GUIDANCE OF UNMANNED LUNAR AND INTERPLANETARY SPACECRAFT
Unmanned spacecraft guidance from earth based station - optimal control and orbit calculations
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Unmanned spacecraft guidance from earth based station - optimal control and orbit calculations
Hansen theory of satellite orbit calculation as modified by musen
Lunar satellite orbit calculation to determine time in umbra and penumbra
Calculating orbital elements of comet Burnham-Slaughter 1958e-1959I
Rendezvous compatible spacecraft orbit calculation for 150 to 850-km region
Concentrations and orbital calculations of meteors and meteoritic and extraterrestrial dust particles - conference
Orbit calculations for size and shape of orbit, required velocity at perigee and apogee, and gravitational effects on satellite orbit
Orbit calculation by fitting functions to osculating orbital elements
Orbit calculation using Encke perturbation method and Fortran IV programming
Physical properties of moon & planets - planetary atmospheres, radiometry, reentry and orbit calculations
A description is provided of ab initio molecular orbital calculations designed to provide accurate predictions for the J = 1 to 0 rotational line of the candidate interstellar molecules HCNH(+) and COH(+). The former is believed to be important in the formation of both HCN and HNC in the interstellar medium. The latter, a metastable isomer of HCO(+), was first proposed as an interstellar molecule by Herbst et al. (1976). Attention is given to thermochemical arguments that this molecule can be formed in the same reactions which are proposed to form HCO(+), taking into account theoretical data which establish its stability to intramolecular rearrangement. Rotational constants are derived by applying an empirical correction to the ab initio rotational constants.
Short period orbit calculations around equilateral libration points in plane restricted three-body problem
Kalman-Schmidt filter stability in orbit calculation, dependence on transition matrix, initial covariance matrix, observations, and covariance of noise in measurements
Calculating orbit for Comet 1941c -1941IV using least squares method, and considering planetary perturbations
Computer program is capable of calculating orbit and geodetic parameter estimates. Program can also be used for translunar and interplanetary trajectories.
The fundamentals of an Earth monitoring Sun-synchronous orbit are presented. A Sun-synchronous Orbit Analysis Program (SOAP) was developed to calculate orbital parameters for an entire year. The output from this program provides the required input data for the TRASYS thermal radiation computer code, which in turn computes the infrared, solar and Earth albedo heat fluxes incident on a space experiment. Direct incident heat fluxes can be used as input to a generalized thermal analyzer program to size radiators and predict instrument operating temperatures. The SOAP computer code and its application to the thermal analysis methodology presented, should prove useful to the thermal engineer during the design phases of Earth monitoring Sun-synchronous space experiments.
NASA’s Orbital Debris Engineering Model was designed to calculate orbital debris fluxes on spacecraft in order to assess collision risk. The newest of these models, ORDEM 3.0, has a number of features not present in previous models. One of the most important is that the populations and fluxes are now broken out into material density groups. Previous models concentrated on debris size alone, but a particle’s mass and density also determine the amount of damage it can cause. ORDEM 3.0 includes a high-density component, primarily consisting of iron/steel particles that drive much of the risk to spacecraft. This paper will outline the methods that were used to separate and identify the different densities of debris, and how these new densities affect the overall debris flux and risk.