Photo: Orion NASA Blog of the Orion EFT-1 launch. It’s almost sunrise. It’s time to rise and shine
Mission Rundown: ULA - Delta IV Heavy - Orion EFT-1
Written: January 18, 2023
Lift Off Time | December 5, 2014 – 07:05:00 EST | 12:05:00 UTC |
Mission Name | Orion EFT-1 |
Launch Provider | ULA - United Launch Alliance |
Customer | NASA - Lockheed Martin |
Rocket | Delta IV Heavy |
Launch Location | Space Launch Complex 37B - SLC-37B Cape Canaveral Air Force Station, Florida |
Payload | Orion Crew Vehicle with mockup ESA Service Module |
Payload mass | 13 270 kg ~ 29 194 pounds |
Where did Orion go? | Low Earth Orbit - Initial 185 km x 888 km x 28,59° Second Orbit 5 790 km x -29.8 km x 28,59° |
Type of launch system? | Delta Evolved Expendable Launch Vehicle - 3 Core’s |
The Side Booster’s fate? | In the Atlantic Ocean east of SLC-37B |
The first stage landing zone? | Bottom of the Atlantic Ocean 2 500 km downrange |
Type of second stage? | 5 meter DCSS RL-10B-2 engine - 17m 06s burn time |
Is DCSS derelict? | No - Main engine 3rd start/cutoff was 58 seconds Last orbit is 5 790 km x -30 km x 28.17° |
Type of customized fairing? | 5.4 meter three part carbon composite side panel Orion capsule ascent cover with launch abort system |
This will be the: | – 90th flight of all ULA rockets – 8th flight of a Delta IV Heavy rocket – 1st orbital test flight of Orion – 1st civilian use of a Delta IV rocket – 19th ULA mission for NASA – 13th mission for ULA in 2014 |
Where to watch Where to read more in depth | NASA/ULA YouTube link provided by Matthew Travis Want to know or learn more go visit or see Tim Dodd |
Launch debriefing (This too did happen) Brandi Dean interviews a number of people Charlie Bolden NASA Mark Geyer NASA John Yembrick NASA Rex Walheim Astronaut M Hawes - Lockheed M Gail Swan - Radworks L-19:00 minutes at 46:06 was the start of a 15 min hold until T-4:00 minute Recording slips evident since L-7:00 happens at 57:40 instead of 58:06 We see the CCB external camera while Steve Agid go through the steps on audio alone Silent Movie at 1:57:09 Sound back at 3:57:49 | L-00:04:38 Host: L-00:07:00 T-00:04:00 T 00:00:00 T+00:01:22 T+00:01:24 T+00:03:48 T+00:05:31 T+00:05:38 T+00:05:51 T+00:06:13 T+00:06:30 T+00:17:18 T+01:55:20 T+03:23:27 T+03:45:00 T+04:11:05 T+04:13:49 T+04:20:42 T+04:21:45 T+04:25:30 Enjoy | NASA/ULA live feed at 01:10 counting down Brandi Dean, Mike Curie, Steve Agid, Rob Navias Final Polling preparing the launch at 57:40 Release -4 minute hold at 1:00:40 Liftoff at 1:04:40 - No T+ clock - 12:05:00.180 UTC MaxQ at 1:06:02 - Maximum aerodynamic pressure Mach 1 at 1:06:04 - Speed Mach One 1225,5 km/h Side Booster separation at 1:08:38 - That’s all folks BECO at 1:10:11 - Core booster is empty - 331 second Stage separation at 1:10:18 - Just losing 90% weight MES-1 at 1:10:31 - DCSS RL-10B-2 engine start Ogive panel separation at 1:10:53 - Just caught it LAS cover separation at 1:11:10 - That's a no show MECO-1 at 1:21:58 - Coasting the World - 11m27s burn MES-2 to SECO-2 doing a 286 second transfer burn Deployment of Orion from DCSS+ESA SM at 04:28:11 MES-3 - SECO-3 - DCSS doing a 58 second deorbit burn DCSS doing a +44g dive into the Pacific Ocean Reentry interface blackout at 5:18:29 - Downlink froze Drouge’s deployed at 5:24:22 - Flailing like crazy Main parachutes seen at 5:25:25 - They are out Orion lands on 23.6° N * 116.46° W at 5:29:10 on video + Recovery operations of Orion on video + Press review |
Rise and shine. A new dawn awaits
For the first time since 1981 NASA test-flew a new vehicle designed to carry astronauts into deep space. The unmanned Exploration Flight Test 1 mission, is the maiden flight of NASA’s Orion spacecraft, launched during the second launch attempt on a Delta IV rocket from Cape Canaveral, prior to a successful splashdown in the Pacific Ocean.
