Beyond cost tools: Spacecraft net present value and the hosted payload paradigm

Geng, Fan; Saleh, Joseph H.; Tien, Andy; Herd, Robert A.

doi:10.1109/taes.2015.140883

Cited by 7 publications

(4 citation statements)

References 10 publications

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“…A more nuanced conclusion is therefore warranted: pre-2005 in GEO, EP exhibited a significantly higher frequency of minor and major anomalies than chemical propulsion. It is worth repeating a point noted earlier in this section that no Hall thruster anomalies occurred in GEO during the 1997-2015 time-period 11 , and therefore the results in this section concern gridded ion engines. The consequences should not be ignored, and it is important to state them explicitly: 11 Should data quality be suspected in these results (e.g., Hall thruster anomalies on GEO Russian not reported), it is useful to note that some 45 Western spacecraft in GEO use Hall thrusters (compared with 55 with gridded ion engines), and these results still hold true when the analysis is restricted to Western spacecraft.…”

Section: Comparative Analysis: Anomaly Rates Of Ep Versus Chemical Prmentioning

confidence: 57%

“…It is worth repeating a point noted earlier in this section that no Hall thruster anomalies occurred in GEO during the 1997-2015 time-period 11 , and therefore the results in this section concern gridded ion engines. The consequences should not be ignored, and it is important to state them explicitly: 11 Should data quality be suspected in these results (e.g., Hall thruster anomalies on GEO Russian not reported), it is useful to note that some 45 Western spacecraft in GEO use Hall thrusters (compared with 55 with gridded ion engines), and these results still hold true when the analysis is restricted to Western spacecraft. It is useful to acknowledge, for the accuracy of the record, that six (hybrid) spacecraft in GEO equipped with the gridded ion engine XIPS-13 had their primary EP thrusters experience malfunction or fail on orbit 13 , and either the secondary failed as well or the satellite manufacturers recommended to the operators not use the redundant EP thrusters (because of the likelihood of a similar/dependent failures).…”

Section: Comparative Analysis: Anomaly Rates Of Ep Versus Chemical Prmentioning

confidence: 57%

“…A more nuanced conclusion is therefore warranted: pre-2005 in GEO, EP exhibited a significantly higher frequency of minor and major anomalies than chemical propulsion. It is worth repeating a point noted earlier in this section that no Hall thruster anomalies occurred in GEO during the 1997-2015 time-period 11 , and therefore the results in this section concern gridded ion engines. The consequences should not be ignored, and it is important to state them explicitly: It is useful to acknowledge, for the accuracy of the record, that six (hybrid) spacecraft in GEO equipped with the gridded ion engine XIPS-13 had their primary EP thrusters experience malfunction or fail on orbit 13 , and either the secondary failed as well or the satellite manufacturers recommended to the operators not use the redundant EP thrusters (because of the likelihood of a similar/dependent failures).…”

Section: Comparative Analysis: Anomaly Rates Of Ep Versus Chemical Pr...mentioning

confidence: 57%

“…Satellite operators will make valueinformed decision regarding the adoption of EP, and it is important to understand under what conditions, and for what missions and markets, would EP tip the value balance in its favor. See Geng et al (2015), and Brathwaite and Saleh (2013) for examples of satellite value analysis in a commercial and government context. conducted to date that included the global set of EP missions.…”

Section: Introductionmentioning

confidence: 99%

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Electric propulsion reliability: Statistical analysis of on-orbit anomalies and comparative analysis of electric versus chemical propulsion failure rates

Saleh

Geng

et al. 2017

Acta Astronautica

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With a few hundred spacecraft launched to date with electric propulsion (EP), it is possible to conduct an epidemiological study of EP's on orbit reliability. The first objective of the present work was to undertake such a study and analyze EP's track record of on orbit anomalies and failures by different covariates. The second objective was to provide a comparative analysis of EP's failure rates with those of chemical propulsion. Satellite operators, manufacturers, and insurers will make reliability-and risk-informed decisions regarding the adoption and promotion of EP on board spacecraft. This work provides evidence-based support for such decisions. After a thorough data collection, 162 EP-equipped satellites launched between January 1997 and December 2015 were included in our dataset for analysis. Several statistical analyses were conducted, at the aggregate level and then with the data stratified by severity of the anomaly, by orbit type, and by EP technology. Mean Time To Anomaly (MTTA) and the distribution of the time to (minor/major) anomaly were investigated, as well as anomaly rates.The important findings in this work include the following: (1) Post-2005, EP's reliability has outperformed that of chemical propulsion; (2) Hall thrusters have robustly outperformed chemical propulsion, and they maintain a small but shrinking reliability advantage over gridded ion engines. Other results were also provided, for example the differentials in MTTA of minor and major anomalies for gridded ion engines and Hall thrusters. It was shown that: (3) Hall thrusters exhibit minor anomalies very early on orbit, which might be indicative of infant anomalies, and thus would benefit from better ground testing and acceptance procedures; (4) Strong evidence exists that EP anomalies (onset and likelihood) and orbit type are dependent, a dependence likely mediated by either the space environment or differences in thrusters duty cycles; (5) Gridded ion thrusters exhibit both infant and wear-out failures, and thus would benefit from a reliability growth program that addresses both these types of problems.

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Section: Comparative Analysis: Anomaly Rates Of Ep Versus Chemical Prmentioning

confidence: 57%

Section: Comparative Analysis: Anomaly Rates Of Ep Versus Chemical Prmentioning

confidence: 57%

“…A more nuanced conclusion is therefore warranted: pre-2005 in GEO, EP exhibited a significantly higher frequency of minor and major anomalies than chemical propulsion. It is worth repeating a point noted earlier in this section that no Hall thruster anomalies occurred in GEO during the 1997-2015 time-period 11 , and therefore the results in this section concern gridded ion engines. The consequences should not be ignored, and it is important to state them explicitly: It is useful to acknowledge, for the accuracy of the record, that six (hybrid) spacecraft in GEO equipped with the gridded ion engine XIPS-13 had their primary EP thrusters experience malfunction or fail on orbit 13 , and either the secondary failed as well or the satellite manufacturers recommended to the operators not use the redundant EP thrusters (because of the likelihood of a similar/dependent failures).…”

Section: Comparative Analysis: Anomaly Rates Of Ep Versus Chemical Pr...mentioning

confidence: 57%

Section: Introductionmentioning

confidence: 99%

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