megahit: let's embrace space presentation
TRANSCRIPT
MEGAHIT
“Megawatt Highly Efficient Technologies For Space Power And Propulsion Systems For Long-
duration Exploration Missions”
Presented by Emmanouil Detsis on behalf of the MEGAHIT consortium
MEGAHIT is funded by the European Commission, under the 7th Framework Programme for Research and Technological Development (FP7), under grant agreement n° 313096. MEGAHIT is an EC – Russia supporting action, in preparation of the Horizon 2020 programme. The consortium consists of 6 partners.
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Part I: Introduction
MEGAHIT Consortium
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The MEGAHIT proposal started in March 2013 and concluded on August 2014. Its objectives were: to construct a road-map for nuclear electric in-space propulsion activities
within the EC Horizon 2020 programme
to create a European community including Russian partners around Nuclear Space Power systems
To analyse the potential collaboration opportunities at international level
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Part I: Introduction
MEGAHIT Objectives
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Part I: Introduction
MEGAHIT Rational
Nuclear power is recognized as an enabling technology. Many past works:
• Europe: ERATO, OPUS, SNPS200…
• USA: Nerva, Snap, SP100, Prometheus, FSP…
• Russia: Buk, Topaz,
Space nuclear propulsion remains a technology « of tomorrow »
• Costly,
• « nuclear »,
• number of missions affordable without it
• Manned Mars mission still a mission « of tomorrow »
Today, a renewed interest ?
• In Russia: currently a «MW class project »
• Topic addressed in DiPoP & next European R&D programme
• Topic addressed in NASA Space Technology roadmaps and priorities
Megawatt level technology is the long term objective and should be a driver for shorter term, lower power projects
Phase 1
High level requirements: Collect inputs from space agencies world-wide on mission-related high level requirements their interest for international cooperation on the subject.
Reference vision: The key technologies will be identified and a reference vision of what the MEGAHIT system aims at will be sketched out.
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Part II: Programmatics
MEGAHIT operational phases
Phase 2
Phase 3
Phase 4
Technological plans: MEGAHIT approached stakeholders that can carry out the development and engaged with them through discussions on the technologies they master
Road-maps: This is the synthesis of the three previous phases, translating into consistent road-maps what has been established in terms of goals, key technologies and technological plans
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Part II: Programmatics
MEGAHIT Topics
The topics addressed by MEGAHIT cover all the areas of space nuclear electric propulsion. The technological plans cover eight topics
1. Fuel and core, relating to nuclear technologies and including shielding. 2. Thermal control, addressing heat transfer and radiating devices. 3. Conversion, addressing the technologies of conversion of thermal energy into
electricity at high power level. 4. Propulsion, relating to electric thrusters technologies 5. Power management and distribution, relating to the high power converters and
distribution cables between the generator and spacecraft. 6. Spacecraft arrangement and system architecture addressing the system
architecture, lightweight structures and assembly in-orbit. 7. Safety and regulations, addressing the nuclear safety and other regulations. 8. Communication and public awareness, addressing the necessary steps to take to
successfully communicate a nuclear space project to the public.
© CNES/Antigravité/A.SZAMES, 2006
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Part III: Roadmap MEGAHIT Reference
MW class NEP power and propulsion system should be a versatile vehicle capable of operating on various types of mission.
The specific mass for the power and propulsion system (excluding propellant but including thrusters) should be lower or equal to 20kg/kW, that is to say 20 tons for 1MW.
Without more detail mission analysis a 10 year of equivalent days at full power should be considered as a preliminary target. The influence of this requirement should be studied.
Radiators should be foldable
A 20 ton system plus the associated payload would not be able to fit in a current launcher shroud so two options can be then be considered: assembly in orbit thanks to robotics, or launch with an ultra heavy launcher.
Key Points
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Part III: Roadmap
MEGAHIT Reference
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Part III: Roadmap
Core and Power
Two candidates for the MEGAHIT fast spectrum reactor concept, required to generate thermal power (greater than 3 MW, with an operating temperature of about 1300 K) for the nuclear electric propulsion system (target 1 MW electrical power overall) over a five to ten years operational life direct, gas cooled reactor loaded with coated particle/composite fuel linked to Brayton conversion system and
in-direct, liquid metal cooled reactor loaded with more conventional fuel, e.g. metallic encapsulated pins filled with fuel pellets, linked to Brayton conversion system.
The leading candidate for power conversion is the Brayton cycle with 1300 K as hot source temperature.
The 20 kg/kWe target would be achievable.
improve performance: increasing the temperature at the turbine inlet (possibly as high as 1600 K) ->new materials needed.
some of the reactor technology options are not scalable with temperature- radically different reactor configurations needed to operate at peak mass efficiency either at 1300 K or 1600 K.
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Part III: Roadmap
Electric Propulsion
Ion Thrusters: Build in Russia, an ion thruster with power of 50 kW is possible at the existing technology level at specific impulse of 8000 s (for Kr) and higher. In Japan half power - 25 kW - ion thrusters are studied.
