Odyssey Space Research (United States)

The Safe & Precise Landing Integrated Capabilities Evolution (SPLICE) project continues to push the development of advanced descent and landing technologies. This paper will focus on the improvements made to the SPLICE Dual Quaternion Guidance (DQG) algorithm, which is a critical software component for generating approach phase and hazard avoidance trajectories. The trajectory performance of SPLICE DQG will be evaluated in preparation for a terrestrial flight test that incorporates a hazard avoidance maneuver. Additionally, the implementation of a customized first order Proportional-Integral Projected Gradient solver will be reviewed, along with preliminary execution results on the SPLICE Descent and Landing Computer (DLC).

We study spherically symmetric spacetimes in Einstein-aether theory in three different coordinate systems, the isotropic, Painlevè-Gullstrand, and Schwarzschild coordinates, in which the aether is always comoving, and present both time-dependent and time-independent exact vacuum solutions. In particular, in the isotropic coordinates we find a class of exact static solutions characterized by a single parameter c14 in closed forms, which satisfies all the current observational constraints of the theory, and reduces to the Schwarzschild vacuum black hole solution in the decoupling limit (c14=0). However, as long as c14≠0, a marginally trapped throat with a finite non-zero radius always exists, and on one side of it the spacetime is asymptotically flat, while on the other side the spacetime becomes singular within a finite proper distance from the throat, although the geometric area is infinitely large at the singularity. Moreover, the singularity is a strong and spacetime curvature singularity, at which both of the Ricci and Kretschmann scalars become infinitely large.

A technique for determining ignition voltage and minimum ignition energy of a combustible gas propellant in near-actual thruster conditions has been developed. The technique employs electrical state-space response analysis in lieu of more conventional methods such as low-resistance shunting or inductive current monitoring. State-space response analysis circumvents direct measurement of impulsive and inherently noisy ignition sparks. The new technique employs commonly available test equipment and an analysis algorithm readily programmed in an open-source numerical computation environment. It is easily repeatable for evaluating a wide range of ignition conditions such as oxidizer-to-fuel mixture ratio, propellant pressure and temperature, and electrode/chamber geometry. It is currently used for static propellant ignition testing but could be extended to flowing propellant conditions and quenching distance analysis.

This study used high fidelity computer simulation to investigate the lighting conditions, specifically the solar radiation flux over the surface, on Phobos. Ephemeris data from the Jet Propulsion Laboratory (JPL) DE405 model was used to model the state of the Sun, Earth, Moon, and Mars. An occultation model was developed to simulate Phobos' self-shadowing and its solar eclipses by Mars. The propagated Phobos state was compared with data from JPL's Horizon system to ensure the accuracy of the result. Results for Phobos lighting conditions over one Martian year are presented, which include the duration of solar eclipses, average solar radiation intensity, surface exposure time, and radiant exposure for both sun tracking and fixed solar arrays. The results show that: Phobos' solar eclipse time varies throughout the Martian year, with longer eclipse durations during the Martian northern spring and fall seasons and no eclipses during the Martian northern summer and winter seasons; solar radiation intensity is close to minimum in late spring and close to maximum in late fall; exposure time per orbit is relatively constant over the surface during the spring and fall but varies with latitude during the summer and winter; and Sun tracking solar arrays generate more energy than a fixed solar array. A usage example of the result is also present in this paper to demonstrate the utility.

a = semimajor axis, m C = hodograph parameter (centerpoint ordinate), m=s e = eccentricity, (unitless) f, g = Lagrangian coefficients (unitless) p = orbit parameter (semilatus rectum), m R = hodograph parameter (radius), m=s r = position vector, m v = velocity vector, m=s x, y = modified hodograph abscissa and ordinate, m=s t = time of flight, s = transfer angle, rad = gravitational parameter, m=s = true anomaly, rad = flight-path angle, rad

NASA fs Kedalion engineering analysis lab at Johnson Space Center is on the forefront of validating and using many contemporary avionics hardware/software development and integration techniques, which represent new paradigms to heritage NASA culture. Kedalion has validated many of the Orion hardware/software engineering techniques borrowed from the adjacent commercial aircraft avionics solution space, with the intention to build upon such techniques to better align with today fs aerospace market. Using agile techniques, commercial products, early rapid prototyping, in-house expertise and tools, and customer collaboration, Kedalion has demonstrated that cost effective contemporary paradigms hold the promise to serve future NASA endeavors within a diverse range of system domains. Kedalion provides a readily adaptable solution for medium/large scale integration projects. The Kedalion lab is currently serving as an in-line resource for the project and the Multipurpose Crew Vehicle (MPCV) program.

use of control in one axis only. To show the feasibility of such a concept, the technique of single-input/single-output feedback linearization using the Lie derivative method is employed. The problem is solved for different numbers of jets and for different configurations of the inertia matrix. In the case of an axisymmetric spacecraft, the closed-loop stability is analyzed through the zero dynamics of the internal dynamics. In the cases in which the inertia matrix has cross products of inertia different from zero, the internal dynamics becomes practically intractable. In these cases, only an assessment of closed-loop stability coming from the analysis of different simulation cases is provided. The results show that for the proposed concept and control method to be feasible, a specific geometric layout of the actuators is required for each inertia configuration and number of jets employed in the system.

Article Formal methods in mathematics Share on Author: Richard Platek Odyssey Research Associates Odyssey Research AssociatesView Profile Authors Info & Claims Conference proceedings on Formal methods in software developmentApril 1990 Pages 100–103https://doi.org/10.1145/99569.99827Online:01 April 1990Publication History 1citation331DownloadsMetricsTotal Citations1Total Downloads331Last 12 Months1Last 6 weeks0 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteGet Access

We give a general formalism for conditional rewriting, with systems containing conditional rules whose antecedents contain literals to be shown satisfiable and/or unsatisfiable. We explore semantic issues, addressing when the associated operational rewriting mechanism is sound and complete. We then give restrictions on the formalism which enable us to construct useful and meaningful specifications using the proposed operational mechanism.KeywordsLogic ProgramLogic ProgrammingFunction SymbolLogical VariableGround TermThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.