LISA Pathfinder micronewton cold gas thrusters: In-flight characterization

Armano, M. et al. (2019) LISA Pathfinder micronewton cold gas thrusters: In-flight characterization. Physical Review D, 99, 122003. (doi: 10.1103/PhysRevD.99.122003)

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The LISA Pathfinder (LPF) mission has demonstrated the ability to limit and measure the fluctuations in acceleration between two free falling test masses down to sub-femto-g levels. One of the key elements to achieve such a level of residual acceleration is the drag free control. In this scheme the spacecraft is used as a shield against any external disturbances by adjusting its relative position to a reference test mass. The actuators used to move the spacecraft are cold gas micropropulsion thrusters. In this paper, we report in-flight characterization of these thrusters in term of noise and artefacts during science operations using all the metrology capabilities of LISA Pathfinder. Using the LISA Pathfinder test masses as an inertial reference frame, an average thruster noise of ∼0.17  μN/Hz is observed and decomposed into a common (coherent) and an uncorrelated component. The very low noise and stability of the onboard metrology system associated with the quietness of the space environment allowed the measurement of the thruster noise down to ∼20  μHz, more than an order of magnitude below any ground measurement. Spectral lines were observed around ∼1.5  mHz and its harmonics and around 55 and 70 mHz. They are associated with the cold gas system itself and possibly to a clock synchronization issue. The thruster noise-floor exhibits an excess of ∼70% compared to characterization that have been made on ground on a single unit and without the feeding system. However this small excess has no impact on the LPF mission performance and is compatible with the noise budget for the upcoming LISA gravitational wave observatory. Over the whole mission, nominal, and extension, the thrusters showed remarkable stability for both the science operations and the different maneuvers necessary to maintain LPF on its orbit around L1. It is therefore concluded that a similar cold gas system would be a viable propulsion system for the future LISA mission.

Item Type:Articles
Additional Information:This work has been made possible by the LISA Pathfinder mission, which is part of the space-science programme of the European Space Agency. The French contribution has been supported by the CNES (Accord Specifique de projet CNES 1316634/CNRS 103747), the CNRS, the Observatoire de Paris and the University Paris-Diderot. E. Plagnol and H. Inchauspé would also like to acknowledge the financial support of the UnivEarthS Labex program at Sorbonne Paris Cité (ANR-10-LABX-0023 and ANR-11-IDEX-0005-02). The Albert-Einstein-Institut acknowledges the support of the German Space Agency, DLR. The work is supported by the Federal Ministry for Economic Affairs and Energy based on a resolution of the German Bundestag (FKZ 50OQ0501 and FKZ 50OQ1601). The Italian contribution has been supported by Agenzia Spaziale Italiana and Istituto Nazionale di Fisica Nucleare. The Spanish contribution has been supported by contracts AYA2010-15709 (MICINN), ESP2013-47637-P, and ESP2015-67234-P (MINECO). M. Nofrarias acknowledges support from Fundacion General CSIC (Programa ComFuturo). F. Rivas acknowledges an FPI contract (MINECO). The Swiss contribution acknowledges the support of the Swiss Space Office (SSO) via the PRODEX Programme of ESA. L. Ferraioli is supported by the Swiss National Science Foundation. The UK groups wish to acknowledge support from the United Kingdom Space Agency (UKSA), the University of Glasgow, the University of Birmingham, Imperial College, and the Scottish Universities Physics Alliance (SUPA). J. I. Thorpe and J. Slutsky acknowledge the support of the U.S. National Aeronautics and Space Administration (NASA).
Glasgow Author(s) Enlighten ID:Robertson, Dr David and Korsakova, Dr Natalia and Ward, Professor Henry and Perreur-Lloyd, Mr Michael and Killow, Dr Christian
Authors: Armano, M., Audley, H., Baird, J., Binetruy, P., Born, M., Bortoluzzi, D., Castelli, E., Cavalleri, A., Cesarini, A., Cruise, A. M., Danzmann, K., de Deus Silva, M., Diepholz, I., Dixon, G., Dolesi, R., Ferraioli, L., Ferroni, V., Fitzsimons, E. D., Freschi, M., Gesa, L., Gibert, F., Giardini, D., Giusteri, R., Grimani, C., Grzymisch, J., Harrison, I., Heinzel, G., Hewitson, M., Hollington, D., Hoyland, D., Hueller, M., Inchauspé, H., Jennrich, O., Jetzer, P., Karnesis, N., Kaune, B., Korsakova, N., Killow, C., Lobo, J. A., Lloro, I., Liu, L., López-Zaragoza, J. P., Maarschalkerweerd, R., Mance, D., Meshksar, N., Martín, V., Martin-Polo, L., Martino, J., Martin-Porqueras, F., Mateos, I., McNamara, P. W., Mendes, J., Mendes, L., Nofrarias, M., Paczkowski, S., Perreur-Lloyd, M., Petiteau, A., Pivato, P., Plagnol, E., Ramos-Castro, J., Reiche, J., Robertson, D., Rivas, F., Russano, G., Slutsky, J., Sopuerta, C. F., Sumner, T., Texier, D., Thorpe, J. I., Vetrugno, D., Vitale, S., Wanner, G., Ward, H., Wass, P. J., Weber, W. J., Wissel, L., Wittchen, A., and Zweifel, P.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physical Review D
Publisher:American Physical Society
ISSN (Online):2470-0029
Copyright Holders:Copyright © 2019 American Physical Society
First Published:First published in Physical Review D 99:122003
Publisher Policy:Reproduced in accordance with the copyright policy of the publisher

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