The Mir Cooperative Solar Array (MCSA) was developed jointly by US and Russia to provide approximately 6 kW of photovoltaic power to the Russian space station Mir. The MCSA was launched to Mir in November 1995 and installed on the Kvant-1 module in May 1996. MCSA operation offered an opportunity to gather multi-year performance data on this technology prior to its implementation on the International Space Station. Two specially designed test sequences were executed in June and December 1996 to measure MCSA performance. Each test period encompassed 3 orbital revolutions whereby the current produced by the MCSA channels was measured. The temperature of MCSA PPMs was also measured. To better interpret the MCSA flight data, a dedicated FORTRAN computer code was developed to predict the detailed thermal-electrical performance of the MCSA. Flight data compared very favorably with computational performance predictions. This indicated that the MCSA electrical performance was fully meeting pre-flight expectations. There were no measurable indications of unexpected or precipitous MCSA performance degradation due to contamination or other causes after 7 months of operation on orbit. Power delivered to the Mir bus was lower than desired as a consequence of the retrofitted power distribution cabling. The strong correlation of experimental and computational results further bolsters the confidence level of performance codes used in critical ISS electric power forecasting. In this paper, MCSA flight performance tests are described as well as the computational modeling behind the performance predictions.

MIR Cooperative Solar Array flight performance data and computational analysis

This paper documents test activities, data and analyses to quantify International Space Station (ISS) Solar Array Wing (SAW) string electrical performance under highly offnominal, low-temperature-low-intensity (LILT) operating conditions with non-solar light sources. This work is relevant for assessing feasibility and risks associated with a Sequential Shunt Unit (SSU) remove and replace (R&R) Extravehicular Activity (EVA). The SSU is an electronics box that regulates the primary power system bus voltage by matching the SAW current output to the channel load demand. It is desirable to conduct the SSU R&R EVA without retracting the SAW. With the SAW deployed, there is an electrical risk of mating/demating SAW input connectors to the SSU. Even during orbital eclipse EVA operations, SAW strings can be energized by low-intensity, non-solar, natural light sources, such as the moon, and artificial light sources, such as EVA suit helmet lights or video camera lights. To quantify SAW electrical performance under this off-nominal, non-solar, lowtemperature, low-intensity (LILT) illumination, solar cell and solar cell panel electrical performance testing was performed using full moon, solar simulator and Video Camera Luminaire (VCL) light sources. Laboratory test conditions included temperatures from ambient to -110oC and illumination intensities from 1-Sun to 0.0001-Suns. Terrestrial full moon testing was conducted under typical ambient conditions of the north eastern Ohio in the late spring. An eclipse orbital lighting assessment was also performed to quantify the maximum lighting intensities on the SAW from all credible natural and artificial sources. By combining the measured steady state electrical performance data and the calculated orbital eclipse lighting intensity, SAW string current and voltage performance levels were calculated and compared with established electrical hazard thresholds. The results of this comparison for all credible light sources are presented in the paper. These results are discussed in the context of crew member shock hazards and connector pin molten metal hazard. Results, uncertainties and limitations are also discussed along with operational solutions to mitigate potential SAW string electrical hazards from VCL illumination. Finally, results from a preliminary assessment of SAW arcing to the space plasma or within power connector pins are discussed. The authors recommend that the SAW string electrical performance assessment under VCL eclipse lighting conditions be repeated/expanded once detailed and accurate SSU R&R EVA procedures have been developed. The product of this assessment would be SAW gimbal and/or VCL pan angle keep-out-zones (KOZs) to decrease SAW current and voltage levels generated as a result of VCL lighting to safe levels.

Off-Nominal Performance of Space Station Solar Array Under Eclipse Lighting Scenarios

