Browsing by Author "Ramanathan, R."

Now showing 1 - 4 of 4

LEO-based optical/microwave terrestrial communications
(2008) Meulenberg, A.; Suresh, R.; Ramanathan, R.
We propose an LEO-based communication system which is built by deploying a nearequatorial, circum-terra, and optic fiber (paired with a conductive fiber) along with perhaps hundreds of small (perhaps) phased-array-communications and RF-signal-transfer antennas around the earth at LEO orbits. The proposed LEO-earth connection will be through microwave links (Ku or Ka band) and ISL's through optic fiber rings. Initially the system would serve to complement existing terrestrial fiber networks, but would eventually expand into non-equatorial planes to provide global connectivity. The proposed system would make use of connectivity & broadcasting capability of satellite constellations as well as the high throughput point-to-point capability of optic fiber systems. The advantages, options, and economics of the proposed LEO optic-fiber / microwave communication system over existing terrestrial- and space-communication systems (of similar functionality) as well as the future development of the system are dealt with in the paper.
LEO-based space-elevator development using new materials and technologies
(2009) Meulenbergb, M.; Karthik Balaji, B.P.S.; Vishnu, M.; Ramanathan, R.
A two-stage LEO-based rotovator model of the space elevator -"Sling on a RingTM was proposed at last year's conference (IAC-08-D4.1.5). Although analogous to the HASTOL (Hypersonic Airplane Space Tether Orbital Launch) system, the Sling-on-a-Ring system, using available materials and readily available subsonic aircraft, bypassed the need for hypersonic aircraft and was proposed as a near-term test bed with limited mass-lifting capabilities. Expectation of new materials (e.g. CNT) led to a timeline that projected full-capacity, man-rated, operation within 2 decades. The recent advent of an unanticipated material, Colossal Carbon Tubes (CCT) with its high tensile strength, extremely-low density, and other favorable properties, allows acceleration of the proposed Ring-system timeline. This new material, along with other new technologies, are the basis for an update of systems that can now be considered as near-future, rather than far-future, answers to some of man's needs and aspirations. This paper provides a new analysis of a single-stage Sling-on-a-Ring concept, in terms of the new high-tensile- strength, low-density material, its potential applications, and the trade offs associated with models proposed earlier. The impact of this material and new technologies (solar-powered lasers, power beaming to near-space and earth, and thermal control systems) on the associated LEO-Ring systems that are developing apace with the sling concept will also be explored.
Perception of space technology in Indian society
(2008) Madgi, S.; Suresh, R.; Ramanathan, R.; Raghavan, S.S.
A survey was conducted by the authors of the paper that aims at understanding the perception and expectations of a wide strata of Indian society from space technology. In this paper, the survey results conducted among 4 specific groups of people including environmentalists, social workers and NGO's, youth, children are presented and analyzed. Sample space of the survey, though small in number, has been carefully chosen, targeting a very specific group of people from academia, NGO's, colleges and schools. The survey was conducted online wherever possible and the remaining through field work.
Sling-on-a-ring: A realizable space elevator to leo?
(2008) Meulenberg, A.; Ramanathan, R.; Suresh, R.; Balaji, K.P.S.
In this paper, we propose a new concept of a rotovator based space elevator system called "sling-on-a-ringâ„¢". The system would consist of a high-tensile-strength equatorial circum-terra conductive fiber, associated solar-power and station-keeping units and a rotating sling module. The long sling assembly would rotate through the ring-bound mass-lifter module and would periodically descend into the atmosphere (13 km). The system would be adjusted so that at perigee, when the sling penetrates into the atmosphere, the rotational tip velocity of the sling end would almost cancel out the orbital velocity of the circum-terra ring relative to the earth's surface. With split-second timing, thepayload would be attached from an ordinary aircraft (at as low as-40000 feet) and jerked into space by the momentum of the sling. An improved version of the system (2-stage sling system) and man-rating aspects have also been discussed in the paper. Through the paper, it is intended to establish that with the availability of stronger materials, the improved version of the proposed system would be comparable to the HASTOL (in terms of tether-to-payload mass ratio), eliminating the need for hypersonic airplanes.