ULA to launch classified NROL-61 payload
United Launch Alliance (ULA) is preparing to launch the latest addition to the National Reconnaissance Office’s (NRO) satellite fleet. On July 28, 2016, a classified payload—designated NROL-61—will launch atop a ULA Atlas V rocket, arranged in the 421 configuration (4-meter payload fairing, 2 solid rocket boosters, and a single engine Centaur upper stage), on a mission in support of national defense.
Encapsulated in its fairing, the payload was mated to the Centaur stage July 19, with an anticipated roll-out to the pad at Cape Canaveral Air Force Station’s (CCAFS) SLC-41 the morning of July 26.
With the nature of the payload being classified, there has been no officially-published launch window for this mission. The U.S. Air Force’s (USAF) 45th Space Wing shows a launch time of 8:37 a.m. EDT (12:37 GMT). However, the 45th Weather Squadron has defined its Launch Mission Execution Forecast to be valid from 8:37 a.m. to 9:34 a.m. EDT (12:37 to 13:34 GMT), so it would appear the launch window is approximately one hour long at a minimum. ULA plans to begin providing launch coverage at 8:17 a.m. (12:17 GMT) July 28.
The current forecast from the 45th Weather Squadron shows an 80 percent chance of favorable conditions at launch. A similar forecast is made for the following day, should a delay be necessary. The primary concern both days is cumulus clouds.
Though outfitted with the smaller-diameter fairing, NROL-61 will be sporting the largest version of the 4-meter family: the Extra Extended Payload Fairing (XEPF). Measuring roughly 45 feet (13.72 meters) in length, the two-piece fairing protects the payload from atmospheric, acoustic, and thermal stresses during launch, and pushes the overall length of the launch vehicle to approximately 194 feet (59.13 meters).
The Atlas V’s first stage is powered by a Russian-made RD-180 engine. Other than an anomaly on the OA-6 mission to resupply the International Space Station, which caused the boost stage to shut-down almost six seconds early, the dual combustion chamber engine has performed practically flawlessly for ULA. The kerolox-fueled (RP-1 kerosene and liquid oxygen) power plant produces 860,000 pounds (3,830 kilonewtons) of thrust at launch.
Providing extra “kick” off the pad, the first stage for this mission is augmented with two Aerojet Rocketdyne AJ-60A strap-on solid rocket boosters. The twin boosters burn for 94 seconds, with each providing 379,600 pounds (1,688 kilonewtons) of thrust. Upon burnout, they will separate from the first stage, eventually impacting in the Atlantic Ocean. They will not be recovered.
The Centaur upper stage is fitted with a single Aerojet Rocketdyne RL10C-1 engine, producing 25,000 pounds (110 kilonewtons) of thrust. Powered by liquid hydrogen and liquid oxygen, the RL10 family of rocket engines has been a staple of upper stage propulsion on ULA’s fleet of launchers and has a legacy dating back to the 1950s. NROL-61 will mark the 13th time the C-1 variant of the RL10 has flown.
United Launch Alliance and the National Reconnaissance Office have been long-time partners. The NROL-61 mission will represent the 23rd NRO launch by ULA, and the 13th on an Atlas V, although it will be the first launch on the 421 configuration for the intelligence agency. This will be the 3rd NRO launch, and ULA’s 6th, of 2016.
Of special note is the mission graphic for NROL-61. This classified operation continues the tradition of NRO missions for having interesting—if not at once meaningful—illustrations, leading to widespread analysis and speculation of the meaning of the artistry. Unfortunately, the NRO remains tight-lipped about the significance, if there is any, of the artwork as to how it relates to the mission.
Video courtesy of United Launch Alliance
Curt Godwin has been a fan of space exploration for as long as he can remember, keeping his eyes to the skies from an early age. Initially majoring in Nuclear Engineering, Curt later decided that computers would be a more interesting - and safer - career field. He's worked in education technology for more than 20 years, and has been published in industry and peer journals, and is a respected authority on wireless network engineering. Throughout this period of his life, he maintained his love for all things space and has written about his experiences at a variety of NASA events, both on his personal blog and as a freelance media representative.