Photo from ULA of the NROL-33 launch. It was the night before dawn. One stood there yawning
Mission Rundown: ULA - Atlas V 401 - NROL-33
Written: January 27, 2023
When might isn’t right, should we fight?
A National Reconnaissance Office (NRO) military payload rode into orbit atop the United Launch Alliance (ULA) Atlas V rocket on Thursday.
Liftoff of the NROL-33 mission from Cape Canaveral occurred on May 22, 2014 at 09:09 EDT local time - 13:09 UTC from Space Launch Complex -41 - SLC-41.
Thursday’s mission made use of the 401 configuration. Designated AV-046, the Atlas consists of two stages; a Common Core Booster powered by an RD-180 engine, with an RL10A-4-2-powered Centaur atop it.
The first stage’s RD-180 engine has recently been at the center of a political dispute. Produced by Russia, the engine was developed from the RD-170 series on the Zenit rocket.
This has attracted criticism due to the United States placing economic sanctions on Russia over its recent intervention in Ukraine. Although a license to produce RD-180s in the United States does exist, at present all engines are imported from Russia.
The NROL-33 payload
Like most missions for the National Reconnaissance Office, many details of Thursday’s launch – for instance the type of satellite being deployed and the rocket’s flight plan – were classified.
Launch hazard warnings and notices to airmen show that the rocket was to head East after liftoff, flying over the Atlantic. This suggests the Atlas will be targeting a geosynchronous transfer orbit, as this is the only low-inclination orbit regime typically used for NRO payloads of this size.
NOTAM warning of hazardous rocket operations at the red zones. 1st stage crash site is shown
The most likely identity of the NROL-33 payload is a Quasar communications satellite. Used to relay data from other NRO satellites to ground stations, Quasar is also known as the Satellite Data System (SDS).
Speculation that the NROL-33 payload is part of the Satellite Data System is reinforced by the patches created to commemorate the launch. The payload patch features a pack of three wolves – before it was edited down for release – and a winged warrior emitting five beams of light from her outstretched hand, against the backdrop of a setting sun.
The wolves most likely denote the three newest satellites in the Quasar fleet, all of which operate in geosynchronous orbit. Five earlier satellites – two geosynchronous and three in elliptical Molniya orbits – have been identified as part of the same generation of satellites – these are presumably denoted by the beams.
A setting sun is usually employed to symbolize the final launch of a particular satellite, so presumably L-33 will be the last third-generation SDS.
The launch patch, meanwhile, features a flying squirrel along with the motto “Defendi nostrae opes”, literally “to defend our resources”. The meaning of this is not entirely clear, however it could be related to the fact that NROL-33 is intended to support the NRO’s reconnaissance fleet, and provide it with resources to return images for analysis.
Europe is prominently featured on the insignia, which suggests the spacecraft is intended for use over that part of the world.
The patch also features eight stars, arranged in two banks of four on either side. While its meaning remains unclear, this symbol has appeared on several past Quasar patches.
The NROL-27 and NROL-38 missions of 2011 and 2012 replaced the two earlier geosynchronous satellites.
Since both geosynchronous satellites have been replaced in the last few years, it is unlikely that L-33 will replace an existing satellite.
It remains unclear whether it will serve as an on-orbit spare, or be used to open a new orbital slot for the constellation. It also remains to be seen whether the geosynchronous element of the constellation has now completely replaced the Molniya component, or whether these planes will be replenished in due course.
The Atlas V 401 launch
Thursday’s launch used the four meter Long Payload Fairing (LPF), which at a length of 12.2 meters (40 feet) is the smallest of those available for the Atlas V. The LPF’s somewhat confusing name comes from its earlier use on the Atlas I, where it provided a longer alternative to the smaller and now long-discontinued Medium Payload Fairing.
While the precise flight plan for AV-046 is classified, it is likely to resemble past Atlas missions to geosynchronous transfer orbits.
All Atlas V missions begin with RD-180 ignition at T-2.7 seconds, with the engine building up thrust before lifting off at T+1.1 seconds.
