No abstract

In the past, clues on the potential radiogenic activity of the lunar interior have been obtained from the isotopic composition of noble gases like Argon. Excess Argon (40) relative to Argon (36), as compared to the solar wind composition, is generally ascribed to the radiogenic activity of the lunar interior. Almost all the previous estimates were based on, 'on the spot' measurements from the landing sites. Relative concentration of the isotopes of 40 Ar and 36 Ar along a meridian by the Chandra's Altitudinal Composition Explorer (CHACE) experiment, on the Moon Impact Probe (MIP) of India's first mission to Moon, has independently yielded clues on the possible spatial heterogeneity in the radiogenic activity of the lunar interior in addition to providing indicative 'antiquity' of the lunar surface along the ground track over the near side of the moon. These results are shown to broadly corroborate the independent topography measurements by the Lunar Laser Ranging Instrument (LLRI) in the main orbiter Chandrayaan-1. The unique combination of these experiments provided high spatial resolution data while indicating the possible close linkages between the lunar interior and the lunar ambience.

Lunar Laser Ranging Instrument (LLRI) proposed for the first Indian lunar mission Chandrayaan-1 is aimed to study the topography of the Moon's surface and its gravitational field by precisely measuring the altitude from a polar orbit around the Moon. Altimetry data close to the poles of the Moon would also be available from the instrument, which was not covered by earlier missions. This instrument supplements the terrain mapping camera and hyper-spectral imager payloads on Chandrayaan-1. The instrument consists of a diode pumped Nd:YAG pulsed laser transmitter having 10 nsec pulse width and a receiver system. The receiver system features 17 cm diameter Ritchey-Chrétien collecting optics, Si Avalanche Photo Detector (APD), preamplifiers, constant fraction discriminators, time-of-flight measurement unit and spacecraft interface. Altimeter resolution of better than 5 m is targeted. The received signal strength of LLRI depends on laser pulse backscatter from the Moon's surface. Moon's surface being a poor reflector, the choice of receiver size and its type and the selection of detector play an important role in getting a good signal-to-noise ratio and in turn achieving the target resolution. At the same time, the spacecraft puts a limitation on payload size and weight. This paper discusses the proposed LLRI system for Chandrayaan-1 and signal-to-noise ratio estimation.

Fertility status of red and medium black soils and their correlation studies were carried out insoils of Warangal District (R) of Telangana State. All samples in red and medium black soils were neutral to alkaline in reaction and pH values ranged from 7.25 to 8.56 by medium black soilfollowed (6.50 to 7.52) by red soil with mean values of 7.64 in medium black soilfollowed 7.53 in red soil. The EC varies from 0.08 to 1.90 dS m-1 in red soil and 0.08 to 2.17 dS m-1 in medium black soil.The calcium carbonate (CaCO3) content varies from 0.59 to 1.95% in red soil and 1.69 to 2.92% in medium black soil and maximum mean valuewas recorded in medium black soil (1.69%) followed by red soil (0.69%). Red soils were Loam to Clay loam whereas medium black soils were clay in texture. Organic carbon content ranges from 0.14 to 0.75% in red soil and from 0.50 to 0.79% in medium black soil with an average value of 0.38% in red soil and 0.53% in medium black soil. 81and 45% of soils were low, 15 and 55% in medium and none of the soil samples were found higher categoryin OC content in red soil and medium black soils, respectively. Available N, P, K and S content varied from 59 to 201kg ha-1, 14 to 133kg ha-1, 211 to 341kg ha-1 and 6.9 to 24.59 mg kg-1with mean values of 144 kg ha-1, 56 kg ha-1, 247 kg ha-1 and 19.26 mg kg-1 in red soils, respectively. In medium black soils available N, P, K and S content varied from 100 to 276 kg ha-1, 21 to 103 kg ha-1, 332 to 450 kg ha-1 and 10.50 to 41.40 mg kg-1with mean values of 177 kg ha-1, 54 kg ha-1, 398 kg ha-1and 27.40 mg kg-1, respectively. In red soils 100% samples were low in available N, 25%low, 32 % medium and 43% higher in available P2O5,1% medium and 99% higher in available K2O and 62% low and 38% medium in available S. In medium black soils 100% samples were low in available N, 22% low, 38% medium and 40% higher in available P2O5, 38% medium and 62% samples were higher in available K2O and 51% low and 49%  medium in available S. The DTPA-Zn in 23% samples were deficient in medium black soil. In case of DTPA-Fe in 47 and 90% samples were found deficient in red and medium black soil, respectively. None of the samples in both soil groups were found deficient in Cu and Mn. In case of available-B in 29 and 34% samples were deficient in red and medium black soils, respectively. The data indicated that only 9.2% samples in medium black soil were deficient in case of available Mo. The nutrient index indicated that the red and medium black soils were low, medium and high in available N, P and K, respectively. Deficiency of micronutrients was in the order: Fe > B in red soils, Fe > B >Zn in medium black soils. Available N, P, K, S, Fe, Cu, Zn, Mn, B decreased, whereas Mo increased with increasing pH. Available N and P decreased, whereas K and S increased with increasing EC. Available N, P, K, S, Fe, Cu, Zn, Mn and B increased with increasing level of organic carbon.

No abstract