The System Power Analysis for Capability Evaluation (SPACE) computer code was initially developed by NASA in 1988 to assess the Space Station Freedom electric power system and later adapted to support contractor electrical power system capability analyses for the International Space Station (ISS). Over time, the code has supported many efforts such as ISS redesign activities in the early 1990s, assessment of time-phased loads against power system operating limits for future ISS assembly flights (including Certification of Flight Readiness reviews by the ISS program office), and determining the optimum solar array gimbal positions while respecting keep-out zones which minimize both solar array contamination and structural loads. The code has been validated by comparisons with ISS on-orbit data in multiple validation episodes. Recent updates to the code include the incorporation of a Lithium-Ion battery model in addition to the Nickel Hydrogen battery model and modifications to the solar array degradation model to better match on-orbit test results. SPACE has also been extended beyond the ISS to include modeling of the Orion Multi-Purpose Crew Vehicle electrical power system (SPACE-MPCV) and Mars Surface Electrical Power Systems (MSEPS). Portions of SPACE were integrated with a trajectory code to form a Solar Electric Propulsion Simulation (SEPSim), which can be used for analyzing solar electric propulsion missions. In addition, SPACE methods and subroutines have been adapted to a multitude of other projects. This paper summarizes the initial code development and subsequent code utilization in the context of the overall ISS program development and on-orbit operations. Recent updates and results from the code are discussed, including preliminary analyses for the Orion power system.

/pdf/the-space-computer-code-for-analyzing-the-international-r4iox9g3j6.pdf

The SPACE Computer Code for Analyzing the International Space Station Electrical Power System: Past, Present, and Future

This paper documents testing and analyses to quantify International Space Station (ISS) Solar Array Wing (SAW) string electrical performance under highly off-nominal, low-temperature-low-intensity (LILT) operating conditions with nonsolar light sources This work is relevant for assessing feasibility and risks associated with a Sequential Shunt Unit (SSU) remove and replace (R&R) Extravehicular Activity (EVA) During eclipse, SAW strings can be energized by moonlight, EVA suit helmet lights or video camera lights To quantify SAW performance under these off-nominal conditions, solar cell performance testing was performed using full moon, solar simulator and Video Camera Luminaire (VCL) light sources Test conditions included 25 to 110 C temperatures and 1- to 00001-Sun illumination intensities Electrical performance data and calculated eclipse lighting intensities were combined to predict SAW current-voltage output for comparison with electrical hazard thresholds Worst case predictions show there is no connector pin molten metal hazard but crew shock hazard limits are exceeded due to VCL illumination Assessment uncertainties and limitations are discussed along with operational solutions to mitigate SAW electrical hazards from VCL illumination Results from a preliminary assessment of SAW arcing are also discussed The authors recommend further analyses once SSU, R&R, and EVA procedures are better defined

/pdf/off-nominal-performance-of-the-international-space-station-34sktqa26j.pdf

Off-Nominal Performance of the International Space Station Solar Array Wings Under Orbital Eclipse Lighting Scenarios

Spacecraft photovoltaic arrays (PVA's) must be carefully handled during ground integration processing and transportation to the launch site. Care is exercised to avoid damage that could degrade on-orbit electrical performance. Because of this damage risk, however, PVA's are typically deployed and illuminated with a light source so performance characteristics can be measured prior to launch. For large-area arrays, such as the Mir Cooperative Solar Array (2.7- by 18-m) and the International Space Station PVA blankets (4.6- by 31.7-m), this integrity check becomes resource intensive. Large test support structures are needed to offload the array during deployment in 1g, and large-aperture illumination equipment is required to uniformly illuminate array panels. Significant program time, funds, and manpower must be allocated for this kind of test program. Alternatively, launch site electrical performance tests can be bypassed with an attendant increase in risk.

https://ntrs.nasa.gov/api/citations/20050181416/downloads/20050181416.pdf

Dark Forward Electrical Test Techniques Developed for Large-Area Photovoltaic Arrays

During July 11 to 13, 1995, a team from the NASA Lewis Research Center performed dark forward electrical testing on the Mir Cooperative Solar Array (MCSA) flight unit in the Space Station Processing Facility at the NASA Kennedy Space Center. The MCSA was jointly designed and built by the United States and Russia to supply approximately 6 kW of electricity to the Russian Mir space station. The primary objective of testing was to assess the overall electrical performance of the flight array after handling and shipment from Russia to NASA Kennedy. This objective was achieved without the high cost and difficulties of deploying and illuminating the MCSA as is usually done with large-area solar arrays. The data obtained provided U.S. and Russian program managers with a high level of confidence in the MCSA electrical performance prior to the array's launch on shuttle mission STS-74 in November 1995 and its deployment on Mir in May 1996.

Dark Forward Electrical Testing of the Mir Cooperative Solar Array

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Dave J. Hoffman

Author Tools

Chat about Author

Papers

Dark Forward Electrical Testing of the Mir Cooperative Solar Array