Atlas V - NROL-33 Launch Updates
Launch Vehicle Information, Countdown Timeline, ULA Archive
The complex propellant loading sequence got underway as soon as clocks started ticking again at T-2 hours. Fueling operations started with the initiation of the chilldown of the Ground Support Equipment on the Liquid Oxygen side to prepare for oxidizer loading. When LOX transfer lines and Mobile Launch Platform equipment had been chilled down, the Centaur Oxidizer Tank began its chilldown followed a short time later by the LOX Tank of the Common Core Booster.
In response to threats from the Russian side that may lead to an unavailability of RD-180 engines, United Launch Alliance announced that the production rate of the Delta IV rocket is being increased to be able to transition satellites planned to launch on Atlas V to the Delta IV if it becomes necessary. Delta IV does not rely on Russian components.
Sitting atop the Common Core Booster, Centaur stands 12.68 meters tall and 3.05 meters in diameter with an empty mass of 2,243 Kilograms. In total, Centaur carries 20,830kg of propellants at liftoff inside pressure stabilized stainless steel tanks. The upper stage is equipped with a single RL-10A-4-2 engine.
Entering the final hour of the countdown, all propellant tanks had reached topping and the launch team began a final round of systems tests. The hydraulic system of the vehicle was pressurized and checked and the RD-180 first stage engine as well as the RL-10 second stage engine were put through a steering profile test. As part of final countdown operations, Atlas V was put through Flight Termination System checks to make sure the system was ready to destroy the launcher in the unlikely event of a major malfunction.
As countdown clocks ticked down, teams loaded new flight software into the launch vehicle’s computers based on the latest weather data. The RD-180 engine completed its Fuel Fill Sequence and teams verified that all tanks had reached flight level.
At T-4 minutes, the countdown entered its final built-in hold of 10 minutes to give the launch team time to complete any open work. During the hold, the NROL-33 spacecraft went to internal power and switched to flight mode. The Launch Team was polled for the GO to press into the Automated Countdown Sequence – all Stations reported GO as the launch vehicle was ready, the range was clear and weather was favorable for liftoff.
Six seconds after CCB Shutdown, the pyrotechnic stage separation system was fired. Eight retrorockets ensured that the large Common Core Booster drifted away from the Centaur Upper Stage. Following staging, Centaur purged its Reaction Control System and pre-started its RL-10 engine on LOX.
Calculations done by space analyst Ted Molczan for the launch of NROL-38 in 2012 that had a similar flight profile showed that the mission was using a two-burn mission of Centaur to reach the injection orbit followed by spacecraft separation and a deorbit maneuver of Centaur almost five hours after liftoff.
Using a standard two-burn mission, Centaur was likely tasked with boosting the stack to a nearly circular Low Earth Parking Orbit as part of an 11-minute burn of the RL-10 engine for shutdown around 15.5 minutes after launch.
“Congratulations to all of our mission partners on today’s successful launch of the NROL-33 mission! The ULA team is honored to deliver another critical national security asset to orbit together with the NRO Office of Space Launch and the Air Force,” said Jim Sponnick, ULA vice president, Atlas and Delta Programs. “Today’s launch occurred six days after last week’s GPS IIF-6 launch – the second time this year that this team has launched back-to-back missions within a week. Successfully launching at this tempo is a testament to the team’s focus on mission success, one-launch-at-a-time, and continuous improvement of our launch processes.”
Seven first generation spacecraft were launched from 1976 to 1987 - each weighing in at about 630 Kilograms, capable of providing 12 channels for UHF communications. The second generation of SDS spacecraft started deployment in 1989 - having three satellites lifted by the Space Shuttle and a fourth launching on a Titan IV in 1996. These satellites featured significantly enhanced capabilities hosting communication payloads supporting several frequencies including K-Band to enable the system to handle high data rates.