Hall Thrusters: Application of Hall thrusters in Russia is justified in the specific impulse range of 3000 s to 4000 s, for Ar up to 5000 s. Available technologies allows to make thrusters with power level up to dozens kW. Increasing specific impulse may have negative effect on the operation stability and lifetime of Hall thrusters.
The available systems of Snecma are based on Hall effect thrusters using Xenon. Snecma provides not only the thrusters but also fully integrated system including thrusters, tanks, PPU, filter units and fluid control subsystems.
Electric Propulsion is a solvable technological challenge.
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Part III: Roadmap
A lot of heat
The entire INPPS space flagship with a total mass about 40 tons needs to be separated at least in two modules.
For short term mission the baseline vehicle (2 x 20 t modules) shall be considered as the most preferable option from in-orbit assembly technologies TRL point of view.
It will be composed of a transport power module (TPM) with the nuclear power propulsion system and another module with all other subsystems
Radiators will work on a high temperature heat pipes system,
Backup option: Droplet radiators
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Part III: Roadmap
MEGAHIT Deployment
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Part III: Roadmap
Mission Scenarios
NEO deflection: Depending on the mass and trajectory of the NEO, a MW class system may be required to deflect it to protect the Earth. A spaceship with 1 MW power level can increase the distance of the asteroid flyby near the Earth in 2036 up to 1 million km and even more. Initial mass will be equal to 20 t and specific impulse value is about 7000 s. Mass at destination should be about 15.5 t to 16.5 t for an Apophis size asteroid. Required duration of asteroid orbit gravitational correction will be between 40 days (20201 approach) and 200 days (2027 approach). Outer Planets : A MW class vehicle would open new exploration mission classes like sample return from Jovian moons. A chemical stage, without gravity assist manoeuver, would put only 300 kg of payload in this orbit. A NEP spacecraft with a 40 t mass will be able to deliver into a Europa orbit payload mass in the range of 3t to 10 t, with EPS specific impulse value varying from 6000 s to 8000 s accordingly. Manned Mars Missions: A manned exploration mission to Mars would require several tens of tons to be put on the surface of the planet, which will amount to 8 to 10 Saturn-V equivalent rocket launches if no other mean that chemical propulsion is used. With NEP and a variation in specific impulse in the range from 4500 s to 9000 , payload of mass 11 to 18 t can be delivered, with a duration between 1 and 2 years for the transfer. Lunar Tags: Assuming that the mass of the payload delivered to the Moon surface, should be no less than 15 to 20 t (mass of manned base module for example), then the mass of the payload delivered by the tug to the low near-lunar orbit in one cycle should be at least 30 t to 40 t. If lunar tug would make two trips per year, 650 t of payload can be brought in lunar orbit in ten years.
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Part III: Roadmap
Final Conclusions
High Power Nuclear Electric Propulsion offers many interesting capabilities and enables diverse classes of missions. The MEGAHIT project aims at mapping the necessary technological steps towards the creation of a Megawatt level powered nuclear electric spacecraft. Contacts with experts, agencies and institutions that have experience in nuclear systems and spacecraft design was initiated and set the technology plans for such an endeavour. It would be highly relevant to design and develop a versatile vehicle capable of doing a large panel of missions needing the same class of power A lower power system can be used as a demonstrator. Such a spacecraft would provide significant business opportunity for all space and space facing nations during the years of transport and assembly. The event will push economic, technological as well as scientific and cultural synergies. A mission to a hazardous asteroid will also serve as a project that protects Earth. Successful project realization is a truly global project and comparable with the Apollo and ISS projects.
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Part V: Continuity
DEMOCRITOS
DEMOCRITOS is an H2020 proposal that will investigate the necessary demonstration activities in order to mature technologies for NEP systems.
Detailed preliminary designs of ground demonstrator : Investigate the interaction of the major subsystems (thermal, power management, propulsion, structures and conversion) between each other and with a (simulated) nuclear core providing high power, in the order of several hundred of kilowatts. The consortium aims to develop preliminary designs of all the subsystems and the required test bench of the necessary ground experiments with the purpose of maturation of the related necessary technologies.
Nuclear reactor studies to provide feedback to the simulated as well as conceptualize the concept of nuclear space reactor and outline the specifications for a Core Demonstrator, including an analysis of the regulatory and safety framework that will be necessary for such a demonstration to take place on the ground.
System architecture and robotic studies that will investigate in detail the overall design of a high power nuclear spacecraft, together with a pragmatic strategy for assembly in orbit of such a large structure coupled with a nuclear reactor. The consortium partners will provide a preliminary design of a nuclear power spacecraft and its subsystems, detailed assembly and servicing strategy in orbit as well as proposal for in space demonstration missions with the aim of maturing various necessary technologies that either do not fit within the ground demonstrator or have the opportunity to fly in synergy with other European or international initiatives.
www.megahit-eu.org
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Additional Info
Website
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Contacts
MEGAHIT consortium
CNES Frédéric Masson [email protected]
DLR Frank Jansen [email protected]
Waldemar Bauer [email protected]
ESF Emmanouil Detsis [email protected]
Jean-Claude Worms [email protected]
KeRC Alexander Semenkin [email protected]
NNL Zara Hodgson [email protected]
TAS-I Enrico Gaia [email protected]
Contact Points