SpaceX is launching a rocket today – no, not the Falcon Heavy, that’s still targeting February 6, but a Falcon 9 carrying a satellite bound for Geostationary Transfer Orbit (GTO). The mission, GovSat-1, is set to take place during a launch window which opens today at 4:25 PM EST (1:25 PM PST) and closes at 6:46 PM EST (3:46 PM PST).

The payload is a government satellite comissioned for launch by the Government of Luxembourg, supplied by Orbital ATK, and operated by satellite company SES (a prior SpaceX client). It’ll serve to provide combination for “tactical operations” and to assist humanitarian crises support efforts.

Thus far, the weather is looking only 40 percent favorable at Cape Canaveral Air Force based in Florida, from which the launch will take place. Conditions could improve throughout the window, however, and a backup launch opportunity is set for 4:25 PM EST on Wednesday, January 31.

The Falcon 9 used for this launch includes a flight-proven booster which was used in a mission last may, and the mission parameters do not include a recovery attempt for the rocket this time around. The stream above should kick off around 15 minutes prior to the opening of the launch window.