Browsing by Author "Suresh, R."

Now showing 1 - 7 of 7

Galex observations of diffuse ultraviolet emission from Draco
(Institute of Physics Publishing michael.roberts@iop.org, 2010) Sujatha, N.V.; Murthy, J.; Suresh, R.; Henry, R.C.; Bianchi, L.
We have studied small-scale (2?) spatial variation of the diffuse ultraviolet (UV) radiation using a set of 11 Galaxy Evolution Explorer deep observations in the constellation of Draco. We find a good correlation between the observed UV background and the infrared (IR) 100 ?m flux, indicating that the dominant contributor of the diffuse background in the field is scattered starlight from the interstellar dust grains. We also find strong evidence of additional emission in the far-ultraviolet (FUV) band which is absent in the near-ultraviolet (NUV) band. This is most likely due to Lyman band emission from molecular hydrogen in a ridge of dust running through the field and to line emissions from species such as Civ (1550 Å) and Siii (1533 Å) in the rest of the field. A strong correlation exists between the FUV/NUV ratio and the FUV intensity in the excess emission regions in the FUV band irrespective of the optical depth of the region. The optical depth increases more rapidly in the UV than the IR and we find that the UV/IR ratio drops off exponentially with increasing IR due to saturation effects in the UV. Using the positional details of Spitzer extragalactic objects, we find that the contribution of extragalactic light in the diffuse NUV background is 49 ± 13 photons cm -2 sr-1 s-1 Å-1 and is 30 ± 10 photons cm -2 sr-1 s-1 Å-1 in the FUV band. © 2010. The American Astronomical Society.
LEO-based optical/microwave terrestrial communications
(2008) Meulenberg, A.; Suresh, R.; Ramanathan, S.
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 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.
Perception of space technology in Indian society
(2008) Madgi, S.; Suresh, R.; Ramanathan, S.; 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.
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, S.; 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-ring�". 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.
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.