Space Test Program 3 Weather Forecast: 80% Chance Favorable

Meteorologists with the U.S. Space Force 45th Weather Squadron predict a 80% chance of favorable weather Tuesday, Dec. 7, 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
A ridge of high pressure at the surface will generally dominate central Florida through Wednesday. For primary launch day Tuesday, a frontal boundary stalls over the Florida panhandle, with extensive cloud cover over north Florida and a slight chance for some mid-level clouds to extend further south near the Spaceport. Therefore, the primary concern for launch day is the Thick Cloud Layer Rule. For Wednesday, this front and associated cloud cover lifts further north. With high pressure at the surface, we can expect mostly clear skies, with a very slight chance for a Cumulus Cloud Rule violation Wednesday morning.

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: