Professional Experience

NASA AMES RESEARCH CENTER, USA
Position Title: Senior Research Scientist at BAER Institute and NASA ARC (June 2014-present)

  1. Research with the Space Technology Mission Directorate - Intelligent Systems Division: Systems Engineering of the Distributed Spacecraft (DSA) project, that is developing a suite of software tools to enable an operator to command/receive data from a swarm as a single entity, enable a swarm to autonomously coordinate its actions via distributed decision making and reactive closed-loop control, and model swarm behavior in the presence of anomalies or failures. Our use case is the mapping of the electron density of the ionosphere using radio tomography by coordinating the selection of appropriate GPS channels, and recording TEC measurements. DSA will be demonstrated onboard the NASA Ames Starling mission – a swarm of four small, LEO spacecraft, scheduled to launch in 2021. We will also perform a ground demonstration with simulated and hardware-in-the-loop elements, to validate the tools for controlling swarms of up to 100 assets.
  2. Research with the Science Mission Directorate - Earth Science Division: Developing an algorithmic framework to run onboard small spacecraft, such that the constellations can make time-sensitive decisions to slew and capture images autonomously, without ground control. We have developed a communication module based on De-lay/Disruption Tolerant Networking (DTN) for onboard data management and routing among the satellites that will work in conjunction with the other modules to optimize the schedule of agile communication and steering. (Constellation Scheduling with DTN)
    Developed a software tool for scheduling pointing operations of narrow field-of-view (FOV) sensors on agile, small spacecraft over mission lifetime for rapid-response imaging for given regions on the Earth, to maximize metrics such as global coverage and revisit statistics. Our algorithm optimizes constellation satellite pointing based on a dynamic programming approach under the constraints of orbital mechanics and existing attitude control systems for small satellites and shows a 2.5-fold increase in images seen compared to static, nadir sensors. Optimality of the algorithm's results are validated using a mixed interger linear programming formulation (Constellation Scheduling)
  3. Research with the Aeronautics Research Mission Directorate - Aviation Systems Division: Co-leading the architecture definition and software prototype development for a Space Traffic Management concept of operations. (STM Autonomy)(STM Architecture)(STM Collision Avoidance)
    Co-Led the communication and navigation working group within NASA's UAS Traffic Management project to simulate, test and reach a consensus on the minimum operating standards for airspace integration and enabling safe, efficient low-altitude UAS operations. The research is in close collaboration with 50+ industry partners in comm/nav technology (e.g. ADS-B) and the Federal Aviation Administration (FAA) and will be transferred to the FAA for further testing. (ADS-B Tech Results)
    Designed, modeled and simulated Cubesat constellations for continuous space-based coverage of remote airspaces (e.g. Alaska, Greenland) using ADS-B signal reception from aircraft with the space-validated payload developed by GomSpace. Optimal constellations were chosen based on tracked airplanes, certainty of their states, delay in relaying to ground and packet cost. ADS-B based communication is now being investigated for low-altitude, small weight/power unmanned aerial vehicles to ensure beyond-line-of-sight operations. (Air Traffic Results)
  4. Research with the Space Technology Mission Directorate - Mission Design Division: Design and optimization of the satellite constellations and formation flight for Earth Observation based on tightly coupled Model-Based Systems Engineering (MBSE) and Observing System Simulation Experiments (OSSE). Developed the framework in collaboration with the Mission Design Center and Earth Science Division and applied it to several mission proposals such as solar occultation measurements of the Earth ionosphere, high frame rate imaging of global coral reefs and rapid response imaging for custom regions of the Earth (Example Framework)

NASA GODDARD SPACE FLIGHT CENTER, USA
Position Title: Senior Research Scientist at BAER Institute and NASA GSFC Software Engineering Division (August 2015-present);
Research Associate at USRA and NASA GSFC Software Engineering Division (June 2013-February 2014);
Research Associate at USRA and NASA GSFC Climate Science and Radiation Division (June-August 2012)

