This report provides an assessment on cold atom interferometry (CAI) gravity sensing for Earth Observation (EO), and is intended as an instrument to facilitate the interactions between the different communities involved in the definition of a related satellite mission. Indeed, the definition of the objectives of future gravity missions and of the technologies needed for their implementation is the result of complex negotiations and compromises: geodesy and geophysics researchers detail the scientific requirements dictated by their investigation areas (e.g. solid Earth dynamics, ocean mass and heat transport, ice sheets and glaciers evolution), policymakers express their concerns and their priorities (e.g. natural hazards risk assessment, ground water monitoring, floods and droughts forecast), engineers and technology experts devise and implement the most suitable techniques to actually build the satellite and its gravity sensing payload. \nAs we will show in this report, the scientific consensus is that the scientific objectives of a next generation gravity mission (NGGM) to be deployed within a ~10 year timeframe can be achieved by upgrading established technologies already used in gravity-measuring satellites. Transformative technologies such as CAI-based gravity sensors leveraging Bose Einstein Condensates (BEC) of ultra-cold atoms may come to play a role in the longer term, provided that several technology challenges are overcome; in addition, further interdisciplinary work and the simulation of detailed mission scenarios are needed to fully establish their actual usefulness with regards to the attainment of future gravity missions scientific objectives.\nThe scientific community seems to agree on the opportunity of an intermediate stepping stone, which could take the form of a scientific mission with a dedicated satellite, in order to test and prove the in-space feasibility and the actual usefulness of CAI-based gravity sensors.
This report provides an assessment on cold atom interferometry (CAI) gravity sensing for Earth Observation (EO), and is intended as an instrument to facilitate the interactions between the different communities involved in the definition of a related satellite mission. Indeed, the definition of the objectives of future gravity missions and of the technologies needed for their implementation is the result of complex negotiations and compromises: geodesy and geophysics researchers detail the scientific requirements dictated by their investigation areas (e.g. solid Earth dynamics, ocean mass and heat transport, ice sheets and glaciers evolution), policymakers express their concerns and their priorities (e.g. natural hazards risk assessment, ground water monitoring, floods and droughts forecast), engineers and technology experts devise and implement the most suitable techniques to actually build the satellite and its gravity sensing payload. \nAs we will show in this report, the scientific consensus is that the scientific objectives of a next generation gravity mission (NGGM) to be deployed within a ~10 year timeframe can be achieved by upgrading established technologies already used in gravity-measuring satellites. Transformative technologies such as CAI-based gravity sensors leveraging Bose Einstein Condensates (BEC) of ultra-cold atoms may come to play a role in the longer term, provided that several technology challenges are overcome; in addition, further interdisciplinary work and the simulation of detailed mission scenarios are needed to fully establish their actual usefulness with regards to the attainment of future gravity missions scientific objectives.\nThe scientific community seems to agree on the opportunity of an intermediate stepping stone, which could take the form of a scientific mission with a dedicated satellite, in order to test and prove the in-space feasibility and the actual usefulness of CAI-based gravity sensors.
This report describes the physical principles underpinning cold atom interferometry (CAI) and shows how they can be leveraged to develop high-performance inertial and gravity sensors; the distinguishing properties and the maturity level of such sensors will also be assessed. \nProof-of-principles demonstrations have been made for CAI-based accelerometers and gyroscopes, which can enable long-term autonomous navigation and precise positioning for ships, submarines, and satellites. CAI-based gravimeters and gravity gradiometers have been developed and are being tested on the ground; satellite-based systems could in the future be used to monitor the Earth gravity field. This would allow a better understanding of several geophysical and climate phenomena which require long-term policies solidly supported by data. \nQuantum sensors based on cold atom interferometry may therefore impact existing and future EU programmes on space, defence, and Earth observation. This report provides background knowledge of the field to a non-specialist audience, and in particular to EU policymakers involved in technology support and potential applications.
