Screenshot from ULA Webcast of the launch of OA-7 Cygnus. Such a sunny day to launch a ‘Swan’
Mission Rundown: ULA - Atlas V - OA-7 Cygnus
Written: December 19, 2022
Delivering goodie packs to ISS
United Launch Alliance on behalf of Orbital ATK launched the OA-7 Cygnus mission to the International Space Station (ISS) on Tuesday. Flying on an Atlas V rocket, Cygnus departed the SLC-41 pad at Cape Canaveral Air Force Station at the start of a thirty-minute window that opened at 11:11 EDT - 15:11 UTC.
Orbital ATK uses the Cygnus to perform space station resupply flights under the Commercial Resupply Services contract. Cygnus consists of a pressurized cargo module for crew supplies, scientific experiments and equipment, together with an associated service module providing solar power and propulsion.
This mission will be the fourth flight of the extended variant of Orbital ATK’s Cygnus pressurized cargo module, which increases the spacecraft’s interior volume capacity by 25 percent, enabling more cargo to be delivered with each mission.
The extended variant of Orbital ATK’s Cygnus pressurized cargo module is built with three ring sections and not just two in the payload body. So the volume should be raised by a third to 150%. Something doesn’t fit in the previous sentence.
The Cygnus OA-7 Payload
The Cygnus OA-7 named the SS John Glenn is carrying 3,459 kilograms (7,626 lb) of cargo, including 954 kilograms (2,103 lb) of supplies and provisions for the crew, 1,215 kilograms (2,679 lb) of hardware for the US and international segments of the Space Station and 18 kilograms (40 lb) for the Russian segment.
The cargo also includes two kilograms (4.4 lb) of computer equipment and 73 kilograms (161 lb) of hardware to support extravehicular activities (EVAs) or spacewalks by the station’s crew.
Another 940 kilograms (2,072 lb) of cargo consists of scientific equipment and experiments to be performed aboard the ISS. The Advanced Plant Habitat will enable the crew to cultivate plants aboard the space station for bioscience research and experiments as well as helping to demonstrate food production in orbit.
Another experiment, Magnetic 3D Cell Culturing, will use magnetism to allow astronauts to manipulate cell cultures and samples in cell growth experiments.
The Antibody Drug Conjugates (ACDs) in Microgravity experiment will test new chemotherapy drugs in space, with the microgravity environment allowing samples of cancer cells to be grown that more accurately model how they would grow in the human body than can be achieved in a laboratory on Earth.
Thirty-eight small satellites are hitching a lift into orbit aboard Cygnus, with a total mass of 83 kilograms (183 lb) and built to CubeSat specifications.
Cygnus will deploy four Lemur CubeSats from the spacecraft following its departure from the space station. 36 CubeSats will remain aboard the ISS for later deployments.
CubeSat deployments from the International Space Station are made via the airlock of the Japanese Kibo module.
Twenty-eight CubeSats will be deployed from the International Space Station form part of the Von Karman Institute’s QB50 program, an international educational initiative aimed at deploying an array of CubeSat-mounted sensors into Earth’s thermosphere.
Originally conceived to consist of fifty satellites sharing a single launch, the project has now switched to use several smaller groups of spacecraft. The QB50-ISS mission will be followed next month by a PSLV launch with eight further satellites.
Another source of CubeSats aboard the Cygnus spacecraft is NASA’s Educational Launch of Nanosatellites program, or ELaNa XVII.
Some CubeSats come from various other independent sources.
Assembly line at Orbital ATK with Cygnus spacecraft. Saffire III is the big ‘match’ box in front - link
Cygnus will after its release raise its orbit in order to deploy the four Lemur satellites. It will also conduct the Saffire III experiment, which will use a self-contained package to ignite a fire within the spacecraft.
The extra 300 kg payload capacity is believed to be used by these experiments and the extra delta-v given by Atlas V will have provided Cygnus with the fuel reserves to perform the necessary orbit changes to conduct these experiments .
A suite of instruments, including thermocouples, radiometers and cameras will record how the fire propagates as it is allowed to burn freely for up to six minutes. OA-7 is the third and final Cygnus spacecraft to carry a Saffire payload, conducting research which is expected to improve fire safety on future manned spacecraft.