Shortly after liftoff, AV-046 performed a roll maneuver to align itself along the required azimuth to achieve the necessary low-inclination orbit. Around eighty seconds into the mission, Atlas passed through the speed of sound, Mach 1, followed by the area of maximum dynamic pressure or Max-Q.
First stage flight concluded around four minutes and three seconds after liftoff, with the RD-180 being throttled back during the last few seconds of powered flight in order to keep the rocket’s acceleration at levels slightly negative which would ‘stretch’ the rocket stack easing the separation and reduce damage done to the Centaur stage and its payload.
Six seconds after cutoff, the spent Common Core Booster separated and the Centaur with a small forward momentum pulled away and began its pre-start sequence. RL10 ignition came ten seconds after the spent stage was jettisoned.
Around ten to twenty seconds into the second stage burn, the payload fairing separated from around AV-046’s payload. This marks a media black out and transmission ends.
The Centaur will likely make two burns, with their lengths dependent upon whether the standard or high-perigee transfer orbit is required. For a standard geosynchronous transfer orbit, the first burn will last around eleven minutes, with a ten minute coast phase before a four-minute second transfer burn is initiated near the Equator.
Missions to a higher-perigee orbit would see the first burn extended by two minutes, with the second being cut to about 80 seconds after a much longer coast of around an hour and a half. Based on past Quasar launches, the standard profile is more likely.
Following spacecraft separation, NROL-33 will be given a USA designation – most likely USA-252 – and will maneuver to geosynchronous orbit under its own power.
The Centaur will make a further 58 second deorbit burn some time after separation. The length of this burn depends on available propellants left in the Centaur tanks.
Reentry is expected to occur after 9-10 hours of mission elapsed time - MET between 22:06 to 23:10 UTC over the Pacific, near Kwajalein in the Marshall Islands.
The Atlas V 401 rocket
The Atlas V is an expendable medium lift launch system and member of the Atlas rocket family. The rocket is one of the most reliable in the world, having more than 45 launches with no complete failures.
The Atlas V 401 rocket, tail no. AV-046 is standing 57.31 meters - 188 feet tall on SLC-41.
The Atlas V, tail number AV-046, consists of a Common Core Booster (CCB), which is powered by an RD-180 engine with two bells and burns kerosene (RP-1) and liquid oxygen (LOX). This is accompanied by up to five strap-on solid rocket boosters. The second stage is the Centaur upper stage, which is powered by one RL10C-1 engine and is burning liquid hydrogen (LH2) with liquid oxygen (LOX).
Atlas V 401 split in its major parts. This is a generic non mission specific graphic configuration
Facts on the Atlas V 401 launch vehicle
Height of Atlas V 401: 188 feet (57.31 meters)
Mass at liftoff: 336,582 kilograms - 740,480 pounds
Thrust at liftoff: 3.8 mega-Newtons - 0.86 million lbf
Fuel onboard: 91,000 gallons of liquid propellant
LOX+LH2 = 66,000 gallon of cryogenic liquid propellant in three tanks
Core stage Atlas: 25,000 gallon RP-1 or 94,64 m3 - 48,800 gallon LOX or 184,73 m3
Core stage weighs fully fueled 306,271.7 kilograms - 675,213.5 pounds
Core stage measures 35.63 meters - 116,9 feet tall and 3.81 meters - 12,5 feet wide
Core stage RD-180 main engine produces 3,826.9 kilonewtons - 860,321.35 pounds of thrust at sea level while the thrust level increases to 933,406.73 pounds in space
Upper Stage Centaur: 13,050 gallon LH2 or 48,07 m3 - 4,150 gallon LOX or 15,71 m3
Upper Stage Centaur weighs fully fueled 23,073 kilograms - 50,867.3 pounds
Upper Stage Centaur measures 12.68 meters - 41,6 feet tall - 3.05 meters - 10 feet wide
RL-10A-4-2 engine is optimized for vacuum usage with a big nozzle - engine bell, so it only produces 99.1 kilonewtons - 22,300 pounds in space
Centaur has 150 kg (340 lb) of Hydrazine + Ammonia is stored in two diaphragm tanks
Centaur has 2-3 Helium 100-150 gallon pressure vessel storage tanks
Atlas V 401 XEPF 4.2 meter fairings weigh 2,487.0 kilograms - 5,482.9 pounds
Atlas V 401 LPF Payload Fairing measures 12.2 meter - 40 feet in length
NROL-33 payload weighs 4 950 kg ~ 10 890 pounds - Maximum for a GTO mission
HAZ GAS operations are completed when the hydrazine is loaded. The RCS thrusters on the Centaur stage are using hydrazine as a monopropellant during orbit insertion.
