Engineering topics

Ayers, J. Kirk

Publications and source records attributed to Ayers, J. Kirk.

24 records · Page 2

NASA NTRS1990

Dynamic characteristics of a Space Station Freedom Mars evolution reference configuration

One concept for a manned mission to Mars uses as a transportation mode an evolutionary version of Space Station Freedom (SSF), termed the Mars Evolution Reference Configuration (MERC). The MERC is configured by adding to SSF dual keels, an upper and lower boom, additional laboratory and habitation modules, increased power, and an assembly platform. A finite-element model of the MERC was formulated to investigate the expected low frequency modes, and its variations with the addition of large payload. A basic reboost procedure using near-continuous firing of reaction control system jets is described with the closed-loop attitude control system. The elastic dynamic behavior at critical points during a reboost of the MERC, both with and without the Mars piloted vehicle installed, is examined.

Ayers, J. Kirk↗

NASA NTRS1990

Low earth orbit infrastructure to accommodate manned lunar missions

In order to establish bases on the lunar and Mars surfaces, a significant amount of orbital infrastructure including assembly platforms, cryogenic fluids depots, and Space Station Freedom, will be required in LEO. These facilities will be required to perform a myriad of functions ranging from orbital demonstration of advanced technology systems and establishment of life science capabilities to servicing and refurbishment of reusable lunar transfer vehicles. This paper addresses the requirements levied on these facilities and provides an overview of potetial LEO infrastructure elements that satisfy various advanced manned missions. Of key importance to the success of the manned lunar mission are (1) the evolutionary growth of Space Station Freedom to serve as a transportation node and (2) the development of a Shuttle-derived launch vehicle to deliver mission elements to LEO.

Cirillo, William M.↗

NASA NTRS1990

Structural dynamic and control considerations for Space Station transportation node concepts

This paper discusses the results of two studies which investigated the expected low frequency dynamic characteristics of conceptual Mars and lunar transportation nodes. Both concepts are based on evolution of the assembly-complete Space Station Freedom configuration by the addition of keels, booms, and modules. Finite-element models of the concepts were developed and a set of undamped modes and frequencies was computed below 2 Hz for each concept. The modes were used as basis vectors for modal analyses describing the dynamic response of the structures to typical reboost maneuvers. The reboost maneuvers had fairly complex loading characteristics since the reaction control system (RCS) jets used for the maneuvers were off-modulated to control pitch and yaw attitude. Interaction of the dynamic response of the structure with the closed-loop attitude control system is investigated for both concepts. The elastic response in the solar dynamic region is investigated to evaluate the severity of the dynamic environment, since the solar dynamic systems have stringent sunpointing requirements which must be maintained during the reboost maneuver.

Cooper, Paul A.↗

NASA NTRS1988

Earth transportation node requirements and design

The objective of this paper is to establish the requirements for an inhabited earth orbiting transportation node and to develop design concepts for such a facility. The use of an earth orbiting transportation node is required to support many of the space flight projects proposed for the beginning of the 21st century. The requirements for such an orbiting facility are derived from the missions which they support. Future missions investigated include automated and human exploration of the solar system, support of a lunar base, and missions to planet earth. Design concepts are presented for transportation nodes based on a variation of the current Space Station Freedom design. Designs accommodate a variety of earth-to-orbit, orbit-to-orbit, and deep-space probe transportation systems. Finally, the technology needed to develop such a transportation node is summarized.

Hook, W. Ray↗

NASA NTRS1988

Manned Mars mission accommodation: Sprint mission

The results of a study conducted at the NASA-LaRC to assess the impacts on the Phase 2 Space Station of Accommodating a Manned Mission to Mars are documented. In addition, several candidate transportation node configurations are presented to accommodate the assembly and verification of the Mars Mission vehicles. This study includes an identification of a life science research program that would need to be completed, on-orbit, prior to mission departure and an assessment of the necessary orbital technology development and demonstration program needed to accomplish the mission. Also included is an analysis of the configuration mass properties and a preliminary analysis of the Space Station control system sizing that would be required to control the station. Results of the study indicate the Phase 2 Space Station can support a manned mission to Mars with the addition of a supporting infrastructure that includes a propellant depot, assembly hangar, and a heavy lift launch vehicle to support the large launch requirements.

Cirillo, William M.↗

NASA NTRS1987

Structural dynamics and attitude control study of early manned capability space station configurations

A study was performed to determine the vibration and attitude control characteristics of critical space station configurations featuring early manned capability during buildup from initial user support through the operations capability reference station. Five configurations were selected and were examined thus determining the changes that are likely to occur in the characteristics of the system as the station progresses from a single boom structure to a mature, dual keel, operations capability reference station. Both 9 foot and 5 meter truss bay sizes were investigated. All configurations analyzed were stable; however, the 5 meter truss bay size structure exhibited superior stability characteristics.

Ayers, J. Kirk↗