Once the research is complete, the SS John Glenn will be deorbited to a destructive reentry. A final experiment, the Reentry Data Collector 2 – RED-DATA-2 – will record flight data as the spacecraft enters the atmosphere and breaks apart.
The experiment will also test two new materials which may be useful for future heat shield development under reentry conditions.
The Atlas V 401 Rocket Launch
Atlas V 401 core number AV-070 began its mission with first stage engine ignition, 2.7 seconds before the countdown clock show’s zero.
The first stage Common Core Booster is powered by a single RD-180 engine. The RD-180, which was developed by Russian engine manufacturer NPO Energomash, is a two-chamber engine based on the RD-170 that was originally developed for the Zenit rocket. The stage consumes RP-1 propellant, oxidized by liquid oxygen.
Following ignition, the RD-180 built up thrust, with liftoff occurring when the engine’s thrust exceeded the weight of the vehicle – about 1.1 seconds after T-0. Atlas climbed away from Cape Canaveral’s Space Launch Complex 41 (SLC-41), before executing a series of pitch and yaw maneuvers beginning at 18.4 seconds into the flight. The rocket established itself on an azimuth downrange of 44.4 degrees. Aka. its compass course.
One minute and 22.5 seconds after liftoff, AV-070 passed through the sound barrier, achieving a speed of Mach 1. This was followed, 11.1 seconds later, by the vehicle passing through the area of maximum dynamic pressure or Max-Q.
The first stage RD-180 engine burned for the first four minutes and 15.6 seconds of the flight before shutting down. This event, designated Booster Engine Cutoff – or BECO – precedes separation of the Common Core Booster by six seconds. After separation, Centaur began its pre-start sequence before igniting ten seconds after staging.
The Centaur is powered by a single RL10C-1 engine, manufactured by Aerojet Rocketdyne. Burning liquid hydrogen and liquid oxygen, the RL10 can make multiple restarts to inject the Atlas’ payload into its designated orbit.
During Tuesday’s launch the Centaur made a single burn to deploy Cygnus, followed by a disposal burn to deorbit itself after spacecraft separation.
Eight seconds after Centaur began its first burn, the payload fairing separated from around Cygnus at the nose of the rocket. For Cygnus missions Atlas flies with a 14-meter (46-foot) long Extra-Extended Payload Fairing (XEPF), the longest of the three available four-meter (13-foot) diameter fairings. The fairing protects Cygnus from Earth’s atmosphere during ascent, and is discarded once the rocket is outside of the atmosphere.
The Centaur burned for thirteen minutes and 40.4 seconds, taking Cygnus into low Earth orbit. Two minutes and 49.1 seconds later – at twenty-one minutes and 1.1 seconds mission elapsed time – Cygnus separated to begin its mission. The launch targeted a circular orbit at an altitude of 230.0 kilometers (142.9 miles, 124.2 nautical miles) and an inclination of 51.6 degrees.
After separating Cygnus, the Centaur coasted for 27 minutes and 29.3 seconds, before restarting for a brief disposal burn. This 10.7-second burn deorbited the stage, guiding it to reentry to the south of Australia before it completes an orbital revolution.
The stage burned up as it reenters the atmosphere, with ULA forecasting that any surviving debris would impact the ocean at around 67 minutes and 6.6 seconds after launch.
Following separation from Atlas, Cygnus will perform a series of maneuvers as it chases the International Space Station ahead of a rendezvous currently planned for Saturday.
In the meantime, the Soyuz MS-04 spacecraft is scheduled to lift off from the Baikonur Cosmodrome carrying Expedition 51 and 52 crew members Fyodor Yurchikhin and Jack Fischer to the outpost. Soyuz will arrive at the station ahead of Cygnus.
Upon its arrival at the ISS on Saturday, the SS John Glenn will be captured by the station’s CanadArm2 remote manipulator system under the control of astronauts Peggy Whitson and Thomas Pesquet. The spacecraft will be berthed at the Unity Module’s nadir, or earth-facing, Common Berthing Mechanism.
