Atomic clock ensemble in space
Open accessAbstract
Atomic Clock Ensemble in Space (ACES) is a mission using high-performance clocks and links to test fundamental laws of physics in space. Operated in the microgravity environment of the International Space Station, the ACES clocks, PHARAO and SHM, will generate a frequency reference reaching instability and inaccuracy at the 1 · 10 −16 level. A link in the microwave domain (MWL) and an optical link (ELT) will make the ACES clock signal available to ground laboratories equipped with atomic clocks. Space-to-ground and ground-to-ground comparisons of atomic frequency standards will be used to test Einstein's theory of general relativity including a precision measurement of the gravitational red-shift, a search for time variations of fundamental constants, and Lorentz Invariance tests. Applications in geodesy, optical time transfer, and ranging will also be supported. ACES has now reached an advanced technology maturity, with engineering models completed and successfully tested and flight hardware under development. This paper presents the ACES mission concept and the status of its main instruments.
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If the higher-order terms O(c -3 ) are omitted, Equation (7) holds only at the accuracy level of 10 -15.
“If we omit the higher-order terms O(c -3 ), Equation ( 7) holds only at the accuracy level of 10 -15 [45].”
From Unification of a Global Height System at the Centimeter-Level Using Precise Clock Frequency Signal Links (2023) · cites this paper as [45]
Section 2.2 says space-to-ground time and frequency transfer at the 10^-16 level requires terms through 1/c^3, while existing links use a 1/c^2 expansion. This supports the need for higher-order terms to reach 10^-16 accuracy, but it does not state that omitting them limits the citing paper’s Equation (7) specifically to 10^-15 accuracy. No page number is available in our copy. (LLM, conf=0.82)
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References 19 · Cited by 56
Research works printed but not linked: 5
- Müller H et al 2010 Nature 463 08776 International Symposium on Physical Sciences in Space IOP Publishing Journal of Physics: Conference Series 327 (2011) 012049 doi:10.1088/1742-6596/327/1/012049
- Schreiber U et al 2009 IEEE Trans 57 728
- Prochazka I et al 2010 Proc. of 2010 European Time and Frequency Forum
- Montenbruck O et al 2011 Journal of Spacecraft and Rockets DOI 10.2514/1.52657 · DOI
- Daganzo E et al 2009 Proc. of EFTF-FCS 2009 DOI 978-1-4244-3510-4/09
- Authors
- Cacciapuoti, L., & Salomon, C.
- Affiliations
- European Space Agency (FR)
- Centre National de la Recherche Scientifique (FR)
- ORCID
- Cacciapuoti, L
- Venue
- Journal of Physics: Conference Series
- Publisher
- IOP Publishing
- Published
- 2011-12-06
- Volume
- 327
- Pages
- 012049
- ISSN
- 1742-6588 (ISSN-L)
- 1742-6596
- OpenAlex
- W2063001585
- Cited by
- 56
- References
- 19
- Citations by year
- 2026: 3 · 2025: 1 · 2024: 4 · 2023: 5 · 2022: 3 · 2021: 4 · 2020: 3 · 2019: 5 · 2018: 2 · 2017: 8 · 2016: 7 · 2015: 7 · 2014: 1 · 2013: 2 · 2012: 1
- FWCI
- 5.77
- Type
- conference paper
- Language
- en
- Open access
- diamond
- doi.org
- Locations
- Journal of Physics Conference Series (publishedVersion)
- arXiv (Cornell University) (submittedVersion, cc-by)
- Funders
- Centre National d’Etudes Spatiales
- Topics
- Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Advanced Frequency and Time Standards
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Relativity and Gravitational Theory
- Physical Sciences › Computer Science › Computer Networks and Communications › Network Time Synchronization Technologies
- Keywords
- adverse childhood experiences, microgravity, International Space Station, PHARAO, microwave links, frequency standards, gravitational redshift, tests of general relativity, variation of fundamental constants, Lorentz invariance tests, optical time transfer, geodesy, distance measurement
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