The LArase Satellites Spin mOdel Solutions (LASSOS): a comprehensive model for the spin evolution of the LAGEOS and LARES satellites

The two LAGEOS and LARES are laser-ranged satellites tracked with the best accuracy ever achieved. Using their range measurements many geophysical parameters were calculated and some General Relativity effects were directly observed. To obtain precise and refined measurements of the effects due to the predictions of General Relativity on the orbit of these satellites, it is mandatory to model with high precision and accuracy all other forces, reducing the free parameters introduced in the orbit determination. A main category of non-gravitational forces to be considered are those of thermal origin, whose fine modeling strongly depends on the knowledge of the evolution of the spin vector. We present a complete model, named LASSOS, to describe the evolution of the spin of the LAGEOS and LARES satellites. In particular, we solved Euler equations of motion considering not-averaged torques. This is the most general case, and the predictions of the model well fit the available observations of the satellites spin. We also present the predictions of our model in the fast-spin limit, based on the application of averaged equations. The results are in good agreement with those already published, but with our approach we have been able to highlight small errors within these previous works. LASSOS was developed within the LARASE research program. LARASE aims to improve the dynamical model of the two LAGEOS and LARES satellites to provide very precise and accurate measurements of relativistic effects on their orbit, and also to bring benefits to geophysics and space geodesy

LAGEOS-type Satellites in Critical Supplementary Orbit Configuration and the Lense-Thirring Effect Detection

In this paper we analyze quantitatively the concept of LAGEOS--type satellites in critical supplementary orbit configuration (CSOC) which has proven capable of yielding various observables for many tests of General Relativity in the terrestrial gravitational field, with particular emphasis on the measurement of the Lense--Thirring effect.Comment: LaTex2e, 20 pages, 7 Tables, 6 Figures. Changes in Introduction, Conclusions, reference added, accepted for publication in Classical and Quantum Gravit

Comparison of Two Trap Net Designs for Sampling Muskellunge

Sampling adequate numbers of muskellunge (Esox masquinongy) is necessary to evaluate stocking success and to collect information on various population metrics (e.g., growth, condition, relative abundance). However, muskellunge are often difficult to sample with standard fish sampling gears. We collected muskellunge in trap nets of two different designs (large trap nets [1.5-m × 1.8-m frames, 1.5-m diameter hoops, double throated, single 1.5-m × 30.5-m lead and 19-mm knotless mesh] and small trap nets [0.9-m × 1.5-m frames, 0.9-m diameter hoops, single throat, single 0.9-m × 15.2-m lead and 19-mm knotted mesh]. We also estimated abundance of muskellunge (\u3e600 mm total length) in three eastern South Dakota waters using marked and recaptured fish collected from the trap net comparisons. Sampling with both large and small trap nets was completed during thespring of 2013 and 2014 soon after ice-out. More muskellunge were collected in large than small trap nets at all three lakes. Mean total lengths of muskellunge did not differ significantly between large and small trap nets; however, length-frequency distribu- tions did differ between net designs. Regardless of trap net design, a small number of muskellunge were collected, likely due to low abundance (population range = 0.10 fish/ha to 0.47 fish/ha) in these populations. Thus, long-term monitoring is necessary to accurately assess populations and associated trends. Sampling with large trap nets during the spring combined with population estimates may improve the ability to monitor and manage muskellunge when compared to sampling with small trap nets

Testing gravitation with satellite laser ranging and the LARASE experiment

The International Laser Ranging Service (ILRS) provides range measurements of pas- sive satellites around the Earth through the powerful Satellite Laser Ranging (SLR) technique. These very precise measurements of the distance between an on-ground laser station and a satellite equipped with cube corner retro-reflectors (CCRs) make possible precise tests and measurements in fundamental physics and, in particular, in gravitational physics. The LAGEOS (NASA 1976) and LAGEOS II (NASA/ASI 1992) satellites are outstanding examples of very good test particles because of their very low area-to-mass ratio as well as the high quality of their tracking data and, consequently, of the precise orbit determination (POD) we can obtain after a refined modeling of their orbit. The aim of our research program LARASE (LAser RAnged Satellites Experi- ment) is to go a step further in testing gravitation in the field of Earth by means of the joint analysis of the orbits of the two LAGEOS satellites together with that of the most recently launched LARES (ASI, 2012) satellite. Therefore, our work falls in the so-called weak field and slow motion (WFSM) limit of Einstein’s general relativity (GR) where, in terms of Newtonian physics, relativistic effects appear as two new fields to be added to the classical gravitational field: the gravitoelectric and the gravitomagnetic fields. A fundamental ingredient to reach such a goal is to provide high-quality updated models for the perturbing non-gravitational perturbations (NGP) acting on the surface of these satellites. In fact, regardless of their minimization thanks to a smaller value for the area-to-mass ratio, the subtle and complex to model perturbing effects of the NGP play a crucial role in the POD of the considered satellites, especially in the case of the thermal thrust effects. A large amount of SLR data of LAGEOS and LAGEOS II has been worked out using a set of dedicated models for the satellite dynamics and the related post-fit residuals have been analyzed. A parallel work was performed with LARES, although at a preliminary stage. Our recent work on the orbit modeling and on the data analysis of the orbit of such satellites is presented and discussed

