In-flight crew training

The Helmet Mounted Display system and Part Task Trainer are two projects currently underway that are closely related to the in-flight crew training concept. The first project is a training simulator and an engineering analysis tool. The simulator's unique helmet mounted display actually projects the wearer into the simulated environment of 3-D space. Miniature monitors are mounted in front of the wearers eyes. Partial Task Trainer is a kinematic simulator for the Shuttle Remote Manipulator System. The simulator consists of a high end graphics workstation with a high resolution color screen and a number of input peripherals that create a functional equivalent of the RMS control panel in the back of the Orbiter. It is being used in the training cycle for Shuttle crew members. Activities are underway to expand the capability of the Helmet Display System and the Partial Task Trainer

Shipping Receipt L.B. Condon July 21 1862

https://digitalmaine.com/blue_hill_documents/1147/thumbnail.jp

Virtual reality applications in robotic simulations

Virtual reality (VR) provides a means to practice integrated extravehicular activities (EVA)/remote manipulator system (RMS) operations in the on-orbit configuration with no discomfort or risk to crewmembers. VR afforded the STS-61 crew the luxury of practicing the integrated EVA/RMS operations in an on-orbit configuration prior to the actual flight. The VR simulation was developed by the Automation and Robotics Division's Telepresence/Virtual Reality Lab and Integrated Graphics, Operations, and Analysis Lab (IGOAL) at JSC. The RMS Part Task Trainer (PTT) was developed by the IGOAL for RMS training in 1988 as a fully functional, kinematic simulation of the shuttle RMS and served as the RMS portion of the integrated VR simulation. Because the EVA crewmember could get a realistic view of the shuttle and payload bay in the VR simulation, he/she could explore different positions and views to determine the best method for performing a specific task, thus greatly increasing the efficiency of use of the neutral buoyancy facilities

The Importance of Lens Galaxy Environments

While many strong gravitational lens galaxies are suspected to lie in groups or clusters of galaxies, environmental effects in lens models are often unconstrained and sometimes ignored. We show that this creates significant biases in a variety of lensing applications, by creating mock lenses associated with each of 13 galaxies in a realistic model group, and then analyzing them with standard techniques. We find that standard models of double lenses, which neglect environment, grossly overestimate the ellipticity of the lens galaxy (de/e~0.5) and the Hubble constant (dh/h~0.22). Standard models of quad lenses, which approximate the environment as a tidal shear, recover the ellipticity reasonably well (|de/e|<~0.24) but overestimate the Hubble constant (dh/h~0.15), and have significant (~30%) errors in the millilensing analyses used to constrain the amount of substructure in dark matter halos. For both doubles and quads, standard models slightly overestimate the velocity dispersion of the lens galaxy (d(sigma)/sigma~0.06), and underestimate the magnifications of the images (d(mu)/mu ~ -0.25). Standard analyses of lens statistics overestimate Omega_Lambda (by 0.05-0.14), and underestimate the ratio of quads to doubles (by a factor of 2). These biases help explain some long-standing puzzles (such as the high observed quad/double ratio), but aggravate others (such as the low value of H_0 inferred from lensing). Most of the biases are caused by neglect of the convergence from the mass associated with the environment, but additional uncertainty is introduced by neglect of higher-order terms. Fortunately, we show that directly observing and modeling lens environments should make it possible to remove the biases and reduce the uncertainties associated with environments to the few percent level. (Abridged)Comment: 14 emulateapj pages; accepted in Ap

Global Topology and Local Violation of Discrete Symmetries

Cosmological models that are locally consistent with general relativity and the standard model in which an object transported around the universe undergoes P, C and CP transformations, are constructed. This leads to generalization of the gauge fields that describe electro-weak and strong interactions by enlarging the gauge groups to include anti-unitary transformations. Gedanken experiments show that if all interactions obey Einstein causality then P, C and CP cannot be violated in these models. But another model, which would violate charge superselection rule even for an isolated system, is allowed. It is suggested that the fundamental physical laws must have these discrete symmetries which are broken spontaneously, or they must be non causal.Comment: 12 pages, 1 figure, latex, Revtex. Charge conjugation which is physically implemented in a cosmology with the appropriate topology is described in more detail. Some minor errors are corrected. Shortened to meet the page limit of Physical Review Letters to which this paper was submitte

Can codimension-two branes solve the cosmological constant problem?

It has been suggested that codimension-two braneworlds might naturally explain the vanishing of the 4D effective cosmological constant, due to the automatic relation between the deficit angle and the brane tension. To investigate whether this cancellation happens dynamically, and within the context of a realistic cosmology, we study a codimension-two braneworld with spherical extra dimensions compactified by magnetic flux. Assuming Einstein gravity, we show that when the brane contains matter with an arbitrary equation of state, the 4D metric components are not regular at the brane, unless the brane has nonzero thickness. We construct explicit 6D solutions with thick branes, treating the brane matter as a perturbation, and find that the universe expands consistently with standard Friedmann-Robertson-Walker (FRW) cosmology. The relation between the brane tension and the bulk deficit angle becomes $\Delta=2\pi G_6(\rho-3 p)$ for a general equation of state. However, this relation does not imply a self-tuning of the effective 4D cosmological constant to zero; perturbations of the brane tension in a static solution lead to deSitter or anti-deSitter braneworlds. Our results thus confirm other recent work showing that codimension-two braneworlds in nonsupersymmetric Einstein gravity do not lead to a dynamical relaxation of the cosmological constant, but they leave open the possibility that supersymmetric versions can be compatible with self-tuning.Comment: Revtex4, 17 pages, references added, typos corrected, minor points clarified. Matches published versio

Concert recording 2019-04-01

[Track 1]. Glory to God -- [Track 2]. Morning tide -- [Track 3]. Name -- [Track 4]. Light from below -- [Track 5]. Demented dances. I. Erratic polka II. Waltz in limbo III. Grandiose gigue

Concert recording 2019-03-30c

[Track 1]. Kokopelli / Katherine Hoover -- [Track 2]. Mélodie in C-sharp minor, op. 4, no. 2 Notturno in G minor / Fanny Cecile Mendelssohn -- [Track 3]. Cowboy songs / Libby Larsen -- [Track 4]. Sound bytes. I. Invention II. Thirds III. Short circuit IV. Get up / Katherine Hoover -- [Track 5]. Overheard on a saltmarsh / Erin Goad -- [Track 6]. Sonatina for clarinet and piano / Caroline Schleicher Krämer -- [Track 7]. Winter spirits / Katherine Hoover -- [Track 8]. The butterfly from I never saw another butterfly / Lori Laitman -- [Track 9]. Erratic polka from Demented dances / Elizabeth Greener -- [Track 10]. Original Latin-American flute duets. I. Pasaje folia II. Torbellino III. Bolero Rhumba IV. Polka Chocoana / Carmen Liliana Marulanda -- [Track 11]. Trio for flute, oboe, and piano / Madeleine Dring