  1. Research with the Space Technology Mission Directorate - Software Engineering Division: Developed a tradespace exploration and optimization software tool for the Distributed Space Missions (DSM) group to study the tradespace of potential earth science mission architectures at the Phase A level, given a known Earth imaging payload. The tool was based on AGI's Systems Tool Kit and integrated to MATLAB using Microsoft Connect, and validated using LandSat case studies. It also had a preliminary cost model that identified the problems with current DSM costing and suggested modifications. This tool served as a prototype to the current GSFC project on Tradespace Analysis Tools for Constellations (TAT-C). Within TAT-C, I am responsible for the executive driver of the entire software, processing inputs from the user to be used by the software, processing outputs from the orbits and payload module to be presented as outputs to the user and optimization algorithms of efficient rapid tradespace exploration. TAT-C is being developed in Python and C++. (Payload Module)(TAT-C Progress 2) (TAT-C Progress 1) (Preliminary Tradespace Tool) (Cost Results)
  2. Research with the Science Mission Directorate - Climate and Radiation Lab: Design and evaluation of nano-satellite clusters in formation flight to make multi-spectral, multi-angular radiometric measurements for the estimation of bi-directional reflectance distribution functions (BRDF) for the major global surface types. The modeling framework included detailed orbital mechanics of formation flight such that the satellites are able to point to the same ground spot at the same time, maintainance through propulsion, attitude control for fine pointing of the imager payload and communication links to ground stations. The simulation results clearly showed improvement in BRDF estimation compared current single satellite systems, and showed more accurate estimations of BRDF-dependent products such as albedo, gross primary productivity (GPP) or indices (NDVI) of vegetation and of the Earth Radiation Budget (ERB). The optical payload was modeled in pre-Phase level of detail, multi-spectral snapshot imaging spectral elements proposed and system performance simulated as feasible. (BRDF Optimization Results) (Albedo and Technology Results) (GPP, NDVI and Modeling Results) (Optical Payload Modeling)


SPACE SYSTEMS LABORATORY, MASSACHUSETTS INSTITUTE OF TECHNOLOGY, USA

  1. Position Title: MIT Graduate Research Assistant (September 2010 - May 2012), Program Lead (January 2011 - February 2012)
    Project Collaborators: NASA Human Exploration and Operations Mission Directorate, DARPA, Aurora Flight Sciences, TopCoder
    Research: Designing, programming and managing the SPHERES Zero Robotics Program, a series of robotics programming tournaments for students aboard the International Space Station. The MIT SSL developed the SPHERES laboratory environment aboard the ISS to provide researchers with an experimental testbed for the validation of high risk control for use in formation flight, autonomous docking, rendezvous and reconfiguration algorithms. Zero Robotics (ZR) enables students - high school, middle school and college level - to participate directly in the science conducted aboard the ISS. The software framework for this program is built in collaboration with TopCoder by crowdsourcing the development to their 300,000 strong community of members via a series of contests. The program itself incentivises thousands of students to play challenging games relevant to current space systems research i.e. they provide insightful solutions to topics on formation flight, strategic mission planning, fuel optimization, etc. Crowdsourcing not only develops the program but is also demonstrate it within the program itself. (NASA Report) (Crowdsourcing Impact Report) (Educational Impact Report) (S/W Development Report)
  2. Position Title: MIT Graduate Research Fellow (March-May 2010)
    Project Collaborators: Orbital Sciences Corporation, VA
    Research: Performed an in-depth analysis of publicly-available fractionated satellite value-centric design tools from Phase 1 of the DARPA System F6 program. The first task focused on a comparative benchmarking study of the four tools in which several use cases were modeled to determine differences in inputs, analysis methods, and outputs. The results found the tools to be substantially diverse in modeling architectures and value interpretation. The second task applied optimization methods to the Phase 1 PIVOT tool created by Orbital Sciences to maximize satellite system value. The results found solution stability is inhibited by uncertainties introduced by the stochastic objective function. (Published Report)
  3. Position Title: Graduate Student in Semester Class of Satellite Engineering (September to December 2009)
    Project Collaborators: Lincoln Laboratory, MA
    Research: Modeled a laser communication downlink from the moon, developed to rapidly explore various system architectures for the Google Lunar X-Prize. Data rates more than 2 MBps were proven possible with microwatt scale power and within Lincoln Lab available capabilities, laser modulation scheme, aperture, gimbal and APD technologies. From the mission geometries, availability was calculated to be between 6 to 13 hours per night. This report is a pre-PDR proposal to fly LaserComm on the team 'Next Giant Leap'. (Published Report)