South Dakota Fisheries: An Evaluation of a Chemical Immersion Marking Technique for Juvenile Yellow Perch and Application to a Stocking Assessment of Marsh-Reared Yellow Perch into Eastern South Dakota Lakes

Currently, yellow perch Perca flavescens stocking needs in South Dakota are met by intensive trap and transfer of juvenile and adult perch. The success of these stocking efforts is largely undocumented, primarily due to problems in distinguishing yellow perch produced within the recipient water body and stocked perch. We first developed a transfer-tank marking protocol to determine immersion duration and optimal concentration of oxytetracycline (OTC) hydrochloride needed to produce an effective mark. Then we validated the protocol for adult yellow perch and determined the persistence of OTC in edible muscle tissue. Marking results indicated that satisfactory OTC marks may be obtained in juvenile yellow perch using 600- to 700-ppm OTC for an immersion period of 6 to 8 h. OTC marks were evident in juvenile yellow perch otoliths and dorsal spines checked at 3 months post-immersion. Mark quality was observed to be slightly better in juvenile dorsal spines than otoliths. OTC marks in adult yellow perch were detectable at otolith margins at 9 d post-immersion. Adult muscle tissues were analyzed with high pressure liquid chromatography to quantify OTC residues. A nonlinear model (In epi-OTC [~g g-I] = 0.960 - 0.389*In time [h]; r\u27- = 0.99) describing the combined OTC base/epi residue relation to time indicated that no more than 0.5 ~g OTC g-I should be present at 73 h following immersion

The Comparative Exploration of the Ice Giant Planets with Twin Spacecraft: Unveiling the History of our Solar System

In the course of the selection of the scientific themes for the second and third L-class missions of the Cosmic Vision 2015-2025 program of the European Space Agency, the exploration of the ice giant planets Uranus and Neptune was defined "a timely milestone, fully appropriate for an L class mission". Among the proposed scientific themes, we presented the scientific case of exploring both planets and their satellites in the framework of a single L-class mission and proposed a mission scenario that could allow to achieve this result. In this work we present an updated and more complete discussion of the scientific rationale and of the mission concept for a comparative exploration of the ice giant planets Uranus and Neptune and of their satellite systems with twin spacecraft. The first goal of comparatively studying these two similar yet extremely different systems is to shed new light on the ancient past of the Solar System and on the processes that shaped its formation and evolution. This, in turn, would reveal whether the Solar System and the very diverse extrasolar systems discovered so far all share a common origin or if different environments and mechanisms were responsible for their formation. A space mission to the ice giants would also open up the possibility to use Uranus and Neptune as templates in the study of one of the most abundant type of extrasolar planets in the galaxy. Finally, such a mission would allow a detailed study of the interplanetary and gravitational environments at a range of distances from the Sun poorly covered by direct exploration, improving the constraints on the fundamental theories of gravitation and on the behaviour of the solar wind and the interplanetary magnetic field.Comment: 29 pages, 4 figures; accepted for publication on the special issue "The outer Solar System X" of the journal Planetary and Space Science. This article presents an updated and expanded discussion of the white paper "The ODINUS Mission Concept" (arXiv:1402.2472) submitted in response to the ESA call for ideas for the scientific themes of the future L2 and L3 space mission

Accurate Measurement in the Field of the Earth of the General-Relativistic Precession of the LAGEOS II Pericenter and New Constraints on Non-Newtonian Gravity

The pericenter shift of a binary system represents a suitable observable to test for possible deviations from the Newtonian inverse-square law in favor of new weak interactions between macroscopic objects. We analyzed 13 years of tracking data of the LAGEOS satellites with GEODYN II software but with no models for general relativity. From the fit of LAGEOS II pericenter residuals we have been able to obtain a 99.8% agreement with the predictions of Einstein's theory. This result may be considered as a 99.8% measurement in the field of the Earth of the combination of the {\gamma} and {\beta} parameters of general relativity, and it may be used to constrain possible deviations from the inverse-square law in favor of new weak interactions parametrized by a Yukawa-like potential with strength {\alpha} and range {\lambda}. We obtained |{\alpha}|\lesssim1\times10-11, a huge improvement at a range of about 1 Earth radius