NASA, United Launch Alliance and Air Force officials hold the pre-launch news conference for the Delta 2 rocket with the agency’s SMAP environmental satellite from Vandenberg Air Force Base on Jan. 27.

The Air Force will launch a second pair of small security probes 22,300 miles above the Earth using a Delta 4 rocket on Friday to alert ground controllers of impending space collisions and monitor potential meddling with U.S. orbiting assets.

The most powerful configuration of United Launch Alliance’s Atlas 5 rocket blasted off April 14 from Cape Canaveral, hauling multiple U.S. Air Force satellites to a perch high above the equator after piercing a clear evening sky over Florida’s Space Coast with 2.6 million pounds of thrust.