Engineering topics

Bowman, Lynn

Publications and source records attributed to Bowman, Lynn.

4 records

NASA NTRS2019

In Space Assembled Telescope (ISAT) Study Preliminary Findings

“When is it advantageous to assemble telescopes in space rather than deploying them from launch vehicle fairings”? This question forms the crux of the objectives of a NASA study we have been conducting in collaboration with colleagues from different NASA centers, industry and academia. In this study, we have engaged a broad cross section of experts from the various fields of optics engineering, that is, telescope design and instrument design, structure and thermal engineering, robotics, launch system engineering, orbital mechanics, integration and testing, astrophysics, and NASA programmatics among others. Initial efforts began with a quick review of the current state of art of the component technologies that contribute towards an in-space assembled telescope. Then, leveraging the collective expertise of the diverse group of experts, we formulated a reference telescope design and attempted to develop a baseline approach to modularize the telescope into components amenable for robotic assembly. The group identified different trades associated with modularization and also developed a set of criteria to discern between the different options as revealed by the trades. Based on the modularization of the telescope, we will assess the impact of various launch vehicles, orbits for assembly and operation, robotic systems and operational approaches, and other related variables. From this, a concept to assemble the reference telescope in space from modular components will be developed. Based on this concept, and definition of the modules, we will develop a mission lifecycle plan for an assembled telescope over different phases of preliminary design, detailed design, assembly-test-and-integration, and in space operations. The mission lifecycle plan will be used to evaluate cost and risk implications of in-space assembly toward answering our fundamental question of the advantages, if any, of assembling a telescope in space as compared to self-deployment. In this paper, we summarize the objectives of the study, a review of the status of the underlying component technologies, a description of the methodology, including three different multi-day technical interchange meetings (TIMs), summary of findings from the TIMs and other related activities. In addition, a detailed description of the various factors that impact in-space assembly, their interplay and criteria for discerning among them, a preliminary description of the life cycle plan, including the test and integration plan, and initial observations on cost and risk implications will be included in the paper.

Mukherjee, Rudranarayan↗

NASA NTRS2016

Commercial Application of In-Space Assembly

In-Space assembly (ISA) expands the opportunities for cost effective emplacement of systems in space. Currently, spacecraft are launched into space and deploy into their operational configuration through a carefully choreographed sequence of operations. The deployment operation dictates the arrangement of the primary systems on the spacecraft, limiting the ability to take full advantage of launch vehicles volume and mass capability. ISA enables vastly different spacecraft architectures and emplacement scenarios to be achieved, including optimal launch configurations ranging from single launch and assembly to on-orbit aggregation of multiple launches at different orbital locations and times. The spacecraft can be visited at different orbital locations and times to effect expansion and maintenance of an operational capability. To date, the primary application of ISA has been in large programs funded by government organizations, such as the International Space Station. Recently, Space Systems Loral (SSL) led a study funded by the Defense Advanced Research Projects Agency (DARPA), called Dragonfly, to investigate the commercial applicability and economic advantages of ISA. In the study, it was shown that ISA enables SSL to double the capability of a commercial satellite system by taking advantage of alternate packaging approaches for the reflectors. The study included an ultra-light-weight robotic system, derived from Mars manipulator designs, to complete assembly of portions of the antenna system using a tool derived from DARPA orbital express and National Aeronautics and Space Administration (NASA) automated structural assembly experience. The mechanical connector that enables robotic ISA takes advantage of decades of development by NASA from the 1970's to 1980's during the Space Station Freedom program, the precursor to the ISS. The mechanical connector was originally designed for rapid astronaut assembly while also providing a high quality structural connection with linear load deflection response. The paper will discuss the business case for ISA, the general approach taken to exploit on-orbit assembly in the GEO communication satellite market, and the concept of operations associated with the ISA approach, thus laying the foundation for ISA to become an accepted operational approach for commercial in-space operations.

Lymer, John↗

NASA NTRS2016

In-Space Structural Assembly: Applications and Technology

As NASA exploration moves beyond earth's orbit, the need exists for long duration space systems that are resilient to events that compromise safety and performance. Fortunately, technology advances in autonomy, robotic manipulators, and modular plug-and-play architectures over the past two decades have made in-space vehicle assembly and servicing possible at acceptable cost and risk. This study evaluates future space systems needed to support scientific observatories and human/robotic Mars exploration to assess key structural design considerations. The impact of in-space assembly is discussed to identify gaps in structural technology and opportunities for new vehicle designs to support NASA's future long duration missions.

Belvin, W. Keith↗

NASA NTRS2006

The TPS Advanced Development Project for CEV

The CEV TPS Advanced Development Project (ADP) is a NASA in-house activity for providing two heatshield preliminary designs (a Lunar direct return as well as a LEO only return) for the CEV, including the TPS, the carrier structure, the interfaces and the attachments. The project s primary objective is the development of a single heatshield preliminary design that meets both Lunar direct return and LEO return requirements. The effort to develop the Lunar direct return capable heatshield is considered a high risk item for the NASA CEV development effort due to the low TRL (approx. 4) of the candidate TPS materials. By initiating the TPS ADP early in the development cycle, the intent is to use materials analysis and testing in combination with manufacturing demonstrations to reduce the programmatic risk of using advanced TPS technologies in the critical path for CEV. Due to the technical and schedule risks associated a Lunar return heatshield, the ADP will pursue a parallel path design approach, whereby a back-up TPS/heatshield design that only meets LEO return requirements is also developed. The TPS materials and carrier structure design concept selections will be based on testing, analysis, design and evaluation of scalability and manufacturing performed under the ADP. At the TPS PDR, the preferred programmatic strategy is to transfer the continued (detailed) design, development, testing and evaluation (DDT&E) of both the Lunar direct and LEO return designs to a government/prime contractor coordinated sub-system design team. The CEV prime contractor would have responsibility for the continued heatshield sub-system development. Continued government participation would include analysis, testing and evaluation as well as decision authority at TPS Final System Decision (FSD) (choosing between the primary and back-up heatshields) occurring between TPS PDR and TPS Critical Design Review (CDR). After TPS FSD the prime CEV contractor will complete the detailed design, certification testing, procurement, and integration of the CEV TPS.

Reuther, James↗