Screenshot from ULA Webcast of the MAVEN launch. Working on a railroad… I knew it. I’m a train
Mission Rundown: ULA - Atlas V 401 - MAVEN
Written: February 16, 2023
Martians needs weather reports
NASA’s MAVEN spacecraft began its journey to Mars following its launch atop the United Launch Alliance (ULA) Atlas V rocket on Monday November 18, 2013.
Liftoff from Cape Canaveral’s Space Launch Complex 41 (SLC-41) was at 13:28 Eastern Standard Time - 18:28 UTC, at the start of what was a two-hour launch window.
MAVEN’s launch was the first heliocentric orbit since Curiosity on November 26, 2011.
The Mars Atmosphere and Volatile Evolution, or MAVEN, spacecraft is the second and final mission in NASA’s Mars Scout program. It will be placed into orbit around Mars, from where it is expected to study the planet’s atmosphere.
MAVEN is expected to launch in a 20-day window between 18 November and 6 December, although further, less desirable, opportunities are available until as late as 23 December. If the spacecraft cannot launch by that date, the planets will have moved out of alignment and another opportunity to launch will not occur until January 2016.
Following launch, MAVEN will begin a ten-month coast to Mars. Launch on 18 November would permit arrival at Mars on 22 September next year. The planned ‘Mars’ areocentric orbit has a periareon of 150 kilometers and an apoaereon of 6,220 km (93 by 3,860 miles).
Planning for a year-long mission; however, up to six years of extended mission operations are possible, in addition to MAVEN acting as a communications relay for spacecraft with a limited communications capacity from the Martian surface.
Propellant reserves remaining in MAVEN are later calculated to last into 2030.
Following the end of its mission the spacecraft is expected to decay from orbit and enter the atmosphere of Mars, and as a result precautions have been taken to ensure it is sterilized in order to minimize contamination of the surface.
The MAVEN payload
MAVEN carries eight scientific instruments to study the Martian atmosphere. Six of these instruments are collectively designated the Particles and Fields Package. The total mass of MAVEN’s instruments is 65 kilograms (143 lb).
The Solar Energetic Particle experiment, or SEP, is part of the Particles and Fields Package designed to study the energies of hydrogen and helium ions emanating from solar storms which interact with Mars. Data collected will be used to help scientists characterize how these particles give energy to, and heat, the upper atmosphere of Mars.
The Solar Wind Ion Analyzer, or SWIA, is designed to study Mars’ interaction of the solar wind. Derived from instruments flown on the WIND, FAST and THEMIS spacecraft, SWIA will develop profiles of the temperature, velocity and density of ions in the solar wind, allowing scientists to calculate the rate at which Mars’ atmosphere is ionized by solar interactions. SWIA is part of the Particles and Fields Package.
STATIC, the Suprathermal and Thermal Ion Composition experiment, is a third part of the Particles and Fields Package. It is designed to profile highly energetic charged particles in the upper atmosphere.
Langmuir Probes and Waves (LPW) is another part of the Particles and Fields Package. Consisting of two sensors deployed away from the spacecraft on seven-meter (23-foot) booms, LPW will be used to conduct studies of Mars’ ionosphere.
An extreme ultraviolet imager is mounted on the body of the spacecraft for comparative observations. It is hoped that the experiment will better characterize the density of Mars’ ionosphere, and establish its boundaries.
The final part of the Particles and Fields Package is a pair of magnetometers mounted on the outside edges of the spacecraft’s solar arrays. The magnetometers are based on a design which has been used on NASA missions since the Voyager programme, while the arrangement of magnetometers on the solar arrays was previously flown on the Mars Global Surveyor mission.
An Imaging Ultraviolet Spectrograph (IUVS) will be used to study light emitted from particles in the upper atmosphere, thereby allowing scientists to determine its chemical composition.
MAVEN’s final instrument is the Neutral Gas and Ion Mass Spectrometer (NGIMS). This will be used to study the composition of the upper atmosphere in terms of low-energy ions and neutral, or unionized, gasses.
A ninth payload aboard MAVEN is the 22-centimeter (8.7-inch) Electra communications array, which will be used to transmit data between spacecraft on the surface of Mars and ground stations back on Earth. Mars orbiters are often used to relay data from landers that are not having to carry a large communications array allowing the mass of the individual Mars lander spacecraft to be reduced.
With a mass of 2,454 kilograms (5,410 lb), MAVEN is expected to operate for a year once it reaches Mars. The spacecraft is carrying 1645 kilograms (3627 lb) of propellant, with a dry mass of 809 kilograms (1,784 lb).
Enlarged graphic from NASA rendering of MAVEN in space during solar panel deployment
The spacecraft is powered by a pair of two-panel solar arrays, which will generate a minimum of 1.15 kilowatts. The spacecraft also carries two lithium ion batteries with capacities of 55 amp-hours which can be recharged by the solar arrays.