The mission required Orion making almost two full orbits of the planet during a four and a half hour mission that ended with the spacecraft’s recovery in the Pacific Ocean.
The Delta IV Heavy rocket with Orion launched from Launch Complex 37B, Cape Canaveral AFB on Friday, December 5, 2014 at 07:05 EST - 12:05 UTC.
Screenshot from NASA TV of the major parts of Delta IV Heavy with Orion, ESA SM, DCSS and LAS
The Orion Payload
The Orion EFT-1 mission allows key systems on the Orion spacecraft to be tested years before it would have otherwise been able to fly.
Orion is designed to carry up to four astronauts into Lunar orbits and return them safely to Earth. When NASA’s Space Launch System (SLS) becomes operational, Orion will use it as a launch vehicle getting into orbit.
As long SLS still is under engineering and development, plagued by budget cuts, Congress meddling and forced to eat from NASA’s other activities, Orion will be ‘grounded’ awaiting its second launch opportunity. That day came in December 2022. Eight years later.
The spacecraft consists of a Crew Module built by Lockheed Martin, paired with a ESA - European Service Module built by Airbus based on the Automated Transfer Vehicle.
For the EFT-1 mission a live Crew Module is flying, however the Service Module is a mockup which will remain attached to the carrier rocket. The third part of the spacecraft is the Launch Abort System (LAS), which is designed to carry the Crew Module clear in the event of a launch failure.
This will be partially functional for EFT-1; LAS will be able to separate under its own power however it will not be used in earnest in the event of an anomaly during the launch.
The EFT-1 launch took place from Space Launch Complex 37B (SLC-37B) at the Cape Canaveral Air Force Station.
The Saturn rocket made its first orbital launch from SLC-37B in January 1964, with a Saturn I carrying the nose of a Jupiter missile into low Earth orbit.
EFT-1 is not the first spacecraft called Orion to launch aboard a Delta IV Heavy; the same name has been given to a series of signals intelligence satellites operated by the NRO. Three Delta IV launches have carried SIGNT Orion satellites, NROL-26, NROL-32 and NROL-15, into geostationary orbit.
The Zero-G indicator, a soft toy that can't damage or trigger any switches, is meant to show visually when the spacecraft reaches the environment of microgravity as it begins to float within the capsule. Such indicators have flown on several spacecraft’s from Russian Soyuz to SpaceX’s Crew Dragon and Boeing’s CST-100 Starliner.
The Orion Crew Module itself is a bigger version of the Apollo Command Module with a titanium pressure vessel surrounded with life support systems, oxygen, nitrogen, water, RCS thrusters, avionics, battery packs, computers, electrical harnesses outside and inside plus a lot of panels. Everything is bolted on with 192 lateral bolts around the perimeter.
The titanium pressure vessel is welded together from seven major parts: A bottom floor bulkhead, a barrel sidewall, a three part cone with four windows and a sidehatch, a sealing top bulkhead and a docking tunnel with one or two hatches. Surrounding the tunnel is room for parachutes, drogue chutes, star cameras and docking avionics.
