UNIFIED LAUNCH VEHICLE (ULV): THE FUTURE SATELLITE LAUNCH VEHICLE OF INDIA: A REAL BEAST IS TAKING SHAPE
While having the highly reliable PSLV operational for many years, and the GSLV Mk-II with the indigenous cryogenic engine (CE-7.5) and CUS (C-15) roaring away into the sky amidst glory, and finally the human rated monster rocket GSLV Mk3 heading to its first experimental flight by mid December, another important development is underway at ISRO, unknown to many and for the past couple of years ISRO has been working on a future vehicle series which is modular in its design and structure, developed primarily in the aim to simplify vehicle integration, efficiency in operations and in the long run achieve major cost accruals. The new series of ULV's will eventually replace the PSLV and the GSLV launch vehicles. ISRO has named it the Unified Launch Vehicle or ULV. As stated in several ISRO resources, the ULV will be a series of 3 to 4 expendable launch vehicles and will feature common liquid stages for all variants resulting in considerable amount of cost benefits, usability, maintainability and reliability.
Though the media has hyped much about GSLV-MkIII as a "Monster" rocket but it is however the ULV which will be a true blue "Monster". This will be the real coming of age for Indian space technology and capabilities which will make India on par with more advanced space fairing nations, it will also augment ISRO's commercial prospects to a very large extent. ULV will also be used to send the first Indians to the Moon and bring them back safely back to earth, and it is certain that the ULV will be used for sending India's own space station into orbit. Besides, we can expect India in a couple of decades aim to send humans to Mars and beyond.
The vehicle, as its name suggests will unify ISRO's various class of launch vehicles which is currently being used into a single launch vehicle. The plan is to have a common liquid semi-cryogenic core as the First stage with variable fuel loading capabilities for all of its variants. The Second stage will also be equipped with a Cryogenic stage which will be highly configurable thus having the ability to satisfy various payload requirements of customers. Currently ISRO has launched the CE-7.5 (Pictured above), which powered the GSLV-Mk2 in January 2014, the other engine currently under development for the Mk-III is the CE-20, further developments are either in progress or planned such as the CE-60 and the CE-100 engines. The vehicle will mate solid propellant Strap-on boosters of different variations (S12, S60, S138, and S200) for the boost phase. Hence, by adjusting the fuel and power levels of the stages, a single launch vehicle can be used to launch various payload mass thus eliminating the requirement to have multiple launch vehicles, this is the sole aim of the ULV project.
ISRO's Semi-Cryogenic Engine
The first stage is liquid Oxygen (LOX) and ISROSENE (indigenous propellant-grade kerosene) powered semi-cryogenic engine (SC-160) with 2000 kn. thrust output and will serve as the main booster of the launch vehicle. The 2nd stage of the launch vehicle is a cryogenic stage. For now ISRO has planned to use the CE-20 cryogenic engine actually designed for the GSLV MK3 but in future they plans to replace it with more powerful cryogenic engines/stages (CE-60, CE-100). There also will be various magnitudes of “variable fuel loading” solid boosters (S-200, S-138, S-60, S-12 etc.) as strap-on boosters which will help in liftoff in boosting phase with heavy payload in various payload mass requirements.
About Cryogenic Rocket Stage
A Cryogenic rocket stage is more efficient and provides more thrust for every kilogram of propellant it burns compared to solid and earth-storable liquid propellant rocket stages. Specific impulse (a measure of the efficiency) achievable with cryogenic propellants (liquid Hydrogen and liquid Oxygen) is much higher compared to earth storable liquid and solid propellants, giving it a substantial payload advantage.
Variants
● The basic version of the ULV uses six S-12 booster and has a launch mass of 274 t. The payload is 1.5 t to GTO and 4.5 t to LEO.
● The second version uses two S-60 booster and has a launch mass of 340 t. The payload is 3 t to GTO or 10 t to LEO.
● The third version uses two S-138 booster and has a launch mass of 560 t. The payload is 4.5 t to GTO and 12 t to LEO.
● The most powerful variant will use the S-200 booster of the GSLV Mk3 and has a launch mass of 700 t. The payload is 6 t to GTO and 15 to LEO.
But as per requirements by the launch mass, ULV can have other variants too.
The ULV is expected to become operational by 2030±3.
Research and Developmental activities of ULV has been initiated as the Union Cabinet approved the development of Semi Cryogenic Engine technology at a estimated cost of Rs. 1,798 crores with a foreign exchange component of Rs. 588 crores. The objective is to design, fabricate and test this advanced technology in India within a span of six years and the engine is likely to ready under current estimates by 2018-20.