Propulsion is provided by six Aerojet MR-107N liquid rocket motors, with six smaller MR-106E thrusters for maneuvering, and MR-103Ds for attitude control.
These are all monopropellant thrusters, fuelled by hydrazine propellant stored in the spacecraft’s central tank. MAVEN was manufactured by Lockheed Martin.
The Atlas V 401 launch
AV-038’s mission to loft MAVEN began with ignition of the first stage engine; an RD-180 built in Russia by NPO Energomash. The RD-180 powers the Common Core Booster; the first stage of the Atlas V, which is fuelled by RP-1 propellant and liquid oxygen oxidiser.
First stage ignition occurred at T-2.7 seconds, allowing the engine to build up thrust before releasing the rocket for liftoff. Around 3.8 seconds after ignition, at T+1.1 seconds, the thrust generated by the engine exceeded the mass of the rocket, and the Atlas V rose from its launch pad to begin the climb into orbit.
The rocket rolled to a launch azimuth of 94 degrees and performed a series of pitch and yaw maneuvers to attain the trajectory necessary for its target orbit, with the first maneuvers beginning at 17.3 seconds into the flight.
About 90.9 seconds after launch the vehicle experienced maximum dynamic pressure, or max-q, the point at which aerodynamic forces acting upon the rocket were their greatest.
The first stage burn lasted until four minutes and 8.4 seconds into the mission, at which point Booster Engine Cutoff, or BECO, occurred. At this point the Common Core Booster exhausted its supply of propellant, and its engine was extinguished.
Stage separation occurred six seconds later, with the upper stage detaching from the CCB to begin second stage flight.
The second stage of the Atlas V was a Single-Engine Centaur - SEC. This stage burns cryogenic propellants: liquid hydrogen and liquid oxygen, in a single RL10A-4-2 engine. Developed in the 1960s for use on Atlas and Saturn rockets, the Centaur has flown over 200 times in varying configurations as an upper stage on Atlas and Titan rockets.
Although traditionally Centaurs were powered by two engines, since the single-engine configuration was introduced with the Atlas III it has become the norm, and the Atlas V is yet to fly with a dual-engine Centaur - DEC - configuration.
During Monday’s launch the Centaur made two burns. The first began 9.9 seconds after the first stage separated and lasted for nine and a half minutes.
Just under eight seconds into the burn the vehicle’s 4.2 meter metallic payload fairing was separated from around the MAVEN spacecraft.
The first Centaur burn culminated in Main Engine Cutoff 1, or MECO-1, 13 minutes, 48.3 seconds after liftoff. A coast phase then began, lasting for around 27 minutes and 36 seconds. At the end of the coast before its second crossing of the Equator, the Centaur began a second burn with a planned duration of five minutes, 28.9 seconds.
With the completion of the second Centaur burn, SECO-2, powered flight was completed.
Five minutes and 13 seconds later MAVEN separated from the upper stage to begin its own journey to Mars.
From the countdown reaching zero to spacecraft separation, the AV-038’s mission lasted only 52 minutes and 42.2 seconds. The Atlas 401 rocket delivered MAVEN flawlessly.
The Atlas V 401 rocket
NASA selected an Atlas V rocket, operated by United Launch Alliance, to send MAVEN on its way to Mars. The Atlas V used for this launch was AV-038; the forty-first Atlas V to fly since the type’s maiden flight in 2002.
Flying in the 401 configuration, with a 4.2 meter payload fairing, no solid rocket motors and a single-engine Centaur upper stage, the Atlas was tasked with delivering MAVEN into a heliocentric orbit: a hyperbolic trajectory in the Earth’s frame of reference with a characteristic energy of 12.2 kilometers squared per second squared.
The asymptote of the planned hyperbola has right ascension of 198.2 degrees, with declination of 17.7 degrees. It will be inclined 28.6 degrees relative to the Earth’s equator.
The Atlas V 401 rocket, tail no. AV-038 is standing 57.31 meters - 188 feet tall on SLC-41.
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: 334,086 kilograms - 734,989 pounds - Calculated mass
Mass on record 336728 kilograms - 742.359 pounds - Stated by George Diller
Thrust at liftoff: 3.8 mega-Newtons - 0.86 million lbf
Fuel onboard: 91,000 gallons of liquid propellant
LOX+LH2 = 66,000 gallons 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
MAVEN payload weighs 2 454 kg ~ 10 890 pounds - Maximum for polar 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/ Reaction Control System - ARS/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 gray 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 MAVEN spacecraft weighs 2,454.0 kilograms - 5,410 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 + 2454 kg MAVEN + 2287 kg = 334086 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.