Atlas V rolled to Launch Pad for Liftoff with classified NRO Payload Thursday
The rollout of the 58-meter tall rocket sitting atop its Mobile Launch Platform got underway around 10 a.m. local time on Tuesday as the MLP emerged from the Integration Facility – starting a 30-minute drive over to the launch pad using two trackmobiles to move the stack. Completing the first 550 meters of its journey, Atlas V arrived at the pad 35 minutes past the hour. Once arriving at the launch pad, the MLP was carefully centered in position to begin the process of connecting propellant umbilicals and electrical & data lines later on Tuesday. The trackmobiles will be removed later in the day and teams will begin preparations for countdown operations that are set to start at 2 a.m. local time on Thursday.
Countdown operations for the launch of NROL-33 will get underway on Thursday at 02:05 UTC - 7 hours ahead of the opening of the launch window. Ahead of the countdown, technicians will already be busy at the pad, completing final hands-on work and closing out the Vertical Integration Facility, pad facilities and the Atlas V launcher. The first step completed at T-6 Hours 20 Minutes is the activation of the Atlas V rocket.
The Atlas V 401 is the most basic and most-flown version of the Atlas V rocket. It uses the Common Core Booster as first stage with the trusted Centaur serving as upper stage. The vehicle stands 58.3 meters tall, is 3.81 meters in diameter and weighs 334,500 Kilograms at liftoff. No solid rocket motors are employed on this version of Atlas V. Atlas V 401 is topped by the short version of the 5-meter fairing.
>>>Atlas V 401 Overview
Without any solid rocket boosters, Atlas V will make a gentle liftoff and start a vertical ascent before initiating the normal pitch and roll maneuver to line up with the planned ascent trajectory. The flight profile of NRO launches is not being disclosed, but navigational warnings issued for this launch clearly indicate a launch to the south-east, headed for a low-inclination transfer orbit.
Also posted for this launch is a navigational warning for the re-entry of the Centaur upper stage that is valid nearly ten hours after launch in an area of the Pacific Ocean which indicates that Centaur will conduct a deorbit maneuver around apogee to be able to re-enter the atmosphere at the given location.
The spacecraft would be separated into an orbit of approximately 269 by 29,816 Kilometers around T+37 minutes. This sub-GTO orbit adds about 41m/s of delta-v to reach a Geosynchronous orbit when compared with the standard GTO that has an apogee at GEO altitude of 35,786 Kilometers.
With the spacecraft separated less than one hour after launch, Centaur would complete the normal Collision and Contamination Avoidance maneuvers before entering a long coast phase to reach apogee for a short burn to reduce its velocity by about 137m/s to place itself onto a trajectory to re-enter over the Pacific Ocean. The apogee maneuver would take place around T+4 hours and 45 minutes followed by re-entry & splashdown of any surviving components close to ten hours after launch to mark the completion of a long Atlas V mission.
Atlas V set for classified NRO Launch this Week
May 19, 2014
After Friday's successful launch of a Delta IV rocket delivering a GPS satellite to orbit, United Launch Alliance is aiming for a quick turnaround with its Atlas V ready to launch from Cape Canaveral this week carrying the classified NROL-33 payload for the U.S. National Reconnaissance Office.
Liftoff is set for Thursday during a 90-minute launch period beginning at 12:45 UTC - the exact launch window is not being disclosed for NRO Missions. Navigational warnings posted for this launch show a window of 13:05 to 14:37 UTC.
Being stacked at Space Launch Complex 41, Atlas V had its payload installed to begin an extensive testing campaign leading up to this week's launch. As with all NRO launches, the nature of the payload that is launched, the flight profile and the target orbit are closely guarded secrets. However, clues like the launch vehicle that is used, navigational warnings that indicate the planned flight path, and hints on the mission patches can help identify the secret satellite. In case of NROL-33, all indications point to it being a Satellite Data System spacecraft that will be placed in a Geosynchronous Transfer Orbit.
The weather forecast for Thursday's launch attempt shows an 80% chance of acceptable conditions during the launch window. "On launch day, high pressure and fair weather persists over Central Florida with a loose pressure gradient and light winds," the launch weather forecast of the 45th Weather Squadron said. "Although slight, the primary concern for launch is Cumulus Clouds associated with coastal showers with on-shore winds in the low and mid-levels of the atmosphere." In the event of a 24-hour delay, odds of good weather remain at 80%.