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Title: Mir Cooperative Solar Array flight performance data and computational analysis

Abstract

The Mir Cooperative Solar Array (MCSA) was developed jointly by the United States (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. Since the MCSA photovoltaic panel modules (PPMs) are nearly identical to those of the International Space Station (ISS) photovoltaic arrays, MCSA operation offered an opportunity to gather multi-year performance data on this technology prior to its implementation on ISS. 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 tomore » 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.« less

Authors:
;  [1]
  1. NASA Lewis Research Center, Cleveland, OH (United States)
Publication Date:
OSTI Identifier:
347784
Report Number(s):
CONF-970701-
TRN: IM9923%%322
Resource Type:
Conference
Resource Relation:
Conference: 32. intersociety energy conversion engineering conference, Honolulu, HI (United States), 27 Jul - 2 Aug 1997; Other Information: PBD: [1997]; Related Information: Is Part Of Proceedings of the thirty-second intersociety energy conversion engineering conference. Volume 1: Aerospace power systems and technologies; PB: 787 p.
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; MIR ORBITAL STATION; SPACECRAFT POWER SUPPLIES; PHOTOVOLTAIC POWER SUPPLIES; SOLAR CELL ARRAYS; PERFORMANCE; FLIGHT TESTING; MATHEMATICAL MODELS; DATA

Citation Formats

Kerslake, T.W., and Hoffman, D.J.. Mir Cooperative Solar Array flight performance data and computational analysis. United States: N. p., 1997. Web.
Kerslake, T.W., & Hoffman, D.J.. Mir Cooperative Solar Array flight performance data and computational analysis. United States.
Kerslake, T.W., and Hoffman, D.J.. Wed . "Mir Cooperative Solar Array flight performance data and computational analysis". United States. doi:.
@article{osti_347784,
title = {Mir Cooperative Solar Array flight performance data and computational analysis},
author = {Kerslake, T.W. and Hoffman, D.J.},
abstractNote = {The Mir Cooperative Solar Array (MCSA) was developed jointly by the United States (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. Since the MCSA photovoltaic panel modules (PPMs) are nearly identical to those of the International Space Station (ISS) photovoltaic arrays, MCSA operation offered an opportunity to gather multi-year performance data on this technology prior to its implementation on ISS. 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.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Dec 31 00:00:00 EST 1997},
month = {Wed Dec 31 00:00:00 EST 1997}
}

Conference:
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  • The Mir Cooperative Solar Array (MCSA) was developed jointly by the United States and Russia to provide approximately 6 kW of photovoltaic power to the Russian space station Mir. After final assembly in Russia, the MCSA was shipped to the NASA Kennedy Space Center (KSC) in the summer of 1995 and launched to Mir in November 1995. Program managers were concerned of the potential for MCSA damage during the transatlantic shipment and the associated handling operations. To address this concern, NASA Lewis Research Center (LeRC) developed an innovative dark-forward electrical test program to assess the gross electrical condition of eachmore » generator following shipment from Russia. The use of dark test techniques, which allow the array to remain in the stowed configuration, greatly simplifies the checkout of large area solar arrays. MCSA dark electrical testing was successfully performed at KSC in July 1995 following transatlantic shipment. Data from this testing enabled engineers to quantify the effects of potential MCSA physical damage that would degrade on-orbit electrical performance. In this paper, an overview of the principles and heritage of photovoltaic array dark testing is given. The specific MCSA dark test program is also described including the hardware, software, testing procedures and test results. The current-voltage (IV) response of both solar cell circuitry and by-pass diode circuitry was obtained. To guide the development of dark test hardware, software and procedures, a dedicated FORTRAN computer code was developed to predict the dark IV responses of generators with a variety of feasible damage modes. By comparing the actual test data with the predictions, the physical condition of the generator could be inferred. Based on this data analysis, no electrical short-circuits or open-circuits were detected. This suggested the MCSA did not sustain physical damage that affected electrical performance during handling and shipment from Russia to the US. Good agreement between the test data and computational predictions indicated MCSA electrical performance was amenable to accurate analysis and was well understood.« less
  • This paper describes the production and on-schedule delivery to Russia of 80-watt solar array panels by Lockheed Missiles and Space Co., Inc. Ninety flight-ready panels were delivered to RSC-Energia in Kaliningrad near Moscow in November and December 1994. After assembly by the Russians they are scheduled to be delivered in October 1995 by the US Space Shuttle Atlantis (STS-74) to the Russian Mir 1 module of International Space Station Alpha.
  • The Mir Cooperative Solar Array (MCSA) project was a joint US/Russian effort to build a photovoltaic (PV) solar array and deliver it to the Russian space station Mir. The MCSA is currently being used to increase the electrical power on Mir and provide PV array performance data in support of Phase 1 of the International Space Station (ISS), which will use arrays based on the same solar cells used in the MCSA. The US supplied the photovoltaic power modules (PPMs) and provided technical and programmatic oversight while Russia provided the array support structures and deployment mechanism and built and testedmore » the array. In order to ensure that there would be no problems with the interface between US and Russian hardware, an accelerated thermal life cycle test was performed at NASA Lewis Research Center on two representative samples of the MCSA. Over an eight-month period (August 1994--March 1995), two 15-cell MCSA solar array mini panel test articles were simultaneously put through 24000 thermal cycles (+80 C to {minus}100 C), equivalent to four years on-orbit. The test objectives, facility, procedure and results are described in this paper. Post-test inspection and evaluation revealed no significant degradation in the structural integrity of the test articles and no electrical degradation, not including one cell damaged early as an artifact of the test and removed from consideration. The interesting nature of the performance degradation caused by this one cell, which only occurred at elevated temperatures, is discussed. As a result of this test, changes were made to improve some aspects of the solar cell coupon-to-support frame interface on the flight unit. It was concluded from the results that the integration of the US solar cell modules with the Russian support structure would be able to withstand at least 24000 thermal cycles (4 years on-orbit).« less
  • The Russian space station MIR was launched in February 1986. Total power system capacity was to be continuously increased by means of additional arrays of docked scientific and technological modules. The current appearance of the MIR with solar arrays is shown. The effects of thermal stresses are evaluated. The results of a detailed analysis of the performance of the solar arrays over the eight years of operation are presented.
  • The Magellan Spacecraft Solar Array, designed to operate over vastly varying environmental conditions, has recently completed over five years of flight operations. Flight performance of the Solar Array has met and/or exceeded all design objectives. Though initially designed for 15 months of cruise plus 8 months of planetary operations, the Solar Array continued to function 42 months past design life. This paper contains a brief description of the mission, a design description, and flight performance data.