EUROPEAN SPACE AGENCY (ESTEC), NOORDWIJK, THE NETHERLANDS
Position Title: International Research Fellow at ACT in Artificial Intelligence (June-August 2010)
Research: Demonstrated the scatter maneuver technique using swarm intelligence and equilibrium shaping applied to a fractionated spacecraft, treated as a multi-agent system, with a limited (but scalable to large) number of heterogeneous satellites with limited communication, collective reconfiguration and distributed computing abilities. Feedback controls were added, technology enablers benchmarked and benefits of autonomous collision avoidance in an uncertain environment with many agents clearly demonstrated. The modular, miniaturized subsystem of CubeSATs was used for the demonstration purposes. (Published Report)

NASA JET PROPULSION LABORATORY, USA
Position Title: Summer Intern in Radar Science and Engineering (May to July 2008)
Research: Modeled Boundary Element Method and crustal kinematic modeling was used to solve fracture development in far fields on Mars constrained by MOLA-DEMs, MOC and THEMIS imagery data as a prime focus in the 'Fundamental Mars Research Project' at NASA. This included developing geometrical models for graben formation in Alba Patera, Mars and non-linear inversion for determining physical and mechanical parameters using gridded satellite data. (Space Grant Abstract) (Space Grant Report)

WOODS HOLE OCEANOGRAPHIC INSTITUTION, USA
Position Title: Summer Student Fellow in Ocean Bottom Seismology (April to July 2007)
Research: Proposed the idea and applied Full-waveform inversion (FWI) (via using Finite Difference Scheme, Filtered Gradient inversion, stochastic fractals) to the very complicated region known to have created the Earth's crust, the mid-Atlantic Ridge. Usually, FWI due to its complexity and unparalleled accuracy is used primarily in Computerized Brain Scanning. Implemented a processing sequence for vertical seismic profiles from the International Ocean Drilling Program Hole 1256D to check the presence of sub-basement reflections in the Multi-channel seismic profiles. (AGU Paper)(AGU Poster)

UNIVERSITY OF CALIFORNIA, BERKELEY, U.S.A. and IIT KHARAGPUR, INDIA
Position Title: Under graduate Thesis research in Exploration Geophysics (November 2008 to April 2009)
Research: Analyzed European Space Agency acquired Satellite Interferometric synthetic aperture radar time series of San Francisco Bay Area by functional, principal component analysis, Empirical Model Decomposition. The slip histories on tectonic faults of the Bay were calculated via the Network Inversion Filter, Kalman Filtering and Green's Functions. (Thesis Summary)

INDIAN INSTITUTE OF SCIENCE Bangalore, INDIA
Position Title: Summer Intern in Instrumentation Engineering (April to July 2006)
Research: Cancerous tissue shows 10 times more elastic than optical change, at a much earlier stage. I computationally solved for elastic parameters directly by using the novel synthesis of photo-elasto-acoustic or a simultaneous 3 wave propagation (via Eikonal, Naviers', Diffusion and Coupled PT Equation), rather than use dependency on a sequential secondary source. This proposes to detect cancer (Lame's Parameters via Finite Element Method) much earlier, more accurately.