b'Engineer Innovation | AerospaceThe space launch, a highlycompetitive marketBy Sylvain Pluchart, Aerospace and defense businessdevelopment manager, Simcenter system simulationIn 2018 a total of 114 orbital launchesBenefits of an engine transientWhen coupled with a model of the were performed globally, reaching thesimulation model controller, transient simulation can be 100 launches mark for the first timeFine-tuning the start/stop sequenceused to support the development and since 1990. 2019 is shaping up to be ofusually requires many trials duringthe validation of control chains.the same kind. ground testing. As an example, 3171 hot-fire tests were performed on theMitsubishi Heavy Industries case Underlying this trend is the ever- NASAs Space Shuttle engine. Itstudy: the H3 as Japans next flagship increasing number of payloads torepresents more than 1,095,677 secondslaunch vehiclelaunch. On top of that, new applicationsof operation. This approach is costly andThe H3 launch vehicle development are emerging in the space economy,does not allow to easily extrapolate thestarted in 2014 to compete and survive such as space tourism or massengine operation in flight conditions.in the global commercial market, as deployment of small satellites to provideDuring tests the safety of the engine andstated by Mitsubishi Heavy Industries worldwide internet access. the test equipment is a concern,Ltd. (MHI) in a technical review in especially at early stages when theDecember 2017. Like ArianeGroups In this context emerging actors from thephysical knowledge of the engineAriane 6 or SpaceXs Falcon9, the design private sector are driving the launchbehavior is not fully understood. of the H3 launcher focuses on reducing costs down thanks to a new way ofboth launch and operational costs, while doing business. One notable trend is theTransient simulation of models allows tokeeping the high reliability of the current development of small launchersfrontload the analysis of the start/stopversions H-IIA/H-IIB.targeting lighter payloads and suitablesequence and implement required for high launch cadence. Another focusdesign changes earlier in theMHI is the primary contractor for the of research is the reusability of somedevelopment. They contribute to thevehicle development, including the part. Since 2010 it has been estimatedcost and risk reduction of the enginedevelopment of the engine system. The that launch cost decreased from 10 todevelopment program by: program is currently in a detailed design 15 percent. phase and progresses towards a firstEvaluating the design performance inflight in 2020.Engine performance holds the key toa virtual environment,launcher success Simulating failure cases and predictingSecond stage engine of the H3 launcher: A key enabler of these innovations is thethe operating redlines (tests safety), and LE-5B-2 transient simulation modelengine performance. Modern rocket Complementing the test resultsAs the LE-5B-2 development started, two engines are designed to be shut downin preparation of the real flightpain points were identified by MHIs and restarted multiple times during theconditions. engineers:flight. The task is challenging for the designers because they must deal with unique constraints linked to propellantLiquid hydrogenmanagement, and thermalLiquid oxygenpreconditioning of feed lines and engineCombustion chamber MFVcomponents. For example, before anLiquid oxygen turbo pump MOVengine restarts, pumps are cooled down using the fuel onboard to avoidCCVcavitation at start-up. This is done through a complex control sequences of TCVLiquid hydrogen valves and actuators. turbo pumpCompared to older designs, the engine controller must be improved as it plays aNozzle MFV: Main fuel valvemajor role in the engine capability toMOV: Main oxidant valvedeal with the severe conditions relatedCCV: Combustion chamber cooling valveto multiple start-up and shut down. TCV: Thrust control valve32'