Orion 2 without panels being welded in the O&C Building cleanroom. Photo: NASA/Kim Shiflett
The parachute system for Orion is composed of 11 different parachutes which operate to slow down the spacecraft and bring it to a safe earth landing. The system's three primary parachutes are made of tough nylon and are the size of football fields.
The parachutes are packed under thousands of pounds of pressure. It takes over a week to pack just one main parachute. NASA has conducted 17 previous parachute drops at the Yuma proving ground. Each in slightly different configurations.
The Crew Module will also be integrated with its heatshield consisting of 186 blocks of Avcoat material, and the heatshield assembly has since gone through thermal testing and application of sealant in the seams between all the blocks. The sealant material is an RTV (Room Temperature Vulcanizer) and phenolic material, that have been tested in the thermal chamber at ambient pressure and it was taken to a high temperature and a low temperature brimming with test sensors searching for flaws.
The titanium pressure vessel is covered with a micrometeoroid and debris protection material made of numerous blocks of Thermal Protection System TPS similar to the 186 Avcoat blocks in the heat shield. During reentry they will protect the crew against the heat backwash from plasma shockwave.
The black backshell panels will be covered with a silicone-oxide coated aluminum kapton tape, in a similar fashion to how the heat shield is taped. It will protect them from direct sunlight in space. The picture below makes me think: ‘Batman’.
Engineers are checking and installing micrometeoroid and debris protection. Photo source
Between the Orion Crew Module and the European Service Module there is a Crew Module Adaptor CMA that is a donut shaped ring filled with extra life support systems, oxygen, nitrogen, water, avionics, battery packs, computers, electrical harnesses plus a lot of outer panels. That also is bolted on with bolts inside and around the perimeter.
The donut-shaped CMA has an inner ring wall with longerons encircling it. There are face-sheet-like walls or panels on the forward and aft faces (or the top and bottom) and then also on the outside edge. Access to the compartment divided by those walls is difficult enough to require a lift to remove the Orion Crew Module.
Protection from Fairings or Ogives
On top of Orion is the forward bay cover. This will protect the Orion’s crew module at speeds of more than 25,000 mph.
After reentry, jettison mechanisms will generate enough thrust to push the cover away from the spacecraft and allow the three main parachutes to unfurl, stabilizing and slowing the capsule to 20 mph or less for a safe splashdown in the Pacific Ocean.
Delta Cryogenic Second Stage DCSS with its adapter cone, European Service Module ESM mockup with Capsule Module Adapter CMA, Orion Crew Module OCM, three ESM cover panels and the Launch Abort System LAS ‘abort tower’ with a four panel cap. American alphabet soup. Yerk.
This will be a test of the Orion spacecraft as an integrated system ahead of crewed flights to the Moon. Although there will be no crew on Orion, the launch abort system will collect flight data during the ascent to space and then pull away exposing Orion.
The Orion spacecraft will be protected by four panels, or ogives, that make up the fairing assembly and protect the spacecraft from heat, air, and acoustic environments during its entry into orbit. Orion will be integrated onto the Delta IV Heavy in the HIF.
On top of the fairing assembly will be mounted the 13,4 meter (44 foot) tall LAS Launch Abort System or Abort Tower, who will pull Orion’s ‘helmet’ away after ascent into orbit. There are several ‘real life’ abort scenarios available. link
The Delta IV Heavy launch
The Delta IV which will launch EFT-1 is Delta 369, and will be flying in the Delta IV Heavy configuration. The rocket’s Delta number, 369, indicates that it is the 369th launch to be counted as a Delta mission.
Ahead of the EFT-1 launch, Orion’s Crew and Service Modules were stacked in NASA’s Operations and Checkout building in early September. Once integration was complete the spacecraft was transported to the Payload Hazardous Servicing Facility for fuelling and subsequently the Launch Abort System Facility - LASF where the launch escape system was fitted on top of four Ogive panels around the capsule.