Specifications of the Semi-Cryo Engine is as follow:
Thrust (vacuum) - 2000 kN
Isp (vacuum) - 3285 N-s/kg
Chamber Pressure - 18 MPa
Mixture Ratio - 2.65
Thrust Throttling - 65-105 (% of nominal thrust)
Engine gimbal - 8 degrees (in two planes)
The Current State of the Semi-Cryogenic engine Development, as stated by ISRO:
The Semi-Cryogenic engine is planned to be developed and qualified over a span of 6 years. In this, the first four years is planned for subsystem development and the remaining two years will be used for development and qualification of the engine. The facilities needed for testing also has to be made ready in 4 years.
The Preliminary Design Review (PDR) for Semi-cryogenic engine development has been completed. Preparation of fabrication drawings of subsystems has been completed. A MOU has been signed with NonFerrous Materials Technology Development Centre (NFTDC)* to realize copper alloy component for the Thrust Chamber. Single element Pre-Burner (PB) injector has been realized and injector spray characterization using Particle Image Velocimetry (PIV)was carried out. Test facility for single element pre-burner commissioned at PRG facility, VSSC. Semi Cryo Test facility design by M/s Rolta has been completed.
[*NFTDC: NonFerrous Materials Technology Development Centre (NFTDC) is an autonomous R&D Centre located in Hyderabad, Telangana, India.]
Flame Deflector with Water Spray System for sound suppression installed on the Launch Pad
Design of the Semi Cryo Engine including heat exchanger and ejector has since been completed Fabrication drawings and documents are generated based on the PDR and joint reviews. Configuration design of subscale engine model is completed. Preliminary Design Review (PDR) of Hydraulic Actuation System (HAS) and Hydraulic Power System (HPS) for Engine Gimbal control is completed and Technical specifications are finalized.
Single Element Pre-Burner injector element has been hot tested successfully. Ignition of LOX/ Isrosene propellant with hypergolic slug igniter and flame holding, demonstration of safe handling of pyrophoric fluid TEA, validation of start sequence, characterization of injector elements and qualification of Hayness-214 material are the major achievements of the tests. 13.5 Design of single element thrust chamber is completed and fabrication drawings are generated. Single element thrust chamber injector elements are realized and cold flow tests were carried out. Special pre burner which will provide hot gases for testing the single element thrust chamber has been realized.
Realization of semi-cryogenic engine involves the development of performance-critical metallic and non-metallic materials and related processing technologies. 23 metallic materials and 6 non-metallic materials have been developed.
Characterization of injector elements and hypergolic slug igniters with different proportion of Tri-ethyl Aluminium and Tri-ethyl Boron has been completed. Sub-scale models of thrust chamber have been realized and ignition trials have been carried out successfully. Single ele-ment thrust chamber hot test in stage combustion cycle mode was also conducted successfully.
Establishment of test facilities like Cold Flow Test Facility and Integrated Engine Test Facility are un-der various stages of realization. Fabrication drawings are realized for all sub-systems and fabrication of booster turbo-pump and pre-burner subsystem commenced.
The semi cryogenic engine uses a combination of Liquid Oxygen (LOX) and ISROSENE as propellants, which are eco-friendly and cost effective. Design of single element thrust chamber was completed and single element thrust chamber injector elements realised and cold flow tested. A rubber composition resistant to ISROSENE was also qualified. Rectangular rings, gaskets and O-rings for control components and turbo pump of semi cryogenic engine as well as Tri-ethyl aluminum (TEA) based hypergolic igniter have also been developed. Hot test was carried out with LOX step injection mode on semi cryogenic pre-burner injector at high pressure after completing cold flow trials and sequence validation tests. Further tests with step injection for ISROSENE and LOX are planned.
References:
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https://defence.pk/…/india-will-develops-a-new-series-of-sl…/
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http://www.b14643.de/Spacerocke…/…/ULV/Description/Frame.htm
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http://forum.nasaspaceflight.com/index.php?topic=31827.0
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http://antariksh-space.blogspot.in/…/isro-unified-launch-ve…
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http://novosti-kosmonavtiki.ru/forum/forum13/topic13732/
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http://www.frontline.in/…/in-mission-mode/article4945199.ece
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http://www.isro.org/pdf/Annual Report 2012-13.pdf
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http://www.isro.org/pdf/Organisation.pdf
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http://www.isro.org/pdf/AnnuaReport2012.pdf
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http://dst.gov.in/about_…/12th-plan/14-wg_dos2905-report.pdf
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http://www.deloitte.com/…/antrix-cii-deloitte_report_on_ind…
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http://xa.yimg.com/…/Newsletter+MITAA+BC+vol+19+issue+1+_FI…
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http://www.isro.org/pdf/Outcome budget2013-14.pdf
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http://www.deloitte.com.br/…/A&D_Overview_Indian_Space_Sect…
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http://www.shar.gov.in/…/annua…/SHAR_Annnual_Report_2012.pdf
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http://www.shar.gov.in/…/annualrepor…/Annual_Report_2013.pdf