Globally, space agencies actively evaluate quantum sensing for its practical applications in space-based Earth Observation (EO), focusing on how it can improve accuracy, stability and enable new operational concepts. The near future looks promising for specific quantum technologies like Cold-Atom Interferometers (CAI), Rydberg Receivers (RR), and Nitrogen-Vacancy (NV) center-based magnetometers. These have the potential to enhance existing EO instrumentation in specific areas. A key task ahead is to identify and evaluate these potential improvements in the context of EO missions and to explore new observational concepts that may be enabled by these technologies. In our presentation, we will discuss the ongoing and planned activities in this area supported by the European Space Agency’s (ESA). This includes work on CAI for gravimetry, RRs in microwave radiometry, and NV center-based magnetometers for studying the Earth’s magnetosphere.
Recent advances in cold atom interferometry have cleared the path for space applications of quantum inertial sensors, whose level of stability is expected to increase dramatically with the longer interrogation times accessible in space. In this study, an in-orbit model is developed for a Mach-Zehnder-type cold-atom accelerometer. Performance tests are realized under different assumptions about the positioning and rotation compensation method, and the impact of various sources of errors on instrument stability is evaluated. Current and future advances for space-based atom interferometry are discussed, and their impact on the performance of quantum sensors on-board satellite gravity missions is investigated in three different scenarios: state-of-the-art scenario(expected to be ready to launch in 5 years), near-future (expected to be launched in the next 10 to 15 years)and far-future scenarios (expected for the next 20 to 25 years). Our results indicate that the highest sensitivity is achievable by positioning the electrostatic accelerometer at the center of mass of the satellite and the quantum accelerometer aside, on the cross-track axis of the satellite. We show that one can achieve a sensitivity level close to 5×10-10m/s2/Hz with the current state-of-the-art technology. We also estimate that in the near and far-future, atom interferometry in space is expected to achieve sensitivity levels of 1×10-11m/s2/Hz and 1×10-12m/s2/Hz, respectively. A roadmap for improvements in atom interferometry is provided that would maximize the performance of future quantum accelerometers, considering their technical capabilities. Finally, the possibility and challenges of having ultra-sensitive atom interferometry in space for future space missions are discussed.
We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with the European Space Agency (ESA) and national space and research funding agencies.
Abstract We summarise the discussions at a virtual Community Workshop on Cold Atoms in Space concerning the status of cold atom technologies, the prospective scientific and societal opportunities offered by their deployment in space, and the developments needed before cold atoms could be operated in space. The cold atom technologies discussed include atomic clocks, quantum gravimeters and accelerometers, and atom interferometers. Prospective applications include metrology, geodesy and measurement of terrestrial mass change due to, e.g., climate change, and fundamental science experiments such as tests of the equivalence principle, searches for dark matter, measurements of gravitational waves and tests of quantum mechanics. We review the current status of cold atom technologies and outline the requirements for their space qualification, including the development paths and the corresponding technical milestones, and identifying possible pathfinder missions to pave the way for missions to exploit the full potential of cold atoms in space. Finally, we present a first draft of a possible road-map for achieving these goals, that we propose for discussion by the interested cold atom, Earth Observation, fundamental physics and other prospective scientific user communities, together with the European Space Agency (ESA) and national space and research funding agencies.
Atomic gravimetry measures the gravitional acceleration of an ensemble of identical neutral atoms through the atom interferometry based on Raman two-photon transition, where the Raman lasers are used as “optical ruler" and the identical neutral atoms play the role of test mass and quantum storage of gravity field information. As the novel gravimetry system suffers no mechanical wear and works at a higher repetition rate, atom gravimetry can reach a much better short-term sensitivity than the classical falling-corner-cube counterpart, and the accuracy is reasonably well. Since the very first in-laboratory device built over 30 years ago, atomic gravimetry has matured to a versatile tool that offers both precise and accurate absolute gravity measurement to fundamental research and metrology, such as testing the weak equivalence principle or linking the mass and weight of the test mass in Watt (Kibble) balance. As the current rapid development of compact cold-atom gravimeters, atomic gravimetry is moving out of the laboratory to be used as a quantum enhancement of classical devices in dynamical measurement, such as geophysics survey, inertial navigation and space mission. We review the roadmap for the development of cold-atom absolute gravimetry, highlight recent advances in the dynamical measurement using compact cold atom gravimeters and discuss the associated technological challenges. In the future, with the maturity of its application in dynamical measurement or civil engineering and the innovation in atom interferometry theory, atomic gravimetry could play a more and more important role in our life.