Following the Delta IV’s Wet Dress Rehearsal (WDR) on 5 November, Orion was transported to the pad on 12 November before being mounted atop the rocket later the same day.
Retraction of the Mobile Service Tower from around the rocket before the launch attempt began at around 04:05 UTC (23:05 local time), with the arrival of Launch Operations, Orion Engineering and Management teams filling their station at around the same time.
Four hours and thirty eight minutes before liftoff the countdown entered the first of two planned built-in holds, the T-4 hour 15 minute hold, with teams conducting a vehicle launch readiness poll lasting 8 minutes.
Propellant loading began when the countdown resumed. Nineteen minutes before launch, with the countdown clocks showing T-4 minutes, the countdown will enter its second and final planned fifteen minute hold used to catch up with last minute problems.
During that hold, Orion will be transferred onto internal power at nine minutes before launch. At L-7:00 ULA and NASA will conduct final polls to ensure readiness to launch.
At T-4 minutes the terminal countdown began with a liftoff aimed at 12:05:00 Zulu, which is an Air Force term for Greenwich Meridian Time - GMT, now known as the more scientific term Universal Time Coordinated - UTC.
With Friday’s countdown going to plan, the attempt proceeded to five seconds before launch, where the three RS-68 engines powering the first stage and boosters ignited.
Liftoff took place at T-0, when the thrust generated by the vehicle exceeded its weight, and the rocket began its ascent towards orbit.
Thirteen seconds into flight Delta 369 conducted a yaw and pitch maneuver to establish the planned launch azimuth - Compass Course - of 95 degrees.
Fifty seconds after launch the center core’s engine was throttled down to 80% thrust.
Delta IV passed the sound barrier Mach-1 at one minute, 22.2 seconds mission elapsed time and experienced maximum dynamic pressure – max-Q – simultaneously.
About three minutes and forty eight seconds after launch the strap-on boosters began to throttle down, with separation occurring at the three minute, fifty-eight second mark.
After the side boosters separated, the core stage was throttled back up, remaining at full thrust until a few seconds before the end of its burn. First stage flight concluded with main engine cutoff, or MECO, 92.6 seconds after booster separation.
The spent first stage was jettisoned a little over seven seconds after MECO, with the second stage’s RL-10B-2 extending its nozzle and beginning its pre-start sequence.
The RL10 ignited 13 seconds after stage separation to begin the first of 3 planned burns.
Early in second stage flight, about twenty five seconds after ignition, the protective fairing separated from around Orion’s Service Module followed five seconds later by the Launch Abort System separating from the nose of the spacecraft.
Lasting 11 minutes and 26.1 seconds, the first burn of DCSS D-369’s established a 185 by 888 kilometer (115 by 552 mile, 100 by 479 nautical mile) parking orbit.
Completing the burn EFT-1 coasted for one hour, 38 minutes and 3.4 seconds.
Commencing at one hour, fifty five minutes and 20.5 seconds elapsed time, the second burn had a duration of 4 minutes and 42 seconds. The final powered phase of Orion’s mission, the burn raised the apogee of the spacecraft’s trajectory while sufficiently lowering its perigee to deorbit it.
After the burn Orion was on an Earth-intersecting trajectory with an apogee of 5,790.0 kilometers (3,597.8 miles, 3,126.4 nautical miles), a perigee 29.8 kilometers (18.5 miles, 16.1 nautical miles) below the Earth’s surface, and inclination to the equator of 28.8o.
For the coast to apogee, Orion remained attached to the DCSS. Around five minutes into the coast phase the vehicle entered a high-intensity region of the lower Van Allen radiation belt, which took around fifteen minutes to clear.
During this time instruments aboard the spacecraft, including cameras, were deactivated to reduce the chance of damage being sustained. No negative impacts were noted.
Orion’s Reaction Control System - RCS was activated during the coast, at about two hours and forty minutes elapsed time.
