Space Test Program 3 Weather Forecast: Remains 90% Favorable

Meteorologists with the U.S. Space Force 45th Weather Squadron predict a 90% chance of favorable weather Sunday, Dec. 5, for launch of the Department of Defense Space Test Program 3 (STP-3) mission on United Launch Alliance (ULA) Atlas V 551 rocket. The two-hour launch window opens at 4:04 a.m. EST.

Lifting off from Launch Complex 41 on Cape Canaveral Space Force Station (CCSFS) in Florida, the ULA rocket will take the U.S. Department of Defense’s (DOD) Space Test Program Satellite-6 (STPSat-6) spacecraft, which hosts NASA’s Laser Communications Relay Demonstration (LCRD) and the NASA-U.S. Naval Research Laboratory Ultraviolet Spectro-Coronagraph (UVSC) Pathfinder.

Forecast Details
High pressure will be in place over central Florida through Sunday morning when it retreats into the Atlantic Ocean slightly by Monday, bringing light winds Sunday coming from the south on Monday, and a slight chance for isolated low topped showers near the coast on Monday. Therefore, there is minimal concern for the Cumulus Cloud Rule on Sunday, and an increased concern for the same on Monday as isolated showers near the coast.

Primary concern: Cumulus Cloud Rule

Join us here on the blog tomorrow morning for live launch updates – live coverage of the launch is scheduled to air on NASA Television, the agency’s website, and the NASA App beginning at 3:30 a.m. EST.

Learn more about tomorrow’s STP-3 launch by visiting the mission home page at To stay updated about LCRD and laser communications, visit: