Interactive modeling, design and analysis of large spacecraft

An efficient computer aided design and analysis capability applicable to large space structures was developed to relieve the engineer of much of the effort required in the past. The automated capabilities can be used to rapidly synthesize, evaluate, and determine performance characteristics and costs for future large spacecraft concepts. The interactive design and evaluation of advanced spacecraft program (IDEAS) is used to illustrate the power, efficiency, and versatility of the approach. The coupling of space environment modeling algorithms with simplified analysis and design modules in the IDEAS program permits rapid evaluation of completing spacecraft and mission designs. The approach is particularly useful in the conceptual design phase of advanced space missions when a multiplicity of concepts must be considered before a limited set can be selected or more detailed analysis. Integrated spacecraft systems level data and data files are generated or subsystems and mission reexamination and/or refinement and for more rigorous analyses

A computer program to calculate radiating viscous stagnation streamline flow with strong blowing

A computer program (program LEE) has been developed to calculate the fully coupled solution of the radiating viscous stagnation streamline flow with strong blowing. The report describes the digital computer program, including FORTRAN IV listing, flow charts, instructions for the user, and a test case with input and output. Program LEE is available through COSMIC

Comparative analyses of space-to-space central power stations

The technological and economical impact of a large central power station in Earth orbit on the performance and cost of future spacecraft and their orbital transfer systems are examined. It is shown that beaming power to remote users cannot be cost effective if the central power station uses the same power generation system that is readily available for provision of onboard power and microwave transmission and reception of power through space for use in space is not cost competitive with onboard power or propulsion systems. Laser and receivers are required to make central power stations feasible. Remote power transmission for propulsion of orbital transfer vehicles promises major cost benefits. Direct nuclear pumped or solar pumped laser power station concepts are attractive with laser thermal and laser electric propulsion systems. These power stations are also competitive, on a mass and cost basis, with a photovoltaic power station

Space Systems Computer Aided Design Technology

Capabilities and advantages of a systemsoriented interactive computer-aided design and analysis system are presented. A single user at an interactive terminal can create, design, analyze, and conduct parametric studies of Earth-orbiting spacecraft such as space station, large antenna and technologically advanced Earth-orbiting spacecraft. The approach is particularly useful in the conceptual design phase where various missions and spacecraft options are to be evaluated in a timely, cost-effective manner. The Interactive Design and Evaluation of Advanced Spacecraft (IDEAS) system consists of an integrated system of about 40 multidiscipline technical applications programs; efficient executive, data base, and file management software, and extensive interactive graphics display capabilities. Current capabilities and planned and potential augmentations to the IDEAS system are reviewed

An implicit finite-difference solution to the viscous shock layer, including the effects of radiation and strong blowing

An implicit finite-difference scheme is developed for the fully coupled solution of the viscous, radiating stagnation-streamline equations, including strong blowing. Solutions are presented for both air injection and injection of carbon-phenolic ablation products into air at conditions near the peak radiative heating point in an earth entry trajectory from interplanetary return missions. A detailed radiative-transport code that accounts for the important radiative exchange processes for gaseous mixtures in local thermodynamic and chemical equilibrium is utilized in the study. With minimum number of assumptions for the initially unknown parameters and profile distributions, convergent solutions to the full stagnation-line equations are rapidly obtained by a method of successive approximations. Damping of selected profiles is required to aid convergence of the solutions for massive blowing. It is shown that certain finite-difference approximations to the governing differential equations stabilize and improve the solutions. Detailed comparisons are made with the numerical results of previous investigations. Results of the present study indicate lower radiative heat fluxes at the wall for carbonphenolic ablation than previously predicted

Interactive design and analysis of future large spacecraft concepts

An interactive computer aided design program used to perform systems level design and analysis of large spacecraft concepts is presented. Emphasis is on rapid design, analysis of integrated spacecraft, and automatic spacecraft modeling for lattice structures. Capabilities and performance of multidiscipline applications modules, the executive and data management software, and graphics display features are reviewed. A single user at an interactive terminal create, design, analyze, and conduct parametric studies of Earth orbiting spacecraft with relative ease. Data generated in the design, analysis, and performance evaluation of an Earth-orbiting large diameter antenna satellite are used to illustrate current capabilities. Computer run time statistics for the individual modules quantify the speed at which modeling, analysis, and design evaluation of integrated spacecraft concepts is accomplished in a user interactive computing environment

