A thermal vacuum test optimization procedure

An analytical model was developed that can be used to establish certain parameters of a thermal vacuum environmental test program based on an optimization of program costs. This model is in the form of a computer program that interacts with a user insofar as the input of certain parameters. The program provides the user a list of pertinent information regarding an optimized test program and graphs of some of the parameters. The model is a first attempt in this area and includes numerous simplifications. The model appears useful as a general guide and provides a way for extrapolating past performance to future missions

Failure rate analysis of Goddard Space Flight Center spacecraft performance during orbital life

Space life performance data on 57 Goddard Space Flight Center spacecraft are analyzed from the standpoint of determining an appropriate reliability model and the associated reliability parameters. Data from published NASA reports, which cover the space performance of GSFC spacecraft launched in the 1960-1970 decade, form the basis of the analyses. The results of the analyses show that the time distribution of 449 malfunctions, of which 248 were classified as failures (not necessarily catastrophic), follow a reliability growth pattern that can be described with either the Duane model or a Weibull distribution. The advantages of both mathematical models are used in order to: identify space failure rates, observe chronological trends, and compare failure rates with those experienced during the prelaunch environmental tests of the flight model spacecraft

Superconductor strip in a closed magnetic environment: exact analytic representation of the critical state

An exact analytic representation of the critical state of a current-carrying type-II superconductor strip located inside a cylindrical magnetic cavity of high permeability is derived. The obtained results show that, when the cavity radius is small, penetration of magnetic flux fronts is strongly reduced as compared to the situation in an isolated strip. From our generic representation it is possible to establish current profiles in closed cavities of various other geometries too by means of conformal mapping of the basic configuration addressed.Comment: 2 pages, 1 figure; accepted in Physica C for the Proceedings of M2S-HTSC, Dresden, 200

The Carotid Arteries and Their Relation to the Circle of Willis in the Cat

The value of the domestic cat as an object of dissection in work introductory to comparative anatomy in general and to mammalian anatomy in particular, makes it important that our knowledge of this form should be as exact as possible

The Innervation of the Lateral Line System of Amphiuma

Kingsbury has given us an account of the general distribution of the sense-organs of the lateral line system in Amphiuma. According to him the arrangement in this form is almost typical of Amphibia. On the head: the supra-orbital group dorsal to the eye extends anteriorly to the tip of the snout; the infra-orbital group runs from the angle of the mouth ventral to the eye to the snout region; the oral line on the lower jaw passes along the lower lip; an angular series connects the oral with the infra-orbital; the gular series is found on the ventral surface of the head extending from the branchial region to the tip of the lower jaw; a post-orbital series passes posteriorly from the infra-orbital to meet the gular in the posterior branchial region; a jugular connects the angular with the meeting point of the gular and post-orbital. On the trunk are three longitudinal series: a dorsal, a lateral or median, and a ventral line