Around the three hour and five minute mark into the mission, Orion reached apogee, the farthest point from the Earth on its trajectory.
Three hours and nine minutes after launch the DCSS reoriented itself for spacecraft separation, with the Orion capsule separating at three hours, twenty three minutes and forty one seconds mission elapsed time.
The spacecraft passed back through the high-intensity region of the inner Van Allen belt at around the three and a half hour mark in the mission, this time taking thirty five minutes to pass through.
While it was in the radiation belt, the Orion capsule conducted a ten second burn of its thrusters to adjust its course for reentry.
This burn occurred three hours, fifty seven minutes and eleven seconds into the mission.
After Orion separated, the DCSS performed its third and final burn to position itself clear of its payload’s operations. DCSS increased its speed to deorbit ahead of Orion.
This disposal burn lasted almost one minute, with the disposal burn ignition scheduled for three and three quarter hours after liftoff.
As a result of making this burn, the upper stage reentered the atmosphere ahead of Orion, at around four hours, 11 minutes and five seconds MET. The DCSS carrying the dummy ESA Service Module was destroyed when it entered the atmosphere.
Entry interface for Orion occurred at a mission elapsed time of four hours, thirteen minutes and thirty five seconds, with the spacecraft traveling at 8.9 kilometers per second (32,000 kph, 20,000 mph). Six seconds after the interface, the spacecraft began to experience an expected two-minute, 24-second communications blackout due to the effects of reentry.
The spacecraft experienced maximum heating of around 2,200 degrees Celsius (4,000 degrees Fahrenheit) about one minute and twenty eight seconds after interface – initiating the key test relating to the spacecraft’s heat shield. It also experienced 8.2 g loads.
Following the reestablishment of communications, Orion continued to descend through the atmosphere. Five minutes and fifty four seconds after interface the spacecraft deploys three drogue parachutes to jettison its forward bay cover, which protects the nose of the spacecraft from heat backwash during the reentry faze.
Two seconds after the forward cover was released, Orion’s two small drogue chutes were deployed. Later followed by two larger drogue chutes breaking the speed even more.
The main parachutes deployed sixty nine seconds after the drogues, with splashdown occurring two minutes and forty nine seconds later, at four hours, twenty three minutes and twenty nine seconds mission elapsed time.
First now did failures crop up as the floating devices failed partially inflating, one main parachute sank during the hour-long salvage operation and the forward bay cover was lost due to either drogue chute failures or floating devices failure to inflate.
Orion splashes down in the Pacific Ocean, approximately 1,000 kilometers (600 miles) off the coast of California. The US Navy positioned two ships in the landing area to recover Orion after its mission. Powerboats and small Rescue Boats delivered divers and recovery personnel to perform salvage operations.
Divers secured the spacecraft, attaching a flotation collar, tethers and a drift anchor.
The USS Anchorage, a San Antonio class amphibious transport ship, was then used to transport Orion back to port using its flooded amphibious well deck.
The USNS Salvor, a Safeguard class salvage ship, was used to collect the parachutes – as much as at least one of the main chutes could not be recovered – and other hardware - the forward bay cover - designed to separate from the capsule exposing the main parachutes and land using its own three drogue parachutes, which also was deemed as lost.
The Delta IV Heavy rocket
The Delta IV is a two-stage rocket, consisting of a Common Booster Core (CBC) first stage with a Delta Cryogenic Second Stage (DCSS) atop it. Both stages are cryogenically fuelled, burning liquid hydrogen as fuel and oxidized by liquid oxygen.
Each Common Booster Core is powered by a single Aerojet Rocketdyne RS-68 engine. In the Heavy configuration two additional CBCs are attached to the first stage CBC in order to provide a significant increase in thrust at liftoff.
The inboard core will be throttled down during the early stages of flight to extend its burn time, with the outboard cores separating around a minute and a half before the end of powered flight. The DCSS has a single RL10B-2 engine.