A modified method of integral relations approach to the blunt-body equilibrium air flow field, including comparisons with inverse solutions

Numerical calculation of inviscid adiabatic flow field around blunt bodies at hypersonic speed

Paper Session III-B - A Lunar Orbiting Node in Support of Missions to Mars

Future Mars missions may use lunar-derived oxygen as a propellant for interplanetary transit. A man-tended platform as a Node in low lunar orbit offers a site for storage and transfer of lunar oxygen to the transport vehicles as well as rendezvous and transfer for lunar-bound cargo and crews. In addition, it could provide an emergency safe-haven for a crew awaiting rescue. A conceptual design study yielded an approximate size for the platform needed to support typical oxygen transfer rates which were based upon NASA studies of Mars missions. The Node consists of a gravity gradient stabilized lunar orbiting tank-farm with a storage capacity of 100,000 kg of lunar oxygen, 3,300 kg of lunar cargo and 9,300 kg of Earth supplied hydrogen. An emergency habitat configuration accomodates 14 persons on-board for 110 days. The Node supports an annual lunar oxygen Ereduction of 106 kg with 220,000 kg of oxygen delivered to Earth orbit for an expenditure of 109,000 g of Earth supplied hydrogen

Solar Particle Induced Upsets in the TDRS-1 Attitude Control System RAM During the October 1989 Solar Particle Events

The three large solar particle events, beginning on October 19, 1989 and lasting approximately six days, were characterized by high fluences of solar protons and heavy ions at 1 AU. During these events, an abnormally large number of upsets (243) were observed in the random access memory of the attitude control system (ACS) control processing electronics (CPE) on-board the geosynchronous TDRS-1 (Telemetry and Data Relay Satellite). The RAM unit affected was composed of eight Fairchild 93L422 memory chips. The Galileo spacecraft, launched on October 18, 1989 (one day prior to the solar particle events) observed the fluxes of heavy ions experienced by TDRS-1. Two solid-state detector telescopes on-board Galileo designed to measure heavy ion species and energy, were turned on during time periods within each of the three separate events. The heavy ion data have been modeled and the time history of the events reconstructed to estimate heavy ion fluences. These fluences were converted to effective LET spectra after transport through the estimated shielding distribution around the TDRS-1 ACS system. The number of single event upsets (SEU) expected was calculated by integrating the measured cross section for the Fairchild 93L422 memory chip with average effective LET spectrum. The expected number of heavy ion induced SEUs calculated was 176. GOES-7 proton data, observed during the solar particle events, were used to estimate the number of proton-induced SEUs by integrating the proton fluence spectrum incident on the memory chips, with the two-parameter Bendel cross section for proton SEU's. The proton fluence spectrum at the device level was gotten by transporting the protons through the estimated shielding distribution. The number of calculated proton-induced SEU’s was 72, yielding a total of 248 predicted SEU’s, very close to the 243 observed SEU’s. These calculations uniquely demonstrate the roles that solar heavy ions and protons played in the production of SEU’s during the October 1989 solar particle events

Design and assembly sequence analysis of option 3 for CETF reference space station

A design and assembly sequence was conducted on one option of the Dual Keel Space Station examined by a NASA Critical Evaluation Task Force to establish viability of several variations of that option. A goal of the study was to produce and analyze technical data to support Task Force decisions to either examine particular Option 3 variations in more depth or eliminate them from further consideration. An analysis of the phasing assembly showed that use of an Expendable Launch Vehicle in conjunction with the Space Transportation System (STS) can accelerate the buildup of the Station and ease the STS launch rate constraints. The study also showed that use of an Orbital Maneuvering Vehicle on the first flight can significantly benefit Station assembly and, by performing Station subsystem functions, can alleviate the need for operational control and reboost systems during the early flights. In addition to launch and assembly sequencing, the study assessed stability and control, and analyzed node-packaging options and the effects of keel removal on the structural dynamics of the Station. Results of these analyses are presented and discussed