The Cygnus is expected to remain at the station for almost three months, with its departure currently slated for around 11 July. At the end of its mission, Cygnus will be unberthed and released by CanadArm2 to begin its last free-flight mission.
The Atlas V 401 rocket
Tuesday's launch of United Launch Alliance’s Atlas V flying in the 401 configuration.
The Atlas V, tail number AV-070, consists of a Common Core Booster (CCB) first stage, with a single-engine Centaur (SEC) upper stage and a four-meter payload fairing fitted atop the Centaur. Although the Atlas V can fly with up to five Aerojet AJ-60A solid rocket motors boosting the first stage, AV-070 will use none.
Atlas V 401 split in its major parts. This is a generic non mission specific graphic configuration
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 70 launches with no complete failures.
The Atlas V 401 rocket, tail no. AV-070 is standing 59.1 meters - 194 feet tall on SLC-41.
The rocket has two stages. The first is 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 or two RL10 engines and burns liquid hydrogen (LH2) and liquid oxygen (LOX).
Atlas V rocket is filled with 344 472 liter - 91 000 gallons of RP-1, liquid oxygen and liquid hydrogen. Question is now how much goes to fill each stage and the four tanks. Together they can contain 344,47 m3 RP-1, cryogenic oxygen and cryogenic hydrogen.
The Common Core Booster holds 184 728 liter - 48 800 gallon liquid oxygen chilled to below -182,96 0C Celsius or -297,33 0F Fahrenheit that can fit in a 184,73 m3 oxygen tank.
The Common Core Booster holds 94 635 liter - 25 000 gallon RP-1 highly refined kerosine at room temperature that can fit in a 94,64 m3 fuel tank.
The Centaur upper stage holds about 49 400 liter - 13 050 gallons of liquid hydrogen chilled to -252,8 0C Celsius or -423 0F Fahrenheit that can fit in a 49,40 m3 hydrogen tank.
The Centaur upper stage holds about 15 709 liter - 4 150 gallons of liquid oxygen chilled to below -182,96 0C Celsius or -297,33 0F Fahrenheit that can fit in a 15,71 m3 fuel tank.
Still to find is data on Helium gas, pressures used and number of COPV to store it. And are there tanks to store propellant used to maneuver during ascent and in orbit.
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 pressure thrust from the tanks and consists of twenty hydrazine monopropellant engines located around the stage in two 2-thruster pods and four 4-thruster pods. For propellant, 150 kg (340 lb) of Hydrazine is stored in a pair of bladder tanks and fed to the RCS engines with pressurized helium gas, which is also used to accomplish some main engine start up functions.
In the 401 configuration, the Atlas V is capable of carrying a structural maximum of 9,050 kg to Low Earth Orbit (LEO), 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 - 675213.5 pounds fully fueled, and is 35.63 meters - 116,9 feet tall and 3.81 meters - 12,5 feet wide.
Its RD-180 main engine produces 860,321.35 pounds of thrust at sea level while the thrust level increases to 933,406.73 pounds in space.
The Centaur V1 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.
Its RL-10C-1 engine is optimized for vacuum usage, so it only produces 22,885.55 pounds in space.
Atlas V 401 weighs 339,056.52 kilograms - 747,491.67 pounds, including the Cygnus CRS OA-7 spacecraft; and is 59.142 meters - 194 feet tall and 4.2 meters - 13,8 feet wide.
The Cygnus CRS OA-7 spacecraft weighs 7,224.82 kilograms - 15,928 pounds on its own, that’s with the fairings weight excluded.
The Atlas V 401 fairings weigh 2,487.0 kilograms - 5,482.9 pounds.
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 14-meter-long (46 ft) XEPF.
The standard four-meter fairing, named the Long Payload Fairing (LPF), measures 12.2 meters (40 feet) in length and was first introduced as an optional larger fairing for the Atlas I rocket in 1990.
One or two 90-centimeter (3-foot) cylindrical segments can be added to the fairing to form an Extended Payload Fairing (EPF) or Extra-Extended Payload Fairing (XEPF) 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. In this case there will be no SRB’s attached to the center core.
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.
