Development of assembly and joint concepts for erectable space structures

The technology associated with the on-orbit assembly of tetrahedral truss platforms erected of graphite epoxy tapered columns is examined. Associated with the assembly process is the design and fabrication of nine member node joints. Two such joints demonstrating somewhat different technology were designed and fabricated. Two methods of automatic assembly using the node designs were investigated, and the time of assembly of tetrahedral truss structures up to 1 square km in size was estimated. The effect of column and node joint packaging on the Space Shuttle cargo bay is examined. A brief discussion is included of operating cost considerations and the selection of energy sources. Consideration was given to the design assembly machines from 5 m to 20 m. The smaller machines, mounted on the Space Shuttle, are deployable and restowable. They provide a means of demonstrating the capabilities of the concept and of erecting small specialized platforms on relatively short notice

Roentgen Satellite (ROSAT)

As result of the Challenger accident, the alternative possibility for launch of the ROSAT mission with an Atlas/Centaur launch vehicle is being considered. An overview of the problems involved in having the ROSAT flight ready for either a Shuttle or Atlas/Centaur launch is presented

Space Shuttle Orbiter Structures and Mechanisms

The Space Shuttle Orbiter has performed exceptionally well over its 30 years of flight experience. Among the many factors behind this success were robust, yet carefully monitored, structural and mechanical systems. From highlighting key aspects of the design to illustrating lessons learned from the operation of this complex system, this paper will attempt to educate the reader on why some subsystems operated flawlessly and why specific vulnerabilities were exposed in others. Specific areas to be covered will be the following: high level configuration overview, primary and secondary structure, mechanical systems ranging from landing gear to the docking system, and windows

Independent Orbiter Assessment (IOA): Analysis of the crew equipment subsystem

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical (PCIs) items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The independent analysis results coresponding to the Orbiter crew equipment hardware are documented. The IOA analysis process utilized available crew equipment hardware drawings and schematics for defining hardware assemblies, components, and hardware items. Each level of hardware was evaluated and analyzed for possible failure modes and effects. Criticality was assigned based upon the severity of the effect for each failure mode. Of the 352 failure modes analyzed, 78 were determined to be PCIs

Space transportation system payload safety guidelines handbook

This handbook provides the payload developer with a uniform description and interpretation of the potential hazards which may be caused by or associated with a payload element, operation, or interface with other payloads or with the STS. It also includes guidelines describing design or operational safety measures which suggest means of alleviating a particular hazard or group of hazards, thereby improving payload safety

Preliminary design polymeric materials experiment

A typical Advanced Technology Laboratory mission flight plan was developed and used as a guideline for the identification of a number of experiment considerations. The experiment logistics beginning with sample preparation and ending with sample analysis are then overlaid on the mission in order to have a complete picture of the design requirements. The results of this preliminary design study fall into two categories. First specific preliminary designs of experiment hardware which is adaptable to a variety of mission requirements. Second, identification of those mission considerations which affect hardware design and will require further definition prior to final design. Finally, a program plan is presented which will provide the necessary experiment hardware in a realistic time period to match the planned shuttle flights. A bibliography of all material reviewed and consulted but not specifically referenced is provided

The 21st Aerospace Mechanisms Symposium

During the symposium technical topics addressed included deployable structures, electromagnetic devices, tribology, actuators, latching devices, positioning mechanisms, robotic manipulators, and automated mechanisms synthesis. A summary of the 20th Aerospace Mechanisms Symposium panel discussions is included as an appendix. However, panel discussions on robotics for space and large space structures which were held are not presented herein

Message in a Bottle

The objective of Project Message in a Bottle is to design a variable buoyancy deployment capsule capable of housing generic payloads. The capsule is designed to deploy from a submersible host vessel at a depth of 65 feet below sea level. Once deployed, the capsule will sink horizontally with about 10% negative buoyancy until it is two capsule lengths from the host vessel. It then reorients vertically and rises to the surface with positive buoyancy. Once the capsule reaches the surface, the payload can be ejected without having been in contact with the water. A primary benchmark of the capsule is its cycle time; it must sink, reorient, and rise to the surface in under a minute. The main function of the capsule is to alter its buoyancy, which was accomplished using a drop weight mechanism. Initially, the team developed an Euler simulation to accurately evaluate the position and time of the capsule during descent and ascent. The simulation was corroborated with an in-water demonstration of a scaled version of the capsule. This model was constructed of PVC. The water demo was performed in two phases: ascent and decent, where weights were manually removed and added between trials. Position versus time plots were compared from both the simulation and water demonstration in ascent and descent. The experimental results of descent were exactly in accordance with the simulation results. The ascent values for the simulation and experiment were slightly off, however the team determined that the simulation’s lack of dynamic reorientation of the capsule is to blame. The water demo revealed that the product sinks horizontally with roughly -2% buoyancy, and rises to the surface with positive buoyancy in a matter of seconds. These results prove the drop weight method is feasible. During the Spring semester, another scaled prototype was designed and constructed. It was made of four inch diameter Schedule 40 PVC, with a threaded male adapter and female end-cap on each end. The drop weight was constructed using low-carbon steel for its magnetic properties. Deployable fins keep the capsule vertical on ascent, and were made using spring hinges. Both items were held in place using rubber straps and pin clevises. The drop weight mechanism consists of an internal motor, which rotates a spool on the exterior of the capsule. The spool is attached to pins, that once pulled, release the straps, deploying the drop weight and fins. This system was governed using an Arduino Uno, breadboard, and depth sensor. Once the capsule has reached the desired depth, the mechanism is triggered. An Euler simulation was completed for this capsule, and it featured reorientation. Flow simulation was completed to calculate drag coefficients at different angles for this simulation. The capsule was tested in a 14 foot dive pool. Five usable trials were recorded, and their results were compared to the simulation data. The simulation proved accurate, and the predicted time to surface of 9.87s was only 8.6% different from the average experimental value of 10.76s

Power system interface and umbilical system study

System requirements and basic design criteria were defined for berthing or docking a payload to the 25 kW power module which will provide electrical power and attitude control, cooling, data transfer, and communication services to free-flying and Orbiter sortie payloads. The selected umbilical system concept consists of four assemblies and command and display equipment to be installed at the Orbiter payload specialist station: (1) a movable platen assembly which is attached to the power system with EVA operable devices; (2) a slave platen assembly which is attached to the payload with EVA operable devices; (3) a fixed secondary platen permanently installed in the power system; and (4) a fixed secondary platen permanently installed on the payload. Operating modes and sequences are described