The Delta IV Heavy rocket with Orion stands 73.76 meters - 242 feet tall, is 16.15 meter - 53 feet wide and weighs 725.75 tons - 1.6 million pounds fully fueled. It will launch on 9.34 Mega Newtons - 2.1 million pounds of thrust from the three RS-68A main engines.
Customers can choose between different payload fairing sizes to better optimize for their specific payload. There is a metallic trisector fairing available for special payloads.
To accommodate payloads of all sizes, ULA offers two different payload fairings both 5.1 meter (16 ft) wide. A 14 meter (47 ft) tall fairing and a 19.1 m (62.7 ft) tall fairing.
The Delta IV Heavy first stage consists of three nearly identical 40.8 meter - 170 foot boosters strapped together. Each booster has one RS-68A engine also manufactured by Aerojet Rocketdyne. The first stage is infamously known for lighting itself on fire just before launch to burn off extra hydrogen.
It does this because it needs to get rid of any residual hydrogen so it does not explode unintentionally during liftoff.
The Delta IV Heavy first stage consists of three boosters strapped together. The Hydrogen and Oxygen tanks hold together 470 000 gallon of liquid propellant in 6 tanks measuring about 1 792 m3 in needed tank volume.
NROL-82 states that 120 000 gallons of liquid Oxygen is loaded. NROL-44 gave me these numbers. Second source found. Is 470 000 gallon of liquid propellant with DCSS +?
Each booster has one RS-68A engine also manufactured by Aerojet Rocketdyne. Together with DCSS and fairing they stand 71,6 meters - 235 feet tall on the launch pad.
The Hydrogen tanks hold 330 000 gallon of liquid Hydrogen chilled to -252,8 0C Celsius or -423 0F Fahrenheit in 3 tanks measuring about 1 254 m3 in estimated tank volume. The three Hydrogen tanks each hold at least 418 m3 cubic meter liquid Hydrogen.
The Oxygen tanks hold 120 000 gallon of liquid Oxygen chilled to below -182,96 0C Celsius or -297,33 0F Fahrenheit in 3 tanks measuring about 454,2 m3 in estimated tank volume. The three Oxygen tanks each hold at least 151,4 m3 cubic meter liquid Oxygen.
Screenshot of Delta Heavy IV split in its major parts. This vehicle launched a bulky NROL mission
The hydrogen ‘fire’ comes from the purging or chilling of the engines prior to ignition. The engine can’t handle the freezing chock of liquid Hydrogen and Oxygen and will split itself apart especially in the turbopump bearings. They will become brittle and shatter.
Each RS-68A engine has the capability to produce 3,160 kN (705,000 lbf) of thrust for a combined 9,420 kN of total thrust. The RS-68A engine has a specific impulse of 362 seconds and burns liquid hydrogen (LH2) and liquid oxygen (LOx).
Graphic demonstration of Delta IV Heavy’s cargo capacity is thanks to the DCSS boost. link
Continuing up the rocket comes the second stage. The Delta Cryogenic Second Stage (DCSS) is powered by a single, vacuum optimized RL10B-2 engine. For its fuel, the DCSS uses liquid hydrogen (LH2) and for the oxidizer, liquid oxygen (LOX).
The LH2 tank - volume of 38 m3 holding 10 000 gallon LH2 - being on top, has the job of supporting the payload and the payload fairing with a strut gage of two rings and is also structurally separated from the other ‘half’ of DCSS. The clearly smaller LOX tank - volume of 23 m3 holding 6 000 gallon LOX - is suspended in a strut gage of two rings below it and is responsible for structurally supporting the RL10B-2 engine.
The RL10B-2 was originally built by Aerojet Rocketdyne and first flew in 1998. It has the capability to produce 110 kN (24,700 lbf) of thrust in a vacuum and has a specific impulse of 462 seconds. It will light up at least four times with 18 minutes 15 seconds of burn time at an unknown throttle setting during the mission.