The reaction control system (RCS) includes the ullage gas pressure thrust from the tanks and consists of twenty hydrazine monopropellant engines located around the stage in two 27 newton twin-thruster pods and four 40 newton quad-thruster pods.
For propellant, 150 kg (340 lb) of Hydrazine and Ammonia is stored in a pair of diaphragm tanks and fed to the RCS engines aided by pressurized helium gas, which is also used to accomplish some of the Centaur RL-10A-4-2 engine start up functions.
The Centaur 2nd stage with a RL-10A-4-2 engine is hanging here in the Vertical Integration Facility
This photo of the Centaur with the RL-10A-4-2 vacuum engine depicts two insulated green pressure vessels - one behind the engine - a white insulated Ammonia sphere and a blue insulated Hydrazine sphere with propellant used to feed the thrusters in the Attitude slash Reaction Control System RCS.
The propellant is visibly divided in a large Hydrogen tank forward and a smaller Oxygen tank below it supporting the engine mount. The RL-10A-4-2 vacuum engine's red nozzle will get a longer nozzle cone extension mounted.
In the 401 configuration, the Atlas V is capable of carrying a structural maximum of 9,050 kg to Low Earth Orbit - LEO, 8,200 kg to the International Space Station - ISS and 4,950 kg to Geostationary Transfer Orbit - GTO.
The Common Core Booster contains a total of 284,089 kilograms - 626,309 pounds of RP-1 kerosene and liquid oxygen, weighs 306,271.7 kilograms - 675,213.5 pounds fully fueled, and is 35.63 meters - 116,9 feet tall and 3.81 meters - 12,5 feet wide.
The Centaur III upper stage contains 20,830 kilograms - 45,922.3 pounds of liquid hydrogen and liquid oxygen, weighs 23,073 kilograms - 50,867.3 pounds fully fueled, and is 12.68 meters - 41,6 feet tall & 3.05 meters - 10 feet wide.
The NROL-33 spacecraft weigh 4,950.0 kilograms - 10,890 pounds on its own, that’s with the fairings weight excluded.
The Atlas V 401 XEPF fairings weigh 2,487.0 kilograms - 5,482.9 pounds. The weight of a 6 foot fairing extension is estimated to be a small part of the LPF fairing. 200 kg at most.
Doing the math: 306272 kg + 23073 kg + 4950 kg NROL-33 + 2287 kg = 336582 kg.
The Atlas V 401 rocket has a three number configuration code.
The first number represents the fairing diameter size in 4 or 5 meters, so in this instance there is a 4 meter fairing. This launch will use the 12.2 meter long (40 ft) LPF.
The standard four-meter fairing, named the Long Payload Fairing (LPF), measures 12.2 meter (40 feet) in length and was first introduced as a larger fairing for the Atlas I rocket that was used as a launch vehicle in 1990.
One or two 90-centimeter (3-foot) cylindrical segments can be added to the fairing to form an Extended Payload Fairing (EPF) 13.1 meters (43 feet) or Extra-Extended Payload Fairing (XEPF) 14.0 meters (46 feet) respectively for payloads that require the additional space.
The second number denotes the number of solid rocket boosters (SRBs), which attach to the base of the rocket. The number of SRBs for a 5 meter fairing can range from 0 – 5.
The third number shows the number of engines on the Centaur Upper Stage, which is 1 in this configuration. So this means that this rocket will have a 4 meter fairing, no solid rocket boosters, and 1 engine bell on the Centaur Upper Stage.
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