nagabhushanam-220
  •     Associate Professor
  •    CORI
  •    ssasa@pes.edu
  •     Ext: 786

    +91.80.2672.1983
    +91.9611.7862.20

Qualifications
MTech (Machine Design) & B.E. (Mechanical Engineering)

Professional Experience

1) Associate Lecturer in Dept. of Mechanical engineering, IIT, Madras
2) Head, Control Components Division, Control Systems Group;
3)Consultant Engineer, Control Systems Group, ISRO Satellite Centre, Bangalore.
4) Visiting Professor PESIT, Banashankari. (Dept: CORI - Crucible of Research & Innovation)

1) Spin Table Facility : Design and Development of Spin Table Facility to test the structural model of Aryabhata, the first Indian satellite for structural integrity and also participated in static testing of the structural model of Aryabhata.

2) Cold Gas Reaction Control System : Design and Development Cold gas reaction control system for Bhaskara-! & II satellites. This called for development and qualification of components such as high pressure regulators, solenoid valves, nozzles and associated plumbing. Also the high pressure pneumatic test facility was established apart from those required for system level tests and charging.

3) Nutation Dampers : Development and Qualification of fluid in tube passive nutation dampers for spin stabilised satellites such as Aryabhata, SEO, SROSS, etc.

4) 3-Axis Angular Motion Simulator : Design and development of spherical gas bearing facility for the 3-axis angular motion simulator for testing the spin axis orientation control (SAOC) of Bhaskara and Apple astellites.

5) Bonded Film Lubrication : Development of Bonded Film Dry Lubrication process for lubricating the rubbing surfaces of deployment mechanisms that are exposed to the harsh space environment. Development of test procedure and elaborate test facilities and exclusive lab for the testing and certification of such lubricated components for flight use. Transfer of this process to industry for catering to the large scale requirement of ISRO. Testing and qualification support for the development of indigenous lubricant.

6) Thin Film Lubrication : Development and qualification of Thin Film lubrication by sputter deposition of molybdenum-di-sulphide. This technology is primarily adopted for lubricating ball bearings that are subjected to large number of cycles unlike the deployment mechanisms. Development of coating and testing procedures for ball bearings, friction test facilities for evaluating friction and wear in vacuum/ambient. Facilities for evaluating the long life of the coated bearings under high vacuum.

7) Magnetic Torquers : Design, Development and Qualification of various sizes / types of Magnetic Torquers for all the satellites since Apple which was launched in 1981. Streamlining of fabrication process, test procedures and design steps for both elecromagnetic as well as mechanical to improve the work output and reliability. Establishment of all the required facilities for fabrication, assembly and testing.

8) Export of Magnetic Torquers : Fulfilled the export order of custom built magnetic torquers through Antrix of ISRO. This called for detailed documentation regarding design, process and testing apart from development of special processes, tests and test procedures as required by the end user. As project manager of the programmme realised engineering and qualification models and delivered 20 and 3 Flight units of magnetic torquers to Hughes Space and Communication, USA and Matra Marconi Space, France respectively.

9) Electric propulsion : Mechanical support for the development and charecterisation of 10 mN Gridded Ion thruster using mercury as a propellant and establishment of test facilities. Fabrication and testing of indigenous hollow cathodes required for the thruster. Development and qualification of 350 W / 15 mN Hall Effect Thruster (HET) which was flown in Gsat-4 satellite. Development and testing of 1400 W / 80 mN HET intended for high power communication satellites. Establishment of large vacuum test facility with provision for thrust and exhaust plume measurements.

10) Magnetic Bearing - Reaction Wheel : Development of magnetic suspension with passive radial bearings and active axial bearing as a substitute for conventional ball bearings to improve the friction and life in the case of reaction and momentum wheels. Design, fabrication and testing of a qualification model of 15 Nms reaction wheel. Establishment of required infrastructure and test facilities for the above activity. The wheel assembly also consists of indigenous brushless DC motor and electronics for eddy current probes, suspension control as well as motor commutation.

11) Brushless DC Motor : Development of brushless DC motor for driving the dual gimbal assembly to keep the antenna pointed to the ground stationn during transmmission of high bit rate data. The motor was developed and qualified as an import substitute using similar procedure and technology adopted for the motor of the reaction wheel.

12) Hardware in Loop Simulation : Taken care of the Mechanical requirements for the entire Hardware in Loop Simulation (HILS) activities for all satellites. This consists of design and fabrication of different sizes /types of earth simulators, custom made fixtures for mounting different sensors in different cofigurations. Mounting fixtures, positioners and adaptors for different types of sun and star simulators.

13) SROSS - AOCS : As project manager of SROSS series of satellites taken care of the AOCS design consisting of actuators like thrusters, momentum wheel, magnetic torquers and sensors namely magneto meters, sun sensor and earth sensor for for both spin and 3-axis stabilised missions of the series. This called for overseeing the configuration, control logic, simulation and implementation aspects. The mission related issues were also taken care of.

14) Mechanical Packages : During the last ten years the mechanical packages required for the AOCE were provided by our Division. Three different types of main packages were catered to as per the AOCE hardware style and altogether about 70 package sets have been delivered. In addition, number of auxiliary and add-on packages were also qualified and supplied for various missions. This calls for fabrication of standard modules, inspection, customisation for the project, thermal treatment, etc..

15) Technical Review Committees : Associated in numer of technical review committees as member and chairman in the areas of AOCS elements, deployment mechanisms and mechanical engineering. Some of them are mentioned below: review of monopropellant thruster during developmental stage, pyro valve design, prpellant tank, pressurant tank for xenon, composite pressurant tank for helium, xenon feed system for electric propulsion, fill and drain valve, helium pressure regulator, bi propellant thruster, latch vave, high pressure latch valve for xenon , development of sterling cycle cryo cooler, facilities for space tribology lab at VSSC, high torque reaction wheel, bearing cage insatability, failure of SADA, solar panel configuration, deployment anamoly of sail boom, qualification of sputtered MoS2 film for SADA, process qualification of bonded film, fill and drain valve, propellant migration between tanks, CNC machine for workshop, diamond turning lathe, instrumentation for plume analysis xenon thruster, catvac chamber, bearing configuration for DGA, etc..

16) Depatmental Promotion Committees : Taken part since long as a Member and Chairman in many departmental and inter centre committees for all grades of Technicians, Draughtsmen, Senior Technicians, Technical Assistants and Engineers SB, SC & SD; Expert member for the promotion to Engineer-SE & SF; Centralised recruitment of Engineer-SC;,

Design, Analysis, Fabrication and Testing of structure for student satellite - PiSat; Preliminary thermal analysis for PiSat.Also developed 4 Pi Sun Sensor, magnetic torquer, integration and handling accessories for the PiSat. Mechanical support for the inhouse development of Robot for the library; Detailed documentation for the development of magnetic torquer & Sun sensor for DRDO Including the realisation of first hardware. Initiated a project on Hull stress monitoring for NSTL; Mechanical support for other student projects like e-Nose, Neat Eater, Goniometer, Tribology test rigs, solar illumination, sun tracking system, mechanical design and fabrication of feed for ground station antenna, etc.; Also recently started project on development of Dialysis Machine for DST and Pay-in Pay-out aystem for fibre optic cable for NSTL.