In order to save costs and weight, the rocket engine's gimbal system either uses battery powered or fuelcell powered electromagnetic actuators over normal hydraulics; this also increases reliability.
With the propellant already consisting of liquid hydrogen (LH2) and liquid oxygen (LOx). I suspect that pumping gasses through a fuel cell to produce electric power is more weight economical than a massive lithium battery pack.
But what do I know about that?
CBC RS-68A Spin Start Pressurization is complete and the CCB helium bottles are at flight pressure. ??? - Status comment heard once on flight controllers comm radio net.
The engine's turbo pumps fan blades are started with Helium gas pressure forced through them from a ground supply compressor and a Helium gas tank.
I’m guessing here.
The RL-10B-2 engine is optimized for vacuum usage with a big nozzle - engine bell, it produces 110 kilonewtons - 24,700 pounds of thrust in space.
The aft RL-10C-1 engine mount of the Centaur upper stage is similar to the DCSS engine mount
This technical image of the aft bulkhead with the RL-10C-1 vacuum engine depicts two green pressure vessels and a gray composite wrapped Hydrazine propellant tank used to feed the Reaction Control System.
Monopropellant hydrazine N2H4 feeds the 9-pound thrusters designed for attitude control and keeping the propellant tanks under a small constant g force.
The wreckage of a hydrazine N2H4 tank from a crashed Atlas V Centaur upper stage, which is produced by ATK as a model 80427-1 pressure vessel. ATK described it as a 59 cm diameter, 86 cm long pressure vessel, constructed of annealed 6AL-4V Titanium and T-1000G graphite hoop wrap, and two spun domes.
Its empty mass is 19 kg; minimum wall thickness is 1 mm; propellant capacity is 153 kg.
The two green pressure vessels with Helium gas are either used to backfill the propellant tanks to prevent structural buckling or to spin a propellant pump up before engine ignition. The Helium gas could also pressurize the Oxygen tank to force a 10 second Oxygen rich startup sequence before hydrogen and spark plugs are applied.
A third pressure vessel with Helium gas is placed inside one of the propellant tanks. All propellant tanks seems to have one pressure vessel with Helium gas inside.
Centaur is equipped with Ullage thrusters fed with boiled off Hydrogen and Oxygen gas that constantly needs to be burned off to prevent the propellant tanks from overpressuring and rupturing during space flight.
The Ullage thrusters help with keeping the propellant tanks under a constant g force thus settling the liquid propellant Hydrogen and Oxygen ai the intake valves ready to use.
HAZ GAS operations involve loading of the hydrazine. The RCS thrusters on the DCSS are using hydrazine N2H4 and ammonia NH3 as propellants during orbit insertion. It is stored in two bladders: a hydrazine diaphragm tank and an ammonia diaphragm tank.
Hydrazine N2H4 burned together with dinitrogen tetroxide, N2O4. A 50:50 mixture by weight of hydrazine N2H4 and unsymmetrical dimethylhydrazine, (CH3)2NNH2 - UDMH was used in the Titan II ICBMs and is known as Aerozine 50.
These bipropellant reactions are extremely exothermic, and the burning is also hypergolic, as it starts burning without any external ignition.
The reaction control system (RCS) includes the ullage pressure thrust from the tanks and consists of twenty hydrazine engines located around the stage in two double-thruster pods and four quadruple thruster pods.
For propellant, 150 kg (340 lb) of Hydrazine and Ammonia is stored in two tanks and fed to the RCS engines. The propellant tanks are backfilled with pressurized helium gas, which is also used to accomplish some of the Centaur RL-10B-2 engine start up functions.
NasaSpaceFlight: William Graham link Gunter’s Space Page: Delta link | Coauthor/Text Retriever Johnny Nielsen link to ULA launch list - Link to ULA Fan |
