This project constitutes the detailed design, fabrication and fight tests of maraal: a low altitude long endurance uav to be operated day-night in a subtropical region. the solar uav prototype fabricated at unmanned aerial laboratory iit kanpur has a wing span of 5.35m, maximum endurance of 18 hours and a maximum payload capacity of 6 kgs. a detailed conceptual design process is established with a set of constraints which are used to generate parameters for 6dof simulation. developments in solar cell encapsulation process ensure a superior aerodynamic performance. the project also highlights the construction efforts and details of the hardware and onboard electronics including surveillance equipment. the optimum path of operation is determined to achieve maximum endurance and the battery sizing algorithm is developed to harvest maximum energy with adding minimal weight. based on the position of the sun, optimal attitude of the aircraft is determined and commanded to achieve it. a novel control surface auxiron is developed that augments the solar power collection. for the handling of auxiron, control laws are developed.