance initiative that provides early warning of missile launches throughout the globe. Specifically, SBIRS looks for special heat signatures that missiles produce, giving the US military enough time to deploy appropriate missile defense systems if necessary.

A surveillance initiative focusing on the early detection of missile launches

To do this, SBIRS utilizes satellites in two different orbital paths, as well as data processing facilities on the ground. SBIRS GEO-3 is the third SBIRS satellite that will go to a geosynchronous orbit — a path 22,000 miles above the Earth’s surface in which spacecraft match the planet’s rotation. In this orbit, the satellite will be located over the same patch of Earth at all times.

ULA’s coverage of the launch begins at 7:22PM ET, so check back then to watch the mission live.