An Atlas V will light up the night sky tonight around Cape Canaveral, FL

The Atlas V at SLC-40 during sunset
Photo // ULA

Tonight at 7:52pm EST, United Launch Alliance will be launching their Atlas V rocket in the 411 configuration. The Atlas V will be carrying the SBIRS GEO Flight 4 satellite for Lockheed Martin. The encapsulation of the payload occurred on Tuesday, January 9th at the Cape Canaveral Air Force Base in Florida. Prior to encapsulation, the satellite went under a lot of testing to ensure that the payload was ready to undergo the stresses during launch. The Atlas V trekked its way to Space Launch Complex 41 (SLC-41) yesterday with the SBIRS GEO-4 satellite mated to the upper centaur stage.

Atlas V rolled onto SLC-41
Photo // ULA

The Atlas V for this mission is in the 411 configuration, which means the rocket has a 4-meter payload fairing while using 1 Solid Rocket Booster (SRB) with one engine on the second stage. The reason for the single SRB is to get the payload up to its desired orbit while having fuel left over to de-orbit the upper stage after mission completion. The 2 RD-180 main engines used on the first stage use their large gimbal range to be able to compensate for the thrust from the SRB.

The Atlas V rolling out to the pad
Photo // ULA

SBIRS GEO-4 is manufactured by Lockheed Martin and will join the three SBIRS GEO satellites that have been launched since 2011. These satellites will provide an early warning of missile launches that are headed for the US, including launched nuclear weapons. Two additional satellites have been ordered by Lockheed Martin and will be launched in the early 2020s. These SBIRS GEO satellites can also register emissions from wildfires, meteors, satellite reentries, and nuclear detonations.