Friday, June 29, for the Delta IV Heavy NROL-15 from Space Launch Complex-37 at Cape Canaveral Air Force Station in Florida. The L-2 weather forecast shows a 70 percent chance of favorable weather conditions for launch.

5:53 a.m.: The NROL-15 broadcast will begin at 5:53 a.m. A simulcast of the broadcast can be viewed here. here:

Weather Forecast: Overall probability of violating weather constraints:  30% Primary concern(s):  Cumulus Clouds, Thick Clouds

Overall probability of violating weather constraints for 24 hour delay:  30%

Primary concern(s):  Cumulus Clouds, Thick Clouds Developed in partnership with the U.S. Air Force (USAF) Evolved Expendable Launch Vehicle (EELV) program, the Delta IV family of launch vehicles combines design simplicity, manufacturing efficiency, and streamlined mission and vehicle integration to meet customer requirements to launch high-priority USAF, National Reconnaissance Office (NRO), NASA, and commercial payloads to orbit. With operational launch pads on both coasts—Space Launch Complex-37 at Cape Canaveral Air Force Station, Florida, and Space Launch Complex-6 at Vandenberg Air Force Base, Calif.—every Delta IV configuration is available to service the requirements of current and future satellite programs.

The Delta IV launch system is available in five configurations: the Delta IV Medium (Delta IV M), three variants of the Delta IV Medium-Plus (Delta IV M+), and the Delta IV Heavy (Delta IV H). Each configuration is comprised of a common booster core (CBC), a cryogenic upper stage and either a 4-m-diameter or 5-m-diameter payload fairing (PLF).

There are three variants of Delta IV M+ configuration. The Delta IV M+(4,2) uses two strap-on solid rocket motors (SRMs) to augment the first-stage CBC and a 4-m diameter PLF. The Delta IV M+(5,2) and Delta IV M+(5,4) have two and four SRMs, respectively and 